Does higher number of lymph nodes (LNs) excised during radical prostatectomy (RP) improve biochemical relapse-free survival (bRFS) in patients with pT2-3a/pN0 prostate cancer?

Abstract

61 Background: In published series of extended pelvic LN dissection (LND), an association between higher number of LNs resected and both higher rate of occult LN disease discovery and long-term bRFS (for pN0) was observed. Despite this, practice patterns of LND extent (and associated number of LNs examined) vary, with the majority being limited to local nodal sampling. It remains unclear whether the LN yield correlates with bRFS in this context. The present investigation examines whether the number of LNs examined at RP is associated with bRFS. Methods: Patients with clinically localized prostate cancer, initial PSA < 30, and pT2-3a/N0 disease at RP were retrospectively identified for inclusion. Those who received pre-RP or adjuvant radiotherapy or hormone therapy were excluded. Kaplan-Meier method was employed for survival probability estimation. Cox regression models were used to assess bRFS differences. Results: From 2002 to 2010, 672 patients were eligible for this analysis. The median age was 61 yrs (range, 43-76). Most patients had cT1c (83%), Gleason Score (GS) 4-6 (63%), and were low risk by D’Amico classification (56%), with median PSA of 5.6 ng/dL (0.9-28.0). At RP, 213 (32%) patients had positive margins (M+). At a median follow-up of 82 months, 140 patients (21%) experienced PSA failure with estimated bRFS of 81%/76% at 5/8 years. Univariate analysis identified GS ³ 7 (biopsy or RP), intermediate/high risk, M+, higher percentage of biopsy cores involved, and performance of LND as adversely associated with bRFS (all p < 0.01). Of 446 patients (66%) who had LN sampling , 396 had a specific number of LNs reported (median 5; range 1-24, with single outlier case [33] excluded for statistical analysis). A higher number of LNs excised was not associated with bRFS for the entire cohort (HR = 0.99, p = 0.60), or for any biopsy GS subgroup (GS4-6 HR = 0.92, GS7 HR = 1.00, GS8-10 HR = 0.11). Conclusions: In the context of limited LND, this study did not demonstrate an association between LN yield and bRFS in patients with clinically localized pT2-3a/pN0 prostate cancer managed with RP alone, either in the entire population or with stratification by GS.