Impact of lymph node dissection on surgical and oncological outcomes in patients undergoing robot-assisted radical cystectomy for bladder cancer: a multicenter retrospective study

This study was performed to clarify the therapeutic and diagnostic roles of lymph node dissection (LND) by examining the impact of LND and lymph node yield (LNY) on oncological outcomes in patients undergoing robot-assisted radical cystectomy (RARC). Between 2014 and 2021, 216 patients underwent LND during RARC at Tokushima University Hospital and affiliated hospitals. Among the 216 patients, we compared 115 patients with an LNY of ≥ 20 and 101 with an LNY of < 20 to investigate the impact of LNY on surgical and oncological outcomes. Furthermore, we investigated the impact of LNY and the extent of LND on oncological outcomes by dividing the extent of LND into two groups (standard and extended). The 3-year rates of overall survival (OS) (p = 0.256), cancer-specific survival (CSS) (p = 0.791), and recurrence-free survival (RFS) (p = 0.953) did not differ between the two groups divided by the LNY. A higher LNY was associated with a significantly higher lymph node positivity rate (p = 0.020). The incidence of LND-related major complications was not significantly different between the two groups (p = 0.910). The 3-year survival rates did not differ between the two groups divided by the extent of LND: OS (p = 0.366), CSS (p = 0.814), and RFS (p = 0.689). The LNY and extent of LND were not associated with oncological outcomes in patients undergoing LND during RARC, whereas a higher LNY was associated with lymph node positivity. In the era of adjuvant therapy with immune checkpoint inhibitors, LND during RARC has an important diagnostic role in the detection of pathological node positivity.