Lack of survival benefit of pelvic lymph node dissection for patients with radical prostatectomy and postprostatectomy radiotherapy.

[INTRODUCTION AND OBJECTIVE] The survival benefit of pelvic lymph node dissection (PLND) during radical prostatectomy (RP) remains unclear. Recent guidelines suggest that PLND may be therapeutic in subsets of patients with limited nodal disease, however, differences in outcome could be obscured by subsequent therapy. Thus, the objective of this study was to evaluate the association between PLND and extent of nodal resection and overall survival (OS) among patients treated with RP and postprostatectomy radiotherapy.

[MATERIALS AND METHODS] Using the National Cancer Database (NCDB), we examined the association between OS and PLND status among patients diagnosed with prostate cancer from 2012 to 2021 who underwent RP with postprostatectomy radiotherapy. Propensity score matching (PSM) was performed based on pathologic T stage, age, PSA, race, hormonal therapy, and the number of nodes examined. We then compared the OS of patients who did and did not undergo pelvic lymph node dissection (PLND) as well as the extent of PLND (1-9 nodes vs. 10+ nodes and 1-14 nodes vs. 15+ nodes thresholds) stratified by National Comprehensive Cancer Network (NCCN) risk group.

[RESULTS] Of 28946 patients treated with RP who later underwent post-RP radiotherapy, 4254 were selected for the matched cohort (2127 PLND and 2127 non-PLND). There was no significant OS difference between PLND and non-PLND patients both overall (P = 0.74) and across all risk groups (low: P = 0.73, intermediate: P = 0.70, high: P = 0.60). There were also no significant OS differences between 1 and 9 node PLND and more extensive 10+ node PLND patients overall and across all risk groups. Patients who received 15+ node PLND had lower Charlson-Deyo scores than those who did not receive a PLND. Thus, while high-risk patients who received a 15+ node PLND did experience initial improved OS compared to those who underwent 1-14 node PLND (baseline aHR 0.52, 95% CI, 0.30-0.92, P = 0.02) and no PLND (baHR 0.35, 95% CI, 0.13-0.95, P = 0.04), a subset analysis of high-risk patients with Charlson-Deyo score of 0 found no survival differences in 1-14 node and 15+ node PLND patients when compared to non-PLND (1-14 node PLND: aHR 0.81, 95% CI, 0.54-1.21, P = 0.31; 15+ node PLND: aHR 0.97, 95% CI, 0.47-1.98, P = 0.93).

[CONCLUSIONS] Among RP patients receiving post-RP radiotherapy, there were no OS differences between patients who received no PLND and PLND as well as between non-PLND, 1-14 node PLND, and 15+ node PLND patients when controlling for Charlson-Deyo comorbidity. These findings suggest that PLND may not be associated with a long-term OS benefit for patients undergoing prostatectomy and post-RP radiotherapy.