Activity and Safety of Immune Checkpoint Inhibitors in Neuroendocrine Neoplasms: A Systematic Review and Meta-Analysis

Neuroendocrine neoplasms of the breast: a review of literature

Primary neuroendocrine neoplasms (NENs) of the breast are characterized by neuroendocrine architectural and cytological features, which must be supported by immunohistochemical positivity for neuroendocrine markers (such as Chromogranin and Synaptophysin). According to the literature, making a diagnosis of primary neuroendocrine breast cancer always needs to rule out a possible primary neuroendocrine neoplasm from another site. Currently, the latest 2022 version of the WHO of endocrine and neuroendocrine neoplasms has classified breast NENs as well-differentiated neuroendocrine tumours (NETs) and aggressive neuroendocrine carcinomas (NECs), differentiating them from invasive breast cancers of no special type (IBCs-NST). with neuroendocrine features. The current review article describes six cases from our series and a comprehensive review of the literature in the field of NENs of the breast.

Potential new applications of immunotherapy for neuroendocrine neoplasms: immune landscape, current status and future perspectives

Neuroendocrine neoplasms (NENs) are a highly heterogeneous class of tumors arising from neuroendocrine cells and peptidergic neurons. After failure of first-line treatment, patients have poor prognosis and limited treatment options. Immune checkpoint inhibitors (ICIs) may be a powerful means of increasing therapeutic efficacy for such patients, but ICIs alone have low response rates and short disease control durations in most NENs and may be effective for only a portion of the population. ICIs combined with other immunotherapies, targeted therapies, or cytotoxic drugs have achieved some efficacy in patients with NENs and are worthy of further exploration to assess their benefits to the population. In addition, accumulating experimental and clinical evidence supports that the interaction between neuroendocrine and immune systems is essential to maintain homeostasis, and assessment of this broad neuroendocrine-immune correlation is essential for NEN treatment. In this review, we summarize the immune microenvironment characteristics, advances in immunotherapy, predictive biomarkers of ICI efficacy for NENs, and the effects of common endocrine hormones on the immune system, highlighting possible new application areas for this promising treatment in neglected NENs.

Immune Checkpoint Inhibitor Therapy in Neuroendocrine Tumors

Neuroendocrine tumors (NETs) occur in various regions of the body and present with complex clinical and biochemical phenotypes. The molecular underpinnings that give rise to such varied manifestations have not been completely deciphered. The management of neuroendocrine tumors (NETs) involves surgery, locoregional therapy, and/or systemic therapy. Several forms of systemic therapy, including platinum-based chemotherapy, temozolomide/capecitabine, tyrosine kinase inhibitors, mTOR inhibitors, and peptide receptor radionuclide therapy have been extensively studied and implemented in the treatment of NETs. However, the potential of immune checkpoint inhibitor (ICI) therapy as an option in the management of NETs has only recently garnered attention. Till date, it is not clear whether ICI therapy holds any distinctive advantage in terms of efficacy or safety when compared to other available systemic therapies for NETs. Identifying the characteristics of NETs that would make them (better) respond to ICIs has been challenging. This review provides a summary of the current evidence on the value of ICI therapy in the management of ICIs and discusses the potential areas for future research.

Identification of a new prognostic score for patients with high-grade metastatic GEP-NEN treated with palliative chemotherapy

PURPOSE

High-grade gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN G3) are rare and heterogeneous malignancies with poor prognosis. Aim of this study was to develop prognosticators identifying those patients that derive the most benefit from currently available systemic therapies.

METHODS

This retrospective analysis included 78 patients with metastatic GEP-NEN G3. For patients with imaging data available (n = 52), the overall response rate (ORR) and disease control rate (DCR) were evaluated according to the Response Evaluation Criteria in Solid Tumors 1.1 (RECIST 1.1). A Cox proportional hazard model was used to analyze the prognostic value of selected clinical and blood-based biomarkers. The impact of palliative chemotherapy regimens on time-to-treatment-failure (TTF) and overall survival (OS) was assessed.

