Overall survival benefit from postoperative radiation therapy for organ-confined, margin-positive prostate cancer.

Abstract

Radical prostatectomy for invasive prostate cancer is associated with positive margin rates in 10% to 50% of resected specimens. Postoperative radiation therapy may benefit patients who have organ-confined prostate cancer with positive margins. We performed a retrospective analysis to examine whether adjunctive radiation therapy enhanced long-term survival for prostate cancer patients who underwent prostatectomy for localized prostate cancer but with positive margins. We used the Hoag Cancer Center database to identify patients diagnosed with invasive prostate cancer. Relative and overall survival rates were calculated. Among 1,474 patients diagnosed with localized invasive prostate cancer during the years 1990 to 2006 and undergoing prostatectomy, 113 (7.7%) were identified who had positive margins and did not have local extension of disease, positive lymph nodes, or distant metastases. A total of 17 patients received adjunctive radiation therapy (Group A), whereas 96 did not (Group B; 3 received hormonal therapy). Both groups had a median age of 64 years and median follow-up of 7.5 years. In Group A, no patients have died as of last follow-up, but in Group B, 18 have died. Estimated 10-year and 15-year overall survival rates were both 100% for Group A compared with 85% and 57% respectively for Group B (p2=0.050, log rank). Relative 10- and 15 year survival rates were both 100% for Group A compared with 100% and 79% respectively for Group B. This retrospective analysis suggests that prostate cancer patients with localized disease but positive margins do derive a survival benefit from adjuvant radiation therapy.