Somatostatin Analogue Therapy in MEN1-Related Pancreatic Neuroendocrine Tumors from Evidence to Clinical Practice: A Systematic Review

Somatostatin analogs for resectable pancreatic neuroendocrine tumors in high-risk surgical patients: Data from a single-center cohort

OBJECTIVES

To evaluate the use of long-acting somatostatin-analogs (SSA) for treating non-advanced, resectable pancreatic neuroendocrine tumors (PNETs) with indications to surgery, in high-risk patients who were not candidates for surgery.

METHODS

Patients diagnosed with histology-proven, non-advanced G1/low-G2 68Ga-TC/PET-positive PNETs >20 mm who did not undergo surgery due to comorbidities/old age/high-risk surgical profile, which were treated with SSA at a single, high-volume institution were included. The efficacy of SSA was evaluated using the analysis of tumor growth rate (TGR). "Negative TGRTx-TpreSSA" was defined as the first time point after the initiation of SSA when a negative TGRTx-TpreSSA was observed.

RESULTS

Between 2014 and 2024, 20 patients were treated with long-acting SSA. The median age was 76 (IQR 72-80), and the median ASA score was 3 (IQR 3-3). Fifteen patients (75 %) received Lanreotide, and five (25 %) octreotide acetate (Sandostatin® LAR). The median overall survival was 68.5 months (IQR 60-99). In four patients (20 %), SSA were interrupted when the tumor had shrunk below 2 cm. In one of them, SSA reintroduction was necessary due to disease progression (after 14 months). In two patients (10 %), the treatment was interrupted due to side effects. In one of these, the disease progressed until death at 87 years old. At the last follow-up, sixteen patients were alive, 3 had died (1 death of disease), and 13 were receiving SSA. T2 PNETs presented a significantly faster response to SSA therapy compared to T3 (Median time to "Negative TGRTx-TpreSSA": 6 [95 % CI 5, na] vs 52 [95 % CI 19, na] months, respectively; p = 0.0092) CONCLUSION: In patients at high surgical risk, with localized, resectable, G1 or low-G2, 68Ga-TC/PET-positive PNETs >20 mm, SSA can obtain disease control with a manageable safety profile.

Long-acting somatostatin analogs and well differentiated neuroendocrine tumors: a 20-year-old story

PURPOSE

The specific indications of somatostatin analogs (SSAs) in patients with neuroendocrine tumor (NET) emerged over the time. The objective of this review is to summarize and discuss the most relevant data concerning long-acting SSAs in NET.

METHODS

A narrative review was performed including publications focusing on therapy with the long-acting octreotide, lanreotide, and pasireotide in patients with NET.

RESULTS

Long-acting SSAs confirm to be a manageable and widely used tool in patients with NET. Both long-acting octreotide and lanreotide are safe as the short-acting formulations, while patient compliance and adherence is further improved. Together with some randomized phase-3 trials, many retrospective and prospective studies have been performed in the last 20 years revealing a variable but substantial impact on progression free survival, not only in gastroenteropancreatic but also in lung and unknown primary NETs. The most frequent tumor response to SSAs is stable disease, but an objective response can be observed, more frequently by using high-dose schedules and in MEN1-related pancreatic NETs. Low tumor burden, low tumor grade (G1 and low G2), good performance status and use as first-line therapy are the main predictive factors to SSAs in NET patients. Pasireotide has been evaluated in few studies. This compound remains a promising SSA and would deserve to be further evaluated as a potential additional indication in NET therapy.

CONCLUSIONS

Long-acting SSAs are an effective and safe initial therapy of patients with well differentiated NET, allowing tumor growth as well as symptoms control for long-time in selected patients.

