A Surveillance, Epidemiology, and End Results analysis of small cell carcinoma of the bladder: epidemiology, prognostic variables, and treatment trends

Background: Small cell carcinoma of the urinary bladder (SCCB) is difficult to characterize and study because of its rarity. For the current study, a large population-based database was used to address ill-defined clinical parameters for this disease.

Methods: The authors analyzed the incidence, sociodemographics, prognostic variables, and treatment trends of this cancer in the Surveillance, Epidemiology, and End Results (SEER) limited database (1991-2005). The SEER-Medicare database (1991-2005) was used to estimate chemotherapy use.

Results: There were 642 patients in the SEER limited dataset. From 1991 to 2005, the incidence of SCCB increased significantly from 0.05 to 0.14 cases per 100,000 population (P < .01; approximately 500 new cases of SCCB per year, representing 0.7% of all bladder malignancies). The median overall survival was 11 months. Elderly Caucasian men were the most commonly affected (ratio of Caucasians to non-Caucasians, 10:1; ratio of men to women, 3:1; median age, 73 years). Age, race, marital status, and TNM staging were identified as independent prognostic variables (P < .05). Patients who had stage IV disease without distant metastasis (ie, positive lymph node status) had overall and cancer-specific survival rates similar to those of patients who had stage I through III disease, but they had significantly better survival compared with patients who had distant metastasis (P < .0001). Transurethral resection of the bladder tumor became the most common surgical treatment (P < .0001), representing 55% of patients from 2001 to 2005. The receipt of radiation and chemotherapy did not change significantly during the study period.

Conclusions: These comprehensive data delineated the patient population for this rare disease, described several independent prognostic variables, and demonstrated clear treatment trends for this disease. The results suggest that a simpler staging system (ie, limited stage vs extensive stage) may be appropriate for patients with SCCB.