Abstract
INTRODUCTION: Pelvic lymphadenectomy (PLND) alongside radical cystectomy (RC), provides crucial diagnostic and therapeutic value in patients with bladder cancer. With the advent of neoadjuvant chemotherapy and prospective data supporting standard PLND, controversy remains regarding the optimal PLND extent and patient selection. Nearly 40% of patients may not receive adequate PLND, even though 25% of patients have positive lymph nodes (LN) at time of RC. We hypothesized that PLND still remains an important facet of bladder cancer treatment. To clarify the prognostic importance of nodal yield, we performed a retrospective investigation of a heterogenous population (pTanyNx/0M0) of patients undergoing RC. METHODS: From the Surveillance, Epidemiology, and End Results (SEER) program, we identified pTanyNx/0M0 bladder cancer patients undergoing RC from 2004 to 2015. Kaplan Meier curves and Cox proportional hazards models assessed cancer-specific survival. Patients were analyzed with PLND performed as the primary covariate. Survival analysis then stratified patients undergoing PLND by LN yield, both as a continuous and categorial variable (≤10, 11-20, 21-30, and >30), and T stage. RESULTS: The final cohort included pTanyNx/0M0 patients with urothelial bladder cancer (n = 12,096); median follow up was 39 (IQR: 17-77) months. PLND was performed in 81.45% of patients with a median LN yield of 14 (IQR: 7-23). Most commonly, patients had T2 disease (44.68%). After controlling for age and T stage, patients receiving PLND had improved CSS (HR = 0.56, [95% CI: 0.51-0.62]) compared to those that did not receive PLND. When grouping patients by LN yield, survival improved in a "dose dependent" manner (>30 LN: HR = 0.76, [95% CI: 0.66-0.87]). We noted similar results when stratifying patients into non-muscle-invasive (NMIBC) and muscle-invasive bladder cancer (MIBC). CONCLUSIONS: In a large contemporary series of pTanyNx/0M0 bladder cancer patients, we found a significant oncologic benefit to PLND. Higher LN yield correlated to improved CSS in non-muscle-invasive and muscle-invasive disease. Our data support the possibility of occult micrometastasis even in non-muscle-invasive disease. Additionally, in light of recent advances in adjuvant immunotherapy, our results emphasize the importance of adequate nodal yield for accurate staging and optimal treatment.