Neuroendocrine neoplasms (NENs) are tumors originating from neuroendocrine cells distributed throughout the human body. With an increasing incidence over the past few decades, they represent a highly heterogeneous group of neoplasms, mostly expressing somatostatin receptors (SSTRs) on their cell surface. Peptide receptor radionuclide therapy (PRRT) has emerged as a crucial strategy for treating advanced, unresectable neuroendocrine tumors by administering radiolabeled somatostatin analogs intravenously to target SSTRs. This article will focus on the multidisciplinary theranostic approach, treatment effectiveness (such as response rates and symptom relief), patient outcomes, and toxicity profile of PRRT for NEN patients. We will review the most significant studies, such as the phase III NETTER-1 trial, and discuss promising new radiopharmaceuticals, including alpha-emitting radionuclide-labeled somatostatin analogs and SSTR antagonists.

Background: Broncho-pulmonary neuroendocrine tumors (bpNETs) are rare malignancies and there is no consensus on therapeutical management of metastatic disease and follow-up after radical resection. Methods: Clinical records of patients with a cytological or histological diagnosis of bpNETs and distant metastases (metachronous or synchronous), evaluated at the European Institute of Oncology between 1997 and 2014, were retrospectively analyzed. Data on patient demographics, pathology, imaging exams, surgical and non-surgical treatments were collected. P value descriptive data, uni- and multi-variate survival analysis were generated for all variables. Results: With a median follow-up of 53 [9–215] months, 61 patients with metachronous and 47 with synchronous metastases were analysed. The most common tool of first recurrence detection was computed tomography. Liver (67%), lymph node (25%), bone (22%) and lung (16%) were the most common sites of relapse. Median time to recurrence was 5 years. Median overall survival (OS) was 72 months for the whole population, with no significant difference between patients with synchronous and metachronous metastases. Age, bone metastases, liver metastases and Ki-67 as a continuous variable all significantly correlated with prognosis at the multivariate analysis. Conclusions: This is one of the largest, single-centre, series of metastatic bpNETs. Among patients with metachronous metastases the pattern of recurrences was heterogeneous as were the follow-up exams used to detect them. The results of our analysis may represent solid bases for designing prospective clinical trials in homogeneous settings of bpNETs.

Background: To investigate the cause of lymphopenia in patients with newly diagnosed COVID-19, we measured [¹⁸F]FDG uptake in several tissues, including the ileum, right colon, and caecum at diagnosis and after recovery and correlated these measurements with haematological parameters. Methods: We studied, by [¹⁸F]FDG PET/CT, 18 newly diagnosed patients with COVID-19. Regions of interest were drawn over major organs and in the terminal ileum, caecum, and right colon, where the bowel wall was evaluable. Five patients were re-examined after recovery, and three of them also performed a white blood cell scan with ^99mTc-HMPAO-WBC on both occasions. Complete blood count was performed on both occasions, and peripheral blood lymphocyte subsets were measured at diagnosis. Data were analysed by a statistician. Results: Patients had moderate severity COVID-19 syndrome. Basal [¹⁸F]FDG PET/CT showed focal lung uptake corresponding to hyperdense areas at CT. We also found high spleen, ileal, caecal, and colonic activity as compared to 18 control subjects. At recovery, hypermetabolic tissues tended to normalize, but activity in the caecum remained higher than in controls. Regression analyses showed an inverse correlation between CD4 + lymphocytes and [¹⁸F]FDG uptake in the caecum and colon and a direct correlation between CD8 + lymphocytes and [¹⁸F]FDG uptake in lungs and bone marrow. WBC scans showed the presence of leukocytes in the caecum and colon that disappeared at recovery. Conclusions: These findings indicate that lymphopenia in COVID-19 patients is associated with large bowel inflammation supporting the hypothesis that CD4 + lymphocytes migrate to peripheral lymphoid tissues in the bowel.