Are G3 ENETS neuroendocrine neoplasms heterogeneous?

Chromothripsis is a novel biomarker for prognosis and differentiation diagnosis of pancreatic neuroendocrine neoplasms

This study aimed to identify the role of chromothripsis as a novel biomarker in the prognosis and differentiation diagnosis of pancreatic neuroendocrine neoplasms (pNENs). We conducted next-generation gene sequencing in a cohort of 30 patients with high-grade (G3) pNENs. As a reference, a similar analysis was also performed on 25 patients with low-grade (G1/G2) pancreatic neuroendocrine tumors (pNETs). Chromothripsis and its relationship with clinicopathological features and prognosis were investigated. The results showed that DNA damage response and repair gene alteration and TP53 mutation were found in 29 and 11 patients, respectively. A total of 14 out of 55 patients had chromothripsis involving different chromosomes. Chromothripsis had a close relationship with TP53 alteration and higher grade. In the entire cohort, chromothripsis was associated with a higher risk of distant metastasis; both chromothripsis and metastasis (ENETS Stage IV) suggested a significantly shorter overall survival (OS). Importantly, in the high-grade pNENs group, chromothripsis was the only independent prognostic indicator significantly associated with a shorter OS, other than TP53 alteration or pathological pancreatic neuroendocrine carcinomas (pNECs) diagnosis. Chromothripsis can guide worse prognosis in pNENs, and help differentiate pNECs from high-grade (G3) pNETs.

Molecular Classification of Gastrointestinal and Pancreatic Neuroendocrine Neoplasms: Are We Ready for That?

In the last two decades, the increasing availability of technologies for molecular analyses has allowed an insight in the genomic alterations of neuroendocrine neoplasms (NEN) of the gastrointestinal tract and pancreas. This knowledge has confirmed, supported, and informed the pathological classification of NEN, clarifying the differences between neuroendocrine carcinomas (NEC) and neuroendocrine tumors (NET) and helping to define the G3 NET category. At the same time, the identification genomic alterations, in terms of gene mutation, structural abnormalities, and epigenetic changes differentially involved in the pathogenesis of NEC and NET has identified potential molecular targets for precision therapy. This review critically recapitulates the available molecular features of digestive NEC and NET, highlighting their correlates with pathological aspects and clinical characteristics of these neoplasms and revising their role as predictive biomarkers for targeted therapy. In this context, the feasibility and applicability of a molecular classification of gastrointestinal and pancreatic NEN will be explored.

Automated imaging analysis of Ki-67 immunohistochemistry on whole slide images of cell blocks from pancreatic neuroendocrine neoplasms

INTRODUCTION

Accurate grading of pancreatic neuroendocrine tumors (PanNETs) relies on the assessment of Ki-67 immunohistochemistry (IHC). While digital imaging analysis (DIA) has been employed for Ki-67 IHC assessment in surgical specimens, its applicability to cytologic specimens remains underexplored. This study aimed to evaluate an automated DIA for assessing Ki-67 IHC on PanNET cell blocks.

MATERIALS AND METHODS

The study included 61 consecutive PanNETs and 5 pancreatic neuroendocrine carcinomas. Ki-67 IHC slides from cell blocks were digitally scanned into whole slide images using Philips IntelliSite Scanners and analyzed in batches using the Visiopharm Ki-67 App in a digital workflow. Ki-67 scores obtained through DIA were compared to pathologists' manual scores.

RESULTS

The Pearson correlation coefficient of the percentage of Ki-67-stained nuclei between DIA reads and the originally reported reads was 0.9681. Concordance between DIA Ki-67 grades and pathologists' Ki-67 grades was observed in 92.4% (61/66) of cases with the calculated Cohen's Kappa coefficient of 0.862 (almost perfect agreement). Discordance between DIA and pathologists' consensus reads occurred in 5 PanNET cases which were upgraded from G1 to G2 by DIA due to contaminated Ki-67-stained inflammatory cells.

CONCLUSIONS

DIA demonstrated excellent concordance with pathologists' assessments, with only minor grading discrepancies. However, the essential role of pathologists in confirming results is emphasized to enhance overall accuracy.

Radiosensitizing Favors Response to Peptide Receptor Radionuclide Therapy in Patients With Highly Proliferative Neuroendocrine Malignancies: Preliminary Evidence From a Clinical Pilot Study

AIM/INTRODUCTION

Peptide receptor radionuclide therapy (PRRT) represents a cornerstone of treatment regimens for patients with low proliferative neuroendocrine tumors (NETs). However, in patients experiencing somatostatin receptor-positive NET with higher proliferation rates, a value and potential therapeutic benefit of PRRT as part of multimodal treatment approaches and potentially with addition of radiosensitizing agents has not yet been established.

PATIENTS AND METHODS

In this study, 20 patients with histologically confirmed gastroenteropancreatic (GEP) NET with proliferation rates (Ki67) between 15% and 55% were treated either with PRRT only (n = 10) or with a combination therapy (n = 10) comprising PRRT and capecitabine/temozolomide (CAP/TEM) for at least 2 consecutive cycles.

RESULTS

Disease control rate in patients treated with PRRT alone was 60% (40% stable disease and 20% partial response). Strikingly, in patients treated with PRRT in combination with radiosensitization (CAP/TEM), the disease control rate was 90% (20% stable disease and 70% partial response). The median progression-free survival in the PRRT only group was 12 months, whereas the median progression-free survival in the PRRT + CAP/TEM group was 26 months and has not been yet reached for all patients in the group during the observation period. The median disease-specific survival for patients with PRRT alone was 51 months, whereas this end point was not yet reached in the PRRT + CAP/TEM group. Moreover, the PRRT + CAP/TEM group showed a significantly higher reduction of SSTR-PET-based metabolic tumor volume and chromogranin A levels compared with the PRRT only group. Importantly, adverse events of all grades did not differ between both groups.

CONCLUSIONS

PRRT + CAP/TEM represents a highly promising and well-tolerated therapeutic regimen for patients experiencing somatostatin receptor-positive NET with higher (Ki67 ≥ 15%) proliferation rate. Prospective randomized clinical trials are warranted.

Treatment modalities favoring outcome in well-differentiated neuroendocrine tumors G3

Introduction

Neuroendocrine neoplasms (NEN) are a rare and heterogenous group of tumors arising from neuroendocrine cells in multiple organs. Neuroendocrine tumors (NET) G3 encompass a small subgroup accounting for less than 10% of all neuroendocrine neoplasms. In contrast to NET G1 and G2 as well as neuroendocrine carcinomas (NEC), in NET G3 data on treatment and patient outcomes are still limited. Especially in a metastasized tumor stage, the role of surgery, peptide receptor radionucleotide therapy (PRRT), and systemic chemotherapy is not clearly defined.

Methods

In this real-life cohort, we consecutively analyzed clinical outcome in NET G3 patients receiving different diagnostic and treatment.

Results and discussion

We found that even metastasized NET G3 patients undergoing surgery, or receiving radiation, somatostatin analogues (SSA), and PRRT showed a clear survival benefit. Interestingly, all treatment regimen were superior to classical chemotherapeutic agents. In addition, somatostatin receptor (SSTR) PET-CT, FDG PET-CT, and repetitive biopsies were shown to be useful diagnostic and prognostic tools in NET G3. Our study demonstrates that patients with highly proliferative NET G3 might benefit from less aggressive treatment modalities commonly used in low proliferative NEN.

