Evaluating Treatment Patterns and the Role of Neoadjuvant Chemotherapy in Plasmacytoid Urothelial Carcinoma: Insights from a Combined National and Institutional Series

Abstract

Background: Plasmacytoid urothelial carcinoma (PUC) is a rare histologic subtype of urothelial carcinoma of the bladder (BC). Our objective was to characterize treatment patterns and outcomes of PUC in the NCDB and our recent institutional experience. Methods: The NCDB was queried for localized PUC cases between 2004 and 2020. Patients with PUC from a single institution (Yale School of Medicine) were also incorporated from 2021 onwards to not double-count patients. The primary outcomes were overall survival and treatment trends. Results: A total of 146 patients were included, 123 from NCDB and 23 from Yale. The median overall survival (mOS) was 28 [IQR 7.5, 50.3] months, 23 [IQR 8.4, 46.3] months for the NCDB patients, and 36 [IQR 4.3, 68.1] for the Yale patients. The mOS for patients receiving neoadjuvant chemotherapy (NAC) was 60.0 [28.0, 91.9] vs. 14.8 months [0, 34.3] for patients without NAC, p = 0.038, though the benefit was not preserved in a Cox proportional hazard analysis incorporating the clinical stage, receipt of NAC, and age. The peritoneum was the most common site of metastasis (78.3%), followed by the liver and bones. Conclusion: Our findings underscore the formidable challenge posed by PUC, emphasizing its limited response to current therapies. Despite higher pT0 rates with NAC, the OS benefit remains inconclusive, highlighting the need for more effective treatments.