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

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.