Purpose: To determine the efficacy of a combined approach of postoperative radiotherapy (RT) plus 2-year androgen suppression (AS) for patients with pathologic T3 disease (pT3) and/or positive surgical margins (PSM) after radical prostatectomy (RP).
Methods and materials: A total of 78 patients with pT3 and/or PSM after RP were treated with RT plus 2-year AS, as per a pilot, prospective study. Androgen suppression started within 1 month after the completion of RT and consisted of nilutamide for 4 weeks and buserelin acetate depot subcutaneously every 2 months for 2 years. Relapse-free rate, including freedom from prostate-specific antigen (PSA) relapse, was estimated using the Kaplan-Meier method. A Cox regression analysis was performed to evaluate prognostic factors for relapse. Prostate-specific antigen relapse was defined as a PSA rise above 0.2 ng/mL, with two consecutive increases over a minimum of 3 months.
Results: The median age was 61 years at the time of RP. The median interval between RP and postoperative RT was 4.2 months. Forty-nine patients had undetectable PSA (<0.2 ng/mL), and 29 had persistently detectable postoperative PSA at the time of the protocol treatment. Median follow-up from RT was 6.4 years. Relapse-free rates at 5 and 7 years were 94.4% and 86.3%, respectively. Survival rates were 96% at 5 years and 93.1% at 7 years. On Cox regression analysis, persistently detectable postoperative PSA and pT3b-T4 were significant predictors for relapse.
Conclusion: The combined treatment of postoperative RT plus 2-year AS yielded encouraging results for patients with pT3 and/or PSM and warrants a confirmatory study.