Salvage radiotherapy for men with rising prostate-specific antigen levels following radical prostatectomy significantly reduces risk of prostate-cancer death, particularly in men whose antigen level doubled in six months or less, according to a presentation at The American Society of Clinical Oncology's 2008 Genitourinary Cancers Symposium.

"These findings are the first to support the effectiveness of salvage radiotherapy for improving survival in men with recurrent prostate cancer," said lead author Bruce Trock, MD, associate professor of urology, epidemiology, oncology and environmental health sciences at Johns Hopkins University School of Medicine. "If validated, these results suggest that for high-risk prostate cancer, radiotherapy should be given promptly when there is evidence for recurrence after radical prostatectomy, as early salvage radiotherapy may improve overall survival."

The investigators compared prostate cancer-specific survival (the probability of not dying from prostate cancer) among 635 men with rising antigen levels after radical prostatectomy. Among the men with biochemical recurrence, 160 had received salvage radiotherapy alone, 78 received radiation plus hormonal therapy and 397 received no radiation or hormonal therapy. Trock noted that this study was not a prospective randomized clinical trial, but a retrospective analysis of men who had already been treated.

After 10 years, 86 percent of men in the radiotherapy group and 82 percent of men in the radiation/hormonal therapy group had not died from prostate cancer versus 62 percent of men who received no salvage therapy. The results did not change after taking into account individual patient characteristics associated with prognosis. The investigators also found that radiation therapy had to be given soon after recurrence - prostate cancer-specific survival improved only when radiation was given less than two years after biochemical recurrence was observed.

The impact of radiotherapy was particularly strong in men whose antigen levels doubled in less than six months; radiotherapy reduced the risk of prostate cancer death in these men by 86 percent. Radiotherapy did not significantly reduce the risk of death among men whose antigen levels doubled in six months or more due to the fact that these men had less aggressive disease and may have fared well even without radiation therapy.

The researchers cautioned that despite the evidence that salvage radiotherapy appears to improve survival, confirmation is needed in other comparable groups of men, and a randomized clinical trial will ultimately be needed to determine the impact of salvage radiotherapy on survival.