Abstract
BACKGROUND: Neuroendocrine tumours of the small intestine (SI-NETs) are rare gastrointestinal neoplasms with an annual incidence of about one per 100 000. Patients with apparently similar tumours have variable outcomes. The aim of this study was to identify postoperative prognostic factors identifiable after initial surgery. METHODS: This was a nested case-control study of patients with SI-NETs who were treated between 1961 and 2001. Data were retrieved from the Swedish Cancer Registry. Patients who died from the SI-NET and corresponding controls (who outlived cases by at least 1 month), matched by age at diagnosis and calendar period, were included. Sex, postoperative symptoms, postoperative 5-hydroxyindoleacetic acid (5-HIAA) values, European Neuroendocrine Tumor Society (ENETS) stage, insufficiency of the tricuspid valve, radical secondary surgery and secondary malignancy were studied as potential prognostic factors. RESULTS: In total, 1122 patients were included (561 cases, 561 controls). Postoperative factors of prognostic importance included hormone-related symptoms, stage IV disease, raised levels of 5-HIAA, insufficiency of the tricuspid valve, secondary surgery not being macroscopically radical and a second malignancy. CONCLUSION: Stage and symptomatic disease are important prognostic factors in SI-NET.