Understanding Cancer Terminology

Published: April 28, 2008

Acute: Symptoms or signs that begin and worsen quickly; not chronic.

Adenocarcinoma: Cancer that begins in cells that line certain internal organs and that have gland-like (secretory) properties.

Adjuvant therapy: Treatment given after the primary treatment to increase the chances of a cure. May include chemotherapy, radiation therapy, hormone therapy or biological therapy.

Advanced cancer: Cancer that has spread to other parts of the body and usually can’t be cured or controlled with treatment.

Allogeneic bone marrow transplantation: A procedure in which a person receives blood-forming stem cells from a genetically similar donor.

Analgesic: A drug that reduces pain.

Angiogenesis: Blood vessel formation. Tumors release chemicals that form new blood vessels needed for growth.

Antibody therapy: Treatment with an antibody, a substance that can directly kill tumor cells or stimulate the immune system to kill tumor cells.

Antiemetic: A drug that prevents or reduces nausea and vomiting.

Antihormone therapy: Treatment with drugs, surgery or radiation to block the production or action of a hormone. May be used in cancer treatment because certain hormones stimulate tumor growth.

Antioxidant: A substance that protects cells from the damage caused by free radicals, which may play a part in cancer, heart disease, stroke and other diseases of aging.

Basal cell carcinoma: A type of cancer that arises from small, round cells found in the lower part of the outer layer of skin.

Benign: Not cancerous; tumors may grow large but don’t spread to other parts of the body.

Biological therapy: Treatment to boost or restore the ability of the immune system to fight cancer and other diseases.

Biopsy: The removal of cells or tissues for examination by a pathologist.

Brachytherapy: Radiation therapy in which sealed radioactive material is placed directly into or near a tumor.

Cancer: A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer: Carcinoma, sarcoma, leukemia, lymphoma and myeloma, and central nervous system cancers.

Carcinogen: Any substance that causes cancer.

Carcinoma: Cancer that begins in the skin or tissues that line or cover internal organs.

Catheter: A flexible tube used to deliver fluids into or withdraw fluids from the body.

Chemotherapy: Treatment with drugs that kill cancer cells.

Clinical trial: A type of research study that tests how well new medical procedures work in people.

Core biopsy: The removal of a tissue sample with a wide needle for examination under a microscope.

Differentiation: In cancer, refers to how mature (developed) the cancer cells are in a tumor.

Dosimetry: Measurement of radiation exposure from X-rays, gamma rays and other types of radiation used in the treatment of cancer and other diseases.

Ductal carcinoma: The most common type of breast cancer. It begins in the cells that line the milk ducts in the breast.

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

Fine-needle aspiration biopsy: Removal of tissue or fluid with a thin needle for examination under a microscope.

Gene therapy: Treatment that alters a gene.

Grade: The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Differs among cancers.

Hospice: A program that provides special care for people who are near the end of life, and their families.

IMRT: Intensity-modulated radiation therapy uses computer-generated images to direct thin beams of radiation of different intensities at a tumor from various angles.

Incisional biopsy: A surgical procedure in which a portion of a lump or suspicious tissue is removed for diagnosis.

Institutional review board: A group that reviews the action plans for clinical trials. Ensures trials are legal, ethical and don’t involve unnecessary risks.

Investigational: In clinical trials, refers to a drug or procedure that has received Food and Drug Administration approval for testing in human subjects. Can also describe a drug or procedure approved for one disease but considered for another.

Leukemia: Cancer that starts in the blood-forming tissue such as bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.

Local cancer: An invasive malignant cancer confined entirely to the area where the cancer began.

Low grade: Describes cells that look nearly normal under a microscope.

Lung cancer: Cancer that forms in the tissues of the lungs, usually in the cells lining the air passages. The two main types are small cell and non-small cell lung cancer. The three main types of non-small cell lung cancer are squamous cell carcinoma, large cell carcinoma and adenocarcinoma.

Lymphoma: Cancer that begins in the cells of the immune system. There are two basic categories of lymphomas: Hodgkin lymphoma and non-Hodgkin lymphoma.

