MULTIVARIATE-ANALYSIS OF FACTORS PREDICTING LOCAL RELAPSE AFTER RADICAL PROSTATECTOMY - POSSIBLE INDICATIONS FOR POSTOPERATIVE RADIOTHERAPY

Between 1970 and 1983, 273 patients underwent radical surgery (radical prostatectomy - 261, radical cystoprostatectomy-12) for newly diagnosed adenocarcinoma of the prostate at Duke University Medical Center and received no adjuvant radiotherapy. A total of 46 patients developed local recurrence. Forty developed local relapse only and six developed simultaneous local and distant failure. The crude local relapse rate was 17% (46/273). The actuarial local failure rate at 5, 10, and 15 years was 12%, 32%, and 35%, respectively. Univariate and multivariate analyses were performed to identify factors predictive of local relapse after radical surgery. Possible prognostic factors analyzed were: age, type of biopsy, use of adjuvant hormonal therapy, histologic grade, histologic involvement of seminal vesicles, positive surgical margins, clinical stage, and elevated acid phosphatase. Factors identified as significant predictors of local relapse by univariate analysis were: poorly differentiated histology (p = 0.001), seminal vesicle involvement (p = 0.0009), and positive surgical margins (p = 0.0001). An elevated preoperative acid phosphatase was of borderline significance (p = 0.06). On multivariate analysis, poorly differentiated histology (p = 0.0007), positive margins (p = 0.0015), and elevated acid phosphatase (p = 0.0273) were significant predictors of local failure. Seminal vesicle involvement was no longer a significant predictor of local failure. However, on subsequent univariate and multivariate analyses, seminal vesicle involvement was the only significant predictor for the development of distant metastases (p = 0.0019, multivariate). Thus, patients with poorly differentiated tumors, positive surgical margins, or elevated preoperative acid phosphatase are at high risk for local relapse after radical prostatectomy. These patients should be included in future clinical trials studying the role of adjuvant radiotherapy after radical prostatectomy, or offered adjuvant radiotherapy if they cannot or will not participate in such trials.