Glossary of Terms

Easily explore the meaning of hundreds of medical terms or words, many directly used in brain tumor-related terminology.

A-V Malformation

A haemangioma or arteriovenous malformation is a tangle of abnormal vessels that forms an abnormal communication between the arterial and venous systems. Most are developmental (congenital). If large enough, they may produce a shunt of sufficient magnitude to raise the cardiac output. AVM's may occur in the brain, brainstem and spinal cord, where they may cause headaches, seizures or bleeding (subarachnoid hemorrhage).

Accelerated Radiation Therapy

Radiation treatment in which the total dose of radiation is given over a shorter period of time (fewer days) compared to standard radiation therapy.

Accelerated-Fraction Radiation Therapy

Radiation treatment in which the total dose of radiation is divided into small doses and the treatments are given more than once a day. The total dose of radiation is also given over a shorter period of time (fewer days) compared to standard radiation therapy.

Acoustic Neuroma

A progressively enlarging, benign tumor, usually within the internal auditory canal. Symptoms, which vary with size and location of the tumor, may include hearing loss, headache, disturbances of balance and gait, facial numbness or pain and tinnitus.

Adenocarcinoma

A cancer that originates in glandular tissue.

Adenoma

A benign tumor of a glandular structure or of glandular origin.

Adenomyoma

A benign tumor composed of muscular and glandular elements

Adjuvant

A treatment used in addition to or accompanying another treatment.

Advanced Cancer

Cancer that has spread to other places in the body and usually cannot be cured or controlled with treatment.

Advanced Directive

A legal document that states the treatment or care a person wishes to receive or not receive if he or she becomes unable to make medical decisions (for example, due to being unconscious or in a coma). Some types of advance directives are living wills and do not resuscitate (DNR) orders.

Adverse Effect

An unexpected medical problem that happens during treatment with a drug or other therapy. Adverse effects do not have to be caused by the drug or therapy, and they may be mild, moderate, or severe. Also called adverse event.

Adverse Event

An unexpected medical problem that happens during treatment with a drug or other therapy. Adverse events do not have to be caused by the drug or therapy, and they may be mild, moderate, or severe. Also called adverse effect.

Amygdala

Amygdala are almond-shaped groups of neurons located deep within the medial temporal lobes of the brain. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.

Analgesics

A drug or medicine given to reduce pain without resulting in loss of consciousness. Analgesics are sometimes referred to as painkiller medications. There are many different types of analgesic medications available in both prescription and over-the-counter preparations. Examples of analgesic drugs include aspirin, acetaminophen (Tylenol), ibuprofen (Motrin, Advil), naproxen (Aleve, Naprosyn), the COX-2 inhibitor celecoxib, and narcotic drugs including morphine, oxycodone, and hydrocodone (Vicodin). Analgesics may also be combined with other drugs in some types of medications (for example, analgesics are combined with decongestants and/or antihistamine in many over-the-counter cold remedies).

Anaplastic

A term used to describe cancer cells that divide rapidly and have little or no resemblance to normal cells.

Anti-angiogenesis

Anti-angiogenesis drugs: These drugs, which include angiostatin and Endostatin, halt the process of developing new blood vessels (angiogenesis). Angiostatin is a piece of a larger and very common protein, plasminogen, that the body uses in blood clotting. Endostatin is a piece of a different protein, collagen 18, that is in all blood vessels. Both angiostatin and Endostatin are normally secreted by tumors. It is hoped that they will provide the basis for a new class of agents to treat cancer.

Anticancer Therapy

Treatment to stop or prevent cancer.

Anticarcinogenic

Having to do with preventing or delaying the development of cancer.

Astrocytes

a star-shaped cell; esp : any comparatively large much-branched neuroglial cell

Astrocytoma

Astrocytes, which can develop in any part of the brain or spinal cord, are star-shaped glial cells where the tumor originates. It can be any grade, but in adults, it most often arises in the cerebrum. Commonly astrocytomas are classified in four grades:

Grade I astrocytoma:
* Called low-grade glioma
* Slow growing
* Well-defined borders
* Rare and almost exclusively found in children or teens

Grade II astrocytoma:
* Rarely spreads to other parts of central nervous system
* Slow growing
* Borders not defined
* Common among men and women, 20s to 50s

Grade III astrocytoma:
* Sometimes called a high-grade or an anaplastic astrocytoma
* More aggressive than grade II astrocytoma
* Cells not uniform
* Invades other tissue
* More common in men than women

Grade IV astrocytoma:
* Called a glioblastoma or malignant astrocytic glioma
* Most invasive type of glial tumor
* Composed of several different cells, making it difficult to treat
* Grows rapidly and invades other tissue
* May have evolved from low-grade tumor
* Common in young adults and among men and women, 50s to 70s
* More common in men
Astrocytoma accounts for 3,000 new cases a year in the U.S. The annual U.S. incidence rate: three per 100,000.

Avastin

A drug used to treat several types of cancer, including certain types of colorectal, lung, and breast cancers and glioblastoma. It is also being studied in the treatment of other types of cancer. Avastin binds to vascular endothelial growth factor (VEGF) and may prevent the growth of new blood vessels that tumors need to grow. It is a type of antiangiogenesis agent and a type of monoclonal antibody. Also called bevacizumab.

Basal Ganglia

The basal ganglia (or basal nuclei) are a group of nuclei in the brain interconnected with the cerebral cortex, thalamus and brainstem. Basal ganglia are associated with a variety of functions: motor control, cognition, emotions, and learning.

Baseline

An initial measurement that is taken at an early time point to represent a beginning condition, and is used for comparison over time to look for changes. For example, the size of a tumor will be measured before treatment (baseline) and then afterwards to see if the treatment had an effect.

Benign

Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body. Also called non-malignant.

Benign Brain Tumor

Benign brain tumors have defined borders and are composed of harmless cells that usually can be entirely removed. The cells do not invade nearby tissues, but can place pressure on sensitive areas, causing severe pain, brain damage or even be life-threatening. When removed, benign brain tumors seldom return. Benign tumors can turn into malignant tumors.

Benign Tumor

A growth that is not cancer. It does not invade nearby tissue or spread to other parts of the body.

Bevacizumab

A drug used to treat several types of cancer, including certain types of colorectal, lung, and breast cancers and glioblastoma. It is also being studied in the treatment of other types of cancer. Bevacizumab binds to vascular endothelial growth factor (VEGF) and may prevent the growth of new blood vessels that tumors need to grow. It is a type of antiangiogenesis agent and a type of monoclonal antibody. Also called Avastin.

Bioinformatics

The science of using computers, databases, and math to organize and analyze large amounts of biological, medical, and health information. Information may come from many sources, including patient statistics, tissue specimens, genetics research, and clinical trials.

Biomarker

A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease. A biomarker may be used to see how well the body responds to a treatment for a disease or condition. Also called molecular marker and signature molecule.

Biopsy

Several of the tests can suggest the presence of a tumor, but the biopsy, which is a piece of the tumor, provides the definitive diagnosis. Depending on the tumor, the biopsy also reveals the type and grade of the tumor and assists in potential treatment. The sample tumor is analyzed by a pathologist, a doctor specializing in tissue, cell and organ evaluation to diagnose disease.

Biopsy Specimen

Tissue removed from the body and examined under a microscope to determine whether disease is present.

Biorespitory

A facility that collects, catalogs, and stores samples of biological material, such as urine, blood, tissue, cells, DNA, RNA, and protein, from humans, animals, or plants for laboratory research. If the samples are from people, medical information may also be stored along with a written consent to use the samples in laboratory studies.

Biospecimen

Samples of material, such as urine, blood, tissue, cells, DNA, RNA, and protein from humans, animals, or plants. Biospecimens are stored in a biorepository and are used for laboratory research. If the samples are from people, medical information may also be stored along with a written consent to use the samples in laboratory studies.

Biostatistics

The science of collecting and analyzing biologic or health data using statistical methods. Biostatistics may be used to help learn the possible causes of a cancer or how often a cancer occurs in a certain group of people. Also called biometrics and biometry.

Brachytherapy

Internal radiation therapy using an implant of radioactive material placed directly into or near the tumor.

Brain cancer

Brain cancer is the abnormal growth of tissue found inside the skull. There are two types of malignant brain tumors: A primary brain tumor is that which originates in the brain. A metastatic (secondary) brain tumor occurs when cancer cells from other parts of the body - such as the lungs, kidneys, breasts and skin - spread to the brain.

Brain Metastasis

Cancer that has spread from the original (primary) tumor to the brain.

Brain shunt

Surgical establishment of a shunt to drain cerebrospinal fluid (as in hydrocephalus) from a ventricle of the brain to the right atrium

Brain Stem

The part of the brain that is connected to the spinal cord.