Selection of Chemotherapy in Advanced Poorly Differentiated Extra-Pulmonary Neuroendocrine Carcinoma

Extra-pulmonary poorly differentiated neuroendocrine carcinoma is rare, and evidence for treatment has been limited. In this article, the evidence behind the cytotoxic chemotherapy choices used for metastatic or unresectable EP-PD-NEC is reviewed. In the first-line setting, etoposide and platinum chemotherapy or irinotecan and platinum have been demonstrated to be equivalent in a large phase III trial. Questions remain regarding the optimal number of cycles, mode of delivery, and the precise definition of platinum resistance in this setting. In the second-line setting, FOLFIRI has emerged as an option, with randomized phase 2 trials demonstrating modest, but significant, response rates. Beyond this, data are extremely limited, and several regimens have been used. Heterogeneity in biological behaviour is a major barrier to optimal EP-PD-NEC management. Available data support the potential role of the Ki-67 index as a predictive biomarker for chemotherapy response. A more personalised approach to management in future studies will be essential, and comprehensive multi-omic approaches are required to understand tumour somatic genetic changes in relation to their effects on the surrounding microenvironment.

Multivisceral resection of nonfunctional pancreatic neuroendocrine neoplasm with nearby organ invasion: a case report

Pancreatic neuroendocrine neoplasms (pNENs) are relatively rare epithelial malignancies originating from pancreatic neuroendocrine cells, pathologically classified into well-differentiated pancreatic neuroendocrine tumors (pNETs) and poorly-differentiated pancreatic neuroendocrine carcinoma (pNECs). Although they also fall under the category of pNENs, the almost entirely distinct biological characteristics and survival prognosis have caused debate among surgeons when it comes to the development of surgical intervention options, particularly for locally advanced G3 pNETs and pNECs. We present a case of 66-year-old male with nonfunctional G3 pNET, invasion of five nearby pancreatic organs and type II liver metastases. The patient achieved good outcomes after undergoing multivisceral resection and postoperative adjuvant chemotherapy. This finding helps surgeons better understand locally advanced pNENs, formulate treatment decisions systematically and confidently, and balance patient benefits and risks of surgery.

Relation between WHO Classification and Location- and Functionality-Based Classifications of Neuroendocrine Neoplasms of the Digestive Tract

Practice of neuroendocrine neoplasms (NENs) of the digestive tract, which comprise of a highly diverse group of tumors with a rising incidence, faces multiple biological, diagnostic, and therapeutic issues. Part of these issues is due to misuse and misinterpretation of the classification and terminology of NENs of the digestive tract, which make it increasingly challenging to evaluate and compare the literature. For instance, grade 3 neuroendocrine tumors (NETs) are frequently referred to as neuroendocrine carcinomas (NECs) and vice versa, while NECs are, by definition, high grade and therefore constitute a separate entity from NETs. Moreover, the term NET is regularly misused to describe NENs in general, and NETs are frequently referred to as benign, while they should always be considered malignancies as they do have metastatic potential. To prevent misconceptions in future NEN-related research, we reviewed the most recent terminology used to classify NENs of the digestive tract and created an overview that combines the classification of these NENs according to the World Health Organization (WHO) with location- and functionality-based classifications. This overview may help clinicians and researchers in understanding the current literature and could serve as a guide in the clinic as well as for writing future studies on NENs of the digestive tract. In this way, we aim for the universal use of terminology, thereby providing an efficient foundation for future NEN-related research.

Updates in histopathological classification and tissue biomarkers of digestive neuroendocrine neoplasms: What the clinician should know

Histopathological classifications of neuroendocrine neoplasms (NEN) change regularly and the latest WHO classification published in 2022, which concerns all NEN in the body, attempts to standardize classifications in the different locations. Differentiation and proliferation mainly assessed by Ki-67 index are still the cornerstone of those classifications. However, many markers are now used for diagnostic (to check neuroendocrine differentiation, to identify the site of origin of a metastasis, to help separating high-grade neuroendocrine tumors/NET and neuroendocrine carcinoma/NEC), prognostic or theranostic purposes. NENs are often heterogeneous and this can lead to difficulties in classifications, biomarker and prognostic assessment. These different points are discussed successively in this review, insisting especially on the frequent digestive, gastro-entero-pancreatic (GEP) localizations.

Potent molecular-targeted therapies for gastro-entero-pancreatic neuroendocrine carcinoma

Neuroendocrine neoplasms (NENs), which are characterized by neuroendocrine differentiation, can arise in various organs. NENs have been divided into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs) based on morphological differentiation, each of which has a distinct etiology, molecular profile, and clinicopathological features. While the majority of NECs originate in the pulmonary organs, extrapulmonary NECs occur most predominantly in the gastro-entero-pancreatic (GEP) system. Although platinum-based chemotherapy is the main therapeutic option for recurrent or metastatic GEP-NEC patients, the clinical benefits are limited and associated with a poor prognosis, indicating the clinically urgent need for effective therapeutic agents. The clinical development of molecular-targeted therapies has been hampered due to the rarity of GEP-NECs and the paucity of knowledge on their biology. In this review, we summarize the biology, current treatments, and molecular profiles of GEP-NECs based on the findings of pivotal comprehensive molecular analyses; we also highlight potent therapeutic targets for future precision medicine based on the most recent results of clinical trials.

Diagnostic Approaches for Neuroendocrine Neoplasms of Unknown Primary (NEN-UPs) and Their Prognostic Relevance-A Retrospective, Long-Term Single-Center Experience

Neuroendocrine neoplasms (NENs) represent a rare and heterogenous group of tumors with predominantly gastroenteropancreatic or pulmonary origin. Despite numerous diagnostic efforts, the primary tumor site remains unknown in up to 20% of the patients diagnosed with NEN. In this subgroup of NEN patients, a standard diagnostic algorithm has not yet been integrated into clinical routine. Of note, an undetermined primary tumor site in NENs is associated with an impaired clinical outcome by at least "formally" limiting treatment options exclusively approved for NENs of a certain histological origin. In this retrospective study, a patient cohort of 113 patients initially diagnosed with NEN of unknown primary (NEN-UP) was analyzed. In 13 patients (11.5%) a primary tumor site could be identified subsequently, amongst others, by performing somatostatin receptor (SSTR)-PET-based imaging, which was irrespective of the initial clinical or demographic features. Diagnostic work-up and therapeutic regimens did not differ significantly between patients with an identified or unidentified primary tumor site; only a detailed immunohistochemical assessment providing additional information on the tumor origin proved to be significantly associated with the detection of a primary tumor site. Our study revealed that a profound diagnostic work-up, particularly including SSTR-PET-based imaging, leads to additional treatment options, finally resulting in significantly improved clinical outcomes for patients with NEN-UPs.

Grade Progression and Intrapatient Tumor Heterogeneity as Potential Contributors to Resistance in Gastroenteropancreatic Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine neoplasms (NENs) are a heterogenous group of tumors that are incurable when metastatic, regardless of grade. The aim of this article is to understand tumor heterogeneity and grade progression as possible contributors to drug resistance in gastroentropancreatic neuroendocrine tumors (GEP-NETs). Heterogeneity has been observed in the genetic, pathological, and imaging features of these tumors at baseline. Diagnostic challenges related to tumor sampling and the potential for changes in grade over time further confound our ability to optimize therapy for patients. A better understanding of NEN biology and tumor heterogeneity at baseline and over time could lead to the development of new therapeutic avenues.

Prognostic value of computed tomography radiomics features in patients with gastric neuroendocrine neoplasm

Purpose

The present study aimed to investigate the clinical prognostic significance of radiomics signature (R-signature) in patients with gastric neuroendocrine neoplasm (GNEN).

Methods and Materials

A retrospective study of 182 patients with GNEN who underwent dual-phase enhanced computed tomography (CT) scanning was conducted. LASSO-Cox regression analysis was used to screen the features and establish the arterial, venous and the arteriovenous phase combined R-signature, respectively. The association between the optimal R-signature with the best prognostic performance and overall survival (OS) was assessed in the training cohort and verified in the validation cohort. Univariate and multivariate Cox regression analysis were used to identify the significant factors of clinicopathological characteristics for OS. Furthermore, the performance of a combined radiomics-clinical nomogram integrating the R-signature and independent clinicopathological risk factors was evaluated.

