The Problem of High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms: Well-Differentiated Neuroendocrine Tumors, Neuroendocrine Carcinomas, and Beyond

PRRT in high-grade digestive neuroendocrine neoplasms (NET G3 and NEC)

Peptide receptor radionuclide therapy (PRRT) has been primarily studied in low and intermediate-grade digestive neuroendocrine tumors (NET G1-G2). The documentation of a similar benefit for high-grade digestive neuroendocrine neoplasms (NEN) has been limited. This review evaluates the use of PRRT for high-grade digestive NEN (well-differentiated NET G3 and poorly differentiated neuroendocrine carcinomas [NEC]). We identified one phase III trial and seven retrospective studies reporting specifically on PRRT outcome of >10 digestive high-grade NEN patients. The retrospective single-arm studies indicate a benefit for PRRT in NET G3. The randomized phase III NETTER-2 trial demonstrates major PFS superiority of PRRT versus somatostatin analog therapy as the first-line treatment for the NET G3 subgroup. PRRT can now be considered a potential first-line treatment for somatostatin receptor-positive NET G3 patients, but whether it should be the first-line standard of care for all NET G3 patients is still not clarified. For NEC, scarce data are available, and pathologic distinction between NEC and NET G3 can be difficult when Ki-67 is below 55%. PRRT could be considered as a treatment for refractory NEC in very selected cases when there is a high uptake on somatostatin receptor imaging, Ki-67 is below 55%, and there is no rapid tumor progression.

Treatment outcome according to genetic tumour alterations and clinical characteristics in digestive high-grade neuroendocrine neoplasms

BACKGROUND

Chemotherapy has limited efficacy in advanced digestive high-grade neuroendocrine neoplasms (HG-NEN) and prognosis is dismal. Predictive markers for palliative chemotherapy are lacking, and prognostic markers are limited.

METHODS

Digestive HG-NEN patients (n = 229) were prospectively included 2013-2017. Pathological re-assessment revealed 188 neuroendocrine carcinomas (NEC) and 41 neuroendocrine tumours (NET G3). Tumour-DNA was sequenced across 360 cancer-related genes, assessing mutations (mut) and copy number alterations. We linked sequencing results to clinical information and explored potential markers for first-line chemotherapy efficacy and survival.

RESULTS

In NEC given cis/carboplatin and etoposide (PE), TP53mut predicted inferior response rate in multivariate analyses (p = 0.009) and no BRAFmut NEC showed response. In overall assessment of PE-treated NEC, no genetic alterations were prognostic for OS. For small-cell NEC, TP53mut were associated with longer OS (p = 0.011) and RB1 deletions predicted lack of immediate-progression (p = 0.003). In non-small cell NEC, APC mut were associated with immediate-progression and shorter PFS (p = 0.008/p = 0.004). For NET G3, ATRXmut, ARID1A- and ERS1 deletions were associated with shorter PFS.

CONCLUSION

Correlations between genetic alterations and response/immediate-progression to PE were frequent in NEC but affected PFS or OS only when subdividing for cell-type. The classification of digestive NEC into large- and small-cell seems therefore molecularly and clinically relevant.

Clinical practice guidelines for molecular tumor marker, 2nd edition review part 2

In recent years, rapid advancement in gene/protein analysis technology has resulted in target molecule identification that may be useful in cancer treatment. Therefore, "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" was published in Japan in September 2021. These guidelines were established to align the clinical usefulness of external diagnostic products with the evaluation criteria of the Pharmaceuticals and Medical Devices Agency. The guidelines were scoped for each tumor, and a clinical questionnaire was developed based on a serious clinical problem. This guideline was based on a careful review of the evidence obtained through a literature search, and recommendations were identified following the recommended grades of the Medical Information Network Distribution Services (Minds). Therefore, this guideline can be a tool for cancer treatment in clinical practice. We have already reported the review portion of "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" as Part 1. Here, we present the English version of each part of the Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition.

Neuroendocrine Tumor Presented With Axillary Mass: A Case Report

ABSTRACT

A 79-year-old man presented with a palpable left axillary mass and ultrasonography findings of conglomerate lymph nodes. The initial clinical suspicion was a lymphoproliferative disorder, but histopathological results revealed a grade 3 neuroendocrine tumor. The mass showed somatostatin receptor overexpression in 99m Tc-HYNIC-TOC scintigraphy and high uptake in 18 F-FDG PET/CT. Bilateral hypermetabolic adrenal nodes suggestive of metastases were also detected. The patient was treated with chemotherapy and immunotherapy, and PET/CT scan showed a partial metabolic response after 4 cycles. According to this case, neuroendocrine tumor should be considered in the differential diagnosis of axillary masses.

Novel ensemble feature selection techniques applied to high-grade gastroenteropancreatic neuroendocrine neoplasms for the prediction of survival

BACKGROUND AND OBJECTIVE

Determining the most informative features for predicting the overall survival of patients diagnosed with high-grade gastroenteropancreatic neuroendocrine neoplasms is crucial to improve individual treatment plans for patients, as well as the biological understanding of the disease. The main objective of this study is to evaluate the use of modern ensemble feature selection techniques for this purpose with respect to (a) quantitative performance measures such as predictive performance, (b) clinical interpretability, and (c) the effect of integrating prior expert knowledge.

METHODS

The Repeated Elastic Net Technique for Feature Selection (RENT) and the User-Guided Bayesian Framework for Feature Selection (UBayFS) are recently developed ensemble feature selectors investigated in this work. Both allow the user to identify informative features in datasets with low sample sizes and focus on model interpretability. While RENT is purely data-driven, UBayFS can integrate expert knowledge a priori in the feature selection process. In this work, we compare both feature selectors on a dataset comprising 63 patients and 110 features from multiple sources, including baseline patient characteristics, baseline blood values, tumor histology, imaging, and treatment information.

RESULTS

Our experiments involve data-driven and expert-driven setups, as well as combinations of both. In a five-fold cross-validated experiment without expert knowledge, our results demonstrate that both feature selectors allow accurate predictions: A reduction from 110 to approximately 20 features (around 82%) delivers near-optimal predictive performances with minor variations according to the choice of the feature selector, the predictive model, and the fold. Thereafter, we use findings from clinical literature as a source of expert knowledge. In addition, expert knowledge has a stabilizing effect on the feature set (an increase in stability of approximately 40%), while the impact on predictive performance is limited.

CONCLUSIONS

The features WHO Performance Status, Albumin, Platelets, Ki-67, Tumor Morphology, Total MTV, Total TLG, and SUVmax are the most stable and predictive features in our study. Overall, this study demonstrated the practical value of feature selection in medical applications not only to improve quantitative performance but also to deliver potentially new insights to experts.

Optimal surgical approach for digestive neuroendocrine neoplasia primaries: Oncological benefits versus short and long-term complications

The rising incidence and the accumulating prevalence of neuroendocrine neoplasia (NEN) in the population makes this a common, prevalent and a clinically relevant disease group. Surgical resection represents the only potentially curative treatment for digestive NENs. Thus, resection should in principle be considered for all patients with NEN, although taking the patients age, relevant comorbidity, and performance status into account for operability. Patients with insulinomas, NEN of the appendix and rectal NENs are usually cured by surgery alone. However, less than a third of patients are amendable to curative surgery alone at time of diagnosis. Furthermore, recurrence is common and may occur years after primary surgery, hence the long follow-up time recommended in most NENs (>10 years). As many patients with NENs present with locoregional or metastatic disease, there is considerable debate regarding the role of debulking surgery in these settings. However, good long-term survival can be achieved in a considerable proportion of patients, with 50-70% alive up to 10 years after surgery. Location and grade are the main determinants of long-term survival. Here we present considerations to surgery for primary neuroendocrine tumors in the digestive tract.

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.

Primary neuroendocrine tumors and primary neuroendocrine carcinomas of the liver: a proposal for a multidiscipline definition

Primary hepatic neuroendocrine tumors and primary hepatic neuroendocrine carcinomas are rare and pose challenges for both diagnosis and for determining whether the tumor is primary to the liver versus metastatic disease. The lack of a uniform definition for primary hepatic neuroendocrine neoplasms is also a limitation to understanding and treating these rare tumors. Recently, there have been significant histological advances in the diagnosis and classification of neuroendocrine tumors in general, as well as significant advances in imaging for neuroendocrine neoplasms, all of which are important for their treatment. This article presents a multiple disciplinary definition and proposed guidelines for diagnosing a neuroendocrine tumor/neuroendocrine carcinomas as being primary to the liver.

