Role of neoadjuvant chemotherapy in micropapillary urothelial carcinoma: a multi-institutional analysis from the Korean Bladder Cancer Research Group

초록

Purpose We evaluated the association of neoadjuvant chemotherapy (NAC) with pathological downstaging and overall survival (OS) in patients with micropapillary urothelial carcinoma (MPUC) in a multi-institutional cohort. Methods We retrospectively analysed patients who underwent radical cystectomy for muscle-invasive bladder cancer between 2003 and 2024. Patients were classified as having pure urothelial carcinoma (UC) or MPUC, and baseline clinicopathological characteristics were compared between the groups. The primary endpoint was complete pathological response (pT0N0; ypT0N0 in NAC-treated patients) and the secondary endpoint was OS, evaluated using logistic regression, Kaplan-Meier, and Cox proportional-hazards analyses. Results Amongst 1634 patients, 88 (5.4%) had MPUC. NAC was administered to 26.6% of patients with pure UC and 23.9% of those with MPUC. The pT0N0 rate was higher with NAC in both groups (pure UC, 22.4% vs 8.0%; MPUC, 33.3% vs 6.0%). NAC was independently associated with pT0N0 in the pure UC group (odds ratio [OR] 3.36, 95% confidence interval [CI] 2.42-4.65) and, on univariable analysis, in the MPUC group (OR 7.87, 95% CI 2.02-30.62). However, OS did not differ significantly by NAC status in either subtype (log-rank P = 0.426 and P = 0.281), and MPUC histology was not independently associated with OS after multivariable adjustment (adjusted hazard ratio 0.87, 95% CI 0.61-1.25). The number of MPUC patients achieving pT0N0 was small (n = 11), limiting the statistical power of the survival analyses. Conclusion Neoadjuvant chemotherapy was associated with a higher pathological complete response rate in micropapillary urothelial carcinoma; however, whether this translates into an OS benefit remains unclear based on the available survival data. These survival findings should be regarded as exploratory and hypothesis-generating.

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