Radiation therapy for men who have had prostate cancer surgery lessens the chance of recurrence as long as it is initiated while the patient's prostate specific antigen (PSA) level is below 1, according to a report in the International Journal of Radiation Oncology*Biology*Physics.

For prostate cancer, postoperative radiation therapy can take place as part of the treatment within several months after surgery (adjuvant therapy), or it can be administered only after signs that the prostate cancer is recurring (salvage therapy).

Many studies have shown that radiation after surgery (adjuvant therapy) reduces the chances of prostate cancer recurring. This study, conducted between 1989 and 1997, was designed to explore whether salvage therapy was equally helpful.

The men in the salvage group received radiation, on average, 40 months after surgery, and researchers found that salvage radiation therapy was significantly less effective when the patient's PSA level rose over 1.

"The PSA level was the key factor in this study," reported Dr. Michael Hagan of Medical College of Virginia Hospitals. "The results from [both approaches] were excellent when radiation treatment was initiated while the serum PSA level was less than 1.

"This study shows that the policy for salvage radiation therapy is likely to be as effective as adjuvant radiation therapy only when the institution or practitioner monitors the patient's PSA level very closely after prostatectomy," he concluded.