Brain Tumor Glossary of Terms

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


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


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.


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.


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.


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.


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.


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.


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.


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.


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


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


A person who determines the proper radiation dose for treatment.


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


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.


A bad taste in the mouth. Also called parageusia.


Upset stomach.


Difficulty swallowing.


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


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


Difficult, painful breathing or shortness of breath.