Population-based study of islet cell carcinoma

Abstract

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.

FIG. 1.

Age at diagnosis of 1310 cases of islet cell carcinoma. The median and mean (SD) ages at diagnosis are 59 and 58 (15) years.

FIG. 2.

Age at diagnosis by race. White patients were older at the time of diagnosis (P = .02). The median age at diagnosis for white, African American, and other racial groups was 60 (mean 58, SD 14.9), 55 (mean 54.5, SD 16.5), and 55.5 (mean 57, SD 16.5), respectively.

FIG. 3.

Stage and survival of 1157 patients from the time of diagnosis. Median duration of survival of patients with localized (n = 167), regional (n = 289), and distant disease (n = 558) was 124, 70, and 23 months, respectively (P < .001).

FIG. 4.

Age and survival. For the <59 age group, the median survival durations for localized, regional, and distant disease were 282 (95% CI, 204–360) months, 114 (95% CI, 83–145) months, and 35 (28–42) months. For the 60+ age group, the median survival durations for localized, regional, and distant disease were 46 (95% CI, 20–72) months, 38 (95% CI, 24–52) months, and 13 (95% CI, 10–16) months (P < .001).