Long-term outcomes of radical prostatectomy versus low-dose-rate brachytherapy in patients with intermediate-risk prostate cancer: Propensity score matched comparison

Purpose: To compare long-term outcomes of radical prostatectomy (RP) and low-dose-rate brachytherapy (LDR-BT) using propensity score-matched analysis in patients with clinically localized, intermediate-risk prostate cancer (PCa).

Methods: Between October 2003 and March 2014, our institution treated 1241 patients with intermediate-risk PCa (RP: n = 531; LDR-BT: n = 710). Biochemical recurrence (BCR) was defined as prostate-specific antigen (PSA) levels of 0.2 ng/ml or greater for RP, and as PSA nadir plus 2 ng/ml or higher (Phoenix definition) for LDR-BT. We calculated propensity scores by multivariate logistic regression based on covariates that included age, pretreatment PSA, biopsy Gleason grade, the percentage of positive biopsy cores (PPBC), and clinical T stage.

Results: Median follow-up was 108 months for RP and 99 months for LDR-BT. After propensity score adjustment, a total of 642 (321 each) patients remained for further analysis. Kaplan-Meier curves showed no statistically significant difference in overall survival (OS) (p = 0.99). LDR-BT was associated with improved BCR-free survival and salvage therapy-free survival compared to RP (p < 0.001), and RP was associated with improved metastasis-free survival (MFS, p < 0.001).

Conclusion: BCR cannot be a surrogate for survival comparison, primarily due to differences between treatment modalities in how this term was defined post-therapy. Long-term follow-up showed that RP was associated with lower MFS in intermediate-risk PCa. However, this has not yet translated into superior OS.