Prophylactic Cholecystectomy in Midgut NETs Patients Who Require Primary Tumor Surgery.

Inclusion Criteria: * Patients must grant the informed consent written, signed and dated. * Male or female older than 18 years old. * Radiological or histological diagnose of midgut NET that can be treated with surgery. * In case of female with childbearing age (time between menarche and menopause), a pregnancy test with negative result. * Neuroendocrine tumors located in any of the aforementioned locations. * Presence or not of distant metastasis. * Presencié or not of gallstones. * Capacity of follow up. Exclusion Criteria: * Neuroendocrine tumors which are not located in jejunum or ileum (bronchial, gastric, pancreatic, descending colon, sigma or rectum.). * Patients that have gone through a previous bowel resection. * Patients with previous cholecystectomy. * Pacients with biliary stone disease. * Patients who are candidate to liver resection or liver transplant. * Patients with a gallbladder polyp bigger than 6 mm. * Pacients with one gallbladder sessile polyp, presence of more than one polyp or patients older than 50 years old with a polyp. * Refusal to participate. * Patients with previous history of malignant neoplasms in the last 5 years, except skin basal cell carcinoma, "in situ" cervical carcinoma or in situ carcinoma found in a polyp removed with a colonoscopy. * Medical criteria that doesn't consider the patient a candidate to participate in the study.