Comparison of external radiation therapy vs radical prostatectomy in lymph node positive prostate cancer patients

Introduction: Treatment options for lymph node positive prostate cancer are limited. We retrospectively compared patients who underwent external radiotherapy (ERT) to patients treated by radical prostatectomy (RPX). Materials and Methods: A total of 102 lymph node positive patients from the RPX series at Ulm University were evaluated. In all, 76 patients received adjuvant androgen withdrawal as part of their primary treatment. In the ERT group, 44 patients were treated at the University of Michigan using a fractionated regimen. Of these, 21 patients received early adjuvant hormonal therapy. Patients with neoadjuvant therapy before RPX or ERT were excluded. Results: In the RPX group, PSA nadir (nadir≤0.2 vs >0.2ng/ml) showed a strong association with outcome. In the ERT group, pretreatment PSA was an independent predictor of outcome (P=0.04) and patients with adjuvant hormonal therapy had a significant longer recurrence-free interval compared to patients without adjuvant therapy (P=0.004). Comparing only patients with adjuvant hormonal treatment after cancer-specific therapy, the ERT-treated patients had a borderline longer PSA recurrence-free survival time compared to the RPX-treated patients (P=0.05). Conclusions: In case of positive lymph nodes, RPX and ERT might be considered and need to be explained to the patient. For future treatment decisions, the presented findings and a potential survival benefit need to be evaluated in a larger prospective setting.