Results

The arteriovenous phase combined R-signature had the best performance in predicting OS, and its C-index value was better than the independent arterial and venous phase R-signature (0.803 vs 0.784 and 0.803 vs 0.756, P<0.001, respectively). The optimal R-signature was significantly associated with OS in the training cohort and validation cohort. GNEN patients could be successfully divided into high and low prognostic risk groups with radiomics score median. The combined radiomics-clinical nomogram combining this R-signature and independent clinicopathological risk factors (sex, age, treatment methods, T stage, N stage, M stage, tumor boundary, Ki67, CD56) exhibited significant prognostic superiority over clinical nomogram, R-signature alone, and traditional TNM staging system (C-index, 0.882 vs 0.861, 882 vs 0.803, and 0.882 vs 0.870 respectively, P<0.001). All calibration curves showed remarkable consistency between predicted and actual survival, and decision curve analysis verified the usefulness of the combined radiomics-clinical nomogram for clinical practice.

Conclusions

The R-signature could be used to stratify patients with GNEN into high and low risk groups. Furthermore, the combined radiomics-clinical nomogram provided better predictive accuracy than other predictive models and might aid clinicians with therapeutic decision-making and patient counseling.

Post-Topotecan Mixed Response and 'Redifferentiation-akin' Phenomenon on Dual Tracer PET-CT in Multiple Treatment-Resistant Metastatic Neuroendocrine Neoplasm

A 50-year-old female patient of heavily pre-treated (chemotherapy and multiple treatment-resistant) and progressive intermediate-grade metastatic neuroendocrine neoplasm is presented, wherein the lesions showed mixed response following topotecan treatment and multiple hepatic metastasis showed increase in the SSTR expression and decrease in FDG concentration on dual-tracer PET/CT ( ⁶⁸ Ga-DOTATATE and ¹⁸ F-FDG PET/CT). Such observation allowed ¹⁷⁷ Lu-DOTATATE PRRT to be considered for an advanced, symptomatic, and multiple treatment-resistant patient with limited palliative treatment options left.

Small bowel neuroendocrine tumours - casting the net wide

PURPOSE OF REVIEW

Our aim is to provide an overview of small bowel neuroendocrine tumours (NETs), clinical presentation, diagnosis algorithm and management options. We also highlight the latest evidence on management and suggest areas for future research.

RECENT FINDINGS

Dodecanetetraacetic acid (DOTATATE) scan can detect NETs with an improved sensitivity than when compared with an Octreotide scan. It is complimentary to small bowel endoscopy that provides mucosal views and allows the delineation of small lesions undetectable on imaging. Surgical resection is the best management modality even in metastatic disease. Prognosis can be improved with the administration of somatostatin analogues and Evarolimus as second-line therapies.

SUMMARY

NETs are heterogenous tumours affecting most commonly the distal small bowel as single or multiple lesions. Their secretary behaviour can lead to symptoms, most commonly diarrhoea and weight loss. Metastases to the liver are associated with carcinoid syndrome.

Targeting neuroendocrine tumors with octreotide and lanreotide: Key points for clinical practice from NET specialists

Octreotide and lanreotide are the two somatostatin analogs (SSA) currently available in clinical practice. They have been approved first to control the clinical syndrome (mainly carcinoid syndrome) associated with functioning neuroendocrine tumors (NET) and later for tumor growth control in advanced low/intermediate grade NET. Although evidence regarding their role, especially as antiproliferative therapy, has been increasing over the years some clinical indications remain controversial. Solicited by AIOM (Italian Association of Medical Oncology) a group of clinicians from various specialties, including medical oncology, endocrinology, and gastroenterology, deeply involved in NET for their clinical and research activity, addressed eight open questions, critically reviewing evidence and guidelines and sharing clinical take-home messages. The questions regarded the use of long-acting octreotide and lanreotide in the following settings: functioning and non-functioning NET refractory to label dose, first-line metastatic pulmonary NET, combination with other therapy with an antiproliferative intent, maintenance in NET responding to other therapies, adjuvant treatment, Ki-67-related cut-off, somatostatin receptor imaging, safety, and feasibility. The level of evidence is not absolute for the majority of these clinical contexts, so it is recommended to distinguish routine versus sporadic utilization in very selected cases. Mention of such specific issues by the main European guidelines (ENETS, European Neuroendocrine Tumor Society, and ESMO, European Society for Medical Oncology) was explored and their position reported. However, different clinical decisions on single patients could be made if the case is carefully discussed within a NET-dedicated multidisciplinary team.

Neuroendocrine Neoplasms of the Gastrointestinal Tract versus Neuroendocrine Neoplasms of the Gynaecological Tract-Comparison of the Risk Factors and Non-Surgical Treatment Efficacy

Neuroendocrine tumours of the gastrointestinal tract are rare. The incidence has increased in recent years due to improvements in diagnostic methods for detecting these lesions. These tumours have a poor prognosis, especially when detected at an advanced stage. The basis of the treatment is resection, and non-surgical treatments are also standard in the treatment process. The situation is similar in even rarer neuroendocrine tumours of the reproductive tract, which are associated with an equally poor prognosis. In this article, we focus on learning about the risk factors (including genetic mutations) that increase the risk of the disease and comparing the effectiveness of non-surgical treatments-chemotherapy, radiotherapy, peptide receptor radionuclide therapy, somatostatin analogues, and immunotherapy. The efficacy of these treatments varies, and immunotherapy appears to be a promising form of treatment; however, this requires further research.

Diagnostic role and prognostic value of tumor markers in high-grade gastro-enteropancreatic neuroendocrine neoplasms

OBJECTIVES

High-grade gastro-enteropancreatic neuroendocrine neoplasms (GEP-NENs) are a heterogeneous group of rare tumors of two different types: well differentiated neuroendocrine tumors grade 3 (NETs G3) and poorly differentiated neuroendocrine carcinomas (NECs). This study aimed to explore the value of eight common preoperative markers in differentiating NETs G3 from NECs and the prognosis prediction of high-grade GEP-NENs.

METHODS

Seventy-two patients diagnosed with high-grade GEP-NENs who underwent surgery at our institution were recruited for this study. Demographic and clinicopathological characteristics, preoperative serum tumor markers, and survival data were collected and analyzed. Kaplan-Meier methods were used to analyze survival rates, and a Cox regression model was used to perform multivariate analyses.

RESULTS

Serum carcinoembryonic antigen (CEA) was dramatically higher in NECs than in NETs G3 (P = 0.025). After follow-up, 57 of the 72 patients remained for survival analysis. Elevated serum carbohydrate antigen 19-9 (CA19-9), CEA, cancer antigen 125 and sialic acid (SA) levels indicated poorer survival of high-grade GEP-NEN patients. Only CA19-9 (HR: 6.901, 95% CI: 1.843 to 25.837, P = 0.004) was regarded as an independent risk factor for overall survival. Serum CA19-9 (HR: 4.689, 95% CI: 1.127 to 19.506, P = 0.034) was also regarded as an independent factor for overall survival in NECs.

CONCLUSIONS

Serum CEA levels can be used to distinguish NETs G3 from NECs. Preoperative CA19-9, CEA, cancer antigen 125 and SA levels have predictive value in the prognosis of high-grade GEP-NENs. Preoperative CA19-9, neuron-specific enolase, and SA levels can predict the prognosis of NECs.