Management and outcomes of mixed adenoneuroendocrine carcinoma of the ampulla of Vater: A systematic review and pooled analysis of 56 patients

BACKGROUND

Tumors of mixed neuroendocrine and nonneuroendocrine histology are classified as collision, combined, or amphicrine and can occur in most organs, including the hepato-pancreato-biliary tract. Given the rarity of mixed adenoneuroendocrine carcinoma (MANEC) of the ampulla of Vater, the patient characteristics, management, and outcomes remain unclear. We sought to systematically review the worldwide literature on ampullary MANECs.

METHODS

Eligible studies were identified through a systematic search of the MEDLINE (via PubMed), Scopus, and Cochrane Library databases (end-of-search-date: January 5th, 2022), according to the PRISMA 2020 statement.

RESULTS

A total of 39 studies reporting on 56 patients with ampullary MANEC were included. The median age was 63.0 (interquartile range [IQR]: 51.0-69.0) years and 55.6% were male (n = 25/45). Most had combined tumors (64.4%; n = 29/45), followed by collision (24.4%; n = 11/45), and amphicrine tumors (11.1%; n = 5/45). More than half had lymph node metastasis (56.8%; n = 25/44), yet only 7.9% had distant metastasis (n = 3/38). Tumor resection (i.e., mostly pancreaticoduodenectomy) was performed in 96.3% (n = 52/54), followed by adjuvant chemotherapy in 61.8% (n = 21/34). Nearly half experienced disease recurrence (47.2%; n = 17/36) over a median follow-up of 12.0 (IQR: 3.0-16.0) months, and 42.1% (n = 16/38) died over a median follow-up of 12.0 (IQR: 4.0-18.0) months. The most common cause of death was disease progression/recurrence in 81.3% (n = 13/16).

CONCLUSION

Early diagnosis and management of ampullary MANEC is challenging yet crucial to improve outcomes since many patients are diagnosed at an advanced disease stage and have unfavorable outcomes. Multicenter granular data are warranted to further understand and improve outcomes in these patients.

Surgical Management of G3 Gastroenteropancreatic Neuroendocrine Neoplasms: A Systematic Review and Meta-analysis

BACKGROUND

Grade 3 (G3) gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are rare, aggressive tumors with poor prognosis. The World Health Organization 2017 and 2019 classifications further subdivided G3 NENs into G3 neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs). Current guidelines favor medical management in most of these patients, and the role of surgical management is not well defined. We performed a systematic literature review and meta-analysis of surgical management versus nonsurgical management for G3 GEP NENs.

MATERIALS AND METHODS

A PRISMA-compliant systematic review of the MEDLINE, Embase, Scopus, and Cochrane Library databases (end-of-search date: 16 July 2021) was conducted. Individual patient survival data were reconstructed, and random-effects meta-analyses were performed.

RESULTS

Fourteen studies comprising 1810 surgical and 910 nonsurgical patients were systematically reviewed. Publication bias adjusted meta-analysis of 12 studies (1788 surgical and 857 nonsurgical patients) showed increased overall survival (OS) after surgical compared with nonsurgical management for G3 GEP NENs [hazard ratio (HR) 0.40, 95% confidence interval (CI) 0.31-0.53]. Subgroup meta-analyses showed increased OS after surgical management for both pancreatic and gastrointestinal primary sites separately. In another subgroup meta-analysis of G3 GEP NETs (not NECs), surgical management was associated with increased OS compared with nonsurgical management (HR 0.26, 95% CI 0.11-0.61).

CONCLUSIONS

Surgical management of G3 GEP NENs may provide a potential survival benefit in well-selected cases. Further research is needed to define which patients will benefit most from surgical versus nonsurgical management. The current literature is limited by inconsistent reporting of survival outcomes in surgical versus nonsurgical groups, tumor grade, differentiation, primary tumor site, and selection criteria for surgical and nonsurgical management.

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.

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.

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.

Recent advances in diagnosis and treatment of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a rare group of tumors originating from neuroendocrine cells of the digestive system. Their incidence has increased over the last decades. The specific pathogenetic mechanisms underlying GEP-NEN development have not been completely revealed. Unfunctional GEP-NENs are usually asymptomatic; some grow slowly and thus impede early diagnosis, which ultimately results in a high rate of misdiagnosis. Therefore, many GEP-NEN patients present with later staged tumors. Motivated hereby, research attention for diagnosis and treatment for GEP-NENs increased in recent years. The result of which is great progress in clinical diagnosis and treatment. According to the most recent clinical guidelines, improved grading standards can accurately define poorly differentiated grade 3 neuroendocrine tumors and neuroendocrine carcinomas (NECs), which are subclassified into large and small cell NECs. Combining different functional imaging methods facilitates precise diagnosis. The expression of somatostatin receptors helps to predict prognosis. Genetic analyses of mutations affecting death domain associated protein (DAXX), multiple endocrine neoplasia type 1 (MEN 1), alpha thalassemia/intellectual disability syndrome X-linked (ATRX), retinoblastoma transcriptional corepressor 1 (RB 1), and mothers against decapentaplegic homolog 4 (SMAD 4) help distinguishing grade 3 NENs from poorly differentiated NECs. The aim of this review is to summarize the latest research progress on diagnosis and treatment of GEP-NENs.

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.

A model for predicting the overall survival of gastroenteropancreatic neuroendocrine neoplasms after surgery

BACKGROUND

The increase in the incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NENs) and refined morphological imaging techniques have led to a rise in the number of patients undergoing surgery. However, there is still a paucity of objective, clinically reliable and personalized tools to evaluate patient prognosis.

MATERIALS AND METHODS

We identified patients from the Surveillance, Epidemiology, and End Results (SEER) database who underwent surgery for GEP-NEN from 1975 to 2018. The predictors associated with OS were investigated by Multivariate Cox proportional hazards (PHs) regression analysis in the primary cohort; a prognostic nomogram was then built based on the multivariate analysis results. The performance of the nomogram was assessed by Harrell's concordance index (C-index) and calibration curve and compared with the eighth edition of the American Joint Committee on Cancer (AJCC) staging system.

RESULTS

A total of 45,889 patients were enrolled in our study; 32,321 were included in the primary cohort, and 13,568 were included in the validation cohort. A nomogram incorporating Age, Differentiation, M staging, and AJCC staging was subsequently built based on the multivariate analysis. The C-index (0.833 for the primary cohort and 0.845 for the validation cohort) and calibration curves indicated good discriminative ability and calibration of the nomogram. Further analysis demonstrated that the nomogram had superior discriminatory ability than the AJCC staging system (C-index= 0.706).

CONCLUSION

The proposed nomogram showed excellent prediction with good calibration and discrimination, which can be used to make well-informed and individualized clinical decisions regarding the clinical management of GEP-NENs.

Advances in the Diagnosis and Therapeutic Management of Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NENs)

Neuroendocrine neoplasms (NENs) are an increasingly common cause of neoplastic diseases. One of the largest groups of NENs are neoplasms localized to the gastroenteropancreatic system, which are known as gastroenteropancreatic NENs (GEP-NENs). Because of nonspecific clinical symptoms, GEP-NEN patient diagnosis and, consequently, their treatment, might be difficult and delayed. This situation has forced researchers all over the world to continue progress in the diagnosis and treatment of patients with GEP-NENs. Our review is designed to present the latest reports on the laboratory diagnostic techniques, imaging tests and surgical and nonsurgical treatment strategies used for patients with these rare neoplasms. We paid particular attention to the nuclear approach, the use of which has been applied to GEP-NEN patient diagnosis, and to nonsurgical and radionuclide treatment strategies. Recent publications were reviewed in search of reports on new strategies for effective disease management. Attention was also paid to those studies still in progress, but with successful results. A total of 248 papers were analyzed, from which 141 papers most relevant to the aim of the study were selected. Using these papers, we highlight the progress in the development of diagnostic and treatment strategies for patients with GEP-NENs.

