Pancreatic neuroendocrine carcinoma G3 may be heterogeneous and could be classified into two distinct groups

An Overview of Altered Pathways Associated with Sensitivity to Platinum-Based Chemotherapy in Neuroendocrine Tumors: Strengths and Prospects

Neuroendocrine neoplasms (NENs) are a diverse group of malignancies with a shared phenotype but varying prognosis and response to current treatments. Based on their morphological features and rate of proliferation, NENs can be classified into two main groups with a distinct clinical behavior and response to treatment: (i) well-differentiated neuroendocrine tumors (NETs) or carcinoids (with a low proliferation rate), and (ii) poorly differentiated small- or large-cell neuroendocrine carcinomas (NECs) (with a high proliferation rate). For certain NENs (such as pancreatic tumors, higher-grade tumors, and those with DNA damage repair defects), chemotherapy is the main therapeutic approach. Among the different chemotherapic agents, cisplatin and carboplatin, in combination with etoposide, have shown the greatest efficacy in treating NECs compared to NETs. The cytotoxic effects of cisplatin and carboplatin are primarily due to their binding to DNA, which interferes with normal DNA transcription and/or replication. Consistent with this, NECs, which often have mutations in pathways involved in DNA repair (such as Rb, MDM2, BRCA, and PTEN), have a high response to platinum-based chemotherapy. Identifying mutations that affect molecular pathways involved in the initiation and progression of NENs can be crucial in predicting the response to platinum chemotherapy. This review aims to highlight targetable mutations that could serve as predictors of therapeutic response to platinum-based chemotherapy in NENs.

Multidisciplinary Approach for the Management of Metastatic Poorly Differentiated Neuroendocrine Carcinoma of the Pancreas: A Case Report of an Exceptional Responder

ABSTRACT

Poorly differentiated pancreatic neuroendocrine carcinomas (pNECs) are rare, highly aggressive neoplasms. Frequently metastatic at diagnosis, prognosis is poor with median overall survival estimated to be less than 1 year. Although multidisciplinary management, including systemic medications and locoregional therapies aimed at reducing and preventing symptoms caused by mass effect, is the mainstay of treatment for patients with metastatic well-differentiated pancreatic neuroendocrine tumors, rapid progression, organ dysfunction, and poor performance status often preclude initiation of even single-modality palliative chemotherapy for patients with metastatic pNEC, limiting the use of and recommendation for multidisciplinary management.We describe the case of a 51-year-old male patient diagnosed with pNEC metastatic to liver and lymph nodes presenting with impending cholestatic liver failure for whom we were able to successfully initiate and dose-escalate cytotoxic chemotherapy with excellent radiographic response. After multidisciplinary review of his case, the patient underwent pancreaticoduodenectomy and hepatic wedge biopsies, with pathology demonstrating a pathologic complete response to chemotherapy in both the pancreas and liver. Surveillance scans at 2 years from initial diagnosis and 1 year from surgery remain without evidence of locoregional or distant recurrence, highlighting the importance and utility of multidisciplinary management in select cases.

BRAF V600E-mutated large cell neuroendocrine carcinoma responding to targeted therapy: a case report and review of the literature

Large cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive high-grade neuroendocrine tumor, commonly arising in the lung or in the gastrointestinal tract, with a frequent proportion of unknown primary origin (20%). In the metastatic setting, platinum-based or fluoropyrimidine-based chemotherapeutic regimens are as considered the first-line treatment, despite the limited duration of response. To date, the prognosis of advanced high-grade neuroendocrine carcinoma remains poor, suggesting the need to explore new treatment strategies in this orphan tumor. The evolving molecular landscape of LCNEC, not yet been completely defined, could explain the heterogeneous response to different chemotherapeutic regimens and suggest that treatment strategy could be driven by molecular features. v-Raf murine sarcoma viral oncogene homolog B (BRAF) mutations, well described in melanoma, thyroid cancer, colon cancer and lung adenocarcinoma, account for approximately 2% of cases in lung LCNEC. Here, we describe the case of a patient with a BRAF V600E-mutated LCNEC of unknown primary origin who partially responded to BRAF/mitogen-activated protein kinase kinase inhibitors after standard treatment. Additionally, BRAF V600E circulating tumor DNA was used to monitor disease response. Thereafter, we reviewed the available literature about the role of targeted therapy in high-grade neuroendocrine neoplasms to provide insight for future research to identify patients with driver oncogenic mutations, who can potentially benefit from target therapy.

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.

