Role of lymph node dissection in radical cystectomy

The number of lymph node dissections (LNDs) is an independent factor influencing the survival time of patients with bladder cancer (BCa) after radical resection (RC). The present study aimed to investigate the association between the number of LNDs and the survival of patients with BCa at different stages and who underwent RC in the United States of America and China. Records from 17,730 American patients with BCa and 158 Chinese patients with BCa were collected from the Surveillance, Epidemiology and End Results (SEER) and the Shanghai Tenth People's Hospital (China) databases, respectively. Kaplan-Meier curve and χ(2) test were used to determine the overall survival time (OS) of patients with BCa. Cox regression analysis was used to analyze the effects of LND number on OS. Overall, 13,421 (75.7%) patients were negative for lymph node metastasis (N0) and 4,309 (24.3%) were positive for lymph node metastasis (N+) among the 17,730 American patients with BCa. In the group of 158 Chinese patients, 125 (79.1%) were N0 and 33 (20.9%) were N+. In the American patients, the median number of dissected nodes was 11.0 [interquartile range (IQR)=3.0–21.0] for N0 patients and 14.0 (IQR=8.0–23.0) for N+ patients. The median number of LNDs was 5.0 (IQR=2.0–7.0) for Chinese N0 patients and 5.0 (IQR=1.5–10.5) for Chinese N+ patients. The number of LNDs may therefore be an independent factor associated with survival in patients who underwent RC. Furthermore, a higher number of LNDs was associated with longer OS in patients with BCa [American patients, ≥13 nodes vs. ≤5 nodes, hazard ratio (HR)=0.62, 95% confidence interval (CI)=0.59–0.65, P<0.001; Chinese patients, ≥5 nodes vs. ≤1 node, HR=0.27, 95% CI=0.12–0.62, P=0.002]. The number of LNDs in patients with BCa and N+ was higher compared with number of LNDs in patients with BCa and N0 who underwent RC. More extensive LND improved the OS in both the patients from USA and China. Increasing the number of LNDs may therefore be crucial when treating patients with BCa.