Brain stem glioma

Brain stem gliomas are tumors located in the area of the brain called the brain stem, which connects the spinal cord with the brain and is located in the lowest portion of the brain, just above the back of the neck. It can be a low-grade or high-grade tumor, but the most common type is a diffuse intrinsic pontine glioma, which affects the pons portion of the brain stem and stymies nervous system functions. Also:
* Because of tumor location, it causes a challenge in treatment
* Gliomas are the most common form of brain cancer, accounting for about 50 percent of malignant brain tumors
* Occurs most often in children between age 3 and 10, but can occur in adults
* Rarely spreads or metastasizes
Peak incidence occurs from age 6 to 9 with brain stem tumors accounting for 10 to 15 percent of childhood brain tumors. The annual U.S. incidence rate of gliomas: seven per 100,000.

Brain Stem Tumor

A tumor in the part of the brain that connects to the spinal cord (the brain stem).

Brain tumor

A tumor in the brain. There are too many to generalize to just brain tumor. There are many different types and locations.

Brain tumor symptoms

Some of the symptoms may include headache, blurred vision, vomiting, mental dulling, seizures. Localizing signs of brain dysfunction can occur when vital areas of the brain that regulate specific functions such as language or motor control are affected.

Butterfly glioma astrocytoma

Butterfly glioma. Butterfly refers to the anatomical aspect of the tumor. A "butterfly" glioma (of any grade or type) is one which crosses the corpus callosum from one side to the other and then grows out into the hemisphere on both sides. Robert A. Fink, M. D., F.A.C.S., P. C.

Calvarium Tumor

Calvarium. One of the bones that makes up the vault of the skull (in humans these are the frontal, 2 parietals, occipital and 2 temporals). A tumor in the area of the calvarium.

Cancer

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

Cancer Antigen 125

A substance that may be found in high amounts in the blood of patients with certain types of cancer, including ovarian cancer. Cancer antigen 125 levels may also help monitor how well cancer treatments are working or if cancer has come back. Also called CA-125.

Cancer Cluster

The occurrence of a larger-than-expected number of cases of cancer within a group of people in a geographic area over a period of time.

Carcinogen

Any substance that causes cancer.

Carcinogenesis

The process by which normal cells are transformed into cancer cells.

Case Report

A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin).

Central Nervous System

The brain and spinal cord. Also called CNS.

Central Nervous System Metastasis

Cancer that has spread from the original (primary) tumor to the central nervous system (CNS). Also called CNS metastasis.

Cerebellar Hemangioblastoma

A benign, slow-growing tumor in the cerebellum (part of the brain at the back of the head), made up of abnormal blood vessel growth. People with von Hippel-Landau disease have an increased risk of developing hemangioblastomas.

Cerebellopontine

Having to do with two structures of the brain, the cerebellum (located at the lower back of the brain) and the pons (located at the base of the brain in front of the cerebellum) and the area between them.

Cerebellum

This part of the brain coordinates body movements.

Cerebellum blastoma

Cerebellum: The portion of the brain in the back of the head between the cerebrum and the brain stem. Blastoma: A tumor thought to arise in embryonic tissue. The term "blastoma" is commonly used as part of the name for a tumor as, for examples, in glioblastoma and medulloblastoma (types of brain tumors), hepatoblastoma (a liver tumor), nephroblastoma ( Wilms tumor of the kidney), neuroblastoma (a childhood tumor of neural origin), osteoblastoma (a bone tumor) and retinoblastoma (a tumor of the retina).

Cerebral Achromatopsia

Cerebral achromatopsia is a form of acquired color blindness that is caused by damage to the cerebral cortex of the brain, rather than abnormalities in the cells of the eye's retina. It is most frequently caused by physical trauma, hemorrhage or tumor tissue growth.

Cerebral Hemisphere

One half of the cerebrum, the part of the brain that controls muscle functions and also controls speech, thought, emotions, reading, writing, and learning. The right hemisphere controls the muscles on the left side of the body, and the left hemisphere controls the muscles on the right side of the body.

Cerebrospinal fluid

(CSF) The entire surface of central nervous system is bathed by a cerebrospinal fluid, a clear, colorless fluid. The CSF is contained within a system of fluid-filled cavities called ventricles. The Cerebral Spinal fluid has several functions: 1. Protection: the CSF protects the brain from damage by "buffering" the brain. The CSF acts to cushion a blow to the head and lessen the impact. 2. Buoyancy: because the brain is immersed in fluid, the net weight of the brain is reduced from about 1,400 gm to about 50 gm. Therefore, CSF reduces pressure at the base of the brain. 3. Excretion of waste products: the one-way flow from the CSF to the blood takes potentially harmful metabolites, drugs and other substances away from the brain. 4. Endocrine medium for the brain: the CSF serves to transport hormones to other areas of the brain. Hormones released into the CSF can be carried to remote sites of the brain where they may act.

Cerebrospinal Fluid Diversion

The fluid that flows in and around the hollow spaces of the brain and spinal cord, and between two of the meninges (the thin layers of tissue that cover and protect the brain and spinal cord). Cerebrospinal fluid is made by tissue called the choroid plexus in the ventricles (hollow spaces) in the brain. Also called CSF.

Cerebrum

The main portion of the brain occupying the upper part of the cranial cavity.

Charged-particle Radiation Therapy

A type of external radiation therapy that uses a special machine to make invisible, high-energy particles (protons or helium ions) that kill cancer cells. This type of radiation may cause less damage to nearby healthy tissue than radiation therapy with high-energy x-rays.

Chelating Agent

A chemical compound that binds tightly to metal ions. In medicine, chelating agents are used to remove toxic metals from the body. They are also being studied in the treatment of cancer.

Chemoembolization

A procedure in which the blood supply to the tumor is blocked surgically or mechanically and anticancer drugs are administered directly into the tumor. This permits a higher concentration of drug to be in contact with the tumor for a longer period of time.

Chemoimmunotherapy

Chemotherapy combined with immunotherapy. Chemotherapy uses different drugs to kill or slow the growth of cancer cells; immunotherapy uses treatments to stimulate or restore the ability of the immune system to fight cancer.

Chemoprevention

The use of drugs, vitamins, or other agents to try to reduce the risk of, or delay the development or recurrence of, cancer.

Chemoprevention Study

In cancer prevention, a clinical trial that studies whether taking certain medicines, vitamins, minerals, or food supplements can prevent cancer. Also called agent study.

Chemoprotective

A quality of some drugs used in cancer treatment. Chemoprotective agents protect healthy tissue from the toxic effects of anticancer drugs.

Chemoradiation

Treatment that combines chemotherapy with radiation therapy. Also called chemoradiotherapy.

Chemoradiotherapy

Treatment that combines chemotherapy with radiation therapy. Also called chemoradiation.

Chemosensitivity

The susceptibility of tumor cells to the cell-killing effects of anticancer drugs.

Chemosensitivity Assay

A laboratory test that measures the number of tumor cells that are killed by a cancer drug. The test is done after the tumor cells are removed from the body. A chemosensitivity assay may help in choosing the best drug or drugs for the cancer being treated.

Chemosensitivity testing

A lab test in which a piece of the tumor is sent to the lab to be grown in a test tube. It is exposed to many drugs, in an attempt to find the drug that works the best on your particular tumor type.

Chemosensitizer

A drug that makes tumor cells more sensitive to the effects of chemotherapy.

Chemotherapeutic Agent

A drug used to treat cancer.

Chemotherapy

Chemotherapy employs the use of drugs to stop or control the growth of cancer cells. The goal of chemotherapy is to kill as many of the tumor cells as possible and to put remaining tumor cells into a non-dividing, sleeping state for as long as possible.

Choroid plexus papilloma

A Choroid plexus papilloma (CPP) is a rare, slow-growing, histologically benign tumor that is commonly located in the ventricular system of the choroid plexus. It may obstruct the cerebrospinal fluid flow, causing increased intracranial pressure. It most commonly affects young children under the age of 5. If it undergoes malignant transformation it is called if is called a choroid plexus carcinoma.

Chronic

A disease or condition that persists or progresses over a long period of time.

Clinical Practice Guidelines

Guidelines developed to help health care professionals and patients make decisions about screening, prevention, or treatment of a specific health condition.

Clinical Researcher

A health professional who works directly with patients, or uses data from patients, to do research on health and disease and to develop new treatments. Clinical researchers may also do research on how health care practices affect health and disease.

Clinical Study

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical trial.

Clinical Trial

An experimental treatment. There are various types - click here for details. the advantage to brain tumor patients is that some of the most promising treatments are only available in clinical trials.

CNS

The brain and spinal cord. Also called central nervous system.

Communicating hydrocephalus

Hydrocephalus is the condition where the fluid spaces in the brain (Ventricles) become enlarged. One of the three basic types is known as Communicating Hydrocephalus. This is a condition where the Cerebro-Spinal Fluid (CSF) inside of the ventricles communicates or is open to, the fluid spaces surrounding the brain. This type usually occurs as a result of some sort of dysfunction of the absorption channels known as the Arachnoid Villi.