Neuroendocrine neoplasms in the context of inherited tumor syndromes: a reappraisal focused on targeted therapies

PURPOSE

Neuroendocrine neoplasms can occur as part of inherited disorders, usually in the form of well-differentiated, slow-growing tumors (NET). The main predisposing syndromes include: multiple endocrine neoplasias type 1 (MEN1), associated with a large spectrum of gastroenteropancreatic and thoracic NETs, and type 4 (MEN4), associated with a wide tumour spectrum similar to that of MEN1; von Hippel-Lindau syndrome (VHL), tuberous sclerosis (TSC), and neurofibromatosis 1 (NF-1), associated with pancreatic NETs. In the present review, we propose a reappraisal of the genetic basis and clinical features of gastroenteropancreatic and thoracic NETs in the setting of inherited syndromes with a special focus on molecularly targeted therapies for these lesions.

METHODS

Literature search was systematically performed through online databases, including MEDLINE (via PubMed), and Scopus using multiple keywords' combinations up to June 2022.

RESULTS

Somatostatin analogues (SSAs) remain the mainstay of systemic treatment for NETs, and radiolabelled SSAs can be used for peptide-receptor radionuclide therapy for somatostatin receptor (SSTR)-positive NETs. Apart of these SSTR-targeted therapies, other targeted agents have been approved for NETs: the mTOR inhibitor everolimus for lung, gastroenteropatic and unknown origin NET, and sunitinib, an antiangiogenic tyrosine kinase inhibitor, for pancreatic NET. Novel targeted therapies with other antiangiogenic agents and immunotherapies have been also under evaluation.

CONCLUSIONS

Major advances in the understanding of genetic and epigenetic mechanisms of NET development in the context of inherited endocrine disorders have led to the recognition of molecular targetable alterations, providing a rationale for the implementation of treatments and development of novel targeted therapies.

Lipid Metabolism and Homeostasis in Patients with Neuroendocrine Neoplasms: From Risk Factor to Potential Therapeutic Target

Lipid metabolism is known to be involved in tumorigenesis and disease progression in many common cancer types, including colon, lung, breast and prostate, through modifications of lipid synthesis, storage and catabolism. Furthermore, lipid alterations may arise as a consequence of cancer treatment and may have a role in treatment resistance. Neuroendocrine neoplasms (NENs) are a heterogeneous group of malignancies with increasing incidence, whose mechanisms of cancer initiation and progression are far from being fully understood. Alterations of lipid metabolism may be common across various cancer types, but data about NENs are scattered and heterogeneous. Herein, we provide an overview of the relevant literature on lipid metabolism and alterations in NENs. The available evidence both in basic and clinical research about lipid metabolism in NENs, including therapeutic effects on lipid homeostasis, are summarized. Additionally, the potential of targeting the lipid profile in NEN therapy is also discussed, and areas for further research are proposed.

What Are the Place and Modalities of Surgical Management for Pancreatic Neuroendocrine Neoplasms? A Narrative Review

Pancreatic neuroendocrine neoplasms (panNENs) are a heterogeneous group of tumors derived from cells with neuroendocrine differentiation. They are considered malignant by default. However, their outcomes are variable depending on their presentation in the onset of hereditary syndromes, hormonal secretion, grading, and extension. Therefore, although surgical treatment has long been suggested as the only treatment of pancreatic neuroendocrine neoplasms, its modalities are an evolving landscape. For selected patients (small, localized, non-functional panNENs), a "wait and see" strategy is suggested, as it is in the setting of multiple neuroendocrine neoplasia type 1, but the accurate size cut-off remains to be established. Parenchyma-sparring pancreatectomy, aiming to limit pancreatic insufficiency, are also emerging procedures, which place beyond the treatment of insulinomas and small non-functional panNENs (in association with lymph node picking) remains to be clarified. Furthermore, giving the fact that the liver is generally the only metastatic site, surgery keeps a place of choice alongside medical therapies in the treatment of metastatic disease, but its modalities and extensions are still a matter of debate. This narrative review aims to describe the current recommended surgical management for pancreatic NENs and controversies in light of the actual recommendations and recent literature.