Is More Always Better? An Assessment of the Impact of Lymph Node Yield on Outcome for Clinically Localized Prostate...

The clinical impact of lymph node dissection extent remains undetermined in the contemporary setting, as reflected in care pattern variations. Despite some series demonstrating a direct relationship between number of lymph nodes identified and detection of nodal involvement, the correlation between lymph node yield and disease control or survival outcomes remains unclear. Patients with clinically localized prostate cancer, pre-RP PSA <30, and pT2-3a/N0 disease at RP were retrospectively identified from two databases for inclusion. Those who received pre- or post-RP radiotherapy or hormone therapy were excluded. Kaplan-Meier method was employed for survival probability estimation. Cox regression models were used to assess bRFS differences between subsets. From 2002 to 2010, 667 eligible patients were identified. The median age was 61 yrs. (range, 43-76), with median PSA 5.6 ng/dL (0.9-28.0). At RP, most patients had pT2c (64%) disease with Gleason Score (GS) ≤6 (43%) or 7 (48%); 218 (33%) patients had positive margins (M+). At median clinical and PSA follow-up of 96 and 87 months, respectively, 146 patients (22%) experienced PSA failure with an estimated bRFS of 81%/76% at 5/8 years. For patients who underwent LND, univariable analysis identified PSA (at diagnosis), higher GS (≥7, at biopsy or RP), intermediate/high risk stratification, M+ as adversely associated with bRFS (all p < 0.01). A higher number of LNs excised was not associated with improved bRFS for the entire cohort (HR = 0.97, p = 0.27), nor for any clinical risk stratum, biopsy GS, or RP GS subgroup. 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 substratification by clinical risk stratum or GS.