Brain Tumor Glossary of Terms

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

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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.