Compassionate Use Trial

A way to provide an investigational therapy to a patient who is not eligible to receive that therapy in a clinical trial, but who has a serious or life-threatening illness for which other treatments are not available. Compassionate use trials allow patients to receive promising but not yet fully studied or approved cancer therapies when no other treatment option exists. Also called expanded access trial.

Computed Tomography Scan (CT or CAT scan)

This CT reveals brain abnormalities. Simply, this is a sophisticated X-ray machine linked to a computer to create two-dimensional images. It is painless and can be completed in 10 minutes or less. Occasionally a special dye is injected into the bloodstream to provide more detail.

Concomitant

Occurring or existing at the same time as something else. In medicine, it may refer to a condition a person has or a medication a person is taking that is not being studied in the clinical trial he or she is taking part in.

Congenital

A condition or trait present at birth. It may be the result of genetic or non-genetic factors.

Continuum of Care

In medicine, describes the delivery of health care over a period of time. In patients with a disease, this covers all phases of illness from diagnosis to the end of life.

Contraindication

A symptom or medical condition that makes a particular treatment or procedure inadvisable because a person is likely to have a bad reaction. For example, having a bleeding disorder is a contraindication for taking aspirin because treatment with aspirin may cause excess bleeding.

Contralateral

Having to do with the opposite side of the body.

Control Group

In a clinical trial, the group that does not receive the new treatment being studied. This group is compared to the group that receives the new treatment, to see if the new treatment works.

Controlled Clinical Trial

A clinical study that includes a comparison (control) group. The comparison group receives a placebo, another treatment, or no treatment at all.

Controlled Study

An experiment or clinical trial that includes a comparison (control) group.

Craniopharyngioma

A benign brain tumor that may be considered malignant because it can damage the hypothalamus, the area of the brain that controls body temperature, hunger, and thirst.

Craniotomy

An operation in which an opening is made in the skull.

CSF

The fluid that flows in and around the hollow spaces of the brain and spinal cord, and between two of the meninges (the thin layers of tissue that cover and protect the brain and spinal cord). CSF is made by tissue called the choroid plexus in the ventricles (hollow spaces) in the brain. Also called cerebrospinal fluid.

Cultured Cell

A human, plant, or animal cell that has been adapted to grow in the laboratory. Cultured cells may be used to diagnose infections, to test new drugs, and in research.

Cultured Cell Line

Cells of a single type (human, animal, or plant) that have been adapted to grow continuously in the laboratory and are used in research.

Cyst

A sac or capsule in the body. It may be filled with fluid or other material.

Cystectomy

Surgery to remove all or part of the bladder (the organ that holds urine) or to remove a cyst (a sac or capsule in the body).

Cytopenia

A condition in which there is a lower-than-normal number of blood cells.

Cytoplasm

The fluid inside a cell but outside the cell's nucleus. Most chemical reactions in a cell take place in the cytoplasm.

Cytotoxic

Cell-killing.

Cytotoxic Chemotherapy

Anticancer drugs that kill cells, especially cancer cells.

De-novo

In cancer, the first occurrence of cancer in the body.

Delirium

A mental state in which a person is confused, disoriented, and not able to think or remember clearly. The person may also be agitated and have hallucinations, and extreme excitement.

Dementia

A condition in which a person loses the ability to think, remember, learn, make decisions, and solve problems. Symptoms may also include personality changes and emotional problems. There are many causes of dementia, including Alzheimer disease, brain cancer, and brain injury. Dementia usually gets worse over time.

Detoxify

1: To make something less poisonous or harmful. It may refer to the process of removing toxins, poisons, or other harmful substances from the body. 2: The process of identifying a disease, such as cancer, from its signs and symptoms.

Diagnostic Trial

A research study that evaluates methods of detecting disease.

Diffuse

Widely spread; not localized or confined.

Digital holography

Digital holography provides three-dimensional map of the tumor and surrounding brain structure.

Disease Progression

Cancer that continues to grow or spread.

Disease-free Survival

The length of time after treatment for a specific disease during which a patient survives with no sign of the disease. Disease-free survival may be used in a clinical study or trial to help measure how well a new treatment works.

Disease-free Survival Rate

The percentage of people in a study or treatment group who have not died from a specific disease in a defined period of time. The time period usually begins at the time of diagnosis or at the start of treatment and ends at the time of death. Patients who died from causes other than the disease being studied are not counted in this measurement.

Distal

In medicine, refers to a part of the body that is farther away from the center of the body than another part. For example, the fingers are distal to the shoulder. The opposite is proximal.

DNA

The molecules inside cells that carry genetic information and pass it from one generation to the next. Also called deoxyribonucleic acid.

Do Not Resuscitate Order

A type of advance directive in which a person states that health care providers should not perform cardiopulmonary resuscitation (restarting the heart) if his or her heart or breathing stops. Also called DNR order.

Dose

The amount of medicine taken, or radiation given, at one time.

Dose-dense Chemotherapy

A chemotherapy treatment plan in which drugs are given with less time between treatments than in a standard chemotherapy treatment plan.

Dose-dependent

Refers to the effects of treatment with a drug. If the effects change when the dose of the drug is changed, the effects are said to be dose-dependent.

Dose-limiting

Describes side effects of a drug or other treatment that are serious enough to prevent an increase in dose or level of that treatment.

Dose-rate

The strength of a treatment given over a period of time.

Dosimetrist

A person who determines the proper radiation dose for treatment.

Dosimetry

Measurement of radiation exposure from x-rays, gamma rays, or other types of radiation used in the treatment or detection of diseases, including cancer.

Double-blinded

A clinical trial in which the medical staff, the patient, and the people who analyze the results do not know the specific type of treatment the patient receives until after the clinical trial is over.

Dysembryoplastic neuroepithelial

Most commonly located in a temporal or frontal lobe of the cerebrum and similar in behavior to the oligodendroglioma, the DNT is a slow-growing, grade I tumor, and occurs in both adults and children.

Dysembryoplastic Neuroepithelial

Most commonly located in a temporal or frontal lobe of the cerebrum and similar in behavior to the oligodendroglioma, the DNT is a slow-growing, grade I tumor, and occurs in both adults and children.

Dysgeusia

A bad taste in the mouth. Also called parageusia.

Dyspepsia

Upset stomach.

Dysphagia

Difficulty swallowing.

Dysphonia

Trouble with the voice when trying to talk, including hoarseness and change in pitch or quality or voice.

Dysplasia

Cells that look abnormal under a microscope but are not cancer.

Dyspnea

Difficult, painful breathing or shortness of breath.

ECG

A line graph that shows changes in the electrical activity of the heart over time. It is made by an instrument called an electrocardiograph. The graph can show that there are abnormal conditions, such as blocked arteries, changes in electrolytes (particles with electrical charges), and changes in the way electrical currents pass through the heart tissue. Also called EKG and electrocardiogram.

Edema

Swelling caused by excess fluid in body tissues.

EEG

A recording of electrical activity in the brain. It is made by placing electrodes on the scalp (the skin covering the top of the head), and impulses are sent to a special machine. An EEG may be used to diagnose brain and sleep disorders. Also called electroencephalogram.

Effector Cell

A cell that performs a specific function in response to a stimulus; usually used to describe cells in the immune system.

Efficacy

Effectiveness. In medicine, the ability of an intervention (for example, a drug or surgery) to produce the desired beneficial effect.

Electrocardiogram

A line graph that shows changes in the electrical activity of the heart over time. It is made by an instrument called an electrocardiograph. The graph can show that there are abnormal conditions, such as blocked arteries, changes in electrolytes (particles with electrical charges), and changes in the way electrical currents pass through the heart tissue. Also called ECG and EKG.

Electrochemotherapy

Uses electric voltage to carry chemotherapy agents into the brain.

Electromagnetic Radiation

Low-energy radiation that comes from the interaction of electric and magnetic fields. Sources include power lines, electric appliances, radio waves, microwaves, and others. Also called electromagnetic field.

Electron Beam

A stream of electrons (small negatively charged particles found in atoms) that can be used for radiation therapy.

Eligibility Criteria

In clinical trials, requirements that must be met for an individual to be included in a study. These requirements help make sure that patients in a trial are similar to each other in terms of specific factors such as age, type and stage of cancer, general health, and previous treatment. When all participants meet the same eligibility criteria, it gives researchers greater confidence that results of the study are caused by the intervention being tested and not by other factors.

Encephalitis

Encephalitis: Inflammation of the brain. Encephalitis occurs, for example, in 1 in 1,000 cases of measles. It may start (up to 3 weeks) after onset of the measles rash and present with high fever, convulsions, and coma. It usually runs a blessedly short course with full recovery within a week. Or it may eventuate in central nervous system impairment or death. Encephalitis can cause brain damage, which may result in or exacerbate the symptoms of a developmental disorder or mental illness. The form called encephalitis lethargica ("sleeping sickness") results in a set of Parkinson's disease-like symptoms called postencephalitic parkinsonianism. In some cases encephalitis causes death. Treatment of encephalitis must begin as early as possible to avoid potentially serious and life-long effects. Depending on the cause of the inflammation, this may include antibiotics, anti-viral medications, and anti-inflammatory drugs. If brain damage results from encephalitis, therapy (such as physical therapy or cognitive restoration therapy) may help patients regain lost functions.