Integrated Genomic and Clinicopathologic Approach Distinguishes Pancreatic Grade 3 Neuroendocrine Tumor From Neuroendocrine Carcinoma and Identifies a Subset With Molecular Overlap

Distinguishing grade 3 pancreatic neuroendocrine tumor (G3 PanNET) from neuroendocrine carcinoma (PanNEC) is a known diagnostic challenge, and accurate classification is critical because clinical behavior and therapies differ. Although current recommendations suggest that immunohistochemistry for p53, Rb, ATRX, and DAXX can distinguish most cases, some cases remain difficult to classify using this approach. In this study, we reviewed 47 high-grade neoplasms originally diagnosed as pancreatic neuroendocrine neoplasms. In addition to the currently recommended stains, we performed capture-based sequencing of approximately 500 cancer genes and immunohistochemistry for p16 and trypsin or chymotrypsin. Using an integrated molecular and clinicopathologic approach, 42 (89%) of 47 cases had a clear final diagnosis of either G3 PanNET (n = 17), PanNEC (n = 17), or mixed acinar-NEC (n = 8). The 17 G3 PanNETs demonstrated frequent alterations in MEN1 (71%), DAXX (47%), ATRX (24%), TSC2 (35%), SETD2 (42%), and CDKN2A (41%). Contrary to prior reports, TP53 alterations were also common in G3 PanNETs (35%) but were always mutually exclusive with CDKN2A alterations in this group. The 17 PanNECs demonstrated frequent alterations in TP53 (88%), cell cycle genes RB1 (47%), CCNE1/CCND1 (12%), CDKN2A (29%), and in KRAS (53%) and SMAD4 (41%); TP53 was coaltered with a cell cycle gene in 76% of PanNECs. Diffuse strong p16 staining was observed in 69% of PanNECs in contrast to 0% of G3 PanNETs. The 8 acinar-NECs had recurrent alterations in ATM (25%), APC (25%), and STK11 (25%). Five cases remained difficult to classify, 3 of which exhibited overlapping molecular features with alterations in MEN1 with or without ATRX, and RB1 with or without TP53, making it unclear whether to classify as PanNET or PanNEC. Our data demonstrate that molecular profiling and immunohistochemistry for p16 greatly improve the diagnostic accuracy of high-grade pancreatic neuroendocrine neoplasms and identify a subset of rare cases with overlapping features of both PanNET and PanNEC.

All Together Now: Standardization of Nomenclature for Neuroendocrine Neoplasms across Multiple Organs

Neuroendocrine neoplasms (NENs) span virtually all organ systems and exhibit a broad spectrum of behavior, from indolent to highly aggressive. Historically, nomenclature and grading practices have varied widely across, and even within, organ systems. However, certain core features are recapitulated across anatomic sites, including characteristic morphology and the crucial role of proliferative activity in prognostication. A recent emphasis on unifying themes has driven an increasingly standardized approach to NEN classification, as delineated in the World Health Organization's Classification of Tumours series. Here, we review recent developments in NEN classification, with a focus on NENs of the pancreas and lungs.

Integrating Functional Imaging and Molecular Profiling for Optimal Treatment Selection in Neuroendocrine Neoplasms (NEN)

PURPOSE OF REVIEW

Gastroenteropancreatic NEN (GEP-NEN) are group of malignancies with significant clinical, anatomical and molecular heterogeneity. High-grade GEP-NEN in particular present unique management challenges.

RECENT FINDINGS

In the current era, multidisciplinary management with access to a combination of functional imaging and targeted molecular profiling can provide important disease characterisation, guide individualised management and improve patient outcome. Multiple treatment options are now available, and combination and novel therapies are being explored in clinical trials. Precision medicine is highly relevant for a heterogenous disease like NEN. The integration of dual-tracer functional PET/CT imaging, molecular histopathology and genomic data has the potential to be used to gain a more comprehensive understanding of an individual patient's disease biology for precision diagnosis, prognostication and optimal treatment allocation.

The Complex Histopathological and Immunohistochemical Spectrum of Neuroendocrine Tumors-An Overview of the Latest Classifications

Neuroendocrine neoplasms (NENs) originate from the neuroendocrine cell system, which may either take the shape of organoid cell aggregations or be composed of dispersed cells across various organs. Therefore, these tumors are heterogenous regarding the site of origin, functional status, degree of aggressiveness, and prognosis. When treating patients with neuroendocrine tumors, one of the most significant challenges for physicians is determining the correct tumor grade and thus classifying patients into risk categories. Over the years, the classification of these tumors has changed significantly, often causing confusion due to clinical, molecular, and immunohistochemical variability. This review aims to outline the latest NENs classifications regardless of their site of origin. Thus, an overview of the key histopathological and immunohistochemical characteristics of NENs could pave the way to validate possible predictive and prognostic markers and also guide the therapeutic conduct.

Long-term organoid culture of a small intestinal neuroendocrine tumor

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare and highly heterogeneous neoplasms whose incidence has markedly increased over the last decades. A grading system based on the tumor cells' proliferation index predicts high-risk for G3 NETs. However, low-to-intermediate grade (G1/G2) NETs have an unpredictable clinical course that varies from indolent to highly malignant. Cultures of human cancer cells enable to perform functional perturbation analyses that are instrumental to enhance our understanding of cancer biology. To date, no tractable and reliable long-term culture of G1/G2 NET has been reported to permit disease modeling and pharmacological screens. Here, we report of the first long-term culture of a G2 metastatic small intestinal NET that preserves the main genetic drivers of the tumor and retains expression patterns of the endocrine cell lineage. Replicating the tissue, this long-term culture showed a low proliferation index, and yet it could be propagated continuously without dramatic changes in the karyotype. The model was readily available for pharmacological screens using targeted agents and as expected, showed low tumorigenic capacity in vivo. Overall, this is the first long-term culture of NETs to faithfully recapitulate many aspects of the original neuroendocrine tumor.

A systematic review of therapeutic strategies in gastroenteropancreatic grade 3 neuroendocrine tumors

Background

Gastroenteropancreatic (GEP) neuroendocrine neoplasms with Ki-67 > 20% were subdivided in the most recent 2019 World Health Organization histopathological classification into grade 3 (G3) neuroendocrine tumors (NETs), described as well-differentiated tumors, and neuroendocrine carcinomas, which are described as poorly differentiated tumors. This classification met the demand noted for different prognoses between these subgroups, prompting the need for treatment recommendations for well-differentiated G3 tumors.

Methods

We systematically searched medical literature databases and oncology conferences for studies on G3 GEP NET to describe epidemiology, diagnosis, molecular features, and treatments used. We excluded studies that did not discriminate G3 NET data. Data were tabulated and described, and a quality analysis of the reports was performed.

Results

We found 23 published studies and six abstracts; 89.7% of studies were retrospective, six were composed exclusively of G3 NETs. Among 761 patients, the median number of patients per study was 15, most were male and older than 60 years, and functional imaging tests were positive in more than 80% of cases. Overall, the scientific evidence supporting the treatment of G3 GEP NETs is limited. For localized disease, resection remains the standard treatment but there is no evidence to support neoadjuvant or adjuvant therapy. For advanced disease, capecitabine and temozolomide seems to be the most effective option, with a response rate, median progression-free survival, and median overall survival up to 37.9%, 20.6 months, and 41.2 months, respectively.

Conclusion

The latest available data on the epidemiology, diagnosis, molecular changes, and treatment of G3 GEP NET are described. Yet, the level of evidence for treatment recommendations is low, as most studies are retrospective. A treatment algorithm for G3 GEP NET is proposed.

Clinicopathological and survival features of neuroendocrine tumors: A retrospective analysis of 153 cases, our current remarks on a heterogeneous tumor group, and still unmet future expectations

Objective

Neuroendocrine neoplasms (NENs) originate from the diffuse neuroendocrine cell system and constitute a heterogeneous group of tumors exhibiting diverse clinical and biological characteristics. NENs include well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). In the present study, we performed a retrospective analysis of patients diagnosed with NET to evaluate clinicopathological characteristics, treatment and outcomes.

Material and Methods

Data from 153 patients diagnosed with NET who were treated and followed up at three tertiary care centers from November 2002 to June 2021 were retrospectively evaluated. Clinicopathological and prognostic factors, treatment modalities and survival data were analyzed. Kaplan-Meier analysis was used to assess survival data and comparisons were performed using the logrank test.

