Bladder preservation is still feasible in the rare aggressive small cell carcinoma subtype

Primary urinary bladder small cell carcinoma (UBSCC) is a rare aggressive malignant neoplasm with no established treatment guidelines. Radical cystectomy (RC) alone is suboptimal in localized disease; therefore, chemotherapy and radiotherapy are required. We aimed to report our outcomes of UBSCC.

UBSCC patients who presented to our institute between 2012 and 2021 were retrospectively evaluated for their clinicopathologic features, management modalities, event-free (EFS) and overall survival (OS).

Sixty patients included. Metastatic disease was present at diagnosis in 12 (20%). For localized disease patients, upfront RC was done in 9(19%); meanwhile, neoadjuvant chemotherapy was employed in the rest. In the latter group,18 patients (46%) achieved complete response (CR), and those proceeded to further concurrent chemoradiation as a bladder preservation management. Platinum-etoposide (PE) regimen was more frequently used than platinum-gemcitabine (PG) in the neoadjuvant/adjuvant and metastatic settings (57%). The latter combination was independent factor associated with less likelihood achievement of CR about 7 times that of PE (OR:7.27;95%CI:1.33-39.86;p = 0.02). The median EFS & OS were 42.4 & 52.7 months, respectively, with cumulative 5-year EFS & OS of 46.9 & 49.5%, respectively. On multivariate analysis, PG protocol was independent factor associated with worse EFS compared to PE, while initially metastatic disease was independent factor linked with poor OS compared to localized disease.

Despite its hostile behavior, the high CR rate in our study confirms the remarkable sensitivity of localized UBSCC to chemotherapy especially PE. Bladder preservation is feasible in those achieved CR, and is associated with favorable outcomes. These findings, however, should be interpreted cautiously and warrant further prospective evaluation.