The oncological outcomes of small cell carcinoma of the bladder.

Introduction: Small cell carcinoma of the bladder (SmCC) is a rare and aggressive genitourinary malignancy. The paucity of clinical trials and outcome data provide no standard treatment guidelines. Accordingly, patient prognosis is poor. Our goal was to present the first comprehensive in-depth analysis of SmCC in a tertiary Canadian centre.

Methods: We retrospectively reviewed all patients diagnosed with primary SmCC at the London Regional Cancer Program between January 1990 and 2016. The primary outcome was overall survival (OS). We examined a number of secondary outcomes and baseline characteristics.

Results: We identified 15 men and six women (median age 72 years) with a SmCC diagnosis (median followup 11.33 months). Median Charlson Comorbidity Index score was 7 (interquartile range [IQR] 5-10) and 15 patients had a smoking history. Most common presentation was gross hematuria (18 patients, 86%), and pT2 stage at transurethral resection of the bladder tumour (TURBT) (n= 7/21, 33%), although five patients had cT4 (24%). Pure SmCC was found in nine individuals (43%), whereas 12 had mixed differentiation (57%). From initial staging, 15 patients had extravesical disease (71%), 10 had positive pelvic lymphadenopathy (48%), and distant metastases occurred in six (29%). In our series, five individuals (24%) underwent cystectomy, 18 (86%) received radiation, and 14 (67%) received adjuvant chemotherapy. The median OS was 15 months (two-year OS was 19%).

Conclusions: SmCC is a rare and aggressive form of bladder cancer. Despite multimodal therapy, prognosis remains guarded, with little improvement seen over the study's 25-year duration. An understanding of study limitations is warranted in interpretation of results.