RESULTS

Median OS of the study cohort was 9.0 months (95% CI 7.0-11.1). The majority of patients received first-line treatment with platinum plus etoposide (83.3%). The ORR and DCR of the RECIST-evaluable subgroup were 34.6% and 76.9%. Median TTF upon first-line treatment was 4.9 months (95% CI 3.4-6.4). Multivariate analysis identified the Eastern Cooperative Oncology Group performance status (ECOG PS), lactate dehydrogenase (LDH) and absolute lymphocyte count as independent prognostic factors. A prognostic score based on these parameters discriminated patients with favorable and unfavorable outcomes.

CONCLUSION

Outcomes of patients with GEP-NEN G3 are still limited. A new prognostic score identifying those patients benefitting from current platinum/etoposide-based chemotherapy protocols may help as stratification factor in future trial design.

PD-L1 rs2890658 Polymorphism Increases Risk for Non-Small-Cell Lung Cancer in Northern China Population Based on Experimental Data and Meta-Analysis

Purpose

To dig the PD-L1 rs2890658 polymorphism with susceptibility of non-small-cell lung cancer (NSCLC) in northern China.

Patients and Methods

There were 600 NSCLC patients and 600 age and sex matched controls from the same ethnic origin recruited in the present research. Polymerase chain reaction-restriction fragment length polymorphism method genotyped PD-L1 rs2890658 polymorphism. PubMed and Embase were searched to get eligible literature for meta-analysis. The association between PD-L1 rs2890658 polymorphism and NSCLC risk was calculated with odds ratio and 95% confidence interval.

Results

It is more likely that individuals who have CC genotype and C allele are 2.15 and 1.41 times to develop NSCLC compared with individuals with AA genotype and A allele, respectively. Meta-analysis showed that the individuals who have C allele and CA genotype increased the risk of suffering from NSCLC.

Conclusion

PD-L1 rs2890658 polymorphism increased NSCLC risk in northern China population and it might predict the occurrence of NSCLC.

Delta-like ligand 3 (DLL3): an attractive actionable target in tumors with neuroendocrine origin

INTRODUCTION

Neuroendocrine carcinomas are very aggressive tumors with few treatment options. DLL3 seems to be an optimal target for therapeutic intervention, as it is expressed mainly on the membrane of tumor cells with neuroendocrine origin.

AREAS COVERED

In this article, we outline the preclinical and clinical studies published in the last years on DLL3 in neuroendocrine neoplasm, above all of lung origin. Furthermore, we review the current literature on the interaction between DLL3 and the tumor microenvironment.

EXPERT OPINION

Several DLL3-targeting strategies have been proposed in the last years with mixed results. Understanding the influence of DLL3 on the tumor (immune) microenvironment and developing adoptive therapies directed against this optimal target might represent the key strategy. Building on the clinical data obtained so far, future trials on in vivo diagnostic tools for predictive purpose and new specific therapies are needed.

Assessment of Clinical Response Following Atezolizumab and Bevacizumab Treatment in Patients With Neuroendocrine Tumors: A Nonrandomized Clinical Trial

Importance

Therapies for patients with advanced well-differentiated neuroendocrine tumors (NETs) have expanded but remain inadequate, with patients dying of disease despite recent advances in NET therapy. While patients with other cancers have seen long-term disease control and tumor regression with the application of immunotherapies, initial prospective studies of single-agent programmed cell death 1 inhibitors in NET have been disappointing.

Objective

To evaluate the response rate following treatment with the combination of the vascular endothelial growth factor inhibitor bevacizumab with the programmed cell death 1 ligand 1 inhibitor atezolizumab in patients with advanced NETs.

Design, Setting, and Participants

This single-arm, open-label nonrandomized clinical study in patients with rare cancers included 40 patients with advanced, progressive grade 1 to 2 NETs (20 with pancreatic NETs [pNETs] and 20 with extrapancreatic NETs [epNETs]) treated at a tertiary care referral cancer center between March 31, 2017, and February 19, 2019. Data were analyzed from June to September 2021.

