Peptide Receptor Radionuclide Therapy (PRRT) in Tumors With High Expression of Somatostatin Receptors (Phase 2)

Inclusion Criteria: * 1\. Age ≥18 years, of both sexes, of any ethnicity; * 2\. Cyto-histological and immunohistochemical diagnosis of NET; * 3\. Evaluation of the cell proliferation index by studying Ki-67 and / or E3 ubiquitin-protein ligase (MIB-1). * 4\. Illness measurable according to RECIST 1.1 criteria by imaging conventional (CT with contrast medium or MRI with contrast medium) not earlier than two months with respect to enrollment; * 5\. Elevated expression of somatostatin receptors documented by PET-CT with 68Ga-DOTATOC in the target lesion (s). It is defined as "high expression of somatostatin receptors "a ratio of Maximum standardized uptake value (SUVmax) lesion / Mean standardized uptake value (SUVmean) muscle ≥ 4: 1 calculated with semi-quantitative analysis on examination PET-CT with 68Ga-DOTATOC; * 6\. Dosage of Chromogranin A (and any other specific markers) not prior to two months of enrollment; * 7\. Evaluation of glucose metabolism in the target lesion (s) by PET-CT with 18F-FDG; * 8\. Preserved haematological, hepatic and renal parameters, in particular: white blood cells ≥2500 / μL; platelets ≥ 90000 / μL; hemoglobin ≥ 9 gr / dL; creatinine ≤ 2 mg / dL; bilirubin ≤ 2.5 mg / dL * 9\. Eastern Cooperative Oncology Group (ECOG) performance status ≤2; * 10\. Life expectancy ≥ 6 months; * 11\. Stable or progressive disease, at any stage, both in operated patients that inoperable; * 12\. Absence of standard treatments already documented and of equal effectiveness; * 13\. Absence of surgical, chemotherapy and / or radiotherapy treatments for at least 30 days. On the other hand, patients in therapy with somatostatin analogues or biologics, such as mechanistic target of rapamycin (m-TOR) inhibitors; * 14\. Voluntary participation in the study by signing the consent form informed, after reading and complete understanding of the information notes. Exclusion Criteria: * 1\. Lack of the requirements listed above; * 2\. State of pregnancy; * 3\. Breastfeeding and relative refusal to suspend breastfeeding; * 4\. Participation in another therapeutic experimental clinical protocol in the four weeks prior to the PRRT; * 5\. Bone marrow invasion of disease\> 25% confirmed; * 6\. Previous extensive radiotherapy treatments.