Should temozolomide be used on the basis of O6-methylguanine DNA methyltransferase status in patients with advanced neuroendocrine tumors? A systematic review and meta-analysis

Precision medicine in gastroenteropancreatic neuroendocrine neoplasms: Where are we in 2023?

Precision medicine describes a target-related approach to tailoring diagnosis and treatment of the individual patient. While this personalized approach is revoluzionizing many areas of oncology, it is quite late in the field of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), in which there are few molecular alterations to be therapeutically targeted. We critically reviewed the current evidence about precision medicine in GEP NENs, focusing on potential clinically relevant actionable targets for GEP NENs, such as the mTOR pathway, MGMT, hypoxia markers, RET, DLL-3, and some general agnostic targets. We analysed the main investigational approaches with solid and liquid biopsies. Furthermore, we reviewed a model of precision medicine more specific for NENs that is the theragnostic use of radionuclides. Overall, currently no true predictive factors for therapy have been validated so far in GEP NENs, and the personalized approach is based more on clinical thinking within a NEN-dedicated multidisciplinary team. However, there is a robust background to suppose that precision medicine, with the theragnostic model will yield new insights in this context soon.

Chemotherapy in Well Differentiated Neuroendocrine Tumors (NET) G1, G2, and G3: A Narrative Review

Neuroendocrine tumors (NETs) are rare neoplasms with a wide spectrum of clinical behavior, from the long survival of well-differentiated NETs to the dismal prognosis of high-grade neuroendocrine carcinomas (NECs), being G3 NETs a recently recognized intermediate entity. While the role of chemotherapy is well established in NECs, data on NETs mostly derives from small studies, experts' opinions, and extrapolating results from small-cell lung cancer studies. This narrative review aims to summarize available evidence about the use of chemotherapy in the setting of G1-2 NETs and G3 NETs. We performed literature research in PubMed Library for all articles published up to September 2022 about the efficacy of chemotherapy in NETs. Treatment regimens with STZ-5FU, CAPTEM, and anti-metabolite-based treatment are the most active and tolerated in gastroenteropancreatic NETs (GEP-NETs) G1-G2, while platinum-based regimens (FOLFOX/XELOX) and TEM/CAPTEM showed the best activity in thoracic NETs. Solid evidence about chemotherapy efficacy in G3 NETs is still lacking. Literature data support the use of chemotherapy in low-intermediate grade NETs after the failure of other therapies or if tumor shrinkage is needed. Studies assessing G3 NETs independently from NECs are needed to better understand the role of chemotherapy in this setting.

Capecitabine and Temozolomide (CAPTEM) in Advanced Neuroendocrine Neoplasms (NENs): A Systematic Review and Pooled Analysis

Background

Retrospective studies and single center experiences suggest a role of capecitabine combined with temozolomide (CAPTEM) in neuroendocrine tumors (NENs).

Methods

We performed a systematic review to assess the efficacy and safety of CAPTEM in patients affected with NENs, with the aim to better clarify the role of this regimen in the therapeutic algorithm of NENs.

Results

A total of 42 articles and 1818 patients were included in our review. The overall disease control rate was 77% (range 43.5%-100%). The median progression free survival ranged from 4 to 38.5 months, while the median overall survival ranged from 8 to 103 months. Safety analysis showed an occurrence of G3-G4 toxicities in 16.4% of the entire population. The most common toxicities were hematological (27.2%), gastrointestinal (8.3%,) and cutaneous (3.2%).

Conclusion

This systematic review demonstrated that CAPTEM was an effective and relatively safe treatment for patients with advanced well-moderate differentiated NENs of gastroenteropancreatic, lung and unknown origin.

Metronomic chemotherapy in patients with advanced neuroendocrine tumors: A single-center retrospective analysis

Neuroendocrine tumors (NETs) are more commonly slow-growing, therefore patients often receive chronic systemic therapies for tumor growth control and preservation of quality of life. Metronomic chemotherapy (mCT) is in line with this goal as it leads to stabilization of tumor growth over time without severe systemic toxicity. This is a retrospective analysis of patients with metastatic NETs receiving metronomic capecitabine (mCAP) or temozolomide (mTEM), at a NET-referral center. The aims of the study were to explore activity and safety of mCT and relationships between some characteristics of the patient population and clinical outcomes. Among a total of 67 patients with metastatic well or moderately differentiated (W/M-D) NETs, mostly gastroenteropancreatic (GEP) and nonfunctioning, 1.2 years (95% CI: 0.8-1.8) median progression-free survival (mPFS), and 3.0 years (95% CI: 2.3-4.9) median overall survival (mOS) were observed. Disease control rate was 85%. Grade 3 adverse events occurred in 15% of patients in mCAP and 13% in mTEM, and were mostly hematological and gastrointestinal. At univariate and multivariate analysis none of the variables analyzed (treatment regimen, sex, age at diagnosis, site of primary tumor and metastases, number of previous mCT lines, baseline tumor status before mCT, Ki67 value) were significantly correlated to OS and PFS. Our retrospective study suggested that mCAP and mTEM can be active and well tolerated in patients with metastatic W/M-D NETs, irrespective of the primary site, site of metastases, line of treatment and baseline tumor status.

Advances in medical treatment for pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms (PanNENs) are rare neoplasms with strong heterogeneity that have experienced an increasing incidence rate in recent years. For patients with locally advanced or distant metastatic PanNENs, systemic treatment options vary due to the different differentiations, grades and stages. The available options for systemic therapy include somatostatin analogs, mole-cularly targeted agents, cytotoxic chemotherapeutic agents, immune checkpoint inhibitors, and peptide receptor radionuclide therapy. In addition, the development of novel molecularly targeted agents is currently in progress. The sequence of selection between different chemotherapy regimens has been of great interest, and resistance to chemotherapeutic agents is the major limitation in their clinical application. Novel agents and high-level clinical evidence continue to emerge in the field of antiangiogenic agents. Peptide receptor radionuclide therapy is increasingly employed for the treatment of advanced neuroendocrine tumors, and greater therapeutic efficacy may be achieved by emerging radio-labeled peptides. Since immune checkpoint inhibitor monotherapies for PanNENs appear to have limited antitumor activity, dual immune checkpoint inhibitor therapies or combinations of antiangiogenic therapies and immune checkpoint inhibitors have been applied in the clinic to improve clinical efficacy. Combining the use of a variety of agents with different mechanisms of action provides new possibilities for clinical treatments. In the future, the study of systemic therapies will continue to focus on the screening of the optimal benefit population and the selection of the best treatment sequence strategy with the aim of truly achieving individualized precise treatment of PanNENs.

Predictive Factors for Resistant Disease with Medical/Radiologic/Liver-Directed Anti-Tumor Treatments in Patients with Advanced Pancreatic Neuroendocrine Neoplasms: Recent Advances and Controversies

Simple Summary

Tumor resistance, both primary and acquired, is leading to increased complexity in the nonsurgical treatment of patients with advanced panNENs, which would be greatly helped by reliable prognostic/predictive factors. The importance in identifying resistance is being contributed to by the increased array of possible treatments available for treating resistant advanced disease; the variable clinical course as well as response to any given treatment approach of patients within one staging or grading system, the advances in imaging which are providing increasing promising results/parameters that correlate with grading/outcome/resistance, the increased understanding of the molecular pathogenesis providing promising prognostic markers, all of which can contribute to selecting the best treatment to overcome resistance disease. Several factors have been identified that have prognostic/predictive value for identifying development resistant disease and affecting overall survival (OS)/PFS with various nonsurgical treatments of patients with advanced panNENs. Prognostic factors identified for patients with advanced panNENs for both OS/PFSs include various clinically-related factors (clinical, laboratory/biological markers, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors. Particularly important prognostic factors for the different treatment modalities studies are the recent grading systems. Most prognostic factors for each treatment modality for OS/PFS are not specific for a given treatment option. These advances have generated several controversies and new unanswered questions, particularly those related to their possible role in predicting the possible sequence of different anti-tumor treatments in patients with different presentations. Each of these areas is reviewed in this paper.

Abstract

Purpose: Recent advances in the diagnosis, management and nonsurgical treatment of patients with advanced pancreatic neuroendocrine neoplasms (panNENs) have led to an emerging need for sensitive and useful prognostic factors for predicting responses/survival. Areas covered: The predictive value of a number of reported prognostic factors including clinically-related factors (clinical/laboratory/imaging/treatment-related factors), pathological factors (histological/classification/grading), and molecular factors, on therapeutic outcomes of anti-tumor medical therapies with molecular targeting agents (everolimus/sunitinib/somatostatin analogues), chemotherapy, radiological therapy with peptide receptor radionuclide therapy, or liver-directed therapies (embolization/chemoembolization/radio-embolization (SIRTs)) are reviewed. Recent findings in each of these areas, as well as remaining controversies and uncertainties, are discussed in detail, particularly from the viewpoint of treatment sequencing. Conclusions: The recent increase in the number of available therapeutic agents for the nonsurgical treatment of patients with advanced panNENs have raised the importance of prognostic factors predictive for therapeutic outcomes of each treatment option. The establishment of sensitive and useful prognostic markers will have a significant impact on optimal treatment selection, as well as in tailoring the therapeutic sequence, and for maximizing the survival benefit of each individual patient. In the paper, the progress in this area, as well as the controversies/uncertainties, are reviewed.

Research Progress of circRNAs in Glioblastoma

Circular RNAs (circRNAs) are a class of single-stranded covalently closed non-coding RNAs without a 5' cap structure or 3' terminal poly (A) tail, which are expressed in a variety of tissues and cells with conserved, stable and specific characteristics. Glioblastoma (GBM) is the most aggressive and lethal tumor in the central nervous system, characterized by high recurrence and mortality rates. The specific expression of circRNAs in GBM has demonstrated their potential to become new biomarkers for the development of GBM. The specific expression of circRNAs in GBM has shown their potential as new biomarkers for GBM cell proliferation, apoptosis, migration and invasion, which provides new ideas for GBM treatment. In this paper, we will review the biological properties and functions of circRNAs and their biological roles and clinical applications in GBM.