Digestive well-differentiated grade 3 neuroendocrine tumors (NET G-3) have been clearly defined since the 2017 World Health Organization classification. They are still a rare category lacking specific data and standardized management. Their distinction from other types of neuroendocrine neoplasms (NEN) not only lies in morphology but also in genotype, aggressiveness, functional imaging uptake, and treatment response. Most of the available data comes from pancreatic series, which is the most frequent tumor site for this entity. In the non-metastatic setting, surgical resection is recommended, irrespective of grade and tumor site. For metastatic NET G-3, chemotherapy is the main first-line treatment with temozolomide-based regimen showing more efficacy than platinum-based regimen, especially when Ki-67 index <55%. Targeted therapies, such as sunitinib and everolimus, have also shown some positive therapeutic efficacy in small samples of patients. Functional imaging plays a key role for detection but also treatment selection. In the second or further-line setting, peptide receptor radionuclide therapy has shown promising response rates in high-grade NEN. Finally, immunotherapy is currently investigated as a new therapeutic approach with trials still ongoing. More data will come with future work now focusing on this specific subgroup. The aim of this review is to summarize the current data on digestive NET G-3 and explore future directions for their management.

Pancreatic neuroendocrine tumors (p-NETs) are rare tumors with a recent growing incidence. In the 2017 WHO classification, p-NETs are classified into well-differentiated (i.e., p-NETs grade 1 to 3) and poorly differentiated neuroendocrine carcinomas (i.e., p-NECs). P-NETs G1 and G2 are often non-functioning tumors, of which the prognosis depends on the metastatic status. In the localized setting, p-NETs should be surgically managed, as no benefit for adjuvant chemotherapy has been demonstrated. Parenchymal sparing resection, including both duodenum and pancreas, are safe procedures in selected patients with reduced endocrine and exocrine long-term dysfunction. When the p-NET is benign or borderline malignant, this surgical option is associated with low rates of severe postoperative morbidity and in-hospital mortality. This narrative review offers comments, tips, and tricks from reviewing the available literature on these different options in order to clarify their indications. We also sum up the overall current data on p-NETs G1 and G2 management.

Background: The current study aimed to evaluate the outcomes of patients with unresectable non-metastatic locally advanced pancreatic adenocarcinoma (LAPA) who did not benefit from resection considering the treatment strategy in the clinical settings. Methods: Between 2010 and 2017, a total of 234 patients underwent induction chemotherapy for LAPA that could not be treated with surgery. After oncologic restaging, continuous chemotherapy or chemoradiation (CRT) was decided for patients without metastatic disease. The Kaplan–Meier method was used to determine overall survival (OS), and the Wilcoxon test to compare survival curves. Multivariate analysis was performed using the stepwise logistic regression method. Results: FOLFIRINOX was the most common induction regimen (168 patients, 72%), with a median of 6 chemotherapy cycles and resulted in higher OS, compared to gemcitabine (19 vs. 16 months, hazard ratio (HR) = 1.2, 95% confidence interval: 0.86–1.6, P = .03). However, no difference was observed after adjusting for age (≤75 years) and performance status score (0–1). At restaging, 187 patients (80%) had non-metastatic disease: CRT was administered to 126 patients (67%) while chemotherapy was continued in 61 (33%). Patients who received CRT had characteristics comparable to those who continued with chemotherapy, with similar OS. They also had longer progression-free survival (median 13.3 vs. 9.6 months, HR = 1.38, 95% confidence interval: 1–1.9, P < .01) and limited short-term treatment-related toxicity. Conclusions: The median survival of patients who could not undergo surgery was 19 months. Hence, CRT should not be eliminated as a treatment option and may be useful as a part of optimised sequential chemotherapy for both local and metastatic disease.