Results

Median age (IQR) was 53 (18-80) years. 85.6% of the patients had gastro-entero-pancreatic (GEP)-NET. The primary tumor was resected in 95 patients (62.1%) and metastasectomy were performed in 22 patients (14.4%). Seventy-eight patients received systemic therapy for metastatic disease. Patients were followed up for a median of 22 (IQR = 33.8) months. The estimated one-year and three-year survival rate was 89.8% and 74.4%, respectively. Median progression-free survival (PFS) were 10.1, 8.5, and 4.2 months after first-, second- and third-line therapy, respectively.

Conclusion

The number of systemic treatment options and diagnostic tools for NETs has significantly improved in the last few years. NET classification, which treatment will be more appropriate for which group of patients, the molecular basis of this disease and the development of treatment strategies are open-ended questions that still need to be investigated.

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.

From morphology to molecular targets—the pathologist’s view in diagnosing gastroenteropancreatic neuroendocrine neoplasms

In the last decade, a number of genetic alterations in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) have been identified. In addition, differences in tumor morphology as well as proliferation index (Ki-67) or number of mitoses have led to changes in the classification of these neoplasms. According to the new World Health Organization (WHO) classification, GEP-NENs are now divided into two genetically and prognostically different categories: (i) well-differentiated neuroendocrine tumors (NET) subdivided into low (G1), intermediate (2) and high (G3) grade tumors, and (ii) poorly differentiated neuroendocrine carcinomas (NEC). In addition, a group of mixed neuroendocrine–non-neuroendocrine neoplasms (MiNEN) has been defined. This review focuses on the clinical, morphological, immunohistochemical and molecular findings of the GEP-NENs and their key diagnostic features that can help the pathologist to differentiate between tumors in this heterogeneous group. In challenging cases, additional immunohistochemical and/or molecular analysis can be helpful to determine the correct diagnosis and proper treatment for the patient.

PRRT for higher-grade neuroendocrine neoplasms: What is still acceptable?

Peptide receptor radionuclide therapy (PRRT) is a widely accepted treatment for progressive grade 1 and 2 (G1-2) gastroenteropancreatic neuroendocrine tumors (NET). There is increasing evidence that PRRT is effective for selected patients with well-differentiated (WD) G3 NET, which are now separated from neuroendocrine carcinoma (NEC). These preliminary data have led to prospective PRRT trials currently in progress. This article provides an update of the current role of PRRT for patients with WD-G3 NET, highlighting the importance of patient selection based on molecular imaging phenotype, as well as outlining some potential future directions in this field. Upcoming prospective trials will help define the role, sequencing, and optimization of PRRT to improve outcomes of patients with WD-G3 NET.

A Clinical Guide to Peptide Receptor Radionuclide Therapy with 177Lu-DOTATATE in Neuroendocrine Tumor Patients

Peptide receptor radionuclide therapy (PRRT) with [¹⁷⁷Lu]Lu-[DOTA⁰,Tyr³]-octreotate (¹⁷⁷Lu-DOTATATE) has become an established second- or third-line treatment option for patients with somatostatin receptor (SSTR)-positive advanced well-differentiated gastroenteropancreatic (GEP) neuroendocrine tumors (NETs). Clinical evidence of the efficacy of PRRT in tumor control has been proven and lower risks of disease progression or death are seen combined with an improved quality of life. When appropriate patient selection is performed, PRRT is accompanied by limited risks for renal and hematological toxicities. Treatment of NET patients with PRRT requires dedicated clinical expertise due to the biological characteristics of PRRT and specific characteristics of NET patients. This review provides an overview for clinicians dealing with NET on the history, molecular characteristics, efficacy, toxicity and relevant clinical specifics of PRRT.

Novel staging for gastric neuroendocrine neoplasms by incorporating the WHO grading into the TNM staging system

BACKGROUND

The 8th tumor-node-metastasis (TNM) classification of the American Joint Committee on Cancer (AJCC) can be used to estimate the prognosis of gastric neuroendocrine tumor (gNET) and gastric neuroendocrine carcinoma (gNEC) patients but not gastric neuroendocrine neoplasms (gNENs).

METHODS

First, in the SEER (training) dataset, a TNMG system was built by combining the WHO G grade (G1-4; NEC grouped into G4) with the 8th AJCC T (T1-4), N (N0-1), and M (M0-1) stage, which was then validated in a Chinese (validation) cohort.

RESULTS

In all, 2245 gNENs cases from the training dataset and 280 cases from the validation dataset were eligible. The T stage, M stage, and G grade were independent prognostic factors for OS in both datasets (all p < 0.05). The TNMG staging system demonstrated better C-index for predicting OS than the 8th AJCC TNM staging system in both the training (0.87, 95%CI: 0.86-0.88 vs. 0.79, 95%CI: 0.77-0.81) and validation (0.77, 95%CI: 0.73-0.80 vs. 0.75, 95%CI: 0.71-0.79) datasets. The AUC of the 3-year OS for the TNMG staging system was 0.936 and 0.817 in the SEER and validation dataset, respectively; higher than those of the 8th AJCC system (vs. 0.843 and 0.779, respectively). DCA revealed that compared with the 8th AJCC TNM staging system, the TNMG staging system demonstrated superior net prognostic benefit in both the training and validation datasets.

CONCLUSIONS

The proposed TNMG staging system could more accurately predict the 3- and 5-year OS rate of gNENs patients than the 8th AJCC TNM staging system.

Fortuitous discovery of an early neuroendocrine tumor during appendicular peritonitis

Introduction

Materials and methods

Results

Conclusion

•

Neuroendocrine tumors of the small bowel are rare but represent the most frequent histological type at this level.

•

Their incidence is increasing thanks to the evolution of diagnostic means.

•

These tumors are most often diagnosed incidentally during the workup of aspecific digestive disorders or during hormonal hypersecretion syndrome or rarely by a complication.

Neuroendocrine tumor G3 of bronchopulmonary origin and its classification

Neuroendocrine tumors (NET) with high proliferative activity (Ki-67 index >20% and/or mitotic counts >2 mm² ) are defined as NET G3 in the 2019 World Health Organization (WHO) classification of digestive system neuroendocrine neoplasms (NENs). NETs G3 occur mostly in the pancreas, colon, rectum, and stomach and only rarely in the small intestine and the appendix. In the bronchopulmonary system, similar tumors have also been recognized and were mostly classified as atypical carcinoid (AC) or large cell neuroendocrine carcinoma. Bronchopulmonary NENs that were classified as NETs G3 are characterized by histological and immunohistochemical similarities with carcinoids/NETs, and a clinical course that is more aggressive than with ACs and similar to that of neuroendocrine carcinomas. The morphomolecular and clinical features of bronchopulmonary neoplasms with a high proliferative activity were reviewed and a future classification system that is applicable for both digestive and bronchopulmonary NETs is proposed.

Effectiveness of Etoposide and Cisplatin vs Irinotecan and Cisplatin Therapy for Patients With Advanced Neuroendocrine Carcinoma of the Digestive System: The TOPIC-NEC Phase 3 Randomized Clinical Trial

Question

For patients with advanced neuroendocrine carcinoma of the digestive system, which of the 2 community standard regimens is more effective: etoposide plus cisplatin (EP) or irinotecan plus cisplatin (IP)?

Findings

In this randomized clinical trial of 170 patients who were chemotherapy naive and had recurrent or unresectable neuroendocrine carcinoma of the digestive system, median overall survival was 12.5 months in the EP arm and 10.9 months in the IP arm.

Meaning

Both EP and IP therapy remain standard first-line chemotherapy options.

Importance

Etoposide plus cisplatin (EP) and irinotecan plus cisplatin (IP) are commonly used as community standard regimens for advanced neuroendocrine carcinoma (NEC).

Objective

To identify whether EP or IP is a more effective regimen in terms of overall survival (OS) in patients with advanced NEC of the digestive system.

