Neuroendocrine Carcinomas of the Digestive Tract: What Is New?

Critical considerations for the management of gastrointestinal mixed neuroendocrine non-neuroendocrine neoplasms and pure neuroendocrine carcinomas

Mixed neuroendocrine non-neuroendocrine neoplasms constitute rare tumors that are located mainly in the gastrointestinal (GI) tract and have high degrees of malignancy, and the frequency of these tumors has been increasing. They consist of a neuroendocrine neoplastic component with another component of adenocarcinoma usually and have a dismal prognosis. The rare GI pure neuroendocrine carcinoma is highly aggressive and requires complex and extensive management since a genetic distinction exists between it and GI non-neuroendocrine neoplasms, which are generally slow-growing lesions. The most common GI-mixed neuroendocrine non-neuroendocrine neoplasms are colorectal, followed by gastric, mainly in the gastroesophageal junction. Current imaging modalities of nuclear medicine and radiology play important roles in the accuracy of diagnosis. Liquid biopsy may contribute to early detection and timely diagnosis. Ultrasonography, either endoscopic or abdominal, is a technique that contributes to a diagnosis; additionally, contrast-enhanced ultrasonography is very helpful in follow-up appointments. Histopathology establishes a definite diagnosis and stage by evaluating the cell differentiation grade and the cell proliferation index Ki67. The genetic profile can be valuable in diagnosis and gene therapy. Surgical resection with wide lymphadenectomy, whenever possible, and adjuvant chemotherapy constitute the main therapeutic management strategies. Targeted therapy and immunotherapy achieve encouraging results.

Ectopic corticotropin-releasing hormone syndrome caused by rectal large cell neuroendocrine carcinoma: a rare case report

Ectopic corticotropin-releasing hormone (CRH) syndrome, a rare subtype of adrenocorticotropic hormone-dependent Cushing syndrome, is associated with tumors of diverse origins. Here, we present a case of a 37-year-old female diagnosed with ectopic CRH syndrome secondary to rectal large cell neuroendocrine carcinoma, a hitherto unprecedented site for CRH-secreting tumