15103 Background: Little is known about the epidemiology and natural history of islet cell carcinoma. In this study, we examine the epidemiology, natural history, and prognostic factors impacting survival duration for islet cell carcinoma using population based registries. Methods: The Surveillance, Epidemiology, and End Results (SEER) Program database (1973 - 2003 release April 2006) was used to identify cases of islet cell carcinoma using histology codes and tumor site. Results: 1,310 (619 women and 691 men) cases were identified. Median age at diagnosis was 59 years. The annual age-adjusted incidence in the periods covered by SEER 9 (1973–1991), SEER 13 (1992–1999), and SEER 17 (2000–2003) were 0.16, 0.14, and 0.12 per 100,000 respectively. The estimated 28-year limited duration prevalence on January 1, 2003 in the United States was 2,705 cases. Insulinomas (57%), glucagonomas (53%), and VIPomas (64%) were more likely to be located in the tail of the pancreas while gastrinomas were more likely to be lo...