Encephalopathy

A disorder of the brain that can be caused by disease, injury, drugs, or chemicals.

Endometrioma

1 : a tumor containing endometrial tissue 2 : ENDOMETRIOSIS -- used chiefly of isolated foci of endometrium outside the uterus

Endometriosis

The presence and growth of functioning endometrial tissue in places other than the uterus that often results in severe pain and infertility.

Ependyma

A thin membrane that lines the fluid-filled spaces in the brain and spinal cord. It is made up of a type of glial cell called an ependymal cell.

Ependymal Cell

A cell that forms the lining of the fluid-filled spaces in the brain and spinal cord. It is a type of glial cell.

Ependymal Tumor

A type of brain tumor that begins in cells lining the spinal cord central canal (fluid-filled space down the center) or the ventricles (fluid-filled spaces of the brain). Ependymal tumors may also form in the choroid plexus (tissue in the ventricles that makes cerebrospinal fluid). Also called ependymoma.

Ependymoma

An ependymoma, part of the glial family (glial cells are the supportive cells of the brain), is a rare type of primary brain or spinal cord tumor. It originates in the ependyma, the cells that line the passageways in the brain where cerebrospinal fluid is produced.
* Usually local to an area of the brain, including the ventricles (cavities in the center of the brain)
* Can block the ventricles causing water in the brain
* Sometimes extends to spinal cord
* Can be slow or fast growing
* More than 90 percent occur in children, the third most common pediatric brain tumor
Ependymomas account for approximately three to six percent of central nervous system tumors and two percent of brain tumors.

Epidemiological studies

A branch of medical science that deals with the incidence, distribution, and control of disease in a population.

Excision

Removal by surgery.

Excisional Biopsy

A surgical procedure in which an entire lump or suspicious area is removed for diagnosis. The tissue is then examined under a microscope.

Experimental

In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the U.S. Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered experimental in other diseases or conditions. Also called investigational.

Experimental Drug

A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. An experimental drug may be approved by the FDA for use in one disease or condition but be considered investigational in other diseases or conditions. Also called investigational agent and investigational drug.

Exploratory Surgery

Surgery to look inside the body to help make a diagnosis.

External Radiation Therapy

A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. Also called external-beam radiation therapy.

External-beam Radiation Therapy

A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. Also called external radiation therapy.

Fast-neuron Beam Radiation

A type of radiation therapy that uses tiny particles called neutrons made by a machine called a cyclotron.

FDA

An agency in the U.S. federal government whose mission is to protect public health by making sure that food, cosmetics, and nutritional supplements are safe to use and truthfully labeled. The FDA also makes sure that drugs, medical devices, and equipment are safe and effective, and that blood for transfusions and transplant tissue are safe. Also called Food and Drug Administration.

Fibrillary Astrocytoma

A type of low-grade glioma that is usually found in the mid-brain has less well-defined margins and, because of the location, less likely to be completely removed.

First-line Therapy

Initial treatment used to reduce a cancer. First-line therapy is followed by other treatments, such as chemotherapy, radiation therapy, and hormone therapy to get rid of cancer that remains. Also called induction therapy, primary therapy, and primary treatment.

Form FDA 1572- Statement of Investigator

A form that must be filed by an investigator running a clinical trial to study a new drug or agent. The investigator agrees to follow the U.S. Food and Drug Administration (FDA) Code of Federal Regulations for the clinical trial. The investigator verifies that he or she has the experience and background needed to conduct the trial and that it will be done in a way that is ethical and scientifically sound. Also called 1572 form.

Functional Magnetic Resonance Imaging

A noninvasive tool used to observe functioning in the brain or other organs by detecting changes in chemical composition, blood flow, or both.

Gamma Irradiation

A type of radiation therapy that uses gamma radiation. Gamma radiation is a type of high-energy radiation that is different from x-rays.

Gamma knife

Gamma knife. A special multi-source irradiation machine which focus a high intensity of irradiation on a small area: it is used as local therapy in especially brain tumors.

Gamma knife surgery

This is also known as radiosurgery. With regular radiation therapy a standard external beam is used. Tumors and much , or all, of the surrounding brain are treated to the same dose of radiation. Gamma Knife radiosurgery treats only the abnormal tissues. This treatment occurs in a single session without significant radiation to the adjacent brain. Click here for more information.

Gamma Knife Therapy

A treatment using gamma rays, a type of high-energy radiation that can be tightly focused on small tumors or other lesions in the head or neck, so very little normal tissue receives radiation. The gamma rays are aimed at the tumor from many different angles at once, and deliver a large dose of radiation exactly to the tumor in one treatment session. This procedure is a type of stereotactic radiosurgery. Gamma Knife therapy is not a knife and is not surgery. Gamma Knife is a registered trademark of Elekta Instruments, Inc.

Gamma Ray

A type of high-energy radiation that is different from an x-ray.

Ganglia

Ganglia, basal: A region located at the base of the brain composed of 4 clusters of neurons, or nerve cells. This area of the brain is responsible for body movement and coordination. The groups of neurons most prominently and consistently affected in Huntington disease -- the pallidum and striatum -- are located in the basal ganglia. (The pallidum is composed of structures called the globus pallidus and the ventral pallidum while the striatum consists of the caudate nucleus, putamen, and ventral striatum.) The term "basal ganglia" refers to the location of these collections of neurons (ganglia) deep within the brain, seemingly at its very base.

Ganglion brain tumors

Rare, benign tumors arising from ganglia-type cells, which are groups of nerve cells. Tumors arising from ganglia most frequently occur in children and young adults. These tumors are small, slow growing, and have distinct margins. Metastasis and malignancy are very rare.

GBM

A fast-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord and has cells that look very different from normal cells. GBM usually occurs in adults and affects the brain more often than the spinal cord. Also called glioblastoma, glioblastoma multiforme, and grade IV astrocytoma.

GCP

An international set of guidelines that helps make sure that the results of a clinical trial are reliable and that the patients are protected. GCP covers the way a clinical trial is designed, conducted, performed, monitored, audited, recorded, analyzed, and reported. Also called Good Clinical Practice.

Gene

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

Gene Amplification

An increase in the number of copies of a gene. There may also be an increase in the RNA and protein made from that gene. Gene amplification is common in cancer cells, and some amplified genes may cause cancer cells to grow or become resistant to anticancer drugs. Genes may also be amplified in the laboratory for research purposes.

Gene Deletion

The loss of all or a part of a gene. There may also be a change in the RNA and protein made from that gene. Certain gene deletions are found in cancer and in other genetic diseases and abnormalities.

Gene Expression

The process by which a gene gets turned on in a cell to make RNA and proteins. Gene expression may be measured by looking at the RNA, or the protein made from the RNA, or what the protein does in a cell.

Gene Expression Profiling

A research method that measures messenger RNA made from many different genes in various cell types. It is being used as a diagnostic test to help identify subgroups of tumor types, to help predict which patients may respond to treatment, and which patients may be at increased risk for cancer relapse.

Gene Therapy

Treatment that alters a gene. In studies of gene therapy for cancer, researchers are trying to improve the body's natural ability to fight the disease or to make the cancer cells more sensitive to other kinds of therapy.

Gene Transfer

The insertion of genetic material into a cell.

Gene-modified

Cells that have been altered to contain different genetic material than they originally contained.

Generic

Official non-brand names by which medicines are known. Generic names usually refer to the chemical name of the drug.

Genetic

Inherited; having to do with information that is passed from parents to offspring through genes in sperm and egg cells.

Genetic Analysis

The study of a sample of DNA to look for mutations (changes) that may increase risk of disease or affect the way a person responds to treatment.

Genetic Marker

lteration in DNA that may indicate an increased risk of developing a specific disease or disorder.

Genetic Predisposition

An inherited increase in the risk of developing a disease. Also called genetic susceptibility.

Genetic Profile

Information about specific genes, including variations and gene expression, in an individual or in a certain type of tissue. A genetic profile may be used to help diagnose a disease or learn how the disease may progress or respond to treatment with drugs or radiation.

Genetic Susceptibility

An inherited increase in the risk of developing a disease. Also called genetic predisposition.

Genetic Testing

Analyzing DNA to look for a genetic alteration that may indicate an increased risk for developing a specific disease or disorder.

Genetics

The study of genes and heredity. Heredity is the passing of genetic information and traits (such as eye color and an increased chance of getting a certain disease) from parents to offspring.

Genomic Profile

Information about all the genes in an organism, including variations, gene expression, and the way those genes interact with each other and with the environment. A genomic profile may be used to discover why some people get certain diseases while other people do not, or why people respond differently to the same drug.

Genomics

The study of the complete genetic material, including genes and their functions, of an organism.

