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.
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.
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.
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. Cancer 2011;. © 2011 American Cancer Society.