Shorter radiation course stops cancer growth in high-risk prostate cancer patients

Hypofractionated radiation treatment, a newer type of radiation treatment that delivers higher doses of radiation in fewer treatments than conventional radiation therapy, is significantly more effective in stopping cancer from growing in high risk patients, compared to receiving standard radiation treatment, according to a study presented November 4, 2009, at the 51st Annual Meeting of the American Society for Radiation Oncology (ASTRO). In addition, findings show there is no increased risk of negative side effects later in patients who undergo hypofractionated radiation. "The study not only shows that hypofractionated radiation improves the control of prostate cancer, but it also cuts the number of treatment visits in half for patients. This is an important benefit for these high-risk patients, who are typically an older, less mobile population," Giorgio Arcangeli, M.D., lead author of the study and a radiation oncologist at the Regina Elena National Cancer Institute in Rome, Italy said. "It's also especially helpful for those living at long distance from radiation treatment centers."

All men in the study were treated with three-dimensional conformal radiation therapy, or 3D-CRT. It is a type of external beam radiation therapy that uses computers and special imaging techniques to show the size, shape and location of the tumor as well as surrounding organs to precisely tailor the radiation beams to the size and shape of the tumor. Because the radiation beams are very precisely directed, nearby normal tissue receives less radiation and is able to heal more quickly.

During external beam radiation therapy, a beam of radiation is directed through the skin to the cancer and the immediate surrounding area in order to destroy the main tumor and any nearby cancer cells.

From January 2003 to December 2007, a total of 168 high risk prostate cancer patients were randomized to receive either hypofractionated or conventional schedules of 3D-CRT to the prostate and surrounding area. Patients who received hypofractionated radiation had only 20 sessions of radiation (four weeks of daily radiation therapy treatments), instead of the 40 to 45 (eight to nine weeks of daily treatments) sessions typically required during standard radiation treatment.

Study findings show that the patients treated with hypofractionated radiation had a better chance (87 percent vs. 79 percent) that their cancer would stop growing, compared to patients treated with standard radiation therapy. There was also no difference in the late side effects of genito-urinary and gastro-intestinal function between the two groups of patients.

"Studies are in progress to test the benefits of even shorter treatment schedules," Dr. Arcangeli said.

Source: American Society for Radiation Oncology