Glia

Supporting tissue that is intermingled with the essential elements of nervous tissue especially in the brain, spinal cord, and ganglia, is of ectodermal origin, and is composed of a network of fine fibrils and of flattened stellate cells with numerous radiating fibrillar processes.

Glial Cell

Any of the cells that hold nerve cells in place and help them work the way they should. The types of glial cells include oligodendrocytes, astrocytes, microglia, and ependymal cells. Also called neuroglia.

Glial Tumor

A general term for tumors of the central nervous system, including astrocytomas, ependymal tumors, glioblastoma multiforme, and primitive neuroectodermal tumors.

Glioblastoma

A fast-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord and has cells that look very different from normal cells. Glioblastoma usually occurs in adults and affects the brain more often than the spinal cord. Also called GBM, glioblastoma multiforme, and grade IV astrocytoma.

Glioblastoma multiforme

This is the most malignant form of astrocytoma, usually classified as Grade IV, one the most common primary tumors of the brain. It is a rapidly growing tumor.

Glioma

Any of the largest group of primary tumors of the brain, composed of malignant glial cells. There are several different types. They can affect children too.

Gliosarcoma

A type of glioma (cancer of the brain that comes from glial, or supportive, cells).

Glomus tumor

A painful benign tumor that develops by hypertrophy of a glomus -- called also glomangioma.

Growth Factor

A substance made by the body that functions to regulate cell division and cell survival. Some growth factors are also produced in the laboratory and used in biological therapy.

Hand-foot Syndrome

A condition marked by pain, swelling, numbness, tingling, or redness of the hands or feet. It sometimes occurs as a side effect of certain anticancer drugs. Also called palmar-plantar erythrodysesthesia.

Hazard Ratio

In cancer research, hazard ratios are often used in clinical trials to measure survival at any point in time in a group of patients who have been given a specific treatment compared to a control group given another treatment or a placebo. A hazard ratio of one means that there is no difference in survival between the two groups. A hazard ratio of greater than one or less than one means that survival was better in one of the groups.

Healthy Control

In a clinical study, a person who does not have the disorder or disease being studied. Results from healthy controls are compared to results from the group being studied.

Helical Computed Tomography

A detailed picture of areas inside the body. The pictures are created by a computer linked to an x-ray machine that scans the body in a spiral path. Also called spiral CT scan.

Hemorrhage

In medicine, loss of blood from damaged blood vessels. A hemorrhage may be internal or external, and usually involves a lot of bleeding in a short time.

High-dose Chemotherapy

An intensive drug treatment to kill cancer cells, but that also destroys the bone marrow and can cause other severe side effects. High-dose chemotherapy is usually followed by bone marrow or stem cell transplantation to rebuild the bone marrow.

High-dose Radiation

An amount of radiation that is greater than that given in typical radiation therapy. High-dose radiation is precisely directed at the tumor to avoid damaging healthy tissue, and may kill more cancer cells in fewer treatments. Also called HDR.

High-energy Photon Therapy

A type of radiation therapy that uses high-energy photons (units of light energy). High-energy photons penetrate deeply into tissues to reach tumors while giving less radiation to superficial tissues such as the skin.

High-grade

A term used to describe cells that look abnormal under a microscope. These cells are more likely to grow and spread quickly than cells in low-grade cancer or in growths that may become cancer.

HIPAA

A 1996 U.S. law that allows workers and their families to keep their health insurance when they change or lose their jobs. The law also includes standards for setting up secure electronic health records and to protect the privacy of a person’s health information and to keep it from being misused. Also called Health Insurance Portability and Accountability Act.

Histologic Examination

The examination of tissue specimens under a microscope.

Histology

The study of tissues and cells under a microscope.

Homeostasis

A state of balance among all the body systems needed for the body to survive and function correctly. In homeostasis, body levels of acid, blood pressure, blood sugar, electrolytes, energy, hormones, oxygen, proteins, and temperature are constantly adjusted to respond to changes inside and outside the body, to keep them at a normal level.

Hospice

A program that provides special care for people who are near the end of life and for their families, either at home, in freestanding facilities, or within hospitals.

Human Participant Protection Regulations

Laws set by the U.S. Department of Health and Human Services (DHHS) to protect a person from risks in research studies that any federal agency or department has a part in. Also called 45 CFR 46, 45 Code of Federal Regulations Part 46, and Protection of Human Subjects.

Hydrocephalus

Hydrocephalus. An abnormal increase in the amount of cerebrospinal fluid within the cranial cavity that is accompanied by expansion of the cerebral ventricles, enlargement of the skull and especially the forehead, and atrophy of the brain.

Hypersensitivity

An exaggerated response by the immune system to a drug or other substance.

Hypothalamic brain tumor

Hypothalamic hamartoma: A benign tumor of the hypothalamus, the area of the brain that controls body temperature, hunger, and thirst. (In technical terms, the hypothalamus lies beneath a structure known as the thalamus and forms the floor of the third ventricle of the brain.) A small hypothalamic hamartoma can cause the person to feel as though they have to laugh. The tumor also causes the patient to have mild epileptic seizures. The seizures can usually be controlled with medication; the laugh cannot. Larger hypothalamic hamartomas often cause more serious symptoms, including changes in mental ability and behavioral problems. Patients with possible hypothalamic hamartomas should have MRI scans, which should be thoroughly scrutinized, since the growths are small and sometimes difficult to detect.

Idiopathic

Describes a disease of unknown cause.

Imaging

In medicine, a process that makes pictures of areas inside the body. Imaging uses methods such as x-rays (high-energy radiation), ultrasound (high-energy sound waves), and radio waves.

Immune Response

The activity of the immune system against foreign substances (antigens).

Immune System

The complex group of organs and cells that defends the body against infections and other diseases.

Immunity

The condition of being protected against an infectious disease. Immunity can be caused by a vaccine, previous infection with the same agent, or by transfer of immune substances from another person or animal.

Immunotherapy

Treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Agents used in immunotherapy include monoclonal antibodies, growth factors, and vaccines. These agents may also have a direct antitumor effect. Also called biological response modifier therapy, biological therapy, biotherapy, and BRM therapy.

In Situ

In its original place. For example, in carcinoma in situ, abnormal cells are found only in the place where they first formed. They have not spread.

In Vitro

In the laboratory (outside the body). The opposite of in vivo (in the body).

In Vivo

In the body. The opposite of in vitro (outside the body or in the laboratory).

Indication

In medicine, a sign, symptom, or medical condition that leads to the recommendation of a treatment, test, or procedure.

Informed Consent

A process in which a person is given important facts about a medical procedure or treatment, a clinical trial, or genetic testing before deciding whether or not to participate. It also includes informing the patient when there is new information that may affect his or her decision to continue. Informed consent includes information about the possible risks, benefits, and limits of the procedure, treatment, trial, or genetic testing.

Intensification Therapy

Treatment that is given after cancer has disappeared following the initial therapy. Intensification therapy is used to kill any cancer cells that may be left in the body. It may include radiation therapy, a stem cell transplant, or treatment with drugs that kill cancer cells. Also called consolidation therapy and postremission therapy.

Intensity Modulated Radiation Therapy (IMRT)

In IMRT, the beam intensity is varied across the treatment field. Rather than being treated with a single, large, uniform beam, the patient is treated instead with many very small beams; each can have a different intensity. By cross firing the tumor with these beams, the physician delivers a relatively uniform radiation dose to the tumor, but protects sensitive, surrounding tissue from high-dose radiation.

Interstitial Chemotherapy

Performed during surgery when a chemotherapy-soaked, biodegradable wafer is placed into the tumor resection cavity in a controlled-release fashion.

Intraaterial chemotherapy

Uses catheter tubes for high-dose delivery of chemotherapy in the brain's arteries.

Intracranial Tumor

A tumor that occurs in the brain.

Intraspinal

Within the spine (backbone).

Intrathecal

Describes the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord. Drugs can be injected into the fluid or a sample of the fluid can be removed for testing.

Intrathecal chemotherapy

Delivers medication directly into the spinal fluid.

Invasive Cancer

Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called infiltrating cancer.

Invasive Procedure

A medical procedure that invades (enters) the body, usually by cutting or puncturing the skin or by inserting instruments into the body.

Investigational Agent

A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. An investigational agent may be approved by the FDA for use in one disease or condition but be considered investigational in other diseases or conditions. Also called experimental drug and investigational drug.

Investigational Drug

A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. An investigational drug may be approved by the FDA for use in one disease or condition but be considered investigational in other diseases or conditions. Also called experimental drug and investigational agent.

Investigator

A researcher in a clinical trial or clinical study.

IRB

A group of scientists, doctors, clergy, and consumers that reviews and approves the action plan for every clinical trial. There is an IRB at every health care facility that does clinical research. IRBs are designed to protect the people who take part in a clinical trial. IRBs check to see that the trial is well designed, legal, ethical, does not involve unneccesary risks, and includes safeguards for patients. Also called Institutional Review Board.

Irradiated

Treated with radiation.

