RAD (dose of radiation)
The Rad (radiation absorbed dose) measures the amount of radiation absorbed by body tissue. The rad has been replaced by the Gray (Gy); 1 Gy is equal to 100 Rad.
Radiation Oncologist
A doctor who specializes in using radiation to treat cancer.
Radiation Therapy (Radiotherapy)
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 (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy or brachytherapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body.
Radical Mastectomy (Halsted Radical)
Surgical removal of the breast, chest muscles and underarm lymph nodes. Used only when the breast tumor has spread to the chest muscles.
Radiologist
A doctor with special training interpreting (reading) x-rays and other types of imaging studies that make pictures of the inside of the body.
Radiotherapy (see Radiation Therapy in R)
Raloxifene
The active ingredient in a drug used to lower the risk of invasive breast cancer in postmenopausal women who are at high risk of breast cancer or who have osteoporosis (bone thinning). It is also used to prevent and treat osteoporosis in postmenopausal women. Raloxifene blocks the effects of the hormone estrogen in breast tissue which may help keep breast cancer cells from growing. It may keep bones from breaking down. It is also being studied to see if it can prevent breast cancer in premenopausal women. Raloxifene is a type of selective estrogen receptor modulator (SERM).
Reconstruction (see Breast Reconstruction in B)
Recurrence (Relapse)
Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected. The cancer may come back to the same place as the original (primary) tumor or to another place in the body. Also called recurrent cancer.
Regimen
A treatment plan that outlines the specific doses, schedule and length of treatment which may include different medicines as well as other methods such as radiation treatments.
Regional Lymph Nodes
The spread of cancer from its primary (original) site to nearby lymph nodes, organs or tissues, but not to distant sites. In breast cancer, the axillary (in the underarm area) lymph nodes, infraclavicular (under the collarbone) lymph nodes, supraclavicular (above the collarbone) lymph nodes and internal mammary nodes. See Lymph Nodes in L.
Regression
Decrease (shrinking) in the size of a tumor or the amount of the cancer in the body.
Relative Risk
A measure of the risk of a certain event happening in one group compared to the risk of the same event happening in another group. In cancer research, relative risk is used in prospective (forward looking) studies, such as cohort studies and clinical trials. A relative risk of one means there is no difference between two groups in terms of their risk of cancer, based on whether or not they were exposed to a certain substance or factor, or how they responded to two treatments being compared. A relative risk of greater than one or of less than one usually means that being exposed to a certain substance or factor either increases (relative risk greater than one) or decreases (relative risk less than one) the risk of cancer, or that the treatments being compared do not have the same effects. Also called risk ratio.
Relative Survival Rate
A way of comparing the survival of people who have a specific disease with those who don’t, over a certain period of time. This is usually five years from the date of diagnosis or the start of treatment for those with the disease. Relative survival rates are usually given as a percentage. For instance, if the 5-year relative survival rate of a certain type of cancer is 50%, it means that people with this cancer are half (50%) as likely to still be alive 5 years after their diagnosis, as compared to people without this cancer.
Risk (of disease)
Probability (chance) of disease developing in a person during a specified time period.
Risk-Benefit Ratio
The relationship between the possible (or expected) side effects and benefits of a treatment or procedure.
Risk Factor
Anything that increases the chance of getting a disease such as cancer. Different cancers have different risk factors. For example, unprotected exposure to strong sunlight is a risk factor for skin cancer; smoking is a risk factor for lung, mouth, throat, and other cancers. Some risk factors, such as smoking and being physically inactive, can be controlled. Others, like a person’s age and gene mutations they were born with, can’t be changed.