Radiation therapy uses high-energy rays to kill cancer cells. Like surgery, radiation therapy is a local therapy, meaning it affects cancer cells only in the treated area. Radiation therapy to the prostate gland can be either external or internal.
External beam radiation therapy is given in a radiation oncology center by specially trained radiation oncologists, usually on an outpatient basis. Prior to treatment, a provider will mark the part of the body that is to be treated with a special pen. The radiation is delivered to the prostate gland using a device that resembles a normal x-ray machine. The treatment itself is generally painless. External beam radiation therapy is usually done five days a week for six to eight weeks.
Internal radiation therapy places radioactive seeds inside of the patient, directly in or near the tumor. This is called brachytherapy. A surgeon makes a small incision in the area to inject the tiny seeds. Because internal radiation therapy is directed to the prostate, it reduces damage to the tissues surrounding the prostate.
Radiation is sometimes used for pain relief when cancer has spread to the bone.