Treatment outcome with adjuvant and salvage irradiation after radical prostatectomy for prostate cancer

Objectives. To determine the factors associated with outcome by reviewing o ur institution's experience treating patients with external beam radiation therapy (RT) after radical prostatectomy. Methods. Sixty-one patients received RT to the prostatic fossa after radica l prostatectomy for prostate cancer (median dose 59.4 Gy). Thirty-eight pat ients received adjuvant RT within 6 months of surgery for adverse pathologi c findings only. Therapeutic RT was administered to 23 patients either for a persistently elevated postoperative prostate-specific antigen (PSA) level (n = 2), a rising PSA level more than 6 months after surgery (n = 9), or a biopsy-proven local recurrence (n = 12). Preoperative and preradiation PSA values, Gleason score, pathologic findings, patient age, total RT dose, an d indication for RT were analyzed for their impact on biochemical control. The median follow-up was 48 months. Results. Patients treated with adjuvant RT achieved 3 and 5-year biochemica l control rates of 84% and 67%, respectively. Multiple clinical, pathologic , and treatment-related factors were analyzed for an association with bioch emical control. No variable was associated with 5-year outcome. The 5-year actuarial rate of biochemical control for patients treated with therapeutic RT was 16%. Multiple clinical, pathologic, and treatment-related factors w ere analyzed for an association with biochemical control. Only a pre-RT PSA level of 2 ng/mL or less was associated with an improved rate of biochemic al control at 3 years (80% versus 27%, P = 0.001). However, at 5 years, thi s difference was not statistically significant. A separate analysis was per formed to determine the prognostic factors associated with outcome for the entire group of patients. Only the indication for RT (adjuvant versus thera peutic) was associated with 5-year outcome. Patients treated with adjuvant RT had a statistically significant improvement in 5-year actuarial rates of biochemical control (67% versus 16%, P < 0.001) and disease-free survival (66% versus 46%, P = 0.037) but not in overall survival. There were no stat istically significant differences between patient groups with respect to ag e, preoperative PSA, Gleason score, pathologic T stage, median follow-up, a nd total RT dose. Conclusions. At our institution, patients treated with adjuvant RT after pr ostatectomy for adverse pathologic findings achieved excellent rates of bio chemical control that were significantly better than that of similar patien ts treated therapeutically for persistent or rising PSA or clinical local r ecurrence. UROLOGY 54: 111-117, 1999. (C) 1999, Elsevier Science Inc.