Cancer Terms

Adenocarcinoma: Cancer that starts in the glandular tissue, such as in the ducts or lobules of the breast or in the gland cells of the prostate.

Adjuvant therapy: Treatment used in addition to the main treatment. It usually refers to treatment after surgery to increase the chances of curing the disease or keeping it in check.

Angiogenesis: The formation of new blood vessels. Some cancer treatments work by blocking angiogenesis, thus preventing blood from reaching the tumor.

Antigen: A substance that can cause the body’s immune system to respond. This response often involves making antibodies. For example, the immune system’s response to antigens that are part of bacteria and viruses helps people resist infections. Certain cancer cells have antigens that can be found by lab tests. They are important in cancer diagnosis and in watching response to treatment. Other cancer cell antigens play a role in immune reactions that could help the body’s resistance against cancer.

Benign tumor: An abnormal growth that is not cancer and does not invade into nearby tissues or spread to other areas of the body.

Biopsy: The removal of a sample of tissue to see whether cancer cells are present.

Brachytherapy: Internal radiation treatment given by placing a radioactive source directly into the tumor or close to it.

Carcinoma: A malignant tumor that begins in the lining layer (epithelial cells) of organs.

Chemotherapy: Systemic treatment with drugs to inhibit cancer cell division. Chemotherapy is often used with surgery or radiation to treat cancer when the cancer has spread, when it has come back (recurred) or when there is a strong chance it could recur.

Clinical trials: Research studies that test new drugs or treatments and compare them with current standard treatments. Before a new treatment is used on people, it is studied in the lab. If lab studies suggest the treatment works, it is tested on human volunteers. These human studies are called clinical trials.

Cytokine: A protein made by certain cells that affect the immune system and can stimulate immunity or slow it down.

DNA (deoxyribonucleic acid): The genetic “blueprint” found in the nucleus of each cell. DNA holds genetic information for proteins involved in cell structure, growth and function.

Enzyme: A protein that starts, helps or speeds up the rate of chemical reactions in living cells.

Gene: A segment of DNA that contains information on hereditary characteristics, such as hair color, eye color and height, as well as susceptibility to certain diseases.

Genetic testing: Tests performed to determine whether a person has certain gene changes known to increase the risk of cancer or other diseases.

Growth factors: Naturally occurring proteins that help cells grow and divide. Some cancer cells are too sensitive to growth factors, which helps them grow quickly.

Hereditary cancer syndrome: Conditions associated with cancers that occur in several family members because of an inherited, mutated gene.

Hormone therapy: Treatment with drugs that interfere with hormone production or hormone action, or the surgical removal of hormone-producing glands. Hormone therapy can help kill or slow the growth of cancer cells that depend on hormones to grow.

Immunotherapy: Treatments that promote or support the body’s immune system response to a disease such as cancer.

Leukemia: Cancer of the blood or blood-forming organs. People with leukemia often have a noticeable increase in white blood cells (leukocytes).

Localized (or local) cancer: A cancer that is confined to the organ where it started; that is, it has not spread to distant parts of the body.

Lymph nodes: Small bean-shaped collections of immune system tissue, such as lymphocytes, found along lymphatic vessels. They remove cell waste, germs and other harmful substances from the lymph. They help fight infections and also have a role in fighting cancer, although cancers sometimes spread through the lymph system.

Lymphoma: A cancer of the immune system cells called lymphocytes (a type of white blood cell). It often affects the lymphatic system, a network of thin vessels and nodes throughout the body. The two main types of lymphoma are Hodgkin and non-Hodgkin.

Malignant: A mass of cancerous cells that invade nearby tissues or spread (metastasize) to distant areas of the body.

Metastasis: The spread of cancer cells to one or more sites elsewhere in the body, often by way of the lymph system or bloodstream. Regional metastasis is cancer that has spread to the lymph nodes, tissues or organs close to the primary site. Distant metastasis is cancer that has spread to organs or tissues that are farther away (such as when prostate cancer spreads to the bones, lungs or liver).

Mutation: A change in the DNA of a cell. Cancer is thought to be due to changes in a cell’s DNA. Most mutations happen after the person is born.

Neoadjuvant therapy: Systemic and/or radiation treatment given before the main treatment to shrink a tumor.

Palliative treatment: Treatment that relieves symptoms, such as pain, but is not expected to cure the disease. Its main purpose is to improve the patient’s quality of life.

Pathologist: A doctor who specializes in diagnosis and classification of diseases by lab tests such as examining tissue under a microscope. The pathologist determines the specifics of a diagnosis.

Radiation therapy: Treatment with high-energy rays (ionizing energy, such as X-rays) or particles to kill or shrink cancer cells. The radiation can come from outside of the body (external radiation) or from radioactive materials placed directly in or near the tumor (brachytherapy or internal radiation).

Recurrence: The return of cancer after treatment. Local recurrence means that the cancer has come back in the same location as the original cancer. Regional recurrence means that the cancer has come back after treatment in the nearby tissues or lymph nodes near the primary site. Distant recurrence occurs when cancer comes back in distant organs or tissues after treatment.

Remission: Complete or partial disappearance of the signs and symptoms of cancer in response to treatment. A remission might not be a cure.

Sarcoma: A malignant tumor that starts in connective tissues, such as cartilage, fat, muscle or bone.

Standard therapy: The most commonly used and widely accepted form of treatment that has been tested and proven.

Stem cell transplantation: A procedure used to restock stem cells in the bone marrow when they have been destroyed by chemotherapy, radiation or disease. Stem cells can be the patient’s own (autologous) or can come from someone else (allogeneic). Bone marrow transplantations were the first method for replacing stem cells.

Targeted therapy: Treatment to attack the part of cancer cells that make them different from normal cells. Targeted agents tend to have different side effects than conventional chemotherapy drugs.