Using higher doses of radiation per visit could cut treatment from about eight weeks to five

ORLANDO—By using higher doses of radiation per treatment, it may be possible to reduce the traditional course of radiotherapy for prostate cancer by two-and-a-half weeks, according to an interim analysis of phase 3 trial data.

Conventional radiotherapy for prostate cancer typically consists of five treatments per week for about eight weeks, leaving patients feeling fatigued and interfering with quality of life. Study findings, however, suggest that a five-week course of radiotherapy using higher doses per treatment (hypofractionation) may work just as well and is well tolerated.

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“The similarity between the two treatments suggests that the hypofractionation regimen could potentially be used in place of standard radiation therapy, improving patients’ quality of life and requiring them to spend less time in treatment,” said lead investigator Alan Pollack, MD, PhD, professor and chairman of the Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine in Florida. 

Dr. Pollack, who presented the study findings here at the 2009 Genitourinary Cancers Symposium, said that while these findings are clinically significant, longer follow-up is needed and a final analysis is planned for 2011.

In this study, he and his colleagues compared biochemical failure rates in two groups of men with prostate cancer. One group of 152 men were randomly assigned to have standard intensity-modulated radiation therapy (IMRT) for 38 treatments over 7.5 weeks (2.0 Gy per treatment for a total dose of 76 Gy), while a second group of 151 men had hypofractionated IMRT for 26 treatments over 5.1 weeks (2.7 Gy of radiation per treatment for a total dose of 70.2 Gy).

After a median follow-up of 39 months, the researchers observed no significant differences in biochemical recurrence rates or side effects between the two groups.  Specifically, 21% of the standard IMRT group and 17% of the hypofractionated IMRT group experienced a biochemical recurrence. The most commonly reported adverse effects were rectal bleeding and increased frequency and urgency of urination. Neither group experienced severe adverse effects.

“Basically, what we found was that there were no differences between the two arms at this interim analysis,” Dr. Pollack told Renal & Urology News. “Although there were some trends, we found nothing that was significant. This news is promising because the hypofractionation treatment was delivered in two-and-a-half weeks less than the standard treatment.”

He said if patients can be treated in less time and still achieve the same results, then it would be highly beneficial for patients and there could be significant cost savings. “If we can develop ways to reduce costs without sacrificing cure rates or increasing toxicity, then that is worthy of further investigation,” explained Dr. Pollack. “I would say for now that hypofractionation looks promising for treating prostate cancer.”

Eric A. Klein, MD, chairman of the Glickman Urological & Kidney Institute at Cleveland Clinic in Ohio, where he also is professor of surgery, said these preliminary findings are interesting and clinically significant. Hypofractionated IMRT would appeal to both patients and clinicians.

“What they have shown here is that this approach is really no different compared with standard radiation therapy,” Dr. Klein said. “It is fewer treatments for the patients, which is convenient. It is less costly, which is good for our overall health-care system. The side effects also looked to be very similar.”