Irreversible Toxicity

Side effects that are caused by toxic substances or something harmful to the body and do not go away.

IV

Into or within a vein. IV usually refers to a way of giving a drug or other substance through a needle or tube inserted into a vein. Also called intravenous.

Jaundice

A condition in which the skin and the whites of the eyes become yellow, urine darkens, and the color of stool becomes lighter than normal. Jaundice occurs when the liver is not working properly or when a bile duct is blocked.

Juvenile Pilocytic Astrocytoma

A slow-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord. Juvenile pilocytic astrocytoma usually occurs in children and young adults. It forms in the brain more often than the spinal cord.

Karnofsky Performance Status

A standard way of measuring the ability of cancer patients to perform ordinary tasks. The Karnofsky Performance scores range from 0 to 100. A higher score means the patient is better able to carry out daily activities. KPS may be used to determine a patient's prognosis, to measure changes in a patient’s ability to function, or to decide if a patient could be included in a clinical trial. Also called KPS.

Kidney Function Test

A test in which blood or urine samples are checked for the amounts of certain substances released by the kidneys. A higher- or lower-than-normal amount of a substance can be a sign that the kidneys are not working the way they should. Also called renal function test.

KPS

A standard way of measuring the ability of cancer patients to perform ordinary tasks. The Karnofsky Performance scores range from 0 to 100. A higher score means the patient is better able to carry out daily activities. KPS may be used to determine a patient's prognosis, to measure changes in a patient’s ability to function, or to decide if a patient could be included in a clinical trial. Also called Karnofsky Performance Status.

Laboratory Study

Research done in a laboratory. These studies may use test tubes or animals to find out if a drug, procedure, or treatment is likely to be useful. Laboratory studies take place before any testing is done in humans.

Laboratory Test

A medical procedure that involves testing a sample of blood, urine, or other substance from the body. Tests can help determine a diagnosis, plan treatment, check to see if treatment is working, or monitor the disease over time.

Laser

A device that forms light into intense, narrow beams that may be used to cut or destroy tissue, such as cancer tissue. It may also be used to reduce lymphedema (swelling caused by a buildup of lymph fluid in tissue) after breast cancer surgery. Lasers are used in microsurgery, photodynamic therapy, and many other procedures to diagnose and treat disease.

Laser Surgery

A surgical procedure that uses the cutting power of a laser beam to make bloodless cuts in tissue or to remove a surface lesion such as a tumor.

Laser Therapy

Treatment that uses intense, narrow beams of light to cut and destroy tissue, such as cancer tissue. Laser therapy may also be used to reduce lymphedema (swelling caused by a buildup of lymph fluid in tissue) after breast cancer surgery.

Leptomeningeal Cancer

Cancer that has spread from the original (primary) tumor to the meninges (thin layers of tissue that cover and protect the brain and spinal cord). The cancer causes inflammation of the meninges. Also called carcinomatous meningitis, leptomeningeal carcinoma, leptomeningeal metastasis, meningeal carcinomatosis, meningeal metastasis, and neoplastic meningitis.

Lesion

An area of abnormal tissue. A lesion may be benign (not cancer) or malignant (cancer).

Limbic system

A group of subcortical structures (as the hypothalamus, the hippocampus, and the amygdala) of the brain that are concerned especially with emotion and motivation.

Lipoma brain tumor

Lipomas are benign fatty growths that can be found virtually anywhere in the body. They generally do not change much in size over time. If they are not causing a problem they will usually be left alone. A lipoma specifically in the brain may or may not be a problem. If in the corpus callosum, depending on size and location, it could conceivably cause hydrocephalus. Furthermore, if large, it could cause a deficit simply via mass effect. An MRI would be instrumental for evaluating this type of condition. Lipomas do not necessarily need to be treated. Only when they cause problems referable to their size and location do lipomas require intervention.

Liver Function Test

A blood test to measure the blood levels of certain substances released by the liver. A high or low level of certain substances can be a sign of liver disease.

Lobe

A portion of an organ, such as the liver, lung, breast, thyroid, or brain.

Lobectomy

Surgery to remove a whole lobe (section) of an organ (such as the lungs, liver, brain, or thyroid gland).

Low-grade

A term used to describe cells that look nearly normal under a microscope. These cells are less likely to grow and spread more quickly than cells in high-grade cancer or in growths that may become cancer.

Lumbar puncture

A procedure in which a thin needle called a spinal needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give drugs. Also called spinal tap.

Lysis

In biology, lysis refers to the breakdown of a cell caused by damage to its plasma (outer) membrane. It can be caused by chemical or physical means (for example, strong detergents or high-energy sound waves) or by infection with a strain virus that can lyse cells.

Magnetic Resonance Angiogram (MRA)

MRA:The magnetic resonance angiogram, or MRA, is a noninvasive test that has demonstrated usefulness in defining the anatomy of blood vessels of certain size in the head and neck. MRA serves as a complement to traditional MRI scanning in evaluation of the brain and neck. Conventional angiograms, whereby contrast material is injected through a catheter into the blood vessels of the head and neck, are the gold standard (most accurate) for determining the anatomy of these vessels. The advantages of MRA is that it is faster and easier (it does not involve the catheters, contrast material, and risks of angiograms). Another advantage is that MRA also gives an image of the tissue of the brain. MRA is a general term that refers to various imaging techniques that are used to visualize the blood vessels by using magnetic resonance (MR) signal changes that are affected by changes in the flow of blood caused by changes in the shape of the blood vessels. MRA can be used to detect small ballooning of the blood vessels (aneurysms) as small as 4 millimeters in diameter. Smaller aneurysms can require an angiogram for detection. The sensitivity of MRA in detecting aneurysms can be affected by bleeding within the brain and the location of the aneurysms within the brain. MRA can also detect abnormal design (malformations), and atherosclerosis of blood vessels within the brain. Atherosclerosis of the carotid arteries of the neck can be visualized with MRA. MRA does not have significant application for the detection or definition of cancer of the brain.

Magnetic Resonance Imaging Scan (MRI)

The MRI, which uses magnetic fields, not X-rays, to provide detailed images, is more sensitive than the CT in detecting a brain tumor's presence. The MRI is a preferential imaging test because it outlines the normal brain structure in unique detail. The test procedure is slightly more time consuming as the patient lies inside a cylinder-type machine for about one hour. A special dye may also be injected in the bloodstream during the procedure (MRI angiogram) to distinguish tumors from healthy tissue.

Magnetic Resonance Perfusion Imaging

A special type of magnetic resonance imaging (MRI) that uses an injected dye in order to see blood flow through tissues. Also called perfusion magnetic resonance imaging.

Magnetic Resonance Spectroscopy (MRS)

A noninvasive imaging method that provides information about cellular activity (metabolic information). It is used along with magnetic resonance imaging (MRI) which provides information about the shape and size of the tumor (spatial information). Also called 1H-nuclear magnetic resonance spectroscopic imaging, MRSI, and proton magnetic resonance spectroscopic imaging.

Malignancy

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Malignant cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of malignancy. Carcinoma is a malignancy that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a malignancy that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a malignancy that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are malignancies that begin in the cells of the immune system. Central nervous system cancers are malignancies that begin in the tissues of the brain and spinal cord. Also called cancer.

Malignant

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

Malignant Brain Tumor

Malignant brain tumors do not have distinct borders and tend to grow rapidly, causing pressure within the brain. It is highly unlikely for malignant brain tumors to spread beyond the central nervous system.
* Malignant tumors are more serious and often life-threatening
* Cells can break from the malignant brain tumor, spreading to other parts of the brain or to the spinal cord. Rarely do these cancerous cells spread to other parts of the body

Mass

In medicine, a lump in the body. It may be caused by the abnormal growth of cells, a cyst, hormonal changes, or an immune reaction. A mass may be benign (not cancer) or malignant (cancer).

Medulla oblongata

The most vital part of the entire brain, continuing as the bulbous portion of the spinal cord just above the foramen magnum and separated from the pons by a horizontal groove. It is one of three parts of the brainstem . The medulla contains the cardiac (heart),vasomotor and the respiratory centers of the brain.

Medulloblastoma

The medulloblastoma is highly malignant (grade IV) and usually originates in the cerebellum, the region of the brain that plays an important role in the integration of sensory perception, coordination and motor control.
* Type of primitive neuroectodermal tumor, which is invasive and rapidly growing
* Unlike most brain tumors, spreads through the cerebrospinal fluid and frequently metastasizes to other locations in the brain and spine
* Most occur near brain stem
* May obstruct fourth ventricle, causing water on the brain
* Occurs most often in children under age 10, but can occur in adults
* Slightly more common in males than females
Medulloblastomas are the most common pediatric brain tumors. The annual U.S. incidence rate: two per 100,000.

Meningeal

Having to do with the meninges (three thin layers of tissue that cover and protect the brain and spinal cord).

Meninges

The three thin layers of tissue that cover and protect the brain and spinal cord.

