Radiation therapy is a commonly used tool to treat many types of cancer. It may be used as the only therapy or it is sometimes given in combination with surgery or chemotherapy.  The goal of radiation treatment is to deliver high doses of radiation to cancer cells while limiting injury to surrounding normal tissues.

Fortunately, in contrast to cancer cells, normal cells have the capacity to repair themselves after radiation so long as they are not exposed to too much radiation at once. This is the reason for radiation therapy being given over several weeks rather than all at once.  The  regenerative characteristic of normal cells, coupled with improvements in techniques to target the cancer and limit the dose to normal tissue, has ushered in a modern era of radiation therapy with excellent cancer cure rates and limited complications.

In the case of prostate cancer, radiation treatments must be administered in a way that adequately covers the entire prostate with an accurate, effective dose of radiation. This is challenging due to the fact that prostates are irregularly shaped and varying in size.  Inadequate or inaccurate treatment will lead to survival of cancer cells in the prostate (termed “local failure”) or excessive dose to normal tissues such as a the hip bones, bladder, urethra, rectum, and nerve bundles which are involved in normal urinary, bowel, and sexual function and lie in close proximity to the prostate gland.

Radiation can be delivered to the prostate from the outside which is called External Beam Radiation, or by implanting radioactive sources within the prostate, called Brachytherapy.  Depending on the aggressiveness and stage of the cancer, either approach may be preferred and sometimes the two approaches are combined.