Nomogram for preoperative estimation of histologic grade in gastrointestinal neuroendocrine tumors

BACKGROUND

The treatment strategies and prognosis for gastroenteropancreatic neuroendocrine tumors were associated with tumor grade. Preoperative predictive grading could be of great benefit in the selection of treatment options for patients. However, there is still a lack of effective non-invasive strategies to detect gastrointestinal neuroendocrine tumors (GI-NETs) grading preoperatively.

METHODS

The data on 147 consecutive GI-NETs patients was retrospectively collected from January 1, 2012, to December 31, 2019. Logistic regression was used to construct a predictive model of gastrointestinal neuroendocrine tumor grading using preoperative laboratory and imaging parameters.The validity of the model was assessed by area under the receiver operating characteristic curve (AUC), calibration curve, and decision curve analysis (DCA).

RESULTS

The factors associated with GI-NETs grading were age, tumor size, lymph nodes, neuron-specific enolase (NSE), hemoglobin (HGB) and sex, and two models were constructed by logistic regression for prediction. Combining these 6 factors, the nomogram was constructed for model 1 to distinguish between G3 and G1/2, achieving a good AUC of 0.921 (95% CI: 0.884-0.965), and the sensitivity, specificity, accuracy were 0.9167, 0.8256, 0.8630, respectively. The model 2 was to distinguish between G1 and G2/3, and the variables were age, tumor size, lymph nodes, NSE, with an AUC of 0.847 (95% CI: 0.799-0.915), and the sensitivity, specificity, accuracy were 0.7882, 0.8710, 0.8231, respectively. Two online web servers were established on the basis of the proposed nomogram to facilitate clinical use. Both models showed an excellent calibration curve through 1000 times bootstrapped dataset and the clinical usefulness were confirmed using decision curve analysis.

CONCLUSION

The model served as a valuable non-invasive tool for differentiating between different grades of GI-NETs, personalizing the calculation which can lead to a rational treatment choice.

Cell-Free DNA and Clinical Characteristics in Patients with Small Intestinal or Pancreatic Neuroendocrine Tumors

INTRODUCTION

Neuroendocrine tumors (NETs) are rare and characterized by a heterogeneous clinical course and an unmet need for better prognostic markers. Plasma cell-free DNA (cfDNA) has prognostic value in other malignancies but is not previously investigated in NETs. We studied cfDNA levels in patients with mainly low-grade small intestinal NET -(siNET) or pancreatic NET (pNET) and evaluated the prognostic potential of cfDNA.

MATERIALS AND METHODS

We included 70 NET patients, siNET (n = 50) and pNET (n = 20). Plasma cfDNA levels were determined by droplet digital PCR for the beta-2-microglobulin gene every 6 months during a period of 3 years, including in a subgroup of 19 patients during peptide receptor radionuclide therapy (PRRT) therapy.

RESULTS

cfDNA levels were higher in both siNET and pNET compared to a previously established healthy cohort (p < 0.0001). -cfDNA levels did not predict overall survival (crude hazard ratio [HR] 0.95 [0.57-1.58], p = 0.837, adjusted for smoking status HR 0.77 [0.51-1.17], p = 0.22). The impact of cfDNA level on progression-free survival showed different trends in siNET and pNET. There was no effect of PRRT treatment on cfDNA levels and no difference in cfDNA levels between patients with and without progressive disease after PRRT (ANOVA p = 0.66). cfDNA levels were significantly higher in never-smokers and previous smokers than in current smokers (p = 0.029).

DISCUSSION/CONCLUSION

cfDNA levels are higher in NET patients than in healthy controls; however, there was no association with prognosis, and cfDNA levels were unaffected by PRRT. Our observations suggest that cfDNA levels are not associated with the disease course in low-grade NET in contrast to other malignancies.

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

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

Primary hepatic neuroendocrine carcinoma diagnosed by needle biopsy: a case report

Background

Primary hepatic neuroendocrine carcinomas (NECs) are extremely rare. The rate of recurrence after resection is extremely high, and the prognosis is poor. It is debatable whether chemotherapy or surgical resection is the optimal initial treatment for primary hepatic NECs. Therefore, selecting an appropriate therapeutic approach for patients with primary hepatic NECs remains clinically challenging. We present a case of primary hepatic NEC in a patient who developed recurrence after undergoing surgical resection.

Case presentation

A 78-year-old man with bone metastases of prostate cancer was referred to our department because of a solitary 66-mm tumor in the left lateral segment of the liver, which was detected on annual follow-up by computed tomography after prostate resection. A biopsy and preoperative diagnostic workup identified the lesion as a primary hepatic neuroendocrine carcinoma; therefore, left lateral segmentectomy was performed. Immunohistochemically, the tumor was positive for chromogranin A, synaptophysin, and CD 56, and the Ki-67 index was 40%. This neuroendocrine carcinoma was classified as a large cell type. Adjuvant chemotherapy with carboplatin + etoposide was initially administered a month after surgery. However, lymph node recurrence occurred 4 months after surgery, and the patient died of systemic metastases 15 months after surgical resection.

Conclusions

Due to the lack of availability of abundant quantities of relevant, high-quality data, there is no standard therapy for primary hepatic NECs. Selecting the most appropriate treatment for patients depending on several factors, such as the stage and differentiation of a tumor and a patient’s performance status and clinical course, is consequently preferred. More cases need to be studied to establish the best treatment strategy for primary hepatic NEC.

Chemotherapy in Neuroendocrine Tumors

The role for cytotoxic chemotherapy in patients with well-differentiated neuroendocrine tumors (NETs) remains debated. Compared to patients with poorly differentiated neuroendocrine carcinomas (NECs) where chemotherapy is utilized ubiquitously, chemotherapy may play a more select role in patients with certain types of NETs (e.g., pancreatic tumors, higher grade tumors, and tumors possessing DNA damage repair defects). The primary types of chemotherapy that have been tested in patients with NETs include alkylating agent- and platinum agent-based combinations. Across regimens, chemotherapy appears to elicit greater antitumor activity in patients with pancreatic or grade 3 NETs. The role for chemotherapy in lower grade extra-pancreatic NETs remains undefined. Furthermore, while chemotherapy has demonstrated clinically meaningful benefit for patients in the systemic setting, its role in the adjuvant or neoadjuvant setting is as-of-yet undetermined. Finally, efforts to combine chemotherapy with targeted therapy and peptide receptor radionuclide therapy are ongoing, in hopes of improving the cytoreductive treatment options for patients with NETs.

Treatment of advanced gastroenteropancreatic neuroendocrine neoplasia, are we on the way to personalised medicine?

Gastroenteropancreatic neuroendocrine neoplasia (GEPNEN) comprises clinically as well as prognostically diverse tumour entities often diagnosed at late stage. Current classification provides a uniform terminology and a Ki67-based grading system, thereby facilitating management. Advances in the study of genomic and epigenetic landscapes have amplified knowledge of tumour biology and enhanced identification of prognostic and potentially predictive treatment subgroups. Translation of this genomic and mechanistic biology into advanced GEPNEN management is limited. 'Targeted' treatments such as somatostatin analogues, peptide receptor radiotherapy, tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors are treatment options but predictive tools are lacking. The inability to identify clonal heterogeneity and define critical oncoregulatory pathways prior to therapy, restrict therapeutic efficacy as does the inability to monitor disease status in real time. Chemotherapy in the poor prognosis NEN G3 group, though associated with acceptable response rates, only leads to short-term tumour control and their molecular biology requires delineation to provide new and more specific treatment options.The future requires an exploration of the NEN tumour genome, its microenvironment and an identification of critical oncologic checkpoints for precise drug targeting. In the advance to personalised medical treatment of patients with GEPNEN, clinical trials need to be based on mechanistic and multidimensional characterisation of each tumour in order to identify the therapeutic agent effective for the individual tumour.This review surveys advances in NEN research and delineates the current status of translation with a view to laying the basis for a genome-based personalised medicine management of advanced GEPNEN.

Nordic guidelines 2021 for diagnosis and treatment of gastroenteropancreatic neuroendocrine neoplasms

BACKGROUND

The diagnostic work-up and treatment of patients with gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) has undergone major advances and new methods are introduced. Furthermore, an update of the WHO classification has resulted in a new nomenclature for GEP-NEN that is implemented in the clinic.

AIM

These Nordic guidelines summarise the Nordic Neuroendocrine Tumour Group's current view on how to diagnose and treat GEP-NEN patients and aims to be useful in the daily practice for clinicians.