Design, Setting, and Participants

This open-label phase 3 randomized clinical trial enrolled chemotherapy-naive patients aged 20 to 75 years who had recurrent or unresectable NEC (according to the 2010 World Health Organization classification system) arising from the gastrointestinal tract, hepatobiliary system, or pancreas. Participants were enrolled across 50 institutions in Japan between August 8, 2014, and March 6, 2020.

Interventions

In the EP arm, etoposide (100 mg/m²/d on days 1, 2, and 3) and cisplatin (80 mg/m²/d on day 1) were administered every 3 weeks. In the IP arm, irinotecan (60 mg/m²/d on days 1, 8, and 15) and cisplatin (60 mg/m²/d on day 1) were administered every 4 weeks.

Main Outcomes and Measures

The primary end point was OS. In total, data from 170 patients were analyzed to detect a hazard ratio (HR) of 0.67 (median OS of 8 and 12 months in inferior and superior arms, respectively) with a 2-sided α of 10% and power of 80%. The pathologic findings were centrally reviewed following treatment initiation.

Results

Among the 170 patients included (median [range] age, 64 [29-75] years; 117 [68.8%] male), median OS was 12.5 months in the EP arm and 10.9 months in the IP arm (HR, 1.04; 90% CI, 0.79-1.37; P = .80). The median progression-free survival was 5.6 (95% CI, 4.1-6.9) months in the EP arm and 5.1 (95% CI, 3.3-5.7) months in the IP arm (HR, 1.06; 95% CI, 0.78-1.45). A subgroup analysis of OS demonstrated that EP produced more favorable OS in patients with poorly differentiated NEC of pancreatic origin (HR, 4.10; 95% CI, 1.26-13.31). The common grade 3 and 4 adverse events in the EP vs IP arms were neutropenia (75 of 82 [91.5%] patients vs 44 of 82 [53.7%] patients), leukocytopenia (50 of 82 [61.0%] patients vs 25 of 82 [30.5%] patients), and febrile neutropenia (FN) (22 of 82 [26.8%] patients vs 10 of 82 [12.2%] patients). While incidence of FN was initially high in the EP arm, primary prophylactic use of granulocyte colony-stimulating factor effectively reduced the incidence of FN.

Conclusions and Relevance

Results of this randomized clinical trial demonstrate that both EP and IP remain the standard first-line chemotherapy options. Although AEs were generally manageable, grade 3 and 4 AEs were more common in the EP arm.

Trial Registration

Japan Registry of Clinical Trials: jRCTs031180005; UMIN Clinical Trials Registry: UMIN000014795

Metastatic Grade 3 Neuroendocrine Tumor in Multiple Endocrine Neoplasia Type 1 (MEN1) Expressing Somatostatin Receptors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) can occur in 30-90% of patients with Multiple Endocrine Neoplasia Type 1 (MEN1). However, only 1% of GEP-NETs are Grade 3 (G3). Given the rarity of these aggressive tumors, treatment of advanced G3 GEP-NETs in MEN1 is based on the treatment guidelines for sporadic GEP-NETs. We report a 43-year-old male with germline MEN1 followed at our institution with clinical features including hyperparathyroidism, a non-functional pancreatic NET, and Zollinger-Ellison Syndrome. On routine surveillances imaging, at age 40, computer tomography (CT/ positron emission tomography (PET)) imaging showed two arterially enhancing intraluminal masses on the medial aspect of the gastric wall. Anatomical imaging confirmed two enhancing masses within the pancreas and a rounded mass-like thickening along the lesser curvature of the stomach. The gastric mass was resected, and pathology reported a well-differentiated G3 NET with a Ki-67 &gt;20%. The patient continued active surveillance. Eighteen months later cross-sectional imaging studies showed findings consistent with metastatic disease within the right hepatic lobe and bland embolization was done. On follow-up scans, including 68Ga-DOTATATE (68Ga-DOTA(0)-Tyr(3)-octreotate) imaging, interval increase in number and avidity of metastatic lesions were compatible with disease progression. Given a paucity of treatment recommendations for G3 tumors in MEN1, the patient was counseled based on standard NET treatment guidelines and recommended 177Lu-DOTATATE treatment. PRRT (peptide receptor radionuclide therapy) with 177Lu-DOTATATE ( 177Lu-tetraazacyclododecanetetraacetic acid-octreotide) is an important therapeutic modality for patients with somatostatin receptor-positive (SSTR) NETs. However, prospective studies are needed to understand the role of PRRT in G3 NETs.

Well-Differentiated Grade 3 Neuroendocrine Tumors: Characteristics, Treatments, and Outcomes From a Population-Based Study

OBJECTIVES

We evaluated a population-based cohort of metastatic well-differentiated grade 3 gastroenteropancreatic neuroendocrine tumors (G3 NETs) to describe their characteristics, prognosis, and treatment outcomes.

METHODS

The British Columbia provincial database was queried for G3 NETs diagnosed 2004 to 2021, and charts were reviewed to describe clinical features and outcomes.

RESULTS

Forty-one patients were identified, most were diagnosed with pancreatic (58.5%) or midgut (26.8%) primary tumor and Ki-67 was less than 55% in 68.3%. The primary was resected in 19 (46.3%) with median disease-free survival of 25.2 months. Once metastatic, patients received a median of one line of systemic therapy. Median overall survival with metastatic disease was 33.8 months. Median progression-free survival was longest in patients treated with capecitabine-temozolomide (20.6 months) or somatostatin analogs (7.9 months), while etoposide-platinum provided little benefit (2.4 months). Limited data of efficacy for targeted therapies and radionuclide therapy was available. Seven patients (17.1%) were also treated with local therapies, which were associated with improved overall survival (median not reached, hazard ratio, 0.23; P = 0.012).

CONCLUSIONS

Capecitabine-temozolomide and somatostatin analogs were associated with clinically meaningful benefit, and use of local therapies provided benefits in selected patients. Multidisciplinary discussion is essential to optimize individual outcomes in this heterogeneous population.

Zufallsbefund NEN Appendix

Neuroendokrine Neoplasien (NEN) der Appendix stellen mit 80% die häufigste Neoplasie dieser Lokalisation dar. In den meisten Fällen werden diese Tumoren als Zufallsbefund nach stattgehabter Appendektomie bei V. a. Appendizitis diagnostiziert. Hierbei handelt es sich meist um hoch differenzierte neuroendokrine Tumoren. Aufgrund ihrer häufigen Lage im Bereich der Appendixspitze sind die NEN der Appendix meist nicht ursächlich für die Appendizitis-typischen Beschwerden.

Die meisten Patienten (80–90%) sind durch die bereits durchgeführte Appendektomie ausreichend onkologisch therapiert. Sollten sich jedoch Risikofaktoren wie eine Tumorgröße > 2 cm, basisnahe Lage, Angioinvasion, Perforation oder Infiltration von Nachbarorganen, Proliferationsindex von > 2% oder eine Infiltration des Mesoappendix von mehr als 3 mm im endgültigen histopathologischen Befund ergeben, so wird eine Nachresektion als onkologische Hemikolektomie rechts empfohlen.

Aufgrund des meist frühen Tumorstadiums bei Diagnosestellung ohne nachgewiesene Lymphknotenmetastasierung weisen Patienten mit einer NEN der Appendix exzellente 5-Jahres-Überlebensraten über alle Tumorstadien hinweg von 70–85% auf.

Treatment Approaches and Outcome of Patients with Neuroendocrine Neoplasia Grade 3 in German Real-World Clinical Practice

Simple Summary

Grade 3 neuroendocrine neoplasms (NEN G3) are a rare and heterogeneous subtype of NEN and include poorly differentiated neuroendocrine carcinomas and well-differentiated neuroendocrine tumors G3 (NET G3). Standard chemotherapy with platinum plus etoposide may not be appropriate for all subgroups, but more tailored approaches suffer from the lack of data. In our study, we provide real-world data from a large center-based cohort of the German NET Registry and hope to stimulate efforts to conduct clinical trials for well-defined entities.

