Impact of lymph node dissection on clinical outcomes during nephroureterectomy in patients with clinically node-negative upper urinary tract urothelial cancer: Subanalysis of a multi-institutional nationwide case series of the Japanese Urological Association

Objective: To evaluate the impact of lymph node dissection (LND) on the clinical outcomes during radical nephroureterectomy (RNU) in patients with clinically node-negative upper urinary tract urothelial cancer (UTUC).Methods: Within the nationwide case series of the Japanese Urological Association, which comprises 1509 patients with UTUC diagnosed in 2005, we identified 823 patients with clinically node-negative UTUC who underwent RNU. The extent of limited LND was defined as the renal hilar region only for renal pelvic cancer and as either the pelvic region or para-aortic/paracaval region only for ureteral cancer, while the extent of wider LND was defined as at least one perilesional LND region in addition to limited LND. Multivariate analysis with a Cox regression hazard model was used to evaluate the survival benefit. Results: Among the 823 patients, LND was performed in 197 (23.9%) patients, and 26 (13.2%) of them had pathologically node-positive disease. Of 197 patients who underwent LND, limited and wider LND was performed in 119 (60.4%) and 78 (39.6%) patients, respectively. Patients with node-positive disease showed significantly shorter overall survival than those with node-negative disease. No LND-associated survival improvement was observed in a direct comparison between patients with and without LND. In addition, limited or wider LND was not associated with overall survival or cancer-specific survival. Conclusions: The therapeutic benefit obtained by LND remains unclear regardless of the extent of LND, although LND has diagnostic value with respect to the prediction of a poor prognosis especially in patients with clinically muscle-invasive disease.