Radical cystectomy in non-metastatic sarcomatoid bladder cancer: A direct comparison vs urothelial bladder cancer.

INTRODUCTION: The effect of radical cystectomy (RC) on cancer-specific mortality (CSM) is unclear in non-metastatic sarcomatoid bladder cancer (SBC) patients. We aimed to test the benefit of RC in SBC, and to perform a direct comparison vs urothelial bladder cancer (UCB). MATERIALS AND METHODS: Within the Surveillance, Epidemiology, and End Results database (SEER 2001-2018) all non-metastatic SBC and UBC patients were identified. Endpoint of interest was CSM. Propensity score matching (PSM), cumulative incidence plots, competing risks regression (CRR) analyses, three-months landmark analyses, and sensitivity analyses were performed. All results were stratified according to organ-confined (OC: T2N0M0) vs non-organ-confined (NOC: T3-4N0M0 or TanyN1-3M0) stages. RESULTS: Of 554 SBC patients, 49 vs 51% harbored OC vs NOC stages. Of 47,741 UBC patients, 62 vs 38% harbored OC vs NOC stages. RC rates were 33 vs 67% in OC vs NOC-SBC patients, and 40 vs 60% in OC vs NOC-UBC patients. After 1:1 PSM, comparison between RC vs no-RC was performed in OC-SBC (67 patients per group), OC-UBC (7611 patients per group), NOC-SBC (63 patients per group), and NOC-UBC patients (4644 patients per group). CRR hazard ratios associated with RC vs no-RC were 0.37 (p < 0.001) in OC-SBC vs 0.45 (p < 0.001) in OC-UBC, and 0.56 (p = 0.01) in NOC-SBC vs 0.68 (p < 0.001) in NOC-UBC. These results were replicated in sensitivity and landmark analyses. CONCLUSIONS: The protective effect of RC vs no-RC is stronger in SBC than UBC patients, regardless of OC vs NOC stages.