Abstract

Background: Neuroendocrine neoplasia grade 3 (NEN G3) represents a rare and heterogeneous cancer type with a poor prognosis. The aim of our study was to analyze real-world data from the German NET Registry with a focus on therapeutic and prognostic aspects. Methods: NEN G3 patients were identified within the German NET Registry. Demographic data and data on treatments and outcomes were retrieved. Univariate analyses were performed using the Kaplan–Meier-method. Multivariate analysis was performed using a Cox proportional hazard model. Results: Of 445 included patients, 318 (71.5%) were diagnosed at stage IV. Well-differentiated morphology (NET G3) was described in 31.7%, 60% of cases were classified as neuroendocrine carcinoma (NEC), and the median Ki67 value was 50%. First-line treatment comprised chemotherapy in 43.8%, with differences in the choice of regimen with regard to NET or NEC, and surgery in 41.6% of patients. Median overall survival for the entire cohort was 31 months. Stage, performance status and Ki67 were significant prognostic factors in multivariate analysis. Conclusions: The survival data of our national registry compare favorably to population-based data, probably mainly because of a relatively low median Ki67 of 50%. Nevertheless, the best first- and second-line approaches for specific subgroups remain unclear, and an international effort to fill these gaps is needed.

Role of surgical treatments in high-grade or advanced gastroenteropancreatic neuroendocrine neoplasms

Over the last 40 years, the incidence and prevalence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) have continued to increase. Compared to other epithelial neoplasms in the same organ, GEP-NENs exhibit indolent biological behavior, resulting in more chances to undergo surgery. However, the role of surgery in high-grade or advanced GEP-NENs is still controversial. Surgery is associated with survival improvement of well-differentiated high-grade GEP-NENs, whereas poorly differentiated GEP-NENs that may benefit from resection require careful selection based on Ki67 and other tissue biomarkers. Additionally, surgery also plays an important role in locally advanced and metastatic disease. For locally advanced GEP-NENs, isolated major vascular involvement is no longer an absolute contraindication. In the setting of metastatic GEP-NENs, radical intended surgery is recommended for patients with low-grade and resectable metastases. For unresectable metastatic disease, a variety of surgical approaches, including cytoreduction of liver metastasis, liver transplantation, and surgery after neoadjuvant treatment, show survival benefits. Primary tumor resection in GEP-NENs with unresectable metastatic disease is associated with symptom control, prolonged survival, and improved sensitivity toward systemic therapies. Although there is no established neoadjuvant or adjuvant strategy, increasing attention has been given to this emerging research area. Some studies have reported that neoadjuvant therapy effectively reduces tumor burden, improves the effectiveness of subsequent surgery, and decreases surgical complications.

Surgical outcomes of gastro-entero-pancreatic neuroendocrine tumors G3 versus neuroendocrine carcinoma

BACKGROUND

To define surgical outcomes of patients with high-grade gastro-entero-pancreatic neuroendocrine neoplasm grade G3 (GEP-NEN G3).

METHODS

Patients who underwent surgical resection between 2000 and 2016 were identified. The overall survival (OS) and recurrence-free survival (RFS) of patients with gastro-entero-pancreatic neuroendocrine tumors grade G3 (GEP-NET G3) versus neuroendocrine carcinoma (NEC) were evaluated.

RESULTS

Fifty-one out of 2182 (2.3%) patients who underwent surgical resection were diagnosed as GEP-NEN G3. The pancreas was the most common primary site (n = 3772.5%). A majority of patients had lymph node metastasis (n = 3262.7%); one in three (n = 1631.4%) had distant metastasis. The median OS and RFS of the entire cohort were 56.4 and 34.5 months, respectively. Perineural invasion was a strong prognostic factor associate with OS after surgical resection. Patients with NEC had a worse survival outcome versus patients with NET G3 (median OS: 33.1 months vs. not attained, p = 0.088). In contrast, among patients who underwent curative-intent resection, patients with NEC had comparable RFS versus patients with NET G3 (median RFS: 35.6 vs. 33.9 months, p = 0.774).

CONCLUSIONS

Surgical resection provided acceptable short- and long-outcomes for well-selected patients with resectable GEP-NEN G3. NEC was associated with a worse OS versus NET G3.

Poor outcome after systemic therapy in secondary high-grade pancreatic neuroendocrine tumors

Longitudinal changes in pancreatic neuroendocrine tumor (panNET) cell proliferation correlate with fast disease progression and poor prognosis. The optimal treatment strategy for secondary panNET grade (G)3 that has progressed from a previous low- or intermediate-grade to high-grade panNET G3 is currently unknown. This was a single-center retrospective cohort study aimed to characterize treatment patterns and outcomes among patients with secondary panNET-G3. Radiological responses were assessed using the Response Evaluation Criteria in Solid Tumors version 1.1. A total of 22 patients were included and received a median of 2 (range, 1-4) treatment lines in 14 different combinations. Median overall survival (OS) was 9 months (interquartile range (IQR): 4.25-17.5). For the 15 patients who received platinum-etoposide chemotherapy, median OS was 7.5 months (IQR: 3.75-10) and median progression-free survival (PFS) was 4 months (IQR: 2.5-5.5). The 15 patients who received conventional panNET therapies achieved a median OS of 8 months (IQR: 5-16.75) and median PFS was 5.5 months (IQR: 2.75-8.25). We observed one partial response on 177Lu DOTA-TATE therapy. In conclusion, this hypothesis-generating study failed to identify any promising treatment alternatives for patients with secondary panNET-G3. This demonstrates the need for both improved biological understanding of this particular NET entity and for designing prospective studies to further assess its treatment in larger patient cohorts.

Gastroenteropancreatic grade 3 neuroendocrine tumors: a single entity or a heterogeneous group? A retrospective analysis

PURPOSE

Grade 3 neuroendocrine tumor (NET G3) is a novel pathologic category within gastro-entero-pancreatic (GEP) neuroendocrine neoplasms (NENs) but its clinical behavior and therapeutic management still remain challenging. Prognostic and predictive factors aiding NET G3 management are needed.

PATIENTS AND METHODS

We performed a retrospective analysis from 2015 to 2020 of all patients with > 20% Ki-67, well-differentiated NETs evaluated within our NEN-dedicated multidisciplinary team. We divided the sample according the timing of NET G3 diagnosis, the radiotracers distribution and Ki-67. We analyzed the correlation between these NET G3 features and clinical outcomes.

RESULTS

Among 3238 multidisciplinary discussion reports, we selected 55 patients, 48 from GEP and 7 from an occult GEP origin. In 45 patients, NET G3 diagnosis occurred at the beginning of clinical history (upfront-NET G3), whereas in 10, during the NET G1-G2 clinical history (late-NET G3). Patients with ≤ 30% (34/55) vs. > 30% Ki-67 (21/55) had a better overall survival (OS) (p = 0.042); patients with a homogeneous vs. inhomogeneous/negative ⁶⁸Gallium(⁶⁸Ga)-DOTA-Peptide Positron Emission Tomography (PET)/computed tomography (CT) showed a trend to a better OS, and a significant better progression-free survival (PFS) (p = 0.033). A better OS was observed for negative/inhomogeneous vs. homogeneous 18-fluorodeoxyglucose (¹⁸FDG)-PET/CT (p = 0.027). A trend to a better OS was reported in late- vs. upfront-NET G3, while the latter showed a significantly better response rate (RR) (p = 0.048).

CONCLUSION

Our findings suggested that Ki-67 cutoff, functional imaging and the timing to NET G3 diagnosis may help clinicians in more accurate selection of NET G3 management. Prospective studies are needed.

