Extended Pelvic Lymph Node Dissection during Robotic Prostate Surgery Reduces Biochemical Recurrence: A Propensity Score- matched Analysis for High-risk Prostate Cancer

Abstract

Objectives To avoid misunderstandings based on the failure to demonstrate oncological benefit from extended pelvic lymph node dissection (PLND) during radical prostatectomy in a recent randomized controlled trial. We evaluated early survival outcome in contemporary patients with limited to high-risk prostate cancer (PCa) using propensity score (PS)-matched analysis. Materials and Methods Three-hundred and forty-seven patients with high-risk PCa were enrolled. They were determined to have a lymph node (LN) involvement probability of greater than 5%. Biochemical recurrence (BCR)-free survival was compared between two groups divided by adherence with extended template and timeframe related to improving PLND procedure. Results The mean LN yield was 23.4 and 2.7, and the positive LN rate was 19.3 and 2.0% in the extended PLND and other groups, respectively. In the entire unmatched cohort, the estimated curve was 13.1% superior in 3-year BCR-free survival for the extended PLND group. The PS-matched cohort was converged in each LN yield group to 99 patients, and the difference in the 3-year BCR-free survival widened to 22.2% (hazard ratio 0.46, 95% confidence interval 0.27–0.80; p = 0.005). The statistical difference was consistent in standard high-risk PCa, and was a significant trend in very high-risk PCa. In the analysis of two groups divided by timeframe, the difference in the BCR-free survival was a significant trend. Conclusion The results possibly demonstrate the therapeutic role of extended PLND in high-risk PCa. Statistical demonstration of benefits depends on the quality of extended PLND and whether the study cohort is the optimal composition of cancer risk.