Hypofractionated 3D-Conformal RT

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 than the older method in stopping cancer growth in high risk patients and causes no increase in negative side effects, an Italian clinical trial shows.

“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.”

Dr. Arcangeli presented the trial findings November 4, 2009 in Chicago at the 51st Annual Meeting of the American Society for Radiation Oncology (ASTRO).

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, Dr. Arcangelli says.

Effect of hyperfractionated radiation on the rectal wall was investigated earlier in a Phase 2 trial (see links below). For 6 months that study followed 114 patients radiated for localized prostate cancer and concluded that “The similar rate of late toxicity in the two arms seems to indicate the feasibility of hypofractionated regimes in prostate cancer.” There was a difference of under 3% in the number of cases of rectal wall side effects reported by these patients and confirmed by the physicians.

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

Sources & Links to Related Material

A summary of the trial, “A Phase III Randomized Study Of High Dose Conventional Vs Hypofractionated Radiotherapy In Patients With High Risk Prostate Cancer,” was presented on Wednesday, November 4, 2009.

For more information on radiation therapy for prostate cancer, visit www.rtanswers.org.

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Dr. Giorgio Arcangeli and colleagues recently published results from a Phase 2 trial comparing rectal side effects from hyperfracationated and standard EBR. This report is available in full free text online:

J Exp Clin Cancer Res. 2009; 28 (1)117. Published online 2009 August 19

Modeling of .. for late rectal toxicity from a randomized phase II study: conventional versus hypofractionated scheme for localized prostate cancer

Reported  by Jacqueline Strax November 4, 2009