MEN1 and pancreatic NETs

Introduction
Pancreatic NETs are present in virtually all patients with MEN-1, but not visualized by imaging or detected by biochemistry in all. The managemnt of these patients are outlined below.

Diagnosis of pancreatic NETs in MEN 1
About 60% develop tumors visible by contrast-enhanced CT or endoscopic ultrasound (EUS). They may secrete a variety of pancreatic hormones, sometimes sufficient to cause a clinical syndrome, such as insulinoma or gastrinoma. Typically the patients are young, between 20-40 years of age. Diagnosis and surveillance after detection are performed by repeated biochemistry and preferably EUS, which is the most sensitive localization method. A standardized meal test may also reveal pathological raise of PP or gastrin in doubtful cases.

Treatment of pancreatic NETs in MEN 1
Patients with signs of clinical symptoms, from insulinoma, gastrinoma, VIPoma or glucagonoma should be treated with surgery, regardless of the size of the detected tumors. Patients with non-functioning NETs should be treated prohylactically to avoid metastases. In Uppsala we have used a limit of approximately 1 cm before surgery. Studies have shown that if tumors grow larger than 1 cm, the rate of metastases increases. Patients who do not fulfil requirements for surgery are surveilled as outlined above.

Surgery.
MEN1 patients are most often subjected to distal subtotal 80% pancreatectomy combined with enucleation of tumours in the pancreatic head. Concomitant duodenotomy is done in patients with raised gastrin (with ZES) to identify and remove duodenal gastrinomas. Pancreatico-duodenectomy is occasionally required in MEN1 patients with large tumours in the pancreatic head or duodenum. Reoperation with enucleation or resection of new tumors may be required in the MEN1 patients.