Purpose: While lymph node dissection (LND) at radical cystectomy (RC) for muscle-invasive bladder cancer has been studied extensively, the role of LND for nonmuscle-invasive bladder cancer (NMIBC) remains incompletely defined. Herein, we aim to assess the association between extent of LND during RC for NMIBC and local pelvic recurrence-free survival (LPRS), cancer-specific survival (CSS) and overall survival (OS).
Materials and methods: A multi-institutional retrospective review was performed of patients with NMIBC undergoing RC at 3 large tertiary referral centers. To identify a threshold for lymph node yield (LNY) to optimize LPRS, CSS and OS, separate Cox regression models were developed for each possible LNY threshold. Model performance including Q-statistics and hazard ratios (HRs) were used to identify optimal LNY thresholds.
Results: A total of 1,647 patients underwent RC for NMIBC, with a median LNY of 15 (quartiles 9,23). Model performance curves suggested LNY of 10 and 20 to optimize LPRS and CSS/OS, respectively. On multivariable regression, LNY >10 was associated with lower risk of LPR compared to LNY ≤10 (HR 0.63, 95% CI 0.42-0.93, p=0.02). Similarly, LNY >20 was associated with improved CSS (HR 0.67, 95% CI 0.52-0.87, p=0.002) and OS (HR 0.75, 95% CI 0.64-0.88, p <0.001) compared to LNY ≤20. Similar results were observed in the cT1 and cTis subgroups.
Conclusions: Greater extent of LND during RC for NMIBC is associated with improved LPRS, CSS and OS, supporting the inclusion of LND during RC for NMIBC, particularly among patients with cTis or cT1 disease. Future prospective studies are warranted to assess the ideal anatomical template of LND in NMIBC.
Keywords: cystectomy; lymph node excision; urinary bladder neoplasms.