Overexpression of ODF1 in Gastrointestinal Tract Neuroendocrine Neoplasms: a Novel Potential Immunohistochemical Biomarker for Well-differentiated Neuroendocrine Tumors

Gastrointestinal tract neuroendocrine neoplasms (NENs) are a group of rare heterogeneous tumors with different prognoses. The 2019 WHO classification of digestive system tumors defines the classification of NENs as neuroendocrine tumors (NETs G1-G3) and neuroendocrine carcinomas (NECs). We investigated outer dense fiber of sperm tails 1 (ODF1) expression in 137 gastrointestinal tract NENs including 53 NETs G1, 29 NETs G2, 3 NETs G3, and 52 NECs. Twenty adenocarcinomas and 6 squamous cell carcinomas also were included in the study. The results showed that ODF1 was positive in 83 of 85 (97.6%) primary gastrointestinal tract NETs, including 9 of 10 (90%) gastric, 19 of 19 (100%) small bowel, 10 of 11 (90.9%) colorectal, and 45 of 45 (100%) appendiceal neoplasms. There was a significantly statistical difference in the rates of ODF1 positivity in NETs (83/85, 97.6%) vs NECs (25/52, 48.1%, P < 0.001). ODF1 showed diffuse staining in NETs G1 (53/53, 100%) and NETs G2 (28/29, 96.6%), > 50% staining in NETs G3 (2/3, 66.7%), and focal staining (< 50%) in NECs (23/52, 44.2%) but 2 cases (2/52) showed > 50% staining. ODF1 showed no expression in all 20 adenocarcinomas and 6 squamous cell carcinomas. In conclusion, ODF1 was firstly identified as a novel marker for NENs, especially for NETs in the gastrointestinal tract. The expression mechanism and clinical significance of ODF1 in NENs needed further study.

Diagnostic and Predictive Role of DLL3 Expression in Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a rare and heterogeneous subgroup of tumors with a challenging management because of their extremely variable biological and clinical behaviors. Due to their different prognosis, there is an urgent need to identify molecular markers which would enable to discriminate between grade 3 neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs), despite both being diagnosed mainly on the basis of proliferation index and cell differentiation. DLL3, a negative Notch regulator, is a promising molecular target highly expressed in several tumors with neuroendocrine features. We conducted a retrospective analysis of DLL3, RB1, and PD-L1 expression by immunohistochemistry (IHC), in formalin-fixed, paraffin-embedded (FFPE) samples from 47 patients with GEP-NENs. Then, we correlated the results with patients' clinical features and outcome. The absence of DLL3 expression in 5 well-differentiated GEP-NETs with high-grade features (G3 NET), and the presence of DLL3 in 76.9% of poorly-differentiated NECs (G3 NEC), highlights DLL3 expression as a marker of G3 NECs (p = 0.007). DLL3 expression was correlated with RB1-loss (p < 0.001), negative ⁶⁸ Ga-PET/CT scan (p = 0.001), and an unfavorable clinical outcome, with important implications for treatment response and patient's follow-up. Median progression-free survival (PFS) and overall survival (OS) were 22.7 months (95% CI 6.1-68.8) and 68.8 months (95% CI 26.0-78.1), respectively, in patients with DLL3-negative tumor compared with 5.2 months (95% CI 2.5-18.5) and 9.5 months (95% CI 2.5-25.2), respectively, in patients with DLL3-positive tumor (PFS p = 0.0083, OS p = 0.0071). Therefore, combined with morphological cell analysis, DLL3 could represent a valuable histological marker, for the diagnosis of poorly differentiated NECs. The high percentage of DLL3 expression in NEC patients also highlights a potential opportunity for a DLL3 targeted therapy in this tumor subset.

Development and Validation of Novel Nomograms Using Serum Tumor Markers for the Prediction of Preoperative Histologic Grades in Gastroenteropancreatic Neuroendocrine Tumors

BACKGROUND

To develop and validate nomogram models for the preoperatively prediction of the histologic grade of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) to provide appropriate treatments.

METHODS

A total of 1014 participants, including 211 healthy controls, 293 patients with benign diseases, 299 patients with cancers, and 211 patients with GEP-NETs were included in the final analysis. Their sociodemographic and laboratory information, including serum tumor markers such as AFP, CEA, CA19-9, CA72-4, Cyfra21-1 and NSE were collected. Nomogram models were developed to preoperatively predict histologic grades of GEP-NETs.

RESULTS

Among six serum tumor markers, only NSE was found to have a statistically significant association with the histologic grades in GEP-NETs (G1 vs. G2: p < 0.05; G2 vs. G3: p < 0.001; G1 vs. G3: p < 0.0001), which was combined with sex and age to develop the nomogram models. The first nomogram (to differentiate grade 1(G1) and grade 2/3 tumor (G2/G3)) showed a strong association to differentiate with an AUC of 0.747 (95% CI: 0.663-0.832) and 0.735 (95% CI: 0.624-0.847) in the training and validation datasets, respectively. The second nomogram (to differentiate G1/G2 and G3 tumors) showed a strong association to differentiate with an AUC of 0.827 (95% CI: 0.744-0.911) and 0.847 (95% CI: 0.744-0.950) in the training and validation datasets, respectively. The ROC, area under ROC curve (AUC), calibration curve and decision curve analysis (DCA) demonstrated the clinical usefulness of both models.

CONCLUSIONS

We proposed two novel nomogram models based on sex, age and serum NSE levels to preoperatively predict the histologic grades in GEP-NETs to assist the clinical decision-making.

Digestive Well-Differentiated Grade 3 Neuroendocrine Tumors: Current Management and Future Directions

Digestive well-differentiated grade 3 neuroendocrine tumors (NET G-3) have been clearly defined since the 2017 World Health Organization classification. They are still a rare category lacking specific data and standardized management. Their distinction from other types of neuroendocrine neoplasms (NEN) not only lies in morphology but also in genotype, aggressiveness, functional imaging uptake, and treatment response. Most of the available data comes from pancreatic series, which is the most frequent tumor site for this entity. In the non-metastatic setting, surgical resection is recommended, irrespective of grade and tumor site. For metastatic NET G-3, chemotherapy is the main first-line treatment with temozolomide-based regimen showing more efficacy than platinum-based regimen, especially when Ki-67 index <55%. Targeted therapies, such as sunitinib and everolimus, have also shown some positive therapeutic efficacy in small samples of patients. Functional imaging plays a key role for detection but also treatment selection. In the second or further-line setting, peptide receptor radionuclide therapy has shown promising response rates in high-grade NEN. Finally, immunotherapy is currently investigated as a new therapeutic approach with trials still ongoing. More data will come with future work now focusing on this specific subgroup. The aim of this review is to summarize the current data on digestive NET G-3 and explore future directions for their management.

Treatment Outcomes of Well-Differentiated High-Grade Neuroendocrine Tumors

INTRODUCTION

Recent classification of neuroendocrine neoplasms has defined well-differentiated high-grade neuroendocrine tumors (NET G3) as a distinct entity from poorly differentiated neuroendocrine carcinoma. The optimal treatment for NET G3 has not been well-described. This study aimed to evaluate metastatic NET G3 response to different treatment regimens.

MATERIALS AND METHODS

This was a retrospective study of patients with NET G3 within the Mayo Clinic database. Patients' demographics along with treatment characteristics, responses, and survival were assessed. Primary endpoints were progression-free survival (PFS) and overall survival. Secondary endpoints were objective response rate (ORR) and disease control rate (DCR).

RESULTS

Treatment data was available in 30 patients with median age of 59.5 years at diagnosis. The primary tumor was mostly pancreatic (73.3%). Ki-67 index was ≥55% in 26.7% of cases. Treatments included capecitabine + temozolomide (CAPTEM) (n = 20), lutetium 177 DOTATATE (PRRT; n = 10), Platinum-etoposide (EP; n = 8), FOLFOX (n = 7), and everolimus (n = 2). CAPTEM exhibited ORR 35%, DCR 65%, and median PFS 9.4 months (95% confidence interval, 2.96-16.07). Both EP and FOLFOX showed similar radiographic response rates with ORR 25.0% and 28.6%; however, median PFS durations were quite distinct at 2.94 and 13.04 months, respectively. PRRT had ORR of 20%, DCR of 70%, and median PFS of 9.13 months.

