Of the 265 patients who had clinical or biochemical progression in the wait-and-see group, 218 received an active treatment, 44 remained on the wait-and-see protocol, and three patients had missing information. Interestingly, the cumulative number of patients who required an active salvage treatment by year 10 was significantly higher in the wait-and-see group (47.5% vs. 21.8% in the postoperative radiotherapy group).  In addition, active salvage treatment was started much earlier in the wait-and-see group (a median of 2.9 years after study entry for the wait-and-see group vs. 4.2 years in the postoperative radiotherapy group).

Even though overall survival was not significantly different between the two treatment arms, the study suggests a role for radiation immediately after surgery in selected patients.  In a subanalysis, those patients under the age of 70 with positive surgical margins who received postoperative radiotherapy appeared to have improved clinical PFS compared to those patients who were over the age of 70 and those patients who had negative surgical margins.

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The study highlighted several important factors in the treatment of locally advanced prostate cancer.  “The most important is that surgery alone is ineffective for the majority of men with high-risk features and that novel treatments are needed for this population,” said Mark Garzotto, MD, Associate Professor of Surgery/Urology, Chief Urologic Oncology at the Portland VA Medical Center, Portland, Oregon.

Therefore, potential risk for adverse events should also be taken into consideration. In the trial, no grade 4 toxicity was reported, yet the 10-year cumulative incidence of grade 3 late toxicity in the immediate irradiation group was twice as high as in the wait-and-see group (5.3% vs. 2.5%).  Dr. Garzotto also noted, “Some patients appeared to not only fail to derive any benefit from pelvic radiation, but may have been actually harmed from the effects of therapy.  Patients over 70 years of age, who underwent radiation, actually had a worse biochemical-free survival, clinical progression-free survival, and overall survival than men who were simply observed. A close look at the data show the death rate was 42% in the radiation group versus only 20% in the observation group.  Thus radiation may worsen overall survival in men who are not well selected for treatment.”

Tomasz Beer, MD, who is Professor of Medicine, Hematology and Medical Oncology at the Oregon Health & Science University, Portland, Oregon, said this study has sufficient follow-up time and is powered enough to affect clinical practice.  “This is an important study that provides evidence that supports the use of radiation after surgery for patients with a high risk of relapse,” Dr. Beer told ChemotherapyAdvisor.com.  “The study, combined with the rest of the available evidence, is robust enough to influence practice.  Many of us had already implemented the approach championed by this study.”

In agreement with Dr. Beer is Sushil Beriwal, MD, Associate Professor of Radiation Oncology at University of Pittsburgh in Pittsburgh, Pennsylvania.  He said this current study provides important data for adequately counseling men who undergo RP.  “The study provides us with objective information to give our patients to discuss whether they should have radiation or not,” said Dr. Beriwal in an interview ChemotherapyAdvisor.com.