Effect of lymph node dissection on stage-specific survival in patients with upper urinary tract urothelial carcinoma treated with nephroureterectomy

Background We aimed to estimate the stage-specific impact of lymph node dissection (LND) on survival for upper urinary tract urothelial carcinoma (UTUC) patients treated with nephroureterectomy (NU). Methods Overall, 7278 UTUC patients undergoing NU within the SEER database from 2004 to 2015 were identified. Kaplan-Meier plots illustrated overall survival (OS) and cancer-specific survival (CSS) rates according to LND status. Multivariable Cox regression analyses assessed the effect of LND on OS and CSS rates stratified by pathological tumor stage. Results LND was performed in 26.9% of patients, and in 18.6, 23.3, 31.2 and 45.9% for pT1, pT2, pT3 and pT4 patients, respectively (P < 0.001). In multivariable Cox regression analyses, LND was associated with a higher OS or CSS in UTUC patients with pT3 and pT4 disease (all P < 0.05), but failed to achieve independent predictor status in patients with pT1 and pT2 disease (all P > 0.05). LND with 1 to 3 regional lymph nodes removed was prone to a higher OS or CSS only in pT4 compared to no LND (both P < 0.01). LND with 4 or more regional lymph nodes removed predisposed to a higher OS or CSS in pT3 or pT4 (all P < 0.05). Conclusions The beneficial effect of LND especially LND with 4 or more regional lymph nodes removed on survival was evident in pT3/4 patients. LND can be considered for pT3 and pT4, for pT1/2 remains to be seen, both of which will be verified by further prospective studies.