Oxaliplatin and 5-Fluorouracil in Advanced Well-Differentiated Digestive Neuroendocrine Tumors: A Multicenter National Retrospective Study from the French Group of Endocrine Tumors

Systemic Therapy for Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PanNETs) account for approximately 2% of all pancreatic malignancies. Several systemic treatment options have been developed over the last four decades, ranging from cytotoxic chemotherapy and octreotide to newer targeted therapies like sunitinib, cabozantinib, and lenvatinib. Although surgery or liver-directed therapy remains cornerstone for management of metastatic PanNETs, however, they remain unfeasible in majority of cases. PanNETs behave differently than SI-NETs (small intestinal NET); the former is more aggressive and less responsive to somatostatin-based therapies. The optimal sequence of the systemic therapies for the advanced PanNETs depends mainly on the tumor burden, Ki-67 index, and the tempo of the disease. In the end, drawing from ENETS (European Neuroendocrine Tumor Society) and ESMO (European Society for Medical Oncology) guidelines, we propose a working algorithm for the management of advanced PanNETs, not amenable to surgery or liver-directed therapies.

[Current views on the treatment of insulinoma]

RELEVANCE

Insulinoma is the most common hormonally active neuroendocrine tumor (NET) of the pancreas. In recent years, there has been a trend towards an increase in the incidence of NET especially insulinoma.

AIM

Summarizing and analyzing current data on various approaches to the treatment of insulinoma. Our review includes a comprehensive assessment of the advantages and disadvantages of currently available insulinoma treatment methods in comparison with past experience, as well as a review of promising methods that are not currently widely used.

MATERIALS AND METHODS

Analysis of literature from such databases as scientific electronic library elibrary.ru, Pubmed, Google Scholar, MedLine, Scopus and Web of Science.

RESULTS

The most common treatment for insulinoma is surgery. For patients with high operative risk, alternative methods such as alcohol ablation, radiofrequency ablation, and tumor embolization may be used. Medications include the use of somatostatin analogues, diazoxide. The literature describes the potential benefit of the use of beta-blockers, phenytoin, glucagon, however, in clinical trials, these drugs have not demonstrated a significant effect. For the treatment of malignant and metastatically advanced insulinoma, targeted therapy (primarily Everolimus), chemotherapy, as well as embolization (including chemoembolization, radioembolization), radiofrequency ablation (RFA), microwave ablation and cryoablation, ultrasound ablation (HIFU), laser ablation, brachytherapy, irreversible electroporation are used.

CONCLUSION

The study of new drugs is an important task for scientists, among medications the most promising are new generations of somatostatin analogues, targeted drugs and chemotherapy drugs. The rare frequency of insulinoma makes it difficult to conduct randomized controlled trials and prospective studies. That is why physicians and scientists need to maintain close contacts with each other and take into account the experience of treating each patient with such disease, which will help develop effective treatment algorithms in the future.

Clinicopathological characteristics of gastric neuroendocrine neoplasms: A comprehensive analysis

OBJECTIVE

This study aimed to explore the clinicopathological characteristics and prognostic implications of gastric neuroendocrine neoplasms (g-NENs).

METHODS

A retrospective enrollment of 142 patients diagnosed with g-NENs was conducted at Zhejiang Cancer Hospital between January 1, 2007 and December 31, 2021. The study compared essential clinicopathological features and survival rates. Additionally, the prognosis of gastric neuroendocrine carcinomas/mixed neuroendocrine-non-neuroendocrine neoplasms (g-NEC/MiNEN) were contrasted with those of gastric adenocarcinoma (GAC) and signet ring cell carcinoma (SRCC).

RESULTS

The study comprised a total of 142 g-NENs cases, with a male-to-female ratio of approximately 2:1. The 5-year survival rates for g-NEC and g-MiNEN were 26.7% and 35.2%, respectively. Corresponding 5-year survival rates for G1 and G2 were observed at 100% and 80.0%, respectively. g-NEC/MiNEN showed a significantly worse prognosis compared to g-NET (p < 0.001). g-NEC/MiNEN exhibited a poor prognosis compared to GAC (p < 0.001), and within poorly differentiated GAC, g-NEC/MiNEN demonstrated a worse prognosis (p = 0.007). Additionally, patients receiving postoperative adjuvant therapy exhibited notably prolonged overall survival (OS) in the case of g-NEC/MiNEN (p = 0.010).