Meningioma

The tumor grows from the meninges, the layers of tissue covering the brain and spinal cord. As it grows, meningioma compresses other brain tissue which can affect cranial nerves. Sometimes the growth extends into facial bones, producing visible changes. It is usually benign (grade I) or low-grade. Still, the meningioma tumor can cause disability and be life-threatening. It also can be grade II or III.
* Cannot predict its rate of growth or how long it was growing prior to diagnosis
* Can arise after previous treatment from ionizing radiation or excessive X-ray exposure
* Grows slowly, which sometimes allows the brain to become accustomed to its presence
* Occurs at any age, but common among men and women, 40s to 50s
* Twice as common in women
* Can invade skull or metastasize to skin or lungs, although rare
Meningiomas are the most common primary brain tumors in adults. The annual U.S. incidence rate is: two per 100,000.

Meningitis

Inflammation of the meninges (three thin layers of tissue that cover and protect the brain and spinal cord). Meningitis is usually caused by a bacterial or viral infection, but sometimes is caused by cancer, drug allergies, or inflammatory diseases.

Metastasectomy

Surgery to remove one or more metastases (tumors formed from cells that have spread from the primary tumor). When all metastases are removed, it is called a complete metastasectomy.

Metastasis

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases.

Metastasize

To spread from one part of the body to another. When cancer cells metastasize and form secondary tumors, the cells in the metastatic tumor are like those in the original (primary) tumor.

Metastatic

Having to do with metastasis, which is the spread of cancer from the primary site (place where it started) to other places in the body.

Metastatic Brain Tumor

A brain tumor caused by cancer elsewhere in the body spreading to the brain.

Metastatic Cancer

Cancer that has spread from the place in which it started to other parts of the body.

Methodology

In medicine, the rules and procedures for doing research and evaluating results.

Micrometastasis

Small numbers of cancer cells that have spread from the primary tumor to other parts of the body and are too few to be picked up in a screening or diagnostic test.

Mitosis

The process by which a single parent cell divides to make two new daughter cells. Each daughter cell receives a complete set of chromosomes from the parent cell. This process allows the body to grow and replace cells.

Mitotic Activity

Having to do with the presence of dividing (proliferating) cells. Cancer tissue generally has more mitotic activity than normal tissues.

Mixed Glioma

A brain tumor that forms from more than one type of brain cell, usually astrocytes and oligodendrocytes.

Morbidity

A disease or the incidence of disease within a population. Morbidity also refers to adverse effects caused by a treatment.

Multicenter Study

A clinical trial that is carried out at more than one medical institution.

Mutation

Any change in the DNA of a cell. Mutations may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment. Mutations can be harmful, beneficial, or have no effect. If they occur in cells that make eggs or sperm, they can be inherited; if mutations occur in other types of cells, they are not inherited. Certain mutations may lead to cancer or other diseases.

Myelography

A medical procedure for examining the spinal cord by means of X rays. It is especially useful in diagnosing spinal abscesses and tumors and dislocated intervertebral disks.

Nerve

A bundle of fibers that receives and sends messages between the body and the brain. The messages are sent by chemical and electrical changes in the cells that make up the nerves.

Nervous System

The organized network of nerve tissue in the body. It includes the central nervous system (the brain and spinal cord), the peripheral nervous system (nerves that extend from the spinal cord to the rest of the body), and other nerve tissue.

Neural

Having to do with nerves or the nervous system, including the brain and the spinal cord.

Neuro-oncologist

A doctor who specializes in diagnosing and treating brain tumors and other tumors of the nervous system.

Neuroblastoma

Cancer that arises in immature nerve cells and affects mostly infants and children.

Neurologic

Having to do with nerves or the nervous system.

Neurological Exam

A series of questions and tests to check brain, spinal cord, and nerve function. The exam checks a person’s mental status, coordination, ability to walk, and how well the muscles, sensory systems, and deep tendon reflexes work.

Neurologist

A doctor who specializes in the diagnosis and treatment of disorders of the nervous system.

Neuron

A type of cell that receives and sends messages from the body to the brain and back to the body. The messages are sent by a weak electrical current. Also called nerve cell.

Neuropathologist

A pathologist who specializes in diseases of the nervous system. A pathologist identifies disease by studying cells and tissues under a microscope.

Neurosurgeon

A doctor who specializes in surgery on the brain, spine, and other parts of the nervous system.

Neurotoxicity

The tendency of some treatments to cause damage to the nervous system.

NIH

A federal agency in the U.S. that conducts biomedical research in its own laboratories; supports the research of non-Federal scientists in universities, medical schools, hospitals, and research institutions throughout the country and abroad; helps in the training of research investigators; and fosters communication of medical information. Also called National Institutes of Health.

NMRI

A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. NMRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. NMRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called nuclear magnetic resonance imaging.

Nodule

A growth or lump that may be malignant (cancer) or benign (not cancer).

Nonblinded

Describes a clinical trial or other experiment in which the researchers know what treatments are being given to each study subject or experimental group. If human subjects are involved, they know what treatments they are receiving.

Observational Study

A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).

Occipital brain tumor

A tumor in the area of or relating to the occipital lobe. The occipital lobe is the posterior lobe of each cerebral hemisphere that is separated medially from the parietal lobe by the parieto-occipital sulcus, is indistinctly separated more laterally from the temporal and parietal lobes, bears the visual areas, and has the form of a 3-sided pyramid.

Off-label

Describes the legal use of a prescription drug to treat a disease or condition for which the drug has not been approved by the U.S. Food and Drug Administration.

Oligo-astrocytoma

Also called a mixed glioma, an astrocytoma with a high proportion of oligodendroglioma cells.

Oligodendrocyte

A cell that forms the myelin sheath (a layer that covers and protects nerve cells) in the brain and spinal cord. An oligodendrocyte is a type of glial cell.

Oligodendroglial Tumor

A rare, slow-growing tumor that begins in oligodendrocytes (cells that cover and protect nerve cells in the brain and spinal cord). Also called oligodendroglioma.

Oligodendroglioma

May be subdivided into primary brain tumors and the more common, secondary brain tumors. Primary brain tumors (for example astrocytoma, craniopharyngioma, glioma, ependymoma, neuroglioma, oligodendroglioma, glioblastoma multiforme, meningioma, medulloblastoma) arise from the uncontrolled proliferation of cells within the brain. Secondary brain tumors occur from the spread of cancer into the brain from a distant cancerous organ (metastasis).

Oncogene

Gene that is a mutated (changed) form of a gene involved in normal cell growth. Oncogenes may cause the growth of cancer cells. Mutations in genes that become oncogenes can be inherited or caused by being exposed to substances in the environment that cause cancer.

Oncologists

A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.

Oncology

The study of cancer.

Oncolysis

The lysis (breakdown) of cancer cells. This can be caused by chemical or physical means (for example, strong detergents or high-energy sound waves) or by infection with a strain of virus that can lyse cells.

Open Label Study

A type of study in which both the health providers and the patients are aware of the drug or treatment being given.

Optic glioma

A slow-growing glioma of the optic nerve or optic chiasm heralded by visual loss, often with secondary strabismus followed by proptosis and loss of ocular movements.

Overall Survival Rate

The percentage of people in a study or treatment group who are alive for a certain period of time after they were diagnosed with or treated for a disease, such as cancer. The overall survival rate is often stated as a five-year survival rate, which is the percentage of people in a study or treatment group who are alive five years after diagnosis or treatment. Also called survival rate.

Papilloma

A benign tumor of epithelium. Warts (caused by papilloma virus) are the most familiar example and each is a clone derived from a single infected cell. The epithelim is the covering of internal and external surfaces of the body, including the lining of vessels and other small cavities. It consists of cells joined by small amounts of cementing substances. Epithelium is classified into types on the basis of the number of layers deep and the shape of the superficial cells.

Parietal lobes

The parietal lobes are found starting above the ear and spanning about three or four inches towards the back of the head on each side of the head. The parietal lobes can be divided into two functional regions. One involves sensation and perception and the other is concerned with integrating sensory input, primarily with the visual system. Individuals with damage to the parietal Damage to the left parietal lobe can result in right-left confusion, difficulty with writing (agraphia) and difficulty with mathematics (acalculia).

Petrous bone

Of, relating to, or constituting the exceptionally hard and dense portion of the human temporal bone that contains the internal auditory (hearing) organs and is a pyramidal process wedged in at the base of the skull between the sphenoid and occipital bones with its lower half exposed on the surface of the skull and pierced by the external auditory meatus (the canal leading from the opening of the external ear to the eardrum).

Positron Emission Tomography (PET)

A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body. Also called PET scan.

Prefrontal lobe

The anterior part of the frontal lobe that is made up chiefly of association areas, mediates various inhibitory controls, and is bounded posteriorly by the ascending frontal convolution.

Primary Brain Tumor

The original tumor of a cancer diagnosis. Cancer cells can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or the lymphatic system. This is how cancer spreads from the original (primary) tumor to form new tumors in other parts of the body.