CONCLUSION

Among patients with NET G3, CAPTEM was the most commonly used treatment with clinically meaningful efficacy and disease control. FOLFOX or PRRT are other potentially active treatment options. EP has some activity in NET G3, but responses appear to be short-lived. Prospective studies evaluating different treatments effects in patients with NET G3 are needed to determine an optimal treatment strategy.

IMPLICATIONS FOR PRACTICE

High-grade well-differentiated neuroendocrine tumors (NET G3) are considered a different entity from low-grade NET and neuroendocrine carcinoma in terms of prognosis and management. The oral combination of capecitabine and temozolomide is considered a good option in the management of metastatic NET G3 and may be preferred. FOLFOX is another systemic option with reasonable efficacy. Similar to other well-differentiated neuroendocrine tumors, peptide receptor radionuclide therapy seems to have some efficacy in these tumors.

Surgery of the primary tumour in 201 patients with high-grade gastroenteropancreatic neuroendocrine and mixed neuroendocrine-non-neuroendocrine neoplasms

The benefit of surgery in high-grade gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) is uncertain. The present study aimed to investigate outcomes after tumour surgery in patients with high-grade (Ki-67 > 20%) GEP NEN or MiNEN stage I-III or stage IV. We analysed data from patients treated in the period 2007-2015 at eight Nordic university hospitals. Overall survival (OS) and progression-free survival (PFS)/disease-free survival (DFS) were analysed by Kaplan-Meier estimates. Prognostic factors were evaluated using Cox regression. We included 201 surgically resected patients, 143 stage I-III and 58 stage IV, with 68% having neuroendocrine carcinoma, 23% MiNEN, 5% neuroendocrine tumour G3 and 4% uncertain NEN G3. Primary tumours were located in colon/rectum (52%), oesophagus/cardia (19%), pancreas (10%), stomach (7%), jejunum/ileum (5%), duodenum (4%), gallbladder (2%) and anal canal (1%). For patients with stage I-III, median DFS was 12 months (95% confidence interval [CI] = 5.5-18.5) and median OS was 32 months (95% CI = 24.0-40.0). For patients with stage I-III and an R0 resection, median DFS was 21 months (95% CI = 4.9-37.1) and median OS was 39 months (95% CI = 25.0-53.0). For patients with stage IV, median PFS/DFS was 4 months (95% CI = 1.9-6.1) and median OS was 11 months (95% CI = 4.8-17.2). For patients with stage IV and an R0 resection, median DFS was 6 months (95% CI = 0-16.4) and median OS was 32 months (95% CI = 25.5-38.5). Performance status > 1 and colorectal primary were associated with poor prognosis. There was no difference in survival between patients with high-grade GEP NEN and MiNEN. Surgery of the primary tumour in patients with loco-regional high-grade GEP NEN or MiNEN led to good long-term results and should be considered if an R0 resection is considered achievable. Highly selected patients with stage IV disease may also benefit from surgery.

The value of MRI in identifying pancreatic neuroendocrine tumour G3 and carcinoma G3

AIM

To explore the magnetic resonance imaging (MRI) differences between pancreatic neuroendocrine tumour grade 3 (pNET-G3) and pancreatic neuroendocrine carcinoma grade 3 (pNEC-G3).

MATERIALS AND METHODS

Between 2009 and 2019, 31 patients underwent pNEN-G3 resection with preoperative MRI in two local hospitals in China. The 31 patients were assigned to a pNET-G3 group (n=13) or a pNEC-G3 group (n=18). The MRI findings between the groups were compared.

RESULTS

There was no statistically significant difference between the two groups in lesion size, clinical characteristics, or laboratory indexes. The lesions showed high or slightly higher signal on diffusion-weighted imaging and decreased apparent diffusion coefficient (ADC) values, which differed between the two groups (p=0.013). The difference between the groups regarding positive enhancement integral, arterial phase and portal phase signal enhancement ratio were statistically significant; however, the delayed phase signal enhancement ratio was not significantly different.

CONCLUSIONS

pNET-G3 and pNEC-G3 showed different characteristics on MRI. In particular, the ADC value and dynamic enhanced imaging could have an important role in distinguishing between the two.

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.

Ki-67 Index of 55% Distinguishes Two Groups of Bronchopulmonary Pure and Composite Large Cell Neuroendocrine Carcinomas with Distinct Prognosis

BACKGROUND

Little information is available concerning prognostic factors for bronchopulmonary large cell neuroendocrine carcinomas (BP-LCNECs) and even less is known about combined LCNECs (Co-LCNECs). We investigated whether an integrated morphological, immunohistochemical, and molecular approach could be used for their prognostic evaluation.

METHODS

Morphological (including combined features), proliferative (mitotic count/Ki-67 index), immunohistochemical (napsin A, p40, TTF-1, CD44, OTP, SSTR2A, SSTR5, mASH1, p53, RB1, and MDM2), and genomic (TP53, RB1, ATM, JAK2, KRAS, and STK11) findings were analyzed in BP-LCNECs from 5 Italian centers, and correlated with overall survival (OS). The Ki-67 index was expressed as the percentage of positive cells in hot spots as indicated in the WHO 2019 Digestive System Tumors and, for Co-LCNECs, the Ki-67 index was evaluated only in the LCNEC component.

RESULTS

A total of 111 LCNECs were distinguished into 70 pure LCNECs, 35 Co-LCNECs (27 with adenocarcinoma [ADC] and 8 with squamous cell carcinoma [SqCC]), and 6 LCNECs with only napsin A immunoreactivity. The Ki-67 index cutoff at 55% evaluated in the neuroendocrine component was the most powerful predictor of OS (log-rank p = 0.0001) in all LCNECs; 34 cases had a Ki-67 index <55% (LCNEC-A) and 77 had a Ki-67 index ≥55% (LCNEC-B). Statistically significant differences in OS (log-rank p = 0.0001) were also observed between pure and Co-LCNECs. A significant difference in OS was found between pure LCNECs-A and Co-LCNECs-A (p < 0.05) but not between pure LCNECs-B and Co-LCNECs-B. Co-LCNEC-ADC and LCNEC napsin A+ cases had longer OS than pure LCNEC and Co-LCNEC-SqCC cases (log-rank p = 0.0001). On multivariable analysis, tumor location, pure versus combined features, and napsin A, but no single gene mutation, were significantly associated with OS after adjustment for Ki-67 index and study center (p < 0.05).

CONCLUSIONS

The Ki-67 proliferation index and the morphological characterization of combined features in LCNECs seem to be important tools for predicting clinical outcome in BP-LCNECs.

A Consensus-Developed Morphological Re-Evaluation of 196 High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms and Its Clinical Correlations

High-grade gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are classified according to morphology as well-differentiated neuroendocrine tumours (NETs) G3 or poorly differentiated neuroendocrine carcinomas (NECs). Little data exist concerning which morphological criteria this subdivision should be based on. Uncertainty exists if the NEC group should be further subdivided according to proliferation rate. Clinical data on NET G3 and NEC with a lower Ki-67 range are limited. A total of 213 patients with high-grade GEP-NEN (Ki-67 >20%) were included from the Nordic NEC Registries. Four experienced NET pathologists re-evaluated the cases to develop the best morphological criteria to separate NET G3 from NEC, assuming longer survival in NET G3. Organoid growth pattern, capillary network in direct contact to tumour cells, and absence of desmoplastic stroma were found to best separate NET G3 from NEC. Of 196 patients with metastatic disease, NET G3 was found in 12.3%, NEC with a Ki-67 <55% (NEC < 55) in 29.6%, and NEC with a Ki-67 ≥55% (NEC ≥ 55) in 56.6%. Only in 1.5%, the morphology was ambiguous. Of 164 patients receiving first-line chemotherapy, 88% received platinum/etoposide treatment. Response rate was higher for NEC ≥ 55 (44%) than that of NEC < 55 (25%) and NET G3 (24%) (p = 0.025 and p = 0.026). Median progression-free survival was 5 months for all groups. Median overall survival was 33 months for NET G3 compared to 11 months for both NEC < 55 and NEC ≥ 55 (p = 0.004 and 0.003). Specific morphological criteria can separate NET G3 from NECs and show prognostic significance. High-grade GEP-NEN patients stratified by morphology and proliferation rate demonstrate significant differences in response to chemotherapy and survival.

