Neuroendocrine tumors (NETs) are highly vascularized malignancies in which angiogenesis may entail cell proliferation and survival. Among the emerging compounds with antivascular properties, cabozantinib (CAB) appeared promising. We analyzed the antitumor activity of CAB against NETs utilizing in vitro and in vivo models. For cell cultures, we used BON-1, NCI-H727 and NCI-H720 cell lines. Cell viability was assessed by manual count coupled with quantification of cell death, performed through fluorescence-activated cell sorting analysis as propidium iodide exclusion assay. In addition, we investigated the modulation of the antiapoptotic myeloid cell leukemia 1 protein under CAB exposure, as a putative adaptive pro-survival mechanism, and compared the responses with sunitinib. The activity of CAB was also tested in mouse and zebrafish xenograft tumor models. Cabozantinib showed a dose-dependent and time-dependent effect on cell viability and proliferation in human NET cultures, besides a halting of cell cycle progression for endoduplication, never reported for other tyrosine kinase inhibitors. In a transplantable zebrafish model, CAB drastically inhibited NET-induced angiogenesis and migration of implanted cells through the embryo body. CAB showed encouraging activity in NETs, both in vitro and in vivo models. On this basis, we envisage future research to further investigate along these promising lines.

Non-metastatic neuroendocrine carcinoma of the cervix (NECC) is a rare and aggressive disease. Lacking prospective studies, the optimal multimodal treatment approach has not yet been clearly defined. This study aims to assess the clinical outcomes of patients with non-metastatic NECC treated with surgery and (neo)adjuvant chemotherapy, according to pathologic prognostic factors and multimodal treatments received. We retrospectively examined data from patients with non-metastatic NECC candidate to receive surgery and (neo)adjuvant chemotherapy and discussed at the European Institute of Oncology’s Multidisciplinary Neuroendocrine Tumor Board, between January 2003 and December 2021. Primary endpoints were event-free survival and overall survival. A total of 27 consecutive patients were evaluated, 15 with early stage NECC and 12 with a locally advanced NECC. Eight patients received neoadjuvant and 19 adjuvant platinum-based chemotherapy; 14 received adjuvant pelvic radiotherapy, half with external-beam radiation therapy alone, and half combined with brachytherapy. No patients progressed or relapsed during (neo)adjuvant chemotherapy. The median event-free survival was 21.1 months and the median overall survival was 33.0 months. Pathological FIGO stage ≥ IIB, adjuvant external-beam radiation therapy with or without brachytherapy emerged as significant and independent prognostic factors for event-free survival. Brachytherapy was also prognostic for overall survival. Non-metastatic NECC requires a multimodal approach, mainly weighted on the FIGO stage. The addition of brachytherapy should be considered, especially in patients with locally advanced disease. Because of the scarcity of robust clinical data, treatment strategy should be discussed in multidisciplinary board, taking into account patient.