Lack of Effectiveness of Postchemotherapy Lymphadenectomy in Bladder Cancer Patients with Clinical Evidence of Metastatic Pelvic or Retroperitoneal Lymph Nodes Only: A Propensity Score-based Analysis

Background: Limited data is available on the role, and extent of, postchemotherapy lymphadenectomy (PC-LND) in patients with clinical evidence of pelvic (cN1–3) or retroperitoneal (RP) lymph node spread from urothelial bladder carcinoma. Objective: To compare the outcomes of operated versus nonoperated patients after first-line chemotherapy. Design, setting, and participants: Data from 34 centers was collected, totaling 522 patients, treated between January 2000 and June 2015. Criteria for patient selection were the following: bladder primary tumor, lymph node metastases (pelvic ± RP) only, first-line platinum-based chemotherapy given. Intervention: LND (with cystectomy) versus observation after first-line chemotherapy for metastatic urothelial bladder carcinoma. Outcome measures and statistical analysis: Overall survival (OS) was the primary endpoint. Multiple propensity score techniques were adopted, including 1:1 propensity score matching and inverse probability of treatment weighting. Additionally, the inverse probability of treatment weighting analysis was performed with the inclusion of the covariates, that is, with doubly robust estimation. Results and limitations: Overall, 242 (46.4%) patients received PC-LND and 280 (53.6%) observation after chemotherapy. There were 177 (33.9%) and 345 (66.1%) patients with either RP or pelvic LND only, respectively. Doubly robust estimation-adjusted comparison was not significant for improved OS for PC-LND (hazard ratio [HR]: 0.86, 95% confidence interval [CI]: 0.56–1.31, p = 0.479), confirmed by matched analysis (HR: 0.91, 95% CI: 0.60–1.36, p = 0.628). This was also observed in the RP subgroup (HR: 1.12, 95% CI: 0.68–1.84). The retrospective nature of the data and the heterogeneous patient population were the major limitations. Conclusions: Although there were substantial differences between the two groups, after accounting for major confounders we report a nonsignificant OS difference with PC-LND compared with observation only. These findings may be hypothesis-generating for future prospective trials. Patient summary: We found no differences in survival by adding postchemotherapy lymphadenectomy in patients with pelvic or retroperitoneal lymph node metastatic bladder cancer. The indication to perform postchemotherapy lymphadenectomy in the most suitable patients requires additional studies.