Purpose: To determine whether the number of lymph nodes (LNs) examined is associated with outcomes in patients without nodal metastasis after radical cystectomy (RC).
Patients and methods: 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.
Results: 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).
Conclusions: 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.