(pa-THOL-o-jist): A doctor who identifies diseases by studying cells and tissues under a microscope.

(fo-toe-dye-NAM-ik): Treatment with drugs that become active when exposed to light and kill cancer cells.

: A surgeon who specializes in reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases.

(pre-KAN-ser-us): A term used to describe a condition that may (or is likely to) become cancer. Also called premalignant.

(prog-NO-sis): The likely outcome or course of a disease; the chance of recovery or recurrence.

(ray-dee-AY-shun): The use of high-energy radiation from x-rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from material called radioisotopes. Radioisotopes produce radiation and can be placed in or near a tumor or near cancer cells. This type of radiation treatment is called internal radiation therapy, implant radiation, or brachytherapy. Systemic radiation therapy uses a radioactive substance such as a radiolabeled monoclonal antibody that circulates throughout the body. Also called radiotherapy.