Sarcomatoid urothelial carcinoma (SUC): A single-institution experience of oncologic outcomes and recurrence patterns.

Abstract

465 Background: SUC is a rare histology with aggressive behavior. We evaluated outcomes and recurrence patterns of patients (pts) with SUC, in comparison with conventional urothelial carcinoma (CUC). Methods: We retrospectively assessed our radical cystectomy (RC) database to identify pts with cT2-4 SUC (any %) or CUC, at RC or transurethral resection specimens. Clinicopathologic/treatment data were captured and compared with t and χ2 tests, as appropriate. Overall survival (OS; diagnosis to death) and recurrence-free survival (RFS; RC to recurrence or death) were estimated (KM method). Significant factors in univariable (UVA) Cox regression for OS were included in multivariable analysis (MVA). Results: We identified 38 consecutive pts with cT2-4 SUC and 287 with CUC (2003-2018); 17 (45%) and 162 (56%) received neoadjuvant chemotherapy (NAC). The primary non-mesenchymal component was urothelial in all SUC cases. SUC had higher rates of pT3/4 (66% vs. 35%, p < .001) but comparable rates of pN+ disease (26% vs. 20%, p = .38). Complete response (ypT0N0) after NAC was lower for SUC (6% vs. 35%, p = .02). Median follow-up was 73.6 months (95%CI 62.6 – 84.7). Median RFS and OS was inferior among pts with SUC (9.4 vs 109.8 months, p < .001, 19.7 vs. 130.4 months, p < .001 respectively). On MVA, SUC was independently associated with worse OS ( Table). Of 17 (45%) pts with SUC who recurred post-RC, 5 presented with abdomino-pelvic cystic masses, with an average time to recurrence < 5 months. Conclusions: SUC was associated with high rates of extravesical spread at RC and worse NAC response, RFS and OS, vs. CUC. Development of abdomino-pelvic fluid collections should raise suspicion of recurrence among pts with this histology. [Table: see text]