Cytoreductive cryosurgery in patients with bone metastatic prostate cancer: A retrospective analysis.

The current study is a retrospective analysis of 49 patients with bone metastatic prostate cancer: 26 receiving androgen deprivation therapy (ADT) alone versus 23 receiving cytoreductive cryosurgery of the primary tumor plus ADT treatment. Progression-free survival (PFS) was the primary outcome variable, and Cox proportional hazards regression analysis was used to identify predictors for PFS. The baseline characteristics were generally comparable between the 2 groups. Median follow-up time was 41 months (range 24-56) and 37 months (range 19-53) in ADT alone group and cryosurgery groups, respectively. Patients receiving cryosurgery had significantly longer PFS (35 vs 25 months, P = 0.0027) and time to castration resistance (36 vs 25 months, P = 0.0011). Cox multivariate analysis associated longer PFS with the following factors: cryosurgery (HR0.207, 95% CI 0.094-0.456), lower prostate specific antigen at diagnosis (≤100 ng/ml, HR0.235, 95% CI 0.072-0.763) and lower Gleason score (≤7, HR0.195, 95% CI 0.077-0.496). Cryosurgery reduced the risk of progression by 79.3%. In conclusion, cytoreductive cryosurgery of the primary tumor in patients with bone metastatic prostate cancer could reduce the risk of progression and delay time to castration-resistant prostate cancer.