A Well-Differentiated Grade-3 Neuroendocrine Tumor in the Ascending Colon: A Case Report

Patient: Male, 60-year-old

Final Diagnosis: Colon mass • neuroendocrine tumor G3

Symptoms: Altered bowel habit • anemia

Medication: —

Clinical Procedure: Rt HemiColectomy

Specialty: Oncology • Surgery

A Case of Pancreatic Neuroendocrine Tumor G3 Which Responded Remarkably to Chemotherapy

Pancreatic neuroendocrine carcinoma (NEC) as classified in the World Health Organization (WHO) 2010 was reclassified in the WHO 2017 as either neuroendocrine tumor (NET) G3 or NEC. An accurate diagnosis based on the WHO 2017 classification is important in order treating this disease appropriately. We report a case diagnosed as NET G3 that responded remarkably well to treatment with streptozocin. The patient would likely not have received the streptozocin treatment if she had been diagnosed with NEC. The WHO 2017 classification is reasonable for the treatment of advanced pancreatic neuroendocrine neoplasms.

Grade 3 Neuroendocrine Tumor (G3NET): An Unusual Tumor With A Histochemical Surprise

Given the rare occurrence and the indolent course of Neuroendocrine tumors (NETs), few epidemiological studies exist on these cancers. A small but interesting subset of these tumors are G3- Neuroendocrine Tumors. Grade 3 Neuroendocrine tumors (or G3-NETs) are unique in their intermediate prognosis. These grade discordant tumors lie in between high-grade poorly differentiated neuroendocrine carcinomas and grade 2 well-differentiated NETs, which have a worse and better prognosis than this rare entity, respectively. In this case report, we present a case of Grade 3 NET with an unusually high Ki67 index, diagnosed upon biopsy of metastasis visualized on imaging. Additionally, we review existing literature for characteristics, immunohistochemical markers, prognosis, and treatment modalities for the same.

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.

Combined Quantification of 18F-FDG and 68Ga-DOTATATE PET/CT for Prognosis in High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms

RATIONALE AND OBJECTIVES

High-grade gastroenteropancreatic neuroendocrine neoplasms (G3 GEP-NENs) are pathologically classified into well differentiated neuroendocrine tumors (G3 NETs) and poorly differentiated neuroendocrine carcinomas (G3 NECs). Using a novel parameter, we examined the prognostic value of ¹⁸F-FDG and ⁶⁸Ga-DOTATATE PET/CT quantification in comparison to pathologic assessment in G3 GEP-NENs.

MATERIALS AND METHODS

A total of 31 patients with G3 GEP-NENs were reviewed. For each patient, the SUVmax on ¹⁸F-FDG and ⁶⁸Ga-DOTATATE PET/CT were used to calculate the FDG-DOTATATE-Z (FDZ) score: a continuous parameter that increases with ⁶⁸Ga-DOTATATE uptake and decreases with ¹⁸F-FDG uptake. The variation in the FDZ score with respect to pathologic variables was examined. Kaplan-Meier and Cox regression analyses were performed to evaluate the effect of FDZ score on overall survival. An external cohort of 21 patients was used for validation.

RESULTS

The FDZ score was significantly higher in G3 NETs compared to G3 NECs (p<0.001), and was inversely correlated with Ki67 index (R²=0.33, p<0.001). Patients in the FDZ>0.05 group showed significantly longer survival compared to those in the FDZ≤0.05 group, with median of 34.9 vs. 12.0 months (p<0.001). On univariate regression, FDZ>0.05 (p=0.005), well differentiated disease (p=0.044), and lower Ki67 index (p=0.042) were predictors of survival. On multivariate regression, only FDZ>0.05 could independently predict longer survival with HR=0.16 (p=0.018), which was reproduced in the external validation cohort.

CONCLUSION

Combined quantification of ¹⁸F-FDG and ⁶⁸Ga-DOTATATE PET/CT into a novel parameter, the FDZ score, reflects the pathologic characteristics of G3 GEP-NENs and is a prognostic indicator of overall survival independent of differentiation.

Gastroenteropancreatic neuroendocrine neoplasms G3: Novel insights and unmet needs

According to the 2019 WHO pathology grading system, high-grade gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) can be divided into well differentiated neuroendocrine tumors G3 (NETs G3) and poorly differentiated neuroendocrine carcinomas (NECs). GEP-NETs G3 and GEP-NECs present significant differences in driver genes and disease origin. NETs G3 and NECs have been confirmed to be two distinct diseases with different genetic backgrounds, however, this issue remains controversial. The prognosis of NETs G3 is significantly better than that of NECs. The differential diagnosis of GEP-NETs G3 and GEP-NECs should be combined with the patient's medical history, tumor histopathology, Ki-67 index, DAXX/ATRX, TP53 and Rb expression as well as other immunohistochemical indicators. In addition, the treatment strategies of these two subgroups are very different. Here, we summarize recent findings focused on the genomics, clinical manifestations, diagnosis, treatment and other aspects of high-grade GEP-NENs (G3). This review may help further our understanding of the carcinogenesis, diagnosis and treatment of GEP-NENs G3.

Management of Primary Hepatopancreatobiliary and Ampulla Large Cell Neuroendocrine Carcinoma

Background: Large cell neuroendocrine carcinoma (LCNEC) of the liver, gallbladder, pancreas, and ampulla is rare and usually arises in case reports, and thus to date, no studies have well described the treatment options and outcomes of those patients. Methods: The data of 108 patients diagnosed as hepatopancreatobiliary and ampulla LCNEC between 2004 and 2015 were retrieved from the surveillance, epidemiology, and final results. Results: In the entire cohort, the median overall survival (OS) was 10 months. For nonmetastatic patients, the median OS was 32 months for surgery of the primary tumor alone (n = 17), 19 months for surgery of the primary tumor and adjuvant therapy (n = 19), and 1 month for nonsurgical treatment (n = 8). For metastatic patients, the median OS was 14 months for patients who received surgery of the primary tumor with and without adjuvant therapy (n = 16), 9 months for patients undergoing adjuvant treatment alone (n = 30), and 1 month for patients who had no treatment (n = 16). Multivariate analysis revealed that surgery of the primary tumor was an independent factor for improved survival. Conclusions: This disease offers a very poor prognosis despite aggressive treatment. Radical resection is the first choice for resectable tumors, whereas surgical resection of the primary tumor plus adjuvant therapy might represent a valid option for metastatic disease. However, further studies are needed to confirm this.

An analysis of 130 neuroendocrine tumors G3 regarding prevalence, origin, metastasis, and diagnostic features

Limited data exist on high-grade neuroendocrine tumors (NETs G3) which represent a new category among neuroendocrine neoplasms (NEN). We analyzed NETs G3 in a consultation series regarding prevalence, origin, metastasis, and diagnostic problems. Based on the WHO classification of digestive system tumors, 130 NETs G3 (9%) were identified in 1513 NENs. NET G3 samples were more often obtained from metastatic sites (69%) than NET G1/G2 samples (24%). NET G3 metastases presented most frequently in the liver (74%) and originated from the pancreas (38/90, 42%), followed by the lung (9%), ileum (7%), stomach (3%), rectum (1%), and rare sites (2%) such as the prostate and breast. The primaries remained unknown in 15%. NETs G3 had a median Ki67 of 30% that distinguished them from NECs (60%), though with great overlap. The expression of site-specific markers, p53, Rb1, and SST2 was similar in NETs G3 and NETs G1/G2, except for p53 and Rb1 which were abnormally expressed in 8% and 7% of liver metastases from NET G3 but not from NET G1/G2. NETs G3 were frequently referred as NECs (39%) but could be well distinguished from NECs by normal p53 (92% versus 21%) and Rb1 expression (93% versus 41%) expression. In conclusion, NETs G3 are frequently discovered as liver metastases from pancreatic or pulmonary primaries and are often misinterpreted as NEC. p53 and Rb1 are powerful markers in the distinction of NET G3 from NEC. Rarely, carcinomas from non-digestive, non-pulmonary organs with neuroendocrine features may present as NET G3.