Interventions

Patients received intravenous bevacizumab and atezolizumab at standard doses every 3 weeks until progression, death, or withdrawal.

Main Outcomes and Measures

The primary end point was objective radiographic response using Response Evaluation Criteria in Solid Tumors, version 1.1, with progression-free survival (PFS) as a key secondary end point.

Results

Following treatment of the 40 study patients with bevacizumab and atezolizumab, objective response was observed in 4 patients with pNETs (20%; 95% CI, 5.7%-43.7%) and 3 patients with epNETs (15%; 95% CI, 3.2%-37.9%). The PFS was 14.9 (95% CI, 4.4-32.0) months and 14.2 (95% CI, 10.2-19.6) months in these cohorts, respectively.

Conclusions and Relevance

In this nonrandomized clinical trial, findings suggest that clinical responses in patients with NET may follow treatment with the combination of bevacizumab and atezolizumab, with a PFS consistent with effective therapies.

Trial Registration

ClinicalTrials.gov Identifier: NCT03074513.

Efficacy of Immune Checkpoint Inhibitors against Advanced or Metastatic Neuroendocrine Neoplasms: A Systematic Review and Meta-Analysis

We performed a systematic review and meta-analysis of the treatment efficacy of immune checkpoint inhibitors (ICIs) in advanced/metastatic neuroendocrine neoplasms (NENs). MEDLINE and EMBASE were searched to identify studies that provide data on treatment response and/or survival outcomes of advanced/metastatic NEN patients treated with ICIs. The overall response rate (ORR) was pooled using a random-effects model. Meta-regression was performed to explore factors influencing the ORR. Individual patient data (IPD) meta-analysis of survival was performed using stratified Cox regression. Ten studies (464 patients) were included. The overall pooled ORR was 15.5% (95% confidence interval (CI), 9.5-24.3%), and it varied according to the primary site (thoracic, 24.7%; gastro-entero-pancreatic, 9.5%), tumor differentiation (poorly differentiated, 22.7%; well-differentiated, 10.4%), and drug regimen (combination, 25.3%; monotherapy, 10.1%). All these variables significantly influenced the ORR. Tumor differentiation was associated with both overall survival and progression-free survival (hazard ratio of poorly differentiated tumors, 4.2 (95% CI, 2.0-8.7) and 2.6 (95% CI, 1.6-4.4), respectively). Thus, the treatment efficacy of ICIs for advanced/metastatic NENs varied according to primary site, tumor differentiation, and drug regimen. Poorly differentiated NENs showed a better ORR than well-differentiated NENs but had a negative impact on survival.

Human Immunocompetent Model of Neuroendocrine Liver Metastases Recapitulates Patient-Specific Tumour Microenvironment

Neuroendocrine liver metastases (LM-NEN) develop in a considerable proportion of patients with gastroenteropancreatic neuroendocrine neoplasms. There is a paucity of experimental models that accurately recapitulate this complex metastatic human liver microenvironment precluding scientific and clinical advancements. Here, we describe the development of a novel personalised immunocompetent precision cut tumour slice (PCTS) model for LM-NEN using resected human liver tissue. The histological assessment throughout the culture demonstrated that slices maintain viability for at least 7 days and retain the cellular heterogeneity of the original tumour. Essential clinical features, such as patient-specific histoarchitecture, tumour grade, neuroendocrine differentiation and metabolic capacity, are preserved in the slices. The PCTS also replicate the tumor-specific immunological profile as shown by the innate and adaptive immunity markers analysis. Furthermore, the study of soluble immune checkpoint receptors in the culture supernatants proves that these immunomodulators are actively produced by LM-NEN and suggests that this process is epithelium-dependent. This model can be employed to investigate these pathways and provides a powerful platform for mechanistic, immunological and pre-clinical studies.

