Performing Extended Pelvic Lymph Node Dissection Before Prostatectomy was Associated with Lower Apical Positive Surgical Margin Rates During Robot-Assisted Radical Prostatectomy: A Single-Centre Retrospective Cohort Study

Abstract

Objective: Positive surgical margins remain clinically relevant after robot-assisted radical prostatectomy (RARP). Whether performing extended pelvic lymph node dissection (ePLND) before, rather than after, prostatectomy is associated with lower apical positive surgical margin (PSM) rates has not been evaluated with adjusted comparative data.Materials and Methods: We performed a retrospective cohort study of 250 consecutive patients who underwent primary RARP with ePLND at a single tertiary centre. Patients were classified by operative sequence as ePLND-first (n = 121) or prostatectomy-first (n = 129). The primary multivariable analyses were conducted in the full 250-patient cohort with nerve-sparing intent coded as a 3-level categorical variable; a pre-specified subgroup analysis was conducted in the 188 patients undergoing any form of nerve-sparing surgery. The primary endpoint was apical PSM. Because apical PSM events were sparse, the adjusted analysis used Firth penalised logistic regression.Results: Baseline characteristics were similar between groups. Apical PSM occurred in 6 of 121 patients (5.0%; 95% confidence interval [CI] 2.3% to 10.4%) in the ePLND-first group and 13 of 129 (10.1%; 95% CI 6.0% to 16.5%) in the prostatectomy-first group. In the primary multivariable analysis of the full 250-patient cohort, ePLND-first sequencing was associated with lower adjusted odds of apical PSM (adjusted OR 0.38; 95% CI 0.14 to 1.03; p = 0.056); in the pre-specified nerve-sparing subgroup (n = 188), the adjusted association was stronger (OR 0.19; 95% CI 0.04 to 0.97; p = 0.046; unadjusted 1.2% vs 8.8%, Fisher’s exact p = 0.023). Total operative time was shorter in the ePLND-first group (195.2 vs 202.9 min; p = 0.029). Lymph node yield and major complication rates were similar between groups.Conclusion: In this retrospective cohort, performing ePLND before prostatectomy was associated with directionally lower adjusted odds of apical PSM during RARP in the full 250-patient cohort, with a stronger association in the pre-specified nerve-sparing subgroup analysis. For men undergoing nerve-sparing RARP with planned ePLND, sequence may represent a practical operative strategy associated with lower apical margin risk without an evident perioperative penalty.