Neuroendocrine Carcinoma of the Anus and Rectum: Patient Characteristics and Treatment Options

INTRODUCTION

Anorectal neuroendocrine carcinomas (NECs) are uncommon malignancies with poor prognosis. Consensus guidelines exist for treating extrapulmonary NEC. However, limited data is available to guide treatment for anorectal NEC. In this study, we sought to review the clinical characteristics and outcomes of patients with NEC of the rectum and/or anus at Mayo Clinic.

PATIENTS AND METHODS

This is a retrospective study of all patients with the diagnosis of NEC of the anus and/or rectum treated across Mayo Clinic sites since 2000. Baseline patient characteristics, tumor pathology, imaging profiles, treatment strategies utilized, and survival outcomes were analyzed. Kaplan-Meier analysis was used with a significance level of P < .05.

RESULTS

The study included a total of 38 patients with primary NEC of the anus and/or rectum. The median age at diagnosis was 55.5 years. The median follow-up was 18.8 months. Fifteen patients had locoregional disease (LRD) at diagnosis. The remaining 23 had metastatic disease. Overall survival was significantly shorter in patients with LRD compared with those with metastatic disease at diagnosis (18.1 vs. 13.8 months; P = .039). The majority (n = 11) of patients with LRD were treated with concurrent chemoradiation therapy, and 10 underwent surgical resection of the primary tumor. The majority (13/15) of patients with LRD progressed, with the majority (11/15) of progressions being distant. The median progression-free survival for patients with LRD was 5.7 months (1-year progression-free survival, 26.7%).

CONCLUSION

Anorectal NEC is an aggressive malignancy with poor prognosis requiring multidisciplinary discussion. In addition, the systemic nature of anorectal NEC with distant recurrences in LRD and poor outcomes in metastatic disease emphasizes the need to further develop better systemic treatment options that can potentially improve outcomes in NEC.

PD-L1 expression in gastroenteropancreatic neuroendocrine neoplasms grade 3

Gastroenteropancreatic neuroendocrine neoplasms grade 3 (GEP-NENs G3) are rare tumors. These highly aggressive neoplasms are traditionally treated with platinum-based chemotherapy in combination with etoposide. Immune checkpoint proteins such as programmed cell death ligand (PD-L1) may have a role in different cancers allowing them escape the immune system and hence, progress. We aimed to investigate the immunohistochemical expression of PD-L1 in GEP-NEN G3 and evaluate its correlation to clinical parameters. In a cohort of 136 patients, 14 (10%) expressed PD-L1 immunoreactivity; four (3%) patients in the tumor cells and 10 (7%) had immunoreactive immune cells. PD-L1 expression did not correlate to clinical parameters, progression-free survival or overall survival. We conclude that PD-L1 expression is present only in a subset of GEP-NEN G3 patients. Further studies are needed to fully understand the role of PD-L1 in patients with GEP-NEN G3, including the future possibility for treatment with immune checkpoint inhibitors.

Neuroendocrine neoplasia of the gastrointestinal tract revisited: towards precision medicine

Over the past 5 years, a number of notable research advances have been made in the field of neuroendocrine cancer, specifically with regard to neuroendocrine cancer of the gastrointestinal tract. The aim of this Review is to provide an update on current knowledge that has proven effective for the clinical management of patients with these tumours. For example, for the first time in the tubular gastrointestinal tract, well-differentiated high-grade (grade 3) tumours and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are defined in the WHO classification. This novel classification enables efficient identification of the most aggressive well-differentiated neuroendocrine tumours and helps in defining the degree of aggressiveness of MiNENs. The Review also discusses updates to epidemiology, cell biology (including vesicle-specific components) and the as-yet-unresolved complex genetic background that varies according to site and differentiation status. The Review summarizes novel diagnostic instruments, including molecules associated with the secretory machinery, novel radiological approaches (including pattern recognition techniques), novel PET tracers and liquid biopsy combined with DNA or RNA assays. Surgery remains the treatment mainstay; however, peptide receptor radionuclide therapy with novel radioligands and new emerging medical therapies (including vaccination and immunotherapy) are evolving and being tested in clinical trials, which are summarized and critically reviewed here.

Lung carcinoids with high proliferative activity: Further support for the identification of a new tumor category in the classification of lung neuroendocrine neoplasms

Highly proliferative lung carcinoids (HPLC) have been recently reported but information about this subset remains scarce.

OBJECTIVES

Clinical and pathological data of 630 patients with lung carcinoids (LC) referred to Gustave Roussy Institute (GR) and European Institute of Oncology (IEO) were retrospectively reviewed to select HPLC and analyze their frequency, behavior and compare their outcome to conventional LC with Ki-67 ≤ 20 % and mitotic count (MC)≤10/2 mm².

MATERIALS AND METHODS

Selection criteria were: diagnosis of LC confirmed by local pathologist, and available clinical and follow-up data. Patients with Ki-67 > 20 % and/or MC > 10/ 2 mm2 in primary or metastatic specimens were identified as HPLC.

RESULTS

30/514 patients (6%) met the selection criteria of HPLC. Based on primary tumor evaluation, 22/25 (88 %) were classified as atypical carcinoids (AC). Median MC was 4.5/2 mm² (1-11) 6/2 mm² (3-15) in primary tumors and metastasis, respectively. Median Ki-67 was respectively 23 % (15-65) and 25 % (8-60). Recurrence rate was 66 % (12/18) in HPLC and 9 % (33/352) in conventional LC. Median RFS was 24 (10-NR) months in HPLC, 288 (141-NR) months in LC with Ki-67 index≤5 % and NR (148-NR) months in LC with Ki-67 6-20% (p < 001). Median OS was 203 (83-NR) months in LC with Ki-67 index≤5%, 101 (79-NR) months in LC with Ki-67 index 6-20 % and 53 (39-NR) months in HPLC (p = 002). Among 20 metastatic patients with HPLC, median PFS under platinum-based chemotherapy, everolimus, alkylating-based chemotherapy, FOLFOX and PRRT was 5.1 (95 % CI 0.7-9.4), 12.1(95 %CI 0.3-24), 6.8 (95 % CI 0-14.9), 10.2 (95 % CI 0.4-19.9) and 14.2 months (95 % CI 0-30) respectively. Best response was stable disease (SD) under platinum-based chemotherapy and partial response (PR) under alkylating-based chemotherapy and FOLFOX.

CONCLUSION

This study confirms the existence and rarity of HPLC. Their characteristics and clinical behavior are more similar to LC rather than neuroendocrine carcinomas (NECs), suggesting that this entity could be managed accordingly.

ENDOCRINOLOGY IN THE TIME OF COVID-19: Clinical management of neuroendocrine neoplasms (NENs)

In viral pandemics, most specifically Covid-19, many patients with neuroendocrine neoplasms (NENs), including phaeochromocytomas, paragangliomas and medullary thyroid carcinoma, may develop Covid-19 in a mild or severe form, or be concerned about the influence of viral infection relative to their anti-tumoral therapy. In general, newly presenting patients should be assessed, and patients recently receiving chemotherapy, targeted therapy or radionuclide therapy, or showing tumour growth, should be closely followed. For previously diagnosed patients, who have indolent disease, some delay in routine follow-up or treatment may not be problematic. However, patients developing acute secretory syndromes due to functional neuroendocrine neoplasms (such as of the pancreas, intestine or lung), phaeochromocytomas and paragangliomas, will require prompt treatment. Patients with life-threatening Covid-19-related symptoms should be urgently treated and long-term anti-tumoral treatments may be temporarily delayed. In patients with especially aggressive NENs, a careful judgement should be made regarding the severity of any Covid-19 illness, tumour grade, and the immunosuppressant effects of any planned chemotherapy, immunotherapy (e.g. interferon-alpha), targeted therapy or related treatment. In other cases, especially patients with completely resected NENs, or who are under surveillance for a genetic disorder, a telephone or delayed consultation may be in order, balancing the risk of a delay against that of the possible development of Covid-19.