CONCLUSION

In short, the prognosis of g-NEC/MiNEN was worse than that of g-NET, GAC and poorly differentiated GAC, but this group benefit from postoperative adjuvant therapy.

Choosing the best systemic treatment sequence for control of tumour growth in gastro-enteropancreatic neuroendocrine tumours (GEP-NETs): What is the recent evidence?

Gastro-enteropancreatic neuroendocrine tumours (GEP-NETs) represent a rare and highly heterogeneous entity with increasing incidence. Based on the results obtained from several trials performed in the last decade, various therapeutic options have been established for the treatment of patients with GEP-NETs. The options include somatostatin analogues, targeted therapies (sunitinib and everolimus), chemotherapy (with temozolomide or streptozocin-based regimens), and peptide receptor radionuclide therapy. The treatment choice is influenced by various clinico-pathological factors including tumour grade and morphology, the primary mass location, hormone secretion, the volume of the disease and the rate of tumour growth, as well as patient comorbidities and performance status. In this review, the efficacy and safety of treatment options for patients with GEP-NETs is discussed and the evidence to inform the best sequence of available therapies to control tumour growth, prolong patient survival, and to lower potential toxicity, while maintaining patient quality of life is explored.

European Neuroendocrine Tumor Society (ENETS) 2023 guidance paper for colorectal neuroendocrine tumours

This ENETS guidance paper, developed by a multidisciplinary working group, provides an update on the previous colorectal guidance paper in a different format. Guided by key clinical questions practical advice on the diagnosis and management of neuroendocrine tumours (NET) of the caecum, colon, and rectum is provided. Although covered in one guidance paper colorectal NET comprises a heterogeneous group of neoplasms. The most common rectal NET are often small G1 tumours that can be treated by adequate endoscopic resection techniques. Evidence from prospective clinical trials on the treatment of metastatic colorectal NET is limited and discussion of patients in experienced multidisciplinary tumour boards strongly recommended. Neuroendocrine carcinomas (NEC) and mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN) are discussed in a separate guidance paper.

Therapy Sequencing in Patients With Advanced Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) comprise a beautifully complicated, exciting landscape of histologies and clinical behaviors. However, the nuanced complexity of low- and high-grade variants can easily overwhelm both patients and providers. In this chapter, we review the ever-expanding literature on both functioning and nonfunctioning small bowel and pancreatic NENs, touching on somatostatin analogs, hepatic-directed therapies, small molecules, radiopharmaceuticals, immunotherapy, cytotoxic chemotherapy, and new promising agents. Furthermore, we suggest some strategies to address the most challenging scenarios seen in clinical practice, including sequencing of agents, treatment of carcinoid syndrome, and options for well-differentiated high-grade disease.

Neuroendocrine Tumors: Genomics and Molecular Biomarkers with a Focus on Metastatic Disease

Neuroendocrine tumors (NETs) are considered rare tumors that originate from specialized endocrine cells. Patients often present with metastatic disease at the time of diagnosis, which negatively impacts their quality of life and overall survival. An understanding of the genetic mutations that drive these tumors and the biomarkers used to detect new NET cases is important to identify patients at an earlier disease stage. Elevations in CgA, synaptophysin, and 5-HIAA are most commonly used to identify NETs and assess prognosis; however, new advances in whole genome sequencing and multigenomic blood assays have allowed for a greater understanding of the drivers of NETs and more sensitive and specific tests to diagnose tumors and assess disease response. Treating NET liver metastases is important in managing hormonal or carcinoid symptoms and is imperative to improve patient survival. Treatment for liver-dominant disease is varied; delineating biomarkers that may predict response will allow for better patient stratification.

Systemic Therapy for Pancreatic Neuroendocrine Tumors

Patients with metastatic or advanced pancreatic neuroendocrine tumors (NETs) carry poorer prognoses relative to patients with other NETs due to bulkier and often, more proliferative baseline disease. Patients with these tumors also possess more approved treatment options relative to patients with other NETs, making therapeutic sequencing nuanced. As such, defining optimal therapeutic sequencing and developing more potent cytoreductive treatments for patients are significant areas of research need in the field. Herein this review, we discuss the current systemic therapy landscape, our approach to therapeutic sequencing in the clinic and ongoing studies seeking to define optimal sequencing of systemic therapies, and novel therapeutics in development, for patients with pancreatic NETs. We limit the scope of this latter topic to agents with preclinical or clinical rationale over the last 8 years to provide a contemporary view of the drug development landscape and focus primarily on new types of peptide receptor radionuclide therapy, anti-vascular endothelial growth factor receptor tyrosine kinase inhibitors and anti-vascular endothelial growth receptor tyrosine kinase inhibitor plus immunotherapy combinations.