Malignancy: A cancerous tumor that can invade and destroy nearby tissue and spread to other parts of the body.

Mammogram: An X-ray of the breast.

Margin: The edge or border of tissue removed in cancer surgery. The margin is described as negative or clean when the pathologist finds no cancer cells at the edge of the tissue.

Mastectomy: Surgery to remove the breast.

Melanoma: A type of cancer that begins in the cells that make the pigment melanin. It may begin as a skin mole but also may begin in other pigmented tissues such as in the eyes.

Mesothelioma: A benign of malignant tumor affecting the lining of the chest or abdomen. Exposure to asbestos particles increases the risk of developing mesothelioma.

Metastasis: The spread of cancer from one part of the body to another. The metastatic tumor contains cells that are like those in the original tumor.

Molecularly targeted therapy: Substances that kill cancer cells by targeting key molecules involved in cancer cell growth.

Morphine: A narcotic drug used in the treatment of pain.

Myeloma: Cancer that arises in plasma cells, a type of white blood cell.

Neoplasia: Abnormal and uncontrolled cell growth.

Oncogene: A gene that normally directs cell growth. If altered, an oncogene can promote or allow the uncontrolled growth of cancer.

Oncologist: A doctor who specializes in treating cancer.

Opiate: A drug used to treat pain. It contains opium or a substance made from opium such as morphine.

Ovarian cancer: Cancer that forms in the tissues of the ovaries. Most ovarian cancers begin in the surface cells of the ovaries or in egg cells.

Palliative care: Activities that ease the symptoms of a disease or the side effects from treatment of a disease. It is not intended to cure the disease.

Pap smear: A procedure in which cells are scraped from the cervix for examination under a microscope. It is used to detect cancer and changes that may lead to cancer.

Pathologist: A doctor who identifies diseases by studying cells and tissues under a microscope.

PET scan: Positron emission tomography scan works by tracking tumor cells’ use of radioactive sugar.

Polyp: A growth that protruded from a mucous membrane.

Precancerous: Used to describe a condition that may (or is likely) to become cancer.

Primary tumor: The original tumor.

PSA test: Prostate-specific antigen tests measure a level of a prostate-produced substance that may be a sign of cancer.

Radiation therapy: The use of high-energy radiation from x-rays, gamma rays, neutrons, protons and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body or from radioactive material placed inside the body.

Radiologist: A doctor who specializes in creating and interpreting pictures of areas inside the body.

Remission: A decrease in or disappearance of the signs or symptoms of cancer. Cancer, however, may still be in the body.

Resection: A procedure that uses surgery to remove tissue or part or all of an organ.

Sarcoma: A cancer of the bone, cartilage, fat, muscle, blood vessels or other connective or supportive tissue.

Scan: A picture of structures inside the body. Scans are used in diagnosing, staging and monitoring diseases. The include CT (computed tomography) and MRI (magnetic resonance imaging). CT scans use an X-ray machine that is linked to a computer that produces detailed pictures of organs inside the body. MRI scans use a large magnet connected to a computer that produces pictures of areas inside the body.

Secondary cancer: Describes either a new primary cancer or a cancer that has spread from the place it began.

Sentinel lymph node: The first lymph node from which cancer is likely to spread from the primary tumor. Cancer may appear first in the sentinel lymph node before spreading to other lymph nodes.

Skin cancer: Cancer that forms in the tissues of the skin. Skin cancer types include melanoma, basal cell carcinoma and squamous cell carcinoma.

Solid tumor: An abnormal mass of tissue that does not contain cysts or liquid areas.

Squamous cell carcinoma: Cancer that begins in squamous cells, which are thin, flat cells that look like fish scales and forms on the surface of the skin, the lining of hollow organs of the body, and the passages of the respiratory and digestive tracts.

Stage: The extent of cancer in the body. Usually based on tumor size, whether the cancer has spread and whether lymph nodes are involved.

Tumor: An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Also called neoplasm.

National Cancer Institute

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