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

Bladder preservation was feasible for selected patients with localized primary urinary bladder small cell carcinoma who achieved a complete response to neoadjuvant chemotherapy and then received concurrent chemoradiation, according to a retrospective study of 60 patients treated at one institute. The researchers reported median event-free survival of 42.4 months and median overall survival of 52.7 months across the full cohort, while emphasizing that the findings require cautious interpretation and prospective confirmation. Primary urinary bladder small cell carcinoma is a rare, aggressive malignant neoplasm for which established treatment guidelines are lacking.

The study included patients who presented to the institute between 2012 and 2021. Twelve of the 60 patients, or 20%, had metastatic disease at diagnosis, while the remaining 48 had localized disease. Among those with localized disease, nine underwent upfront radical cystectomy and the others received neoadjuvant chemotherapy.

Platinum-etoposide was used more frequently than platinum-gemcitabine in the neoadjuvant, adjuvant and metastatic settings, accounting for 57% of recorded treatment use. Of the 39 patients with localized disease who received neoadjuvant chemotherapy, 18, or 46%, achieved a complete response. These complete responders proceeded to concurrent chemoradiation as part of the bladder-preserving strategy.

Platinum-etoposide was associated with greater odds of complete response than platinum-gemcitabine: the reported odds ratio was 7.27, with a 95% confidence interval of 1.33 to 39.86 and a p-value of 0.02. The wide confidence interval indicates substantial uncertainty around the estimate, which came from a retrospective cohort with relatively few patients and more than one chemotherapy regimen. Across the study population, cumulative five-year event-free survival was 46.9% and cumulative five-year overall survival was 49.5%.

Multivariable analysis identified the platinum-gemcitabine protocol as an independent factor associated with worse event-free survival compared with platinum-etoposide. Initially metastatic disease was an independent factor associated with poorer overall survival compared with localized disease. These were statistical associations within the retrospective cohort, not evidence from a randomized comparison that either regimen or disease status caused the observed differences.

The findings support the feasibility of bladder preservation in selected patients whose localized disease responds completely to neoadjuvant chemotherapy and who subsequently undergo concurrent chemoradiation. The study did not provide a randomized comparison between bladder-preserving treatment and radical cystectomy, so it cannot establish that preserving the bladder produces equivalent survival outcomes. Retrospective selection, the small sample and treatment delivered at a single institution also limit generalization.

The investigators called for further prospective evaluation, and the results should therefore be interpreted as an encouraging observation rather than definitive evidence for changing treatment standards.

Subject of Research: Bladder-preserving treatment after chemotherapy for localized primary urinary bladder small cell carcinoma

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

Article References: Ismail, Y., Kamal, A., Aboulkassem, H., Ashour, M. G., AbouGabal, A. A., Allam, R. M., Gad, M., Mostafa, M. E., & Taher, M. (2026). Bladder preservation is still feasible in the rare aggressive small cell carcinoma subtype. Medical Oncology, 43(11), Article 339. https://doi.org/10.1007/s12032-026-03437-w

Image Credits: AI Generated

DOI: 10.1007/s12032-026-03437-w

Keywords: bladder cancer, small cell carcinoma, bladder preservation, neoadjuvant chemotherapy, chemoradiation, platinum-etoposide, complete response, retrospective cohort, event-free survival, overall survival, Bladder, preservation