Hospital lymph node counts and survival after radical cystectomy

Several studies suggest that patients in whom more lymph nodes are examined have improved survival after radical cystectomy for bladder cancer. Despite growing calls for using lymph node counts as a hospital quality indicator, it has not been established that hospitals that obtain more lymph node have better outcomes.

Using the national Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database (1992-2003), all patients undergoing radical cystectomy for cancer were identified (n = 3603). Hospitals were ranked and sorted into 3 evenly sized groups: low (no patients with >or=10 lymph nodes removed), medium (up to 20% of patients), and high (greater than 20% of patients). Survival rates were assessed for each hospital group, adjusting for potentially confounding patient and hospital characteristics.

On average, low lymph node count hospitals had higher observed mortality rates compared with high lymph node count hospitals (unadjusted hazards ratio [HR], 1.25; 95% confidence interval [95% CI], 1.13-1.39). Low lymph node count hospitals tended to treat patients who were older, had more comorbidity, were of lower socioeconomic status, had higher admission acuity, and had lower procedure volumes. After adjusting for these differences, low lymph node count hospitals tended to have slightly higher mortality (adjusted HR, 1.12; 95% CI, 0.99-1.27), although this finding did not reach statistical significance. Similar findings were evident when other thresholds (lymph node counts >or=5, >or=14, and >or=20) were used.

Hospitals with high lymph node counts tend to have higher survival rates after radical cystectomy for bladder cancer. However, this effect is modest and is explained, in large part, by confounding patient and hospital factors.