Androgen deprivation therapy in men with node-positive prostate cancer treated with postoperative radiotherapy

Abstract

BackgroundIn men with node-positive prostate cancer after radical prostatectomy there are limited data on the value of adding androgen deprivation therapy (ADT) to postoperative radiotherapy. ObjectiveTo determine whether there is a clear oncologic benefit to ADT in the setting of node-positive prostate cancer treated with postoperative radiotherapy. MethodsWe analyzed data for 372 prostate cancer patients treated at San Raffaele Hospital with postoperative radiotherapy for node-positive disease after radical prostatectomy, 272 received both ADT and radiotherapy. Eighty-six men were followed without an event for more than 10 years. ResultsPatients who received postoperative radiotherapy + ADT had more aggressive disease, with higher preoperative PSA level, higher rate of ISUP grade 5, pT3b-T4 tumors and ≥3 positive nodes. At multivariable Cox regression, the comparison between men treated by postoperative radiotherapy + ADT vs. radiotherapy alone did not show a significant difference for overall (hazards ratio: 0.91; 95% confidence interval: 0.45, 1.84; P = 0.8) and cancer-specific survival (hazards ratio: 5.39; 95% confidence intervalI: 0.70, 41.39; P = 0.11). These results remained consistent in a number of sensitivity analyses, including propensity score matching. Consideration of 95% CIs suggests that a clinically significant benefit of ADT in node-positive patients receiving radiotherapy after surgery is unlikely. ConclusionsWe can exclude the sort of large survival benefit that would be required to justify the risks and toxicities of ADT in men with node-positive disease receiving postoperative radiotherapy. Awaiting larger and more powered studies on this topic, men with pN+ prostate cancer treated with postoperative radiotherapy should not receive ADT outside well-controlled clinical trials.