Role of postoperative radiotherapy after pelvic lymphadenectomy and radical retropubic prostatectomy: a single institute experience of 415 patients

Abstract

Purpose To evaluate the clinical benefit deriving from early (within 6 months) radiotherapy (ERT) after pelvic lymphadenectomy and radical retropubic prostatectomy for localized/locally advanced adenocarcinoma of the prostate in a single-institution series. Methods and materials We retrospectively analyzed 415 patients who underwent pelvic lymphadenectomy and radical retropubic prostatectomy between 1986 and 1998 for pT2b-pT4, pN0-pN1 prostate carcinoma. Of the 415 patients, 237 underwent ERT for adverse pathologic findings and 178 patients did not receive RT or underwent salvage RT ≤6 months (salvage or no RT [SNRT]). Results After a median follow-up of 62 months, the 8-year actuarial freedom from biochemical, local and systemic failure, and cause-specific survival rate was 69% vs. 31% ( p <0.0001, log–rank), 93% vs. 63% ( p <0.0001), 88% vs. 75% ( p = 0.04), and 93% vs. 80% ( p = 0.02) in the ERT and SNRT group, respectively. A subgroup analysis indicated that an improvement in 8-year actuarial cause-specific survival was associated with ERT in patients with positive resection margins (91% vs. 67%, p = 0.007), extracapsular extension (92% vs. 75%, p = 0.002), Gleason score ≥7 (88% vs. 72%, p = 0.02), and lymph node metastases (88% vs. 68%, p = 0.04). This strong association between ERT and cause-specific survival persisted at multivariate analysis in the whole group of patients examined (hazard ratio, 4.3) and in the subgroups of patients with extracapsular extension (hazard ratio, 4.9), positive resection margins (hazard ratio, 4.7), Gleason score ≥7 (hazard ratio, 4.4), and lymph node metastases (hazard ratio, 7.4). Conclusion The results of this retrospective analysis indicate that ERT after pelvic lymphadenectomy and radical retropubic prostatectomy improved the 5-year and actuarial 8-year cause-specific survival of patients with adverse pathologic findings such as extracapsular extension, positive resection margins, Gleason score ≥7, and/or positive lymph nodes.