Two new studies reported at the American Society for Radiation Oncology (ASTRO) annual meeting yesterday discuss the potential of shorter courses of “hypofractionated” radiation therapy in the treatment of localized prostate cancer.
In the first study, Pollack and colleagues report that “hypofractionated” radiation therapy is just as safe and effective as standardized radiation delivered over a longer time frame.
According to Pollack, “The study shows that hypofractionated radiation could potentially be used in place of standard radiation therapy for intermediate and high risk prostate cancer patients, but the results are still preliminary. We are excited about this research because the shorter course of treatment is more convenient, would reduce health care costs and appears just as effective.” Alan Pollack, MD is a radiation oncologist at the University of Miami Miller School of Medicine in Miami, FL.
The study involved 303 men with intermediate- and high-risk prostate cancer who were randomized to receive 26 treatments of hypofractionated intensity modulated radiation therapy (IMRT) over a period of 5 weeks or 38 treatments of standard IMRT over 7.5 weeks. High-risk patients also received treatment to the pelvic lymph nodes.
In addition to radiation treatment, 34/200 intermediate-risk patients (17 percent) received short-term hormone therapy for a median of 4 months, while 102/103 high-risk patients (99 percent) received long-term hormone therapy for 25 months.
The study shows that, 39 months after treatment, there is no significant difference in the rates of cancer recurrence between patients who underwent hypofractionated IMRT (14 percent) and standard IMRT (19 percent). There is also no difference in genitourinary and gastrointestinal side effects between the two groups.
“Although these are significant findings, longer follow-up is needed and a final analysis is planned for 2011,” Dr. Pollack said. “Other clinical trials are exploring hypofractionation and I encourage men with prostate cancer interested in shorter treatments to talk to their radiation oncologist about joining a study.”
In the second study, Arcangeli et al. report that hypofractionated radiation treatment is significantly more effective in stopping prostate cancer from growing in high-risk patients, compared to standard radiation treatment.
In this second study, between January 2003 and December 2007, a total of 168 high-risk prostate cancer patients were randomized to receive either hypofractionated or conventional schedules of three-dimensional conformal beam radiation therapy (3D-CRT) to the prostate and surrounding tissues. Patients who received hypofractionated radiation had only 20 radiation sessions (4 weeks of daily radiation therapy for 5 days a week), instead of the 40 to 45 sessions (8 or 9 weeks of radiation therapy for 5 days a week) sessions typically required during standard radiation treatment.
Data from this study show that the patients treated with hypofractionated radiation had a small but significantly better chance (87 vs. 79 percent) that their cancer would stop growing, compared to patients treated with standard radiation therapy. There was no difference in the late side effects of the radiation on genitourinary and gastrointestinal function between the two groups of patients.
According to Giorgio Arcangeli, MD, the lead author of the study and a radiation oncologist at the Regina Elena National Cancer Institute in Rome, Italy, “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. It’s also especially helpful for those living at long distance from radiation treatment centers.” Dr. Arcangeli added that, “Studies are in progress to test the benefits of even shorter treatment schedules.”
There seems to be little doubt that hypofractionated courses of radiation therapy will become the norm for the first-line treatment of localized prostate cancer in the near future. Since the long time period over which radiation has had to be delivered has always been a problem for the patients, any ability to offer this therapy over a significantly reduced time frame will be beneficial, especially if the patient outcomes are at least the same as previously. The combination of shorter courses of radiation with greater accuracy in the focus of radiation to the target tissues will also mean that radiation therapy becomes a more attractive option than even minimally invasive forms of surgery for a subset of patients.
Filed under: Management, Treatment Tagged: | hypofractionated, outcome, radiation, risk
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This study proves to be very promising. We have gone one step further and are currently treating low-risk patients with CyberKnife robotic radiosurgery in 5 treatments, and can treat higher grade prostate cancers with a combination of both traditional IMRT and a CyberKnife radiosurgery “boost.”