Plasmacytoid urothelial carcinoma: A clinicopathological study.

Abstract

482 Background: Plasmacytoid urothelial carcinoma (PUC) is a rare variant histology with poor prognosis. We report clinical outcomes on patients with PUC. Methods: We retrospectively reviewed treatments and outcomes in patients with PUC seen at our institution from 1996 through 2016. The Kaplan-Meier method was used to calculate overall survival. Results: A total of 69 patients with a median age of 68 years were identified. Five patients presented with metastatic disease, whereas 64 were diagnosed with clinically localized PUC. Fifty-seven patients underwent radical cystectomy and the remainder elected for bladder preservation approaches. At time of cystectomy, 6 patients were found to have pathologically organ-confined disease (≤pT2 N0), and 51 had non-organ-confined disease (pT3,T4 or N+), 2 of which were noted to have diffuse peritoneal carcinomatosis. Twenty-eight patients had positive surgical margins, most of which had extensive infiltrative disease not amenable to complete excision. Of the 14 patients who received neoadjuvant cisplatin-based chemotherapy, 10 (71.4%) patients had lymph node involvement and 12 (85.7%) had pT3/4 disease at cystectomy. Only one patient had a pathologic complete response with pT0N0. Thirteen patients received adjuvant chemotherapy, 2 of which received neoadjuvant chemotherapy as well. Two patients received immunotherapy, with only a short-lived response. Median survival for all patients with PUC from time of initial diagnosis was 17.7 months (mo), and 14.0 mo from time of cystectomy for patients undergoing radical cystectomy. Patients with desmoplastic morphology tended to have the worst clinical outcomes (median survival 10.1 mo), whereas classic and pleomorphic subtypes had better survival (median survival 18.6 and 30.4 mo, respectively) (p = 0.083). Conclusions: PUC is an aggressive variant with overall poor outcomes. There appeared to be three morphologic subtypes of plasmacytoid disease; classic, desmoplastic and pleomorphic, with potentially distinct survival outcomes. Chemotherapy, whether in the neoadjuvant or adjuvant setting, or immunotherapy, appeared to have little effect on this cohort. Molecular markers/genomic analysis may provide insight to novel therapeutic approaches.