Adjuvant radiotherapy following radical prostatectomy is more effective and less toxic than salvage radiotherapy for a rising prostate specific antigen.

Despite the trend toward earlier diagnosis of adenocarcinoma of the prostate, approximately 25% of men undergoing radical prostatectomy will have pathologic evidence of cancer extending outside of the prostate. These patients are at high risk for subsequent recurrence. Such relapses are almost always manifested initially as a rise in the Prostate Specific Antigen (PSA). Currently utilized PSA assays, however, will not detect a recurrence smaller than 10(7) to 10(8) cells, nor does PSA identify the site of recurrence. In contrast, the pathologic findings at the time of surgery can be used to reliably distinguish patients at risk for local recurrence from those more likely to fail distantly. Furthermore, adjuvant pelvic radiotherapy after prostatectomy, given to patients with an undetectable PSA who are at high risk for local recurrence, results in a higher disease free survival and fewer side effects than if radiotherapy is delayed until the PSA begins to rise. Thus, patients at high risk for local failure following radical prostatectomy, but at low risk for distant metastases (i.e., those with positive surgical margins and an undetectable PSA) should be offered immediate adjuvant radiotherapy.