Does increasing the nodal yield improve outcomes in patients without nodal metastasis at radical cystectomy?

Abstract

To determine whether the number of lymph nodes (LNs) examined is associated with outcomes in patients without nodal metastasis after radical cystectomy (RC). We retrospectively analyzed data from 4,188 patients treated at 12 centers with RC and pelvic lymphadenectomy without neo-adjuvant chemotherapy for urothelial carcinoma of the bladder (UCB). Outcomes of patients without LN metastasis (n = 3,088) were examined according to the LN yield analyzed as continuous variable, tertiles, and using the cutoffs of ≥ 9 and ≥ 20. The median nodal yield was 18 (range 1-123; IQR:20). A total of 2591 (84 %) and 1445 (47 %) patients had a LN yield ≥ 9 and ≥ 20, respectively. Median follow-up was 47 months (IQR:70). In multivariable analyses that adjusted for the standard clinicopathologic factors, higher LN yield was associated with a decreased risk of disease recurrence (continuous: HR = 0.996, p = 0.05; 3rd vs 1st tertile: HR = 0.853, p = 0.048; cutoff ≥ 20: HR = 0.851, p = 0.032). In the subgroups of patients with muscle-invasive UCB or those with ≥ 9 LN removed, LN yield was not associated with outcomes (p values >0.05). In this large multicenter cohort of patients with node-negative UCB, higher nodal yield improved recurrence-free survival when all patients were analyzed. Patients with a high LN yield (≥ 20 LN removed or 3rd tertile) had the largest benefit. The lack of prognostic significance of LN yield in patients with muscle-invasive UCB or those stratified by 9 LNs removed suggests that this effect is weak. Further prospective studies are needed to help identify preoperatively the optimal template for each patient.