The number of dissected lymph nodes contributes to good prognosis after robot-assisted radical cystectomy for muscle-invasive bladder cancer without lymph node metastasis at clinical staging

Purpose: Robot-assisted radical cystectomy (RARC) with lymph node (LN) dissection is a curative treatment for muscle-invasive bladder cancer (MIBC). We aimed to investigate the association between the number of dissected LNs in RARC and the prognosis of MIBC. Methods: We retrospectively assessed 304 patients with cT2–T4N0M0 MIBC who underwent RARC between 2018 and 2024. Associations between the number of dissected LNs and regression-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) were analyzed using a Cox proportional hazards regression model. We explored a better cutoff number by comparing the hazard ratio (HR) and p value for each cutoff. Results: The median number of dissected LNs was 14 (range: 0–76). Among 304 cases, 54 had LN metastases (17.7%). The number of dissected LNs was significantly associated with RFS, CSS, and OS (p = 0.010, 0.007, and 0.003, respectively) after adjusting for performance status and preoperative laboratory data. When the cutoff value was 20, the HR (95% confidence interval) and p value were 0.624 (0.396–0.982) and 0.041 in RFS, respectively; 0.495 (0.275–0.892) and 0.019 in CSS, respectively; and 0.535 (0.317–0.904) and 0.019 in OS, respectively. The postoperative complication rate did not increase with an increasing number of dissected LNs. Patients with ≥20 dissected LNs demonstrated a significantly lower complication rate (P = 0.009). Conclusion: The number of dissected LNs contributed to good prognosis after RARC for MIBCwithout LN metastasis at clinical staging. A cutoff value of 20 enabled the clear stratification of the prognosis.