Radiation Oncology

During your treatment for cancer, you are likely to encounter unfamiliar words and terms. To help your understanding of procedures and treatments, we created this glossary.

Adjuvant therapy (ad-ju-vant): Treatment that is added to increase the effectiveness of a primary therapy.

Atypical (a-tip-i-kal): Unusual or different, out of the ordinary.

Biopsy (BY-op-see): The removal of a sample of tissue that is looked at under a microscope to see if cancer cells are present. Biopsy is the most important procedure in diagnosing cancer.

Cancer: A general term for a large group of diseases (more than 100), all characterized by uncontrolled growth and spread of abnormal cells. Cancer cells are abnormal and eventually form tumors that invade and destroy surrounding tissue; they may even spread via they lymph system or bloodstream to distant areas of the body.

Carcinoma (kar-son-O-ma): A form of cancer that develops in tissues covering or lining organs of the body, such as the skin, the uterus, the lung or the breast.

Clinical trial: A study conducted with cancer patients, usually to evaluate anew treatment. Each study is designed to answer scientific questions and to find better ways to treat patients.

Diagnosis (di-ag-NO-sis): The process of indentifying a disease by its characteristics signs, symptoms and laboratory findings.

Dosimetirst (doh-SIM-i-trist): A person who plans and calculates the proper radiation dose for treatment.

Electrons (e-LEK-trons): High energy particles produced by a linear accelerator whose depth of penetration is related to their energy. Electrons are usually used to treat cancers near the surface of the body.

External radiation therapy: Radiation therapy whose source is outside the body. Patient receiving external radiation therapy usually lies underneath a linear accelerator or other source of radiation.

Five-year survival: A term commonly used as the statistical basis for successful treatment.

Internal radiation therapy: A procedure in which the physician places radioactive material directly into the area to be treated. This is referred to as brachytherapy treatment. It is sealed in a container and inserted into a body cavity, placed directly into the tissue, given orally or injected.

Linear accelerator: A machine that produces and uses high energy x-rays or electrons to treat cancer.

Lymph nodes (limf nodes): Small, bean-shaped organs which are part of the body's normal immune system. Lymph nodes are a potential site into which cancer cells spread. They may also be referred to as lymph glands.

Lymphatic system (lim-FAT-ik): The tissues and organs (including the bone marrow, spleen, thymus, and lymph nodes) which produce and store cells that fight infection and the channels that carry lymph fluid.

Malignant tumor (ma-LIG-nant): A mass of cancer cells.

Metastasis (me-TAS-ta-sis): The spread of cancer cells to distant areas of the body by way of the lymph system or bloodstream. Cells in the metastatic tumor (second tumor) are like those in the original cancer.

Neoplasm (ne-o-plazm): Any new abnormal growth. Neoplasms may be benign or malignant, but the term is generally used to describe a cancer.

Remote afterloader: A special machine that delivers a radioactive source through tubes directly into the cancer tissue.