Prognostic Factors across Poorly Differentiated Neuroendocrine Neoplasms: A Pooled Analysis

INTRODUCTION

Poorly differentiated neuroendocrine carcinomas (NECs) are characterized by aggressive clinical course and poor prognosis. No reliable prognostic markers have been validated to date; thus, the definition of a specific NEC prognostic algorithm represents a clinical need. This study aimed to analyze a large NEC case series to validate the specific prognostic factors identified in previous studies on gastro-entero-pancreatic and lung NECs and to assess if further prognostic parameters can be isolated.

METHODS

A pooled analysis of four NEC retrospective studies was performed to evaluate the prognostic role of Ki-67 cut-off, the overall survival (OS) according to primary cancer site, and further prognostic parameters using multivariable Cox proportional hazards model and machine learning random survival forest (RSF).

RESULTS

422 NECs were analyzed. The most represented tumor site was the colorectum (n = 156, 37%), followed by the lungs (n = 111, 26%), gastroesophageal site (n = 83, 20%; 66 gastric, 79%) and pancreas (n = 42, 10%). The Ki-67 index was the most relevant predictor, followed by morphology (pure or mixed/combined NECs), stage, and site. The predicted RSF response for survival at 1, 2, or 3 years showed decreasing survival with increasing Ki-67, pure NEC morphology, stage III-IV, and colorectal NEC disease. Patients with Ki-67 <55% and mixed/combined morphology had better survival than those with pure morphology. Morphology pure or mixed/combined became irrelevant in NEC survival when Ki-67 was ≥55%. The prognosis of metastatic patients who did not receive any treatment tended to be worse compared to that of the treated group. The prognostic impact of Rb1 immunolabeling appears to be limited when multiple risk factors are simultaneously assessed.

CONCLUSION

The most effective parameters to predict OS for NEC patients could be Ki-67, pure or mixed/combined morphology, stage, and site.

Insights into Epigenetic Changes Related to Genetic Variants and Cells-of-Origin of Pancreatic Neuroendocrine Tumors: An Algorithm for Practical Workup

Simple Summary

Pancreatic neuroendocrine tumors are composite entities due to their heterogeneity illustrated in clinical behavior, mutational pattern, and site of origin. Pancreatic neuroendocrine tumors display a low mutation burden with frequently epigenetic alterations, such as histone modifications, chromatin remodeling, or DNA methylation status. Using the epigenomic data of the pancreatic neuroendocrine tumors converged to the identification of molecularly distinct subgroups. Furthermore, epigenetic signatures could be used as biomarkers due to their link to cell lineages and genetic driver mutations. We integrated the current knowledge on genetic and epigenetic alterations involved in endocrine lineage associated with these neoplasms to present a pathway-based overview. In this review, we suggest a simplified algorithm on how to manage pancreatic neuroendocrine tumors from a practical perspective based on pathologist ’analysis.

Abstract

Current knowledge on the molecular landscape of pancreatic neuroendocrine tumors (PanNETs) has advanced significantly. Still, the cellular origin of PanNETs is uncertain and the associated mechanisms remain largely unknown. DAXX/ATRX and MEN1 are the three most frequently altered genes that drive PanNETs. They are recognized as a link between genetics and epigenetics. Moreover, the acknowledged impact on DNA methylation by somatic mutations in MEN1 is a valid hallmark of epigenetic mechanism. DAXX/ATRX and MEN1 can be studied at the immunohistochemical level as a reliable surrogate for sequencing. DAXX/ATRX mutations promote alternative lengthening of telomeres (ALT) activation, determined by specific fluorescence in situ hybridization (FISH) analysis. ALT phenotype is considered a significant predictor of worse prognosis and a marker of pancreatic origin. Additionally, ARX/PDX1 expression is linked to important epigenomic alterations and can be used as lineage associated immunohistochemical marker. Herein, ARX/PDX1 association with DAXX/ATRX/MEN1 and ALT can be studied through pathological assessment, as these biomarkers may provide important clues to the mechanism underlying disease pathogenesis. In this review, we present an overview of a new approach to tumor stratification based on genetic and epigenetic characteristics as well as cellular origin, with prognostic consequences.

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.

An update on the development of concepts, diagnostic criteria, and challenging issues for neuroendocrine neoplasms across different digestive organs

Digestive neuroendocrine neoplasms (NENs) are a group of heterogeneous neoplasms found throughout the digestive tract, with different behaviour and genetic background. In the last few years, nomenclature and WHO/UICC classifications of digestive NENs have changed, and molecular classifications have emerged, especially in pancreatic locations. Increasing patho-molecular details are needed to diagnose the different categories of NEN, including the use of helpful immunohistochemical markers. In this review, we address these topics in three successive chapters. We first briefly review recent updates in classifications, discuss important grading and proliferating issues and advances in the molecular understanding of NEN. Then, we provide an update on diagnosis, including the most important differential diagnoses of NEN, with a focus on high-grade neoplasms and mixed tumours. Finally, we highlight a variety of currently used and next-generation predictive and prognostic biomarkers as well as biomarkers of tumour origin and describe some site specificities of gastrointestinal NEN. We specifically focus on biomarkers available to pathologists with the potential to change the way patients with NEN are diagnosed and treated.

