Re: Association Between Lymph Node Yield and Survival Among Patients Undergoing Radical Nephroureterectomy for Urothelial Carcinoma of the Upper Tract

BACKGROUND Prior studies examining the value of lymph node (LN) dissection (LND) in patients with urothelial carcinoma of the upper urinary tract (UTUC) have produced conflicting results. The objective of the current study was to assess the relationship between LN yield and survival among patients undergoing radical nephroureterectomy (RNU). METHODS The National Cancer Data Base was used to identify patients with non-metastatic UTUC who were treated with RNU between 2004 and 2012. The association between LN yield and overall survival (OS) was assessed using Cox proportional hazards regression, with adjustment for patient, tumor, and facility characteristics. RESULTS Of the 14,472 patients, 2926 (20%) underwent LND. The median yield was 2 LNs (interquartile range 1-6 LNs). Among the entire cohort and the LN-negative (pN0) subgroup, a higher LN yield was associated with lower all-cause mortality (multivariable hazard ratio [HR] 0.94 per 5 LNs removed, 95% confidence interval [95% CI] 0.89-1.00 [P = .034] for the entire cohort and HR 0.86, 95% CI 0.79-0.94 [P = .001] for the pN0 subgroup). Among patients with positive LNs (pN+), there was no association noted between LN yield and OS; however, positive and negative LN counts were found to be independent predictors of OS (HR 1.27 per 5 positive LNs, 95% CI 1.16-1.39 [P