Pseudo tumor

An enlargement that resembles a tumor. It may result from inflammation, accumulation of fluid or other causes, and may or may not regress spontaneously.

Pseudo tumor cerebri

Intracranial pressure, headaches of varying intensity, and papilledema without any demonstrable intracranial lesion and that tends to occur in overweight women from 20 to 50 years of age -- called also benign intracranial hypertension.

Radiation Oncologists

A doctor who specializes in using radiation to treat cancer.

Radiation Therapy

Radiation therapy (also called radiotherapy)uses high-energy radiation from x-rays, neutrons, and other sources to kill cancer cells and shrink tumors. It may come from a machine outside the body (external beam) or from materials that produce radiation that are placed in or near the tumor in the area where the cancer cells are found.

Radionuclide brain scintigraphy

Views capillaries feeding the tumor after highlighting them with a radioactive substance.

Sagittal

Of, relating to, or being the sagittal suture of the skull; or of, relating to, situated in, or being the median plane of the body or any plane parallel to it (a sagáitátal section dividing the body into unequal right and left parts).

Sagittal meningioma

A tumor of meningioma type, of, relating to, or being in area of the sagittal suture of the skull. Also, see meningioma.

Single-Photon Emission Computed Tomography (SPECT)

A special type of computed tomography (CT) scan in which a small amount of a radioactive drug is injected into a vein and a scanner is used to make detailed images of areas inside the body where the radioactive material is taken up by the cells. Single-photon emission computed tomography can give information about blood flow to tissues and chemical reactions (metabolism) in the body. Also called SPECT.

Spinal tap

A procedure in which a thin needle called a spinal needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give drugs. Also called lumbar puncture.

Spongioblastoma

A malignant tumor of the central nervous system and usually of a cerebral hemisphere -- called also glioblastoma.

Steroids

Synthetic anti-inflammatory compounds used to reduce the amount of swelling within brain, or other, tissue.

Subarachnoid hemorrhage

Subarachnoid hemorrhage: Bleeding within the head into the space between two membranes that surround the brain. The bleeding is beneath the arachnoid membrane and just above the pia mater. (The arachnoid is the middle of three membranes around the brain while the pia mater is the innermost one.) The subarachnoid space is a potential space. It is normally filled with cerebrospinal fluid. With a subarachnoid bleed, the cerebrospinal fluid in the subarachnoid space is bloody. Subarachnoid hemorrhages are typically acute (sudden). They may follow a head injury or rupture of a blood vessel in the central nervous system (brain and spinal cord) as, for example, because of an aneurysm in the vessel. Nearly half of people admitted to a hospital with a subarachnoid hemorrhage die within a month. Many of the survivors are left with severe disabilities. The first-degree relatives of patients with subarachnoid hemorrhage are more likely to develop the condition than those who do not have a family history of it. Smoking, alcohol abuse, and high blood pressure are risk factors for subarachnoid hemorrhage.

Subependymoma

An ependymoma in which there is a diffuse proliferation of subependymal fibrillary astrocytes among the ependymal tumor cells. A few are malignant and others cause obstructive hydrocephalus, but many are clinically silent and are discovered only at autopsy.

Swelling

Swelling is the enlargement of organs caused by accumulation of excess fluid in tissues, called edema. It can occur throughout the body (generalized), or a specific part or organ can be affected (localized). Swelling is considered one of the five characteristics of inflammation; along with pain, heat, redness, and loss of function. A body part may swell in response to injury, infection, or disease, as well as because of an underlying lump, or tumor in the case of brain disease. Generalized swelling, or massive edema (also called anasarca), is a common sign in severely ill people. Although slight edema may be difficult to detect to the untrained eye, especially in an overweight person, massive edema is very obvious. Brain edema is often treated with steroids, particularly Decadron. A newer drug, Xerecpt, is being tested. Some brain tumor patients use boswellia, a supplement, with some success. Severe brain edema is a serious condition that should be adequately controlled/treated.

Temporal Lobe

The lateral region of the cerebrum, below the lateral fissure. Within The temporal lobe of the brain is the center for smell, some association areas for memory and learning, and a region where choice is made of thoughts to express.

Tumor

1. Swelling, one of the cardinal signs of inflammation; morbid enlargement. 2. A new growth of tissue in which the multiplication of cells is uncontrolled and progressive. Also called neoplasm.

Tumor calcification

Calcification. The process by which organic tissue becomes hardened by a deposit of calcium salts within its substance.

Tumor Debulking

Surgical removal of as much of a tumor as possible. Tumor debulking may increase the chance that chemotherapy or radiation therapy will kill all the tumor cells. It may also be done to relieve symptoms or help the patient live longer. Also called debulking.

Tumor Infiltrating Lymphocyte

A white blood cell that has left the bloodstream and migrated into a tumor.

Tumor Initiation

A process in which normal cells are changed so that they are able to form tumors. Substances that cause cancer can be tumor initiators.

Tumor Load

Refers to the number of cancer cells, the size of a tumor, or the amount of cancer in the body. Also called tumor burden.

Tumor Lysis Syndrome

A condition that can occur after treatment of a fast-growing cancer, especially certain leukemias and lymphomas (cancers of the blood). As tumor cells die, they break apart and release their contents into the blood. This causes a change in certain chemicals in the blood, which may cause damage to organs, including the kidneys, heart, and liver.

Tumor Marker

A substance that may be found in tumor tissue or released from a tumor into the blood or other body fluids. A high level of a tumor marker may mean that a certain type of cancer is in the body. Examples of tumor markers include CA 125 (in ovarian cancer), CA 15-3 (in breast cancer), CEA (in ovarian, lung, breast, pancreas, and gastrointestinal tract cancers), and PSA (in prostate cancer).

Tumor Microenvironment

The normal cells, molecules, and blood vessels that surround and feed a tumor cell. A tumor can change its microenvironment, and the microenvironment can affect how a tumor grows and spreads.

Tumor Model

Cells, tissues, or animals used to study the development and progression of cancer, and to test new treatments before they are given to humans. Animals with transplanted human tumors or other tissues are called xenograft models.

Tumor Necrosis Factor

A protein made by white blood cells in response to an antigen (substance that causes the immune system to make a specific immune response) or infection. Tumor necrosis factor can also be made in the laboratory. It may boost a person’s immune response, and also may cause necrosis (cell death) of some types of tumor cells. Tumor necrosis factor is being studied in the treatment of some types of cancer. It is a type of cytokine. Also called TNF.

Tumor Promotion

A process in which existing tumors are stimulated to grow. Tumor promoters are not able to cause tumors to form.

Tumor Suppressor Gene

A type of gene that makes a protein called a tumor suppressor protein that helps control cell growth. Mutations (changes in DNA) in tumor suppressor genes may lead to cancer. Also called antioncogene.

Tumor Volume

The size of a cancer measured by the amount of space taken up by the tumor. For example, the tumor volume of prostate cancer is the percentage of the prostate taken up by the tumor.

Tumor-derived

Taken from an individual's own tumor tissue; may be used in the development of a vaccine that enhances the body's ability to build an immune response to the tumor.

Tumor-specific Antigen

A protein or other molecule that is unique to cancer cells or is much more abundant in them. These molecules are usually found in the plasma (outer) membrane, and they are thought to be potential targets for immunotherapy or other types of anticancer treatment.

Typical brain stem glioma

A brain stem glioma that infiltrates diffusely throughout the pons (the middle portion of the brain stem), sometimes spreading to the midbrain (the upper portion of the brain stem) or he medulla (the bottom portion of the brain stem). The term diffuse intrinsic pontine glioma is synonymous. By pathology, this tumor is most often a fibrillary astrocytoma or its higher grade counterparts (anaplastic astrocytoma and glioblastoma multiforme).

WHO grade

WHO stands for World Health Organization, the entity which developed the widely used and accepted classification system for brain tumors. Brain tumors are graded from low grade (grade I) to high grade (grade IV). The grade of a tumor refers to the way the cells look under a microscope. Cells from higher grade tumors are more abnormal looking and generally grow faster than cells from lower grade tumors; higher grade tumors are more malignant than lower grade tumors. Higher grade tumors may also be referred to as anaplastic, for example, an Anaplastic Astrocytoma is a grade III tumor. Because they are located in the brain, it is important to recognize that even a low grade brain tumor can be dangerous because, as a tumor in the brain grows, it presses upon normal brain tissues which can cause inflammation and brain swelling. It is therefore very important that both low and high grade tumors be treated as early as possible, even if the treatment is only serial MRIs for low grade tumors.

X-knife

A device which radiates small areas of the brain. The x-knife can focus radiation therapy to a specific small area. Use of this type of radiation therapy allows a patient to receive radiation in smaller doses on repeated occasions and to be treated for tumors that are very close to very critical structures such as the visual nerves, which are sensitive to radiation. The x-knife is often used to remove pieces of the tumor left behind during surgery.

X-ray therapy

A type of radiation therapy that uses high-energy radiation from x-rays to kill cancer cells and shrink tumors.

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