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

Background: There are pros and cons regarding the benefit of extended pelvic lymph node dissection (PLND) during surgery for prostate cancer (PCa). A randomized controlled trial failed to demonstrate any survival benefits, and the therapeutic role of PLND remains unclear. We evaluated early survival outcome using a propensity score (PS)-matched analysis. Methods: Three hundred ninety-nine patients with intermediate- to high-risk PCa were enrolled. They were determined to have a lymph node (LN) invasion probability of greater than 7% on the established nomogram. The National Comprehensive Cancer Network classification was used as risk stratification. Biochemical recurrence (BCR)-free survival was compared between the two groups divided by the threshold of the LN yield set at 15. Results: The mean LN yield was 23.7 and 3.4 in the sufficient (n = 217) and insufficient (n = 182) LN yield groups, respectively. In the unmatched cohort, the advantage of the 3-year BCR-free survival for sufficient LN yield remained at 10.0% (hazard ratio [HR] 0.68, 95% confidence interval [CI] 0.43-1.07; p = 0.098). In the PS-matched cohort with 133 patients in each group, the difference in the 3-year BCR-free survival rate widened to 15.8% (HR 0.54, 95% CI 0.31-0.93; p = 0.027). A Cox regression multivariate analysis performed on the model with postoperative pathological factors showed an independent predictive value of LN yield. Conclusions: The results demonstrate the therapeutic role of PLND in intermediate- to high-risk PCa. The benefit of PLND depends on the surgeon adhering to the template and removing a sufficient number of LNs in patients with an optimal risk-range.