DNA methylation reveals distinct cells of origin for pancreatic neuroendocrine carcinomas and pancreatic neuroendocrine tumors

Background

Pancreatic neuroendocrine neoplasms (PanNENs) fall into two subclasses: the well-differentiated, low- to high-grade pancreatic neuroendocrine tumors (PanNETs), and the poorly-differentiated, high-grade pancreatic neuroendocrine carcinomas (PanNECs). While recent studies suggest an endocrine descent of PanNETs, the origin of PanNECs remains unknown.

Methods

We performed DNA methylation analysis for 57 PanNEN samples and found that distinct methylation profiles separated PanNENs into two major groups, clearly distinguishing high-grade PanNECs from other PanNETs including high-grade NETG3. DNA alterations and immunohistochemistry of cell-type markers PDX1, ARX, and SOX9 were utilized to further characterize PanNECs and their cell of origin in the pancreas.

Results

Phylo-epigenetic and cell-type signature features derived from alpha, beta, acinar, and ductal adult cells suggest an exocrine cell of origin for PanNECs, thus separating them in cell lineage from other PanNENs of endocrine origin.

Conclusions

Our study provides a robust and clinically applicable method to clearly distinguish PanNECs from G3 PanNETs, improving patient stratification.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-022-01018-w.

Therapeutic strategies for gastroenteropancreatic neuroendocrine neoplasms: State-of-the-art and future perspectives

Although gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) have always been considered rare tumors, their incidence has risen over the past few decades. They represent a highly heterogeneous group of neoplasms with several prognostic factors, including disease stage, proliferative index (Ki67), and tumor differentiation. Most of these neoplasms express somatostatin receptors on the cell surface, a feature that has important implications in terms of prognosis, diagnosis, and therapy. Although International Guidelines propose algorithms aimed at guiding therapeutic strategies, GEP-NEN patients are still very different from one another, and the need for personalized treatment continues to increase. Radical surgery is always the best option when feasible; however, up to 80% of cases are metastatic upon diagnosis. Regarding medical treatments, as GEP-NENs are characterized by relatively long overall survival, multiple therapy lines are adopted during the lifetime of these patients, but the optimum sequence to be followed has never been clearly defined. Furthermore, although new molecular markers aimed at predicting the response to therapy, as well as prognostic scores, are currently being studied, their application is still far from being part of daily clinical practice. As they represent a complex disease, with therapeutic protocols that are not completely standardized, GEP-NENs require a multidisciplinary approach. This review will provide an overview of the available therapeutic options for GEP-NENs and attempts to clarify the possible approaches for the management of these patients and to discuss future perspectives in this field.

Management of Large Cell Neuroendocrine Carcinoma

BACKGROUND

Large cell neuroendocrine carcinoma (LCNEC) is a rare, aggressive cancer with a dismal prognosis. The majority of cases occur in the lung and the gastrointestinal tract; however, it can occur throughout the body. Recently advances in the understanding of the molecular underpinnings of this disease have paved the way for additional novel promising therapies. This review will discuss the current best evidence for management of LCNEC and new directions in the classification and treatment of this rare disease.

METHODS

We performed a PubMed search for "Large cell neuroendocrine carcinoma" and "High grade neuroendocrine carcinoma." All titles were screened for relevance to the management of LCNEC. Papers were included based on relevance to the management of LCNEC.

RESULTS

Papers were included reviewing both pulmonary and extra pulmonary LCNEC. We summarized the data driven best practices for the management of both early and advanced stage LCNEC. We describe emerging therapies with promising potential.

DISCUSSION

LCNEC are rare and aggressive neoplasms. In advanced disease, the historical regimen of platinum based therapy in combination with etoposide or irinotecan remains among the commonly used first line therapies, however for extra thoracic LCNEC regimens like FOLFOX, FOLFOIRI and CAPTEM can also be used. Further effective and safe treatment options are desperately needed. Recently, new advances including a new understanding of the genetic subcategories of LCNEC and immunotherapy agents may guide further treatments.

