Population-based study of islet cell carcinoma.

BACKGROUND: We examine the epidemiology, natural history, and prognostic factors that affect the duration of survival for islet cell carcinoma by 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 by histology codes and tumor site.

RESULTS: A total of 1310 (619 women and 691 men) cases with a median age of 59 years were identified. The annual age-adjusted incidence in the periods covered by SEER 9 (1973-1991), SEER 13 (1992-1999), and SEER 17 (2000-2003) were .16, .14, and .12 per 100,000, respectively. The estimated 28-year limited duration prevalence on January 1, 2003, in the United States was 2705 cases. Classified by SEER stage, localized, regional, and distant stages corresponded to 14%, 23%, and 54% of cases. The median survival was 38 months. By stage, median survival for patients with localized, regional, and distant disease were 124 (95% CI, 80-168) months, 70 (95% CI, 54-86) months, and 23 (95% CI, 20-26) months, respectively. By multivariate Cox proportional modeling, stage (P < .001), primary tumor location (P = .04), and age at diagnosis (P < .001) were found to be significant predictors of survival.

CONCLUSIONS: Islet cell carcinomas account for approximately 1.3% of cancers arising in the pancreas. Most patients have advanced disease at the time of diagnosis. Despite the disease's reputation of being indolent, survival of patients with advanced disease remains only 2 years. Development of novel therapeutic approaches is needed.