What the words mean, in the NCI’s own definitions.

Copied from the NCI Dictionary of Cancer Terms. Long entries stop at a sentence break, marked “…”; the full entry is on cancer.gov.

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Benign: Not cancer. Benign tumors may grow larger but do not spread to other parts of the body. Also called nonmalignant.
Biomarker testing: A laboratory method that uses a sample of tissue, blood, or other body fluid to check for certain genes, proteins, or other molecules that may be a sign of a disease or condition, such as cancer. …
Biopsy: The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. …
Chemotherapy: Treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. …
Clinical trial: A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.
Complete remission: The disappearance of all signs of cancer in response to treatment. This does not always mean the cancer has been cured. Also called complete response.
Immunotherapy: A type of therapy that uses substances to stimulate or suppress the immune system to help the body fight cancer, infection, and other diseases. …
Informed consent: A process in which patients are given important information, including possible risks and benefits, about a medical procedure or treatment, genetic testing, or a clinical trial. This is to help them decide if they want to be treated, tested, or take part in the trial. …
Malignant: A term used to describe cancer. Malignant cells grow in an uncontrolled way and can invade nearby tissues and spread to other parts of the body through the blood and lymph system.
Metastasis: The spread of cancer cells from the place where they first formed to another part of the body. … The new, metastatic tumor is the same type of cancer as the primary tumor.
Oncologist: A doctor who has special training in diagnosing and treating cancer. Some oncologists specialize in a particular type of cancer treatment. …
Palliative care: Care given to improve the quality of life and help reduce pain in people who have a serious or life-threatening disease, such as cancer. … Palliative care may be given with other treatments from the time of diagnosis until the end of life.
Pathology report: The description of cells and tissues made by a pathologist based on microscopic evidence, and sometimes used to make a diagnosis of a disease.
Placebo: An inactive substance or other intervention that looks the same as, and is given the same way as, an active drug or treatment being tested. …
Prognosis: The likely outcome or course of a disease; the chance of recovery or recurrence.
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. …
Recurrence: Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected. …
Remission: A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some, but not all, signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although cancer still may be in the body.
Second opinion: In medicine, the opinion of a doctor other than the patient’s current doctor. The second doctor reviews the patient’s medical records and gives an opinion about the patient’s health problem and how it should be treated. …
Side effect: An effect of a drug or other type of treatment that is in addition to or beyond its desired effect. Side effects can be harmful or beneficial, and most go away on their own over time. …
Stage: The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.
Standard of care: Treatment that is accepted by medical experts as a proper treatment for a certain type of disease and that is widely used by health care professionals. Also called best practice, standard medical care, and standard therapy.
Survival rate: The percentage of people in a study or treatment group who are still alive for a certain period of time after they were diagnosed with or started treatment for a disease, such as cancer. …
Targeted therapy: A type of treatment that uses drugs or other substances to target specific molecules that cancer cells need to survive and spread. …

National Cancer Institute NCI Dictionary of Cancer Terms Definitions as published on the reading date

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