Epidemiology of Neuroendrocine Intestinal Tumours

Little is known about the epidemiology of digestive neuroendocrine tumours (NETs). NETs remain a rare cancer, representing 1% of all digestive cancers. In France, incidence rates are estimated to around 1.1/100,000 inhabitants in males and 0.9/100,000 in females. The incidence rates got increased over time, with probably more than 1,000 new cases per year in France. Because of their relatively good prognosis, NETs are the second more prevalent digestive cancer after colorectal cancer. Most digestive NETs are well-differentiated (WDNETs); poorly differentiated neuroendocrine carcinomas (PDNEC) account for less than 20% of the cases in most of the series. Among bowel-NETs, the most frequent anatomical localisations are colorectal and small bowel. Functional NETs are rare (<20%); most of them are carcinoids, insulinomas and gastrinomas. More than half NETs are metastatic at diagnosis, mainly in the liver. Tumour differentiation, histologic grade, anatomic site and stage are the main prognostic factors. WD-NETs are slow-growing tumours (relative survival of 55% at 5 years), whereas PDNEC are highly aggressive (relative survival of 4.5% at 5 years).