Epidemiology of Small Bowel Carcinoids in a Defined Population

Background This retrospective study describes the epidemiology of small bowel carcinoids in a geographically defined population, with no other selection bias. Methods All patients (n = 145) resident in Jonkoping County when diagnosed with carcinoid in the jejunum or ileum from 1960 to 2005 were included. Medical records were reviewed in detail, and tumor specimens were histopathologically and immunohistochemically reexamined when required (n = 44). Results The annual age-adjusted incidence of small bowel carcinoids was 1.12 (95% confidence interval 0.95-1.31) per 100,000 persons. Median age at diagnosis was 69 years. The predominating presenting symptom was uncharacteristic abdominal pain (50%), whereas a smaller number suffered from typical flushes (13%). Surprisingly, 14% presented with overt gastrointestinal hemorrhage. Most of the patients diagnosed based on their symptoms had metastases at diagnosis (44% regional, 40% distant). Metastasized tumors by definition belong to World Health Organization (WHO) histopathologic group 2; and when reexamined, most (83%) of the localized tumors were also found to belong to WHO group 2. Conclusions In comparison to previous reports, a higher age-adjusted incidence of small bowel carcinoids was observed, and the patients were clearly older at the time of diagnosis. Even with metastatic disease, the presenting symptoms were usually uncharacteristic, and the carcinoid syndrome was infrequently seen.