A practical proposal on treatment sequencing of metastatic well-differentiated neuroendocrine tumours

According to the neuroendocrine tumour (NET) characteristics, 3 to 7 different treatment options are available, corresponding to 6 to 5,040 theoretical different sequences. Even though each patient is unique and despite a large heterogeneity in NET characteristics, the present review aims to discuss the main sequences and addresses how one can propose the best sequence to treat metastatic NET (mNET) on a case-by-case basis. Each treatment must be discussed during dedicated multi-disciplinary meetings, and inclusions in clinical trials should be favoured. After a thorough characterization of patients and their mNET, and taking into account the availability of drugs, the first-line treatment should be chosen according to the treatment aim. The latter is determined based on three main topics (efficacy, safety, and patient preferences) that do not necessarily converge and must be defined a priori. At baseline, physicians should design an a priori full therapeutic sequence, which may evolve at each step depending on the response to previous treatment, the occurrence of chronic toxicities, and the patients' perception of the prior treatment. To improve knowledge in terms of effectiveness and risk of cumulative toxicities regarding the different sequences, real-world data using long follow-up durations are necessary; such issues will not be resolved by randomized clinical trials.

FOLFOX-bevacizumab chemotherapy in patients with metastatic neuroendocrine tumors

Neuroendocrine tumors (NETs) are highly vascularized neoplasms. While FOLFOX chemotherapy has shown efficacy in patients with advanced NETs, its combination with antiangiogenics has been scarcely described. Here, we report the efficacy and tolerance of FOLFOX-bevacizumab in this setting. We retrospectively studied all consecutive patients with metastatic NET treated by FOLFOX-bevacizumab in two expert centers from 2013 to 2020. We assessed time to treatment failure (TTF), objective response rate (ORR) and toxicity. We explored factors associated with TTF and ORR using multivariate analyses. We included 57 patients (35.1% female, median age 61.7 years), with pancreatic (66.7%), small-intestine (14%) or lung (7%) NETs. Most patients (57.9%) had extra-hepatic metastases and G3 NETs accounted for 40.3% of cases. Patients received a median of 17 cycles of treatment, including a median of seven cycles of bevacizumab and/or 5-fluorouracile maintenance. Median TTF was 15.5 months (95% CI: 9.8-21.2) and was shorter in patients age > 60 years (HR 2.56, 95% CI: 1.16-5.64), p = .020) and >1 previous systemic treatment line (HR 4.15, 95% CI: 1.96-8.78), p < .001). The ORR was 42.9% and was higher in cases of performance status at 0 (OR 5.25, 95% CI: 1.13-24.35), p = .034) and G3 NET (OR 5.39, 95% CI: 1.23-23.52), p = .025). The FOLFOX-bevacizumab combination has promising efficacy in patients with progressive metastatic NETs and notably for G3 NETs, for which optimal treatment as yet remains ill-defined. Hence, it could be a relevant alternative to alkylating-based chemotherapy in this setting and should be further explored prospectively.

Chemotherapy in Neuroendocrine Tumors

The role for cytotoxic chemotherapy in patients with well-differentiated neuroendocrine tumors (NETs) remains debated. Compared to patients with poorly differentiated neuroendocrine carcinomas (NECs) where chemotherapy is utilized ubiquitously, chemotherapy may play a more select role in patients with certain types of NETs (e.g., pancreatic tumors, higher grade tumors, and tumors possessing DNA damage repair defects). The primary types of chemotherapy that have been tested in patients with NETs include alkylating agent- and platinum agent-based combinations. Across regimens, chemotherapy appears to elicit greater antitumor activity in patients with pancreatic or grade 3 NETs. The role for chemotherapy in lower grade extra-pancreatic NETs remains undefined. Furthermore, while chemotherapy has demonstrated clinically meaningful benefit for patients in the systemic setting, its role in the adjuvant or neoadjuvant setting is as-of-yet undetermined. Finally, efforts to combine chemotherapy with targeted therapy and peptide receptor radionuclide therapy are ongoing, in hopes of improving the cytoreductive treatment options for patients with NETs.