Postoperative radiotherapy for carcinoma of the prostate: impact on both local control and distant disease-free survival.

Abstract

The role of postoperative irradiation in patients with clinically localized prostate cancer, either as an adjuvant or salvage radiotherapy, remains controversial. In this study, we evaluate the impact of postoperative radiotherapy on patients diagnosed with prostate cancer with respect to biochemical and clinical disease free survival. Between 1987 and 1996, 179 patients with clinically localized prostate cancer were found to have adverse histopathologic findings on radical prostatectomy specimens (positive surgical margins, extracapsular extension, and seminal vesicle invasion). Of these patients, 42 were referred for postoperative adjuvant radiotherapy, whereas 73 were referred for salvage irradiation because of rising serum prostate-specific antigen (PSA) levels postoperatively. The remaining 64 patients underwent prostatectomy only. The 10-year biochemical relapse-free survival (RFS) from date of surgery were 88%, 45%, and 25% for patients treated with postoperative adjuvant radiotherapy, salvage irradiation, and with surgery alone, respectively (p = 0.046). Ten-year distant RFS from date of surgery were 82%, 74%, and 44% for adjuvantly treated patients, those with salvage radiotherapy, and those with surgery alone, respectively (p = 0.0180). Ten-year overall disease RFS from date of surgery was 89%, 76%, and 30% for adjuvantly treated patients, those with salvage radiotherapy, and those with surgery alone, respectively (p = 0.0237). Multivariate analyses revealed that a preoperative PSA greater than 20 ng/ml and pathologic Gleason Score of 8 to 10 were adverse predictors for biochemical relapse, whereas pathologic Gleason Score of 8 to 10, seminal vesicle invasion, and extracapsular extension were adverse predictors of distant metastases. Postoperative radiotherapy, either delivered as adjuvant treatment for adverse histopathologic findings or as salvage therapy for local relapses, appear to confer superior local, distant disease RFS, and overall disease RFS than surgery alone.