Glossary of Cancer Terms

Cancer-related definitions and medical terminology

Below are many of the terms most commonly used in the field of cancer treatment.

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radiation oncologist

Radiation oncologists are physicians with specialized training in cancer treatment who use radiation therapy to destroy cancer. Scripps radiation oncologists use advanced radiation techniques, such as intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery (SRS) to target cancer cells while minimizing radiation exposure to nearby healthy tissues and organs. Learn more about radiation therapy and our cancer care team.

radiation therapist

Radiation therapists are licensed professionals who administer radiation treatments prescribed by a radiation oncologist. They also handle daily treatment schedules, monitor radiation treatment, maintain patient records and perform regular quality assurance reviews on equipment. Learn more about radiation therapy and our cancer care team.

radiation therapy

Used in cancer treatment, radiation therapy utilizes invisible forms of high-energy such as X-rays, gamma rays and charged particles to eliminate tumors and cancer cells. Radiation is harnessed and targeted to damage the DNA of cancer cells — either directly or through the creation of charged particles known as free radicals that attack cancer cells. The two main categories of radiation therapy are external-beam radiation therapy, in which doses are delivered through powerful, flexible and fast equipment outside the body, and internal radiation therapy, most commonly called brachytherapy, in which radioactive substances are either temporarily or permanently placed inside the body near a cancerous tumor. Learn more about radiation therapy.

radical nephrectomy

Radical nephrectomy involves the surgical removal of the entire kidney along with nearby lymph nodes, adrenal gland and surrounding tissues.

radical prostatectomy

Used in treating prostate cancer, radical prostatectomy (prostate removal) is surgery to remove all of the prostate gland and some of the tissue around it. 

radical retropubic prostatectomy

Radical retropubic prostatectomy is an “open” surgery in which a single incision is made to access the prostate gland through the wall of the abdomen. This surgical approach has been largely replaced by minimally invasive surgical procedures.

radioactive iodine therapy

Radioactive iodine (RAI) therapy is a type of radiation treatment sometimes used in treating thyroid cancer. It involves the use of radioactive iodine, usually given by mouth, to kill any remaining thyroid cancer cells that have not been surgically removed. Because only the thyroid absorbs iodine, radioactive iodine can kill cancer cells without harming healthy tissue. Learn more about this type of systemic radiation therapy.

radiofrequency ablation (RFA)

Used to treat cancer by interventional radiologists, radiofrequency ablation is a minimally invasive procedure that uses an electric current to heat and destroy cancer cells.

radioiodine scan

Used in diagnosing thyroid cancer, a radioiodine scan involves the use of radioactive iodine that is swallowed or injected into a vein, and absorbed by the thyroid gland. A camera tracks where the radioactivity is. Because medullary thyroid cancer does not absorb iodine, this test is used only for other thyroid cancer types.

rectal cancer

Often called colorectal cancer, rectal cancer is an intestinal cancer that starts when cells lining the rectum begin to grow out of control. While colon cancer may also be called colorectal cancer, with rectal cancer, the cancerous cells develop in the lower six inches of the colon (also called the large intestine). Rectal cancer usually begins as a growth called a polyp on the inner lining of the rectum. 

renal cell carcinoma (RCC)

About 90 percent of kidney cancers are renal cell carcinomas (RCC), also known as renal cell cancer or renal cell adenocarcinoma. RCC usually beings as a single tumor in one kidney, but in some cases there may be multiple tumors in one or both kidneys. Learn more about kidney cancer.

renal sarcoma

Renal sarcoma is a rare type of kidney cancer that starts in the blood vessels or connective tissue. Learn more about kidney cancer.

resectable cancer

Resectable cancer is a designation given when surgery may be a possibility for removing all of the cancer when tumors are detected early and the rest of the organ, such as the stomach in cases of stomach cancer, is in good health. 

retroperitoneal sarcoma

Retroperitoneal sarcoma is a rare subtype of soft tissue sarcoma that can develop within the abdominal cavity directly against the perineum. Most patients will need surgery to remove the tumor and surrounding tissue that may be affected. Chemotherapy and radiation also may be part of treatment. Learn more about retroperitoneal sarcoma in our section on sarcoma and bone cancer.

rigid proctosigmoidoscopy

Used in diagnosing certain types of cancer such as anal cancer, this procedure allows the physician to examine the anus and lower rectum with a lighted tube.

robotic radical prostatectomy

Robotic radical prostatectomy is a minimally invasive surgery to remove the entire prostate. The procedure is performed with a robotic tool through small incisions, the use of a magnified 3-D high-definition vision system and tiny, highly maneuverable instruments that provide surgeons greater range of mobility and dexterity than their own human hands and wrists. The robot’s movements are completely controlled by the urologic surgeon.