This is a randomized phase II, parallel group study. Patients with gastro-entero-pancreatic neuroendocrine tumors (GEP-NET) well differentiated G1 - G2 (ki67≤ 20%) and G3 (ki67≤ 50%), SSR positive and 18-fluorodeoxyglucose (FDG) positive will be enrolled in the study and will be randomly assigned to 2 different arms: