Sandostatin (Octreotide LAR) May Lead to Clinical Improvement Through Receptor Occupation Optimisation

This is a multi-centric prospective interventional study in which patients with a symptomatic GEP-NET will receive octreotide LAR every 2, 3 or 4 weeks. The basal dose and the dose adaptation will be left at the discretion of the investigator depending on the rate of symptom control. Dose increase up to doses of 60 mg octreotide every 4 weeks, or increase of frequency up to 30 mg every 2 weeks can be done to obtain control of carcinoid symptoms, defined by at least a 50% decrease of the mean number of bowel movements per day and the total number of flushes over 7 days AND a maximum frequency of less than 4 bowel movements a day. If only one symptom is present, analysis will be done for that symptom only: refer to table in statistical analysis The concentration of serum octreotide level will be realized with LCMS/MS following the method of Capron \& Wallemacq. Each blood sample should be taken 4 times per year just before the next injection of Octreotide LAR.