Computed tomography-based radiomics approach in pancreatic tumors characterization

Radiomics (or texture analysis) is a new imaging analysis technique that allows calculating the distribution of texture features of pixel and voxel values depend on the type of ROI (3D or 2D), their relationships in the image. Depending on the software, up to several thousand texture elements can be obtained. Radiomics opens up wide opportunities for differential diagnosis and prognosis of pancreatic neoplasias. The aim of this review was to highlight the main diagnostic advantages of texture analysis in different pancreatic tumors. The review describes the diagnostic performance of radiomics in different pancreatic tumor types, application methods, and problems. Texture analysis in PDAC is able to predict tumor grade and associates with lymphovascular invasion and postoperative margin status. In pancreatic neuroendocrine tumors, texture features strongly correlate with differentiation grade and allows distinguishing it from the intrapancreatic accessory spleen. In pancreatic cystic lesions, radiomics is able to accurately differentiate MCN from SCN and distinguish clinically insignificant lesions from IPMNs with advanced neoplasia. In conclusion, the use of the CT radiomics approach provides a higher diagnostic performance of CT imaging in pancreatic tumors differentiation and prognosis. Future studies should be carried out to improve accuracy and facilitate radiomics workflow in pancreatic imaging.

FOLFIRINEC: a randomized phase II trial of mFOLFIRINOX vs platinum-etoposide for metastatic neuroendocrine carcinoma of gastroenteropancreatic or unknown origin

BACKGROUND

Poorly differentiated neuroendocrine carcinomas (NEC) are rare diseases with a poor prognosis. Platinum-etoposide (PE) has been the recommended first-line treatment for decades. FOLFIRINEC (NCT04325425) is a national multicenter randomized phase II study which aims to challenge this standard regimen.

METHODS

The primary objective is to compare the median progression-free survival (PFS) under mFOLFIRINOX versus PE. The secondary objectives are to evaluate the objective response rates (ORR), median overall survival (OS), safety and quality of life. The associated real-time translational study will establish a molecular profile for each patient enrolled.

MAIN INCLUSION CRITERIA ARE

NEC of gastroenteropancreatic (GEP) or unknown origin, metastatic and RECIST 1.1 evaluable disease, tumor sample available and no contraindication to chemotherapy. Patients will be randomized 1:1 between PE every 21 days for 6-8 cycles and mFOLFIRINOX every 14 days for up to 12 cycles and stratified according to center, performance status, Ki67 and pathological subtype. This trial will randomize 218 patients (24 months of follow-up) to have 80% power to detect an improvement of the median PFS from 5 months under PE to 7.5 months under mFOLFIRINOX (HR of 0.67, α =5%, two-sided). An intermediate analysis is planned at 50% of events. Recruitment started on October 20, 2020.

Biomarkers of Response to Etoposide-Platinum Chemotherapy in Patients with Grade 3 Neuroendocrine Neoplasms

Etoposide-platinum (EP) chemotherapy has long been the reference treatment for grade 3 neuroendocrine neoplasms (G3 NEN). However, G3 NEN are heterogeneous, including well-differentiated tumors (NET) and poorly differentiated large (LCNEC) or small (SCNEC) cell carcinomas, whose response to EP chemotherapy varies considerably. Our aim was to evaluate predictive biomarkers for the response to EP chemotherapy in G3 NEN. We retrospectively studied 89 patients with lung (42%) and digestive (58%) G3 NEN treated by EP chemotherapy between 2006 and 2020. All cases were centrally reviewed for cytomorphology/Ki-67 and immunohistochemistry of retinoblastoma protein (Rb)/p53/p16, analyzed using a semi-quantitative score. The absence of Rb staining (Rbinap) or the absence of very intense p53 staining (p53inap) were considered inappropriate. Rb staining was also studied as a quantitative marker, the best threshold being determined by ROC curve. Intense p16 staining (p16high) also suggested cell cycle dysregulation. Our primary endpoint was the objective response rate (ORR). We included 10 G3 NET, 31 LCNEC and 48 SCNEC, which showed ORR of 20%, 32% and 75%, respectively (NET vs. NEC, p = 0.040; LCNEC vs. SCNEC, p < 0.001). The ORR was significantly higher in NEN presenting with Rbinap (63% vs. 42%, p = 0.025) and p16high (66% vs. 35%, p = 0.006). Rb < 150 optimally identified responders (AUC = 0.657, p < 0.001). The ORR was 67% in Rb < 150 (vs. 25%, p = 0.005). On multivariate analysis, only Rb < 150 was independently associated with ORR (OR 4.16, 95% CI 1.11-15.53, p = 0.034). We confirm the heterogeneity of the response to EP treatment in G3 NEN. Rb < 150 was the best predictive biomarker for the response to EP, and p53 immunostaining had no additional value.