ECE2015 Guided Posters Endocrine tumours and neoplasia – NETS (9 abstracts)
Cliniques Universitaires Saint Luc, Brussels, Belgium.
Background: Insulinomas are the most common functional neuroendocrine tumours of the pancreas. Hypoglycaemic manifestations are highly variable and largely independent on tumour size and severity of insulin hypersecretion.
Objectives: In this study we investigated the clinical, biological and tumoural characteristics of a large series of patients with insulinoma and we evaluated the sensitivity of peripheral tissues to insulin before and after surgery.
Patients and methods: This is a retrospective analysis of 40 patients followed between 1982 and 2012 in our academic hospital. Insulin sensitivity and β-cell function could be evaluated by HOMA test in a subset of these patients.
Results: The mean age at onset of symptoms was 48.8±20.1 years and the mean age at diagnosis was 50.7±19.9 years. A sex ratio of 0.6 (15 men for 25 women) was found. Adrenergic symptoms were observed in 75% of patients and neuroglucopenic symptoms in 90%. In addition, 33% of patients suffered from epileptic disorders and 20% from psychiatric manifestations. Weight gain was observed in 40% of the patients. The most effective imaging techniques to localize the tumour were endoscopic ultrasound (90% sensitivity) and intraoperative ultrasound (94% sensitivity). Insulin sensitivity (measured outside hypoglycaemic episodes) was greatly reduced in patients with insulinoma (38.9±22.3%), while β-cell function was increased (359.0±171.5%), but to a variable extent (range 110.6678.6%). After complete resection of the tumour and disappearance of hypoglycaemia, insulin sensitivity normalizes from 36.9±19.0 to 80.6±18.4% (P<0.001) in 12 cured patients with available pre- and post-operative HOMA tests.
Conclusion: The general characteristics of our series are consistent with the general features reported for insulinomas in the literature. We also show that in response to chronic hyperinsulinaemia, patients with insulinoma develop protective mechanisms responsible for a marked insulin resistance, which is fully reversible after complete resection of the tumour.