Radiation therapy uses high-energy rays to stop cancer cells from growing and dividing. It is a local treatment aimed at killing, controlling or easing symptoms of visible tumors. Two avenues of treatment include external beam radiation and brachytherapy (internal radiation).
External beam radiation technology has improved with the advent of Intensity Modulated Radiation Therapy (IMRT), a type of conformal radiation that shapes the radiation beams to closely approximate the shape of the tumor. The intensity of the radiation in IMRT can be changed during treatment to deliver increased doses of radiation to the tumor while sparing more adjoining normal tissue than is possible during conventional radiation therapy.
Brachytherapy, sometimes called seed implantation, is best known for prostate cancer seed implants. It was used for decades for other types of cancer including cervical, thyroid and endometrial as well as coronary artery disease. Mammosite for some Stage I breast cancer patients uses a newer type of brachytherapy that places radioactive fluid in a small balloon on the tip of a thin rod inserted after a lumpectomy. For five days, twice a day, the fluid is injected into the balloon, left there for a few minutes and removed. The FDA approved this 5-day procedure when survival results equaled those of external beam radiation for six weeks.
Radiation side effects depend on the tumor site. Fatigue and sunburn-like skin changes are two of the most frequent complaints. Colorectal patients may experience diarrhea, cramping or nausea. Depending on the tumor location, radiation also can affect fertility changes and sexuality. A rare long-term side effect is the small risk years later of a secondary tumor at the radiation site, which is why follow-up care is important. Some patients who received chest radiation for Hodgkin’s lymphomas as children are developing breast cancer in their adult years.