Influence of node-positive disease after radical prostatectomy on biochemical recurrence and oncologic outcomes in men with prostate cancer.

Abstract

306 Background: The diagnostic and therapeutic value of pelvic lymph node dissection (LND) at radical prostatectomy (RP) remains unclear. Thus, we aim to characterize the oncologic value of LND and secondary treatment on oncologic outcomes for a contemporary cohort of men with nodal disease on surgical pathology at RP. Methods: Men who underwent primary RP with LND for PCa were identified and stratified by pN status. Detectable PSA was defined as a PSA>0.05 ng/ml within 2-6 months after RP. Multivariable Cox proportional hazards regression models were fit for biochemical recurrence-free survival (RFS), overall survival (OS), and PCa-specific mortality (PCSM). Results: Of 1,635 identified patients, 167 (10.2%) had nodal disease. Mean age at diagnosis was 62 years (SD 7.1). Median follow-up after RP was 31 months (IQR 13-58). Those with nodal disease had more extensive LND (mean 17.7, SD 8.3 vs mean 13, SD 7.6, p<0.01). The number of positive LNs was associated with worse 7-year outcomes [RFS, HR 1.2, 95% CI 1.1-1.2, p<0.01; OS, HR 1.2, 95% CI 1.1-1.4, p<0.01] but not PCSM (p=0.2) after adjustments. Median number of positive LN was 1 (IQR 1, 3) in pN1 patients. 31 (19%) had an UDT PSA after RP, 25 (15%) had UDT PSA and received adjuvant therapy, and 106 (66%) had a detectable PSA. On multivariable analysis, number of positive LNs (HR 1.1, 95% CI 1.0-12, p=0.02) and detectable PSA (vs UDT, HR 5.1, 95% CI 1.8-14.3, p<0.01) were associated with increased risk of recurrence after RP but not OS (p>0.05 for all). After salvage treatment, 7-year RFS, OS, and PCSM did not differ significantly between the groups (p>0.05 for all). Conclusions: In a contemporary cohort of men with pN1 disease, more extensive LND was not associated with improved outcomes. Amongst those who underwent secondary treatment after RP, UDT PSA after RP conferred greater biochemical recurrence free survival at 7 years. In this subset of men, adjuvant treatment was not associated with improved post-salvage biochemical or treatment-free survival. Further investigation into the potential therapeutic benefit of LND at RP is warranted to better estimate the potential risk overtreatment of men with nodal disease.