Neuroendocrine Neoplasms of the Breast: The Latest WHO Classification and Review of the Literature

Simple Summary

Breast tumors exhibiting neuroendocrine differentiation are a heterogeneous group of tumors that have been variously defined in previous World Health Organization (WHO) classifications. In the WHO Classification of Tumours, 5th edition, neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs) of the breast, both of which are invasive cancers, are classified as neuroendocrine neoplasms (NENs) of the breast. However, the clinical significance of NE differentiation in breast cancers, especially in NETs of the breast, is not yet fully understood, and a large overlap appears to exist between breast cancers showing NE differentiation and invasive breast cancer of no special type (IBC-NST). While breast NECs show distinct clinical and morphological features, diagnosis of NETs based on the morphological characteristics alone can be challenging; one reason is that breast NETs do not necessarily have the same morphological characteristics as those of NENs arising in other organs. Thus, the heterogeneity of breast tumors with neuroendocrine differentiation and the changes in their classifications over the years have left many open issues that still need to be resolved. In this review, we shall summarize the history of breast “NENs,” including of mixed types of tumors and the characteristics of these tumors, and discuss their differences from NENs arising in other organs.

Abstract

Breast tumors with neuroendocrine (NE) differentiation comprise an uncommon and heterogeneous group of tumors, including invasive breast cancer of no special type (IBC-NST) with NE features, neuroendocrine tumors (NETs), and neuroendocrine carcinoma (NEC). The most recent World Health Organization (WHO) classification in 2019 defined neuroendocrine neoplasms (NENs) of the breast (Br-NENs) as tumors in which >90% of cells show histological evidence of NE differentiation, including NETs (low-grade tumors) and NEC (high-grade). Due to the low prevalence of these tumors and successive changes in their diagnostic criteria over the years, only limited evidence of these tumors exists, derived mainly from case reports and retrospective case series. Breast tumors with NE differentiation are usually treated like the more commonly occurring IBC-NSTs. Immunohistochemistry (IHC) of breast tumors with NE differentiation usually shows a hormone receptor (HR)-positive and human epidermal growth factor type 2 (HER2)-negative profile, so that hormonal therapy with cyclin-dependent kinase (CDK)4/6 inhibitors or other targeted agents would be reasonable treatment options. Herein, we present a review of the literature on breast tumors with NE differentiation as defined in the latest WHO 2019 classification, and discuss the clinical management of these tumors.

Immunotherapies for well-differentiated grade 3 gastroenteropancreatic neuroendocrine tumors: A new category in the World Health Organization classification

According to the 2019 World Health Organization (WHO) classification, well-differentiated grade 3 (G3) gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are a new category of cancer of the digestive system. G3 GEP-NET research and treatment are not as robust as those of lower grade (G1/2) NETs and poorly differentiated neuroendocrine carcinomas (NECs). Previously, the management of high-grade NETs was mainly based on NEC therapies, as high-grade NETs were classified as NECs under the previous WHO classification. Despite this, G3 GEP-NETs are significantly less responsive to platinum-based chemotherapy regimens than NECs, due to their distinct molecular pathogenesis and course of pathological grade transition. Patients with advanced G3 GEP-NETs, who have progressed or are intolerant to chemotherapy regimens such as capecitabine plus temozolomide, have limited treatment choices. Immunotherapy has helped patients with a variety of cancers attain long-term survival through the use of immune checkpoint inhibitors. Immunotherapies, either alone or in combination with other therapies, do not have a clear function in the treatment of G3 GEP-NETs. Currently, the majority of immunotherapy studies, both prospective and retrospective, do not reliably differentiate G3 GEP-NETs from NECs. By contrast, a significant number of studies include non-GEP neuroendocrine neoplasms (NENs). Therefore, there is an urgent need to summarize and evaluate these data to provide more effective therapeutic approaches for patients with this rare tumor. The purpose of this mini-review was to screen and summarize information on G3 GEP-NETs from all studies on NENs immunotherapy.