Background & aims
Small intestinal neuroendocrine tumours (SI-NETs) are the most frequent malignant tumours of the small intestine. Population based studies on SI-NETs are scarce. We aimed to examine the incidence, presentation of disease and prognosis of SI-NET and to determine patient prognosis in those undergoing emergency or elective surgery.
This was a retrospective population-based study. Information on all patients diagnosed with neuroendocrine tumours of the small intestine (excluding duodenum) from the beginning of the Icelandic Cancer Registry and the pathology departments in the country (1966–2017). Detailed phenotypic information was obtained from medical records on symptoms at diagnosis, treatment, recurrence and survival.
A total of 113 patients with SI-NETs were identified, 3 patients were excluded due to lack of data and/or diagnostic error, leaving 110 patients for final analysis. The incidence of SI-NET was 0.78/100,000 and did not increase during the study period. A total of 42 % (n = 46) of patients were diagnosed incidentally. Long-term prognosis, after a landmark of 12 months, was better in patients who were diagnosed incidentally (HR 0.52; p = 0.03). Overall 89 % (n = 98) of cases underwent surgical resection of the primary tumor, 31 % (n = 30) patients acute or semi-acute surgery and 69 % (n = 68) elective surgery. Emergency surgery was associated with a 6-fold risk of death in the first 12 months after surgery (HR: 5.99; p = 0.01) and associated with more severe surgical complications. However, there was no difference in the long-term risk of death after the first 12 months (HR: 1.39; p = 0.27).
The incidence of SI-NETs has not changed significantly in the last decades. Incidentally diagnosed SI-NET was associated with a favorable long-term prognosis. Emergency surgery in patients with SI-NET was associated with a significantly worse short-term risk of mortality compared to those who underwent elective surgery.
- • Despite advances in imaging and endoscopy incidence of SI-NETs did not change over time.
- • Incidental diagnosis of SI-NET was associated with an earlier stage disease and improved long-term prognosis.
- • Emergency surgery was associated with a 6-fold risk of death in the first 12 months after surgery.
Small intestinal neuroendocrine tumors (SI-NETs) originating from enterochromaffin cells of the small intestine are the most frequent malignant tumors of the small bowel yet their annual incidence has been reported to be only 1–1.8 per 100.000 .
Neuroendocrine tumors are known for a more indolent course of disease than many other malignancies and the 5-year survival of patients with disseminated disease at diagnosis has been reported to be 60–70 % . Probably due to the relative rarity of these tumors, there is a lack of knowledge of their natural history and what affects their prognosis. Particularly, population based studies with well characterized patients with long-term follow-up are lacking.
The presentation of SI-NET varies and the disease can be detected incidentally or in symptomatic patients. It is not clear whether that affects prognosis. The effect of acute or emergency surgery on prognosis needs to be further evaluated. In a Swedish study SI-NET patients who underwent emergency surgery had better prognosis than patients who underwent elective surgery . This was somewhat unexpected and in contrast with studies on patients with colorectal cancer (CRC) where an acute presentation has been associated with a worse prognosis .
The aims of the current study were to examine the incidence and clinical presentation of SI-NET in the Icelandic population and to evaluate the prognosis of SI-NET patients and whether it has changed in the last decades. Furthermore, to examine the relationship between clinical presentation and surgical acuity and prognosis.