Candidate protein biomarkers in pancreatic neuroendocrine neoplasms grade 3

Pancreatic neuroendocrine neoplasms (PanNENs) are rare tumours that compose 1–2% of all pancreatic tumours. Patients with metastatic grade 3 neoplasia are usually treated with chemotherapy but have a poor progression-free and overall survival. According to the WHO 2017 classification, they are divided into neuroendocrine tumours (NETs) G3 and neuroendocrine carcinomas (NECs). Despite the new classification, new diagnostic and prognostic biomarkers are needed to sub-categorise the patients and to help guide therapy decisions. Blood from 42 patients and 42 healthy controls were screened for the presence of 92 proteins with the Immuno-Oncology panel using the Proximity Extension Assay provided by Olink Biosciences. Immunohistochemical staining of FAS ligand (FASLG) was performed on 16 patient tumour specimens using a commercial antibody. Fifty-four out of 87 evaluable proteins differed significantly in concentration between blood from patients and blood from healthy controls. FASLG was the only protein for which the concentration in blood was significantly lower in patients compared to controls and the levels correlated negatively to Ki-67 index. Seven of 14 evaluable PanNEN G3 specimens showed FASLG immunoreactivity in the tumour cells while there was scattered immunoreactivity in immune cells. Positive FASLG immunoreactivity correlated to well-differentiated morphology. FASLG concentration in blood was significantly lower in patients with pancreatic NENs G3 compared to controls, and the expression in tumour tissue was variable. Furthermore, FASLG was negatively correlated to Ki-67 and was more frequently expressed in well-differentiated tumours. Taken together, these results may suggest a role of FASLG in PanNENs.

Efficacy of Second-Line Chemotherapy in Extrapulmonary Neuroendocrine Carcinoma

OBJECTIVES

A platinum/etoposide doublet is standard first-line therapy for poorly differentiated neuroendocrine carcinoma (PD NEC); however, evidence to guide treatment beyond first-line regimens is lacking. This study aimed to evaluate the efficacy of second-line regimens in PD NEC.

METHODS

We performed a retrospective analysis of patients treated with second-line chemotherapy for PD NEC. Inclusion criteria were previous first-line therapy with platinum/etoposide, extrapulmonary PD NEC, and follow-up data. The primary end points were overall survival (OS) and progression-free survival (PFS) after second-line therapy. Secondary end points included OS and PFS from first-line therapy.

RESULTS

Sixty-four patients were included. The median OS from initiation of second-line therapy was 6.2 months (95% confidence interval [CI], 4.9-8.9). The median PFS was 2.3 months (95% CI, 2.0-3.2). No second-line regimen showed a statistically significant difference in OS or PFS. There was a significant increase in OS for cisplatin first-line regimens compared with carboplatin (17.0 months [95% CI, 12.5-22.6] vs 11.7 months [95% CI, 8.0-14.0]).

CONCLUSIONS

The efficacy of current second-line therapy in PD NEC is poor. No second-line regimen showed statistically significant superiority. Cisplatin was associated with longer OS regardless of second-line regimen or age. However, unmeasured confounders such as performance status or comorbidities may explain this effect.

Pembrolizumab monotherapy in patients with previously treated metastatic high-grade neuroendocrine neoplasms: joint analysis of two prospective, non-randomised trials

Background

Metastatic high-grade neuroendocrine neoplasms (G3NENs) have limited treatment options after progression on platinum-based therapy. We addressed the role of Pembrolizumab in patients with previously treated metastatic G3NENs.

Methods

Two open-label, phase 2 studies enrolled patients with G3NEN (Ki-67 > 20%) to receive Pembrolizumab at 200 mg I.V. every 3 weeks. Radiographic evaluation was conducted every 9 weeks with overall response rate as the primary endpoint.

Results

Between November 2016 and May 2018, 29 patients (13 males/16 females) with G3NENs were enrolled. One patient (3.4%) had an objective response and an additional six patients (20.7%) had stable disease, resulting in a disease control rate of 24.1%. Disease control rate (DCR) at 18 weeks was 10.3% (3/29). There was no difference in the DCR, PFS or OS between the PD-L1-negative and -positive groups (p 0.56, 0.88 and 0.55, respectively). Pembrolizumab was well tolerated with only 9 grade 3, and no grade 4 events considered drug-related.

Conclusions

Pembrolizumab can be safely administered to patients with G3NENs but has limited activity as a single agent. Successful completion of our trials suggest studies in G3NENs are feasible and present an unmet need. Further research to identify active combination therapies should be considered.

Clinical trial registration number

NCT02939651 (10/20/2016).

P53, Somatostatin receptor 2a and Chromogranin A immunostaining as prognostic markers in high grade gastroenteropancreatic neuroendocrine neoplasms

Background

High grade gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) with a Ki67 proliferation index > 20%, include well-differentiated tumours grade 3 (NET G3) and poorly differentiated (PD) neuroendocrine carcinomas (NEC). Abnormal p53-expression is a feature of PD tumours, while expression of chromogranin A (CgA) and somatostatin-receptor 2a (SSTR-2a) may be a feature of well-differentiated tumours. The aim of this study was to elucidate the expression and prognostic value of these three markers in 163 GEP-NEN patients with a Ki67-index > 20%.

Method

Clinical data, histopathology and overall survival were analysed according to Kaplan-Meier’s method and Cox regression. The expression of SSTR-2a, CgA and synaptophysin was analysed in tumour specimens by immunohistochemistry, and semi-quantitatively scored as negative (< 5%), heterogeneously positive (5–30%) or strongly positive (> 30%). P53 was defined as normal when scored as heterogeneously positive (1–30%), and abnormal when negative (0%) or strongly positive (> 30%).

Results

In multivariate analysis, better survival was observed among patients with heterogeneously positive p53 compared to strongly positive (p < 0.001). When dichotomised, tumours with a heterogeneously positive p53 vs. negative and strongly positive p53 also showed a significantly better survival (p = 0.002).

Survival was significantly worse for negative CgA compared to heterogeneously positive CgA (p = 0.02). Strongly positive SSTR-2a expression was found in 26% of the 163 included patients. Well-differentiated morphology correlated with strong expression of SSTR-2a and CgA, and heterogeneously positive p53-staining, and was more frequent in pancreatic primaries. In pancreatic primaries, strongly positive SSTR-2a was associated with longer survival (univariate analysis, p = 0.02). A significantly lower Ki67 proliferation index was found in patients with a heterogeneously positive p53, a positive SSTR-2a and CgA expression.

Conclusion

Our results suggest that abnormal p53-expression is an independent negative prognostic marker in GEP-NEN with a Ki67-index > 20%. Patients with heterogeneously positive p53 had the best prognosis. SSTR-2a was a positive prognostic marker in pancreatic NEN. Negative CgA was associated with a significantly worse OS compared to heterogeneously positive CgA-expression in a multivariate sub-analysis. Lower Ki67 index correlated significantly with heterogeneously positive p53, positive SSTR-2a and CgA expression.

Trends of incidence and prognosis of gastric neuroendocrine neoplasms: a study based on SEER and our multicenter research

BACKGROUND

To investigate the recent epidemiological trends of gastric neuroendocrine neoplasms (GNENs) and establish a new tool to estimate the prognosis of gastric neuroendocrine carcinoma (GNEC) and gastric neuroendocrine tumor (GNET).

METHODS

Nomograms were established based on a retrospective study on patients diagnosed with GNENs from 1975 to 2016 in Surveillance, Epidemiology and End Results database. External validation was performed among 246 GNENs patients in Jiangsu province to verify the discrimination and calibration of the nomograms.

RESULTS

The age-adjusted incidence of GNENs has increased from 0.309 to 6.149 per 1,000,000 persons in the past 4 decades. Multivariate analysis indicated independent prognostic factors for both GNEC and GNET including age, distant metastasis and surgical intervention (P < 0.05). In addition, T, N staging and grade were significantly associated with survival of GNEC, while size was a predictor for GNET (P < 0.05). The C-indexes of the nomograms were 0.840 for GNEC and 0.718 for GNET, which were higher than those of the 8th AJCC staging system (0.773 and 0.599). Excellent discrimination was observed in the validation cohorts (C-index of nomogram vs AJCC staging for GNEC: 0.743 vs 0.714; GNET: 0.945 vs 0.927). Survival rates predicted by nomograms were close to the actual survival rates in the calibration plots in both training and validation sets.

CONCLUSIONS

The incidence of the GNENs is increasing steadily in the past 40 years. We established more excellent nomograms to predict the prognosis of GNENs than traditional staging system, helping clinicians to make tailored decisions.

