Who will benefit most from lymph node dissection in invasive upper tract urothelial carcinoma: a matched case-control study

Background: Limited or regional lymphadenectomy (lymph node dissection, LND), which can help in postoperative risk stratification, is performed with radical nephroureterectomy (RNU). However, the specific ones are appropriate for LND in upper tract urothelial carcinoma (UTUC) has long been debated. We determined the clinical value of LND in different groups of UTUC patients who underwent RNU and someone who benefit most from LND in this study.Methods: Patients diagnosed with UTUC between 2004 and 2015 with available TNM stage classification were identified from 18 Surveillance, Epidemiology and End Results (SEER) registries. Propensity score analysis was used to match the baseline differences of patients. Results: This study included 5426 patients, and 2000 patients with invasive UTUC were matched (1000 patients with LND vs. 1000 patients without LND). The 5-year cancer-specific survival (CSS) estimate for the total cohort was 73.5%. After matching, the LND group had a higher 5-year CSS rate than the no-LND group (77.2% vs. 70.1%, P = 0.002). In heterogeneity analysis, there were significant differences between LND groups and no-LND in stage T4 (52.5% vs. 23.3%, P< 0.001), lymph node metastatic tumors (48.0% vs. 21.2%, P=0.015) and non-distant metastatic tumors (78.5% vs. 71.5%, P = 0.002). According to the most recent pathological prognostic groups classification, significant differences in survival were found between groups only with stage IV tumors (52.0% vs. 25.1%, P< 0.001). However, only stage T4NxM0 tumor patients were found a significant difference between LND groups in subgroup analysis (57.4% vs. 29.9%, P< 0.001). Conclusions:LND may improve the survival of invasive UTUC patients who undergo RNU, especially in T4NxM0 tumor patients. However, this hypothesis requires further confirmation.