Differential risk of castration resistance after initial radical prostatectomy or radiotherapy for prostate cancer

Background/Aim: Salvage androgen-deprivation therapy (ADT) is standard treatment for recurrent prostate cancer after curative therapy. However, the prognostic impact of different treatment modalities on the time to castration resistance remains unclear. In this study, we investigated the prognosis of men treated with salvage ADT after initial radical prostatectomy or radiotherapy for prostate cancer. Patients and Methods: Between 2000 and 2013, 149 Japanese men with recurrent prostate cancer who were initially treated with radical prostatectomy (n=95) or radiotherapy (n=54) and were subsequently treated with salvage ADT after disease recurrence were enrolled in this study. The prognostic significance of the curative treatment modality and clinicopathological findings were analyzed. Results: During a median follow-up period of 4.7 years after recurrence, castration-resistant progression was observed in 22 men. The 5-year progression-free survival, metastasis-free survival, cause-specific survival, and overall survival rates for all patients were 86.3%, 81.4%, 95.7%, and 94.5%, respectively. Multivariate analysis identified the biopsy Gleason score at initial diagnosis and the initial curative treatment modality as significant predictors of castration resistance. Conclusion: This study showed that low biopsy Gleason score (≤7) at diagnosis and radical prostatectomy as the curative treatment may be favorable prognostic factors for treatment with salvage ADT.