Diabetes in Patients With Pancreatic Neuroendocrine Neoplasms

OBJECTIVE

Diabetes mellitus (DM) is probably a risk factor for pancreatic neuroendocrine neoplasms (PNENs). However, the prevalence of DM in PNEN patients remains inconclusive. In the present study we observed the prevalence of DM and possible risk factors in PNEN patients.

METHODS

After excluding those with insulinoma, a total of 197 patients with PNENs were included. The demographic data, pathological characteristics, and data of blood biochemical tests were recorded. DM was considered if there was evidence of a fasting plasma glucose level of ≥7.0 mmol/L or a 2-h plasma glucose level of ≥11.1 mmol/L, or a history of DM at the time of PNEN diagnosis. Impaired fasting glucose was considered if fasting plasma glucose level was between 6.1 and 7.0 mmol/L.

RESULTS

The prevalence of DM, new-onset DM, and impaired fasting glucose were 17.26, 9.14, and 7.1%, respectively. The prevalence of DM was 26.0% in patients ≥60 years old (19/73) and 12.1% in patients <60 years old. Multivariable logistic regression analysis demonstrated that age, tumor size, and nerve invasion were independent risk factors for DM and impaired fasting glucose + DM (p < 0.05). Age, organs and nerve invasion were independent risk factors for impaired fasting glucose. Low high-density lipoprotein (HDL) was also a risk factor for incident of DM (OR = 0.15, 95%CI: 0.03-0.66). G2/G3 was an independent risk factor for DM in women.

CONCLUSION

Our data shows that the prevalence of DM is 17.26% in patients with PNENs and is 26.0% in patients ≥60 years of age after excluding insulinoma. Age, nerve invasion, tumor size, and HDL are risk factors for DM in PNEN patients.

Gastroenteropancreatic High-Grade Neuroendocrine Neoplasms: Histology and Molecular Analysis, Two Sides of the Same Coin

BACKGROUND

In gastroenteropancreatic (GEP) high-grade neuroendocrine neoplasms (H-NENs), Ki-67 threshold of 55% defines three prognosis subclasses: neuroendocrine tumor (NET) G3, neuroendocrine carcinoma (NEC) <55%, and NEC ≥55%. We investigated whether the molecular profiling of H-NENs differs among these subcategories and evaluated potential therapeutic targets, including PD-L1.

METHODS

In GEP-NEN patients, we evaluated: (i) 55% threshold for Ki-67 labeling index for further stratifying NEC and (ii) immunoreactivity and gene mutations by immunohistochemistry and targeted next-generation sequencing (T-NGS).

RESULTS

Fifteen NETs G3 and 39 NECs were identified. Ki-67 labeling index was <55% in 9 NECs and ≥55% in 30 NECs. Gene mutations by NGS (TP53, 32.9%; KRAS, 5.5%; BRAF, 4.1%) were detected in 46.6% NENs, significantly enriched in NEC ≥55% (76.7%) compared to NEC <55% (55.6%) or NET (20.0%). PD-L1 staining in tumor-infiltrating lymphocytes was observed in NEC ≥55% (36.7%; p = 0.03). Median OS was 4.3 years in NET G3, 1.8 years in NEC <55%, and 0.7 years in NEC ≥55% (p <0.0001); it was 2.3 years with NGS wild-type, 0.7 years with ≥1 mutation (p <0.0001), 0.8 years in PD-L1-positive patients, and 1.7 years in PD-L1-negative subjects (p = 0.0004). In multivariate analysis, only the proposed subclassification approach yielded statistically significant differences between groups (NEC <55% vs. NET G3, HR 14.1, 95% CI 2.2-89.8, p = 0.005; NEC ≥55% vs. NET G3, HR 25.8, 95% CI 3.9-169, p = 0.0007).

CONCLUSIONS

These findings identify NEC ≥55% as a biologically and prognostically distinct subtype and pave the way for more personalized treatment.

Value of computed tomography evaluation in pathologic classification and prognosis prediction of gastric neuroendocrine tumors

Background

The study aims to investigate the correlation of CT characteristics with pathological classifications and the prognostic value of CT features in patients with gastric neuroendocrine neoplasms (g-NENs).

Methods

Ninety-one cases of pathologically diagnosed g-NENs, including 15 cases of well-differentiated neuroendocrine tumors (NETs) (G1 and G2) and 76 cases of poor-differentiated neuroendocrine carcinomas (NECs) (G3 and MANEC) were retrospectively studied. All cases were included in correlation analysis of CT characteristics with pathologic grades. Among them, 76 patients who had fulfilled follow-up data were included for overall survival (OS) and disease-free survival (DFS) analysis.

Results

CT characteristics that favor poor differentiation include tumor location (fundus and cardia), larger tumor size (>3.0 cm), infiltrative growth, unclear tumor margin, serosa involvement, ulceration and lymph node metastasis (P<0.05). Most variables had sensitivities >80% and specificities >60% to distinguish NECs from NETs. Through log-rank analysis, it was revealed that serosa involvement, cystic degeneration, necrosis, heterogeneous enhancement and lymph node metastasis led to worse DFS and OS for patients with g-NENs (P<0.05). COX regression analysis showed that serosa involvement and lymph node metastasis were independent risk factor for DFS and OS, respectively, despite of grading, staging and therapeutic choices (P<0.05). Moreover, high Ki-67 index (>55%) in G3 g-NENs is in correlation with serosa involvement and lymph node metastasis; accordingly, patients with higher Ki-67 index had worse 1-year DFS (61.7% vs. 92.3%; P<0.05).

Conclusions

CT characteristics can be useful discriminators and prognostic factors for g-NENs and may help identify G3 g-NEC from G3 g-NEN by revealing its poor differentiation and high invasive potential.

Analysis of 72 patients with colorectal high-grade neuroendocrine neoplasms from three Chinese hospitals

BACKGROUND

Colorectal high-grade neuroendocrine neoplasms (HGNENs) are rare and constitute less than 1% of all colorectal malignancies. Based on their morphological differentiation and proliferation identity, these neoplasms present heterogeneous clinicopathologic features. Opinions regarding treatment strategies for and improvement of the clinical outcomes of these patients remain controversial.

AIM

To delineate the clinicopathologic features of and explore the prognostic factors for this rare malignancy.

METHODS

This observational study reviewed the data of 72 consecutive patients with colorectal HGNENs from three Chinese hospitals between 2000 and 2019. The clinicopathologic characteristics and follow-up data were carefully collected from their medical records, outpatient reexaminations, and telephone interviews. A survival analysis was conducted to evaluate their outcomes and to identify the prognostic factors for this disease.

RESULTS

According to the latest recommendations for the classification and nomenclature of colorectal HGNENs, 61 (84.7%) patients in our cohort had poorly differentiated neoplasms, which were categorized as high-grade neuroendocrine carcinomas (HGNECs), and the remaining 11 (15.3%) patients had well differentiated neoplasms, which were categorized as high-grade neuroendocrine tumors (HGNETs). Most of the neoplasms (63.9%) were located at the rectum. More than half of the patients (51.4%) presented with distant metastasis at the date of diagnosis. All patients were followed for a median duration of 15.5 mo. In the entire cohort, the median survival time was 31 mo, and the 3-year and 5-year survival rates were 44.3% and 36.3%, respectively. Both the univariate and multivariate analyses demonstrated that increasing age, HGNEC type, and distant metastasis were risk factors for poor clinical outcomes.

CONCLUSION

Colorectal HGNENs are rare and aggressive malignancies with poor clinical outcomes. However, patients with younger age, good morphological differentiation, and without metastatic disease can have a relatively favorable prognosis.

Management of Well-Differentiated High-Grade (G3) Neuroendocrine Tumors

OPINION STATEMENT

In 2017, the World Health Organization (WHO) classification for pancreatic NET was updated to include a new category of well-differentiated high-grade (Ki 67 > 20%) pancreatic tumors (NET G3), distinct from high-grade poorly differentiated neuroendocrine carcinoma (NEC). NET G3 are considered a molecularly, radiologically, and prognostically distinct entity compared to NEC and NET G1/G2. The optimal first-line management in NET G3 and sequencing therapies remains a challenge awaiting future trials taking into consideration the unique characteristics of this category. In this review, we aim to summarize the current evidence in the management of NET G3.