Radionuclide therapy for neuroendocrine tumors is a form of systemic radiotherapy that allows the administration of targeted radionuclides into tumor cells that express a large quantity of somatostatin receptors. The two most commonly used radio-peptides for radionuclide therapy in neuroendocrine tumors are ⁹⁰Y-DOTATOC and ¹⁷⁷Lu-DOTATATE. Radio-peptides have been used for several years in the treatment of advanced neuroendocrine tumors. Recently, the randomized Phase III study NETTER-1 compared¹⁷⁷Lu-DOTATATE versus high-dose (double-dose) octreotide LAR in patients with metastatic midgut neuroendocrine tumors, and demonstrated its efficacy in this setting. Strong signals in favor of efficiency seem to exist for other tumors, in particular for pancreatic and pulmonary neuroendocrine tumors. This focus on radionuclide therapy in gastroenteropancreatic and pulmonary neuroendocrine tumors addresses the treatment modalities, the validated and potential indications, and the safety of the therapy.

Patients and methods: we performed a retrospective case-control study, including cases with repeat EUS FNB for a solid pancreatic lesion, matched on a 1:2 ratio on age, sex, tumor location and presence of chronic pancreatitis with cases diagnosed on the first EUS FNB. Results: thirty-four cases and 68 controls were included in the analysis. Diagnostic accuracies were 80% and 88% in the repeat and single EUS FNB groups, respectively (p = 0.824). The second EUS FNB had a sensitivity of 80%, a specificity of 75%, a positive predictive value of 96%, and a negative predictive value of 33%. Of the 34 patients in the repeat EUS FNB group, 25 (74%) had a positive diagnosis with the second EUS FNB, 4 (12%) after surgery due to a second negative EUS FNB, 4 (12%) during clinical follow-up, and 1 (3%) after a third EUS FNB. Of the 25 patients diagnosed on the repeat EUS FNB, 17 (68%) had pancreatic adenocarcinomas, 2 (8%) neuroendocrine tumors, 2 (8%) other autoimmune pancreatitis, 2 (8%) chronic pancreatitis nodules, 1 (4%) renal cancer metastasis, and 1 (4%) other malignant diagnostic. There were no complications reported after the second EUS FNB in this study. Conclusion: repeat EUS FNB made a diagnosis in three fourths of patients with solid pancreatic lesions and a first negative EUS FNB, with 26% of benign lesions. This supports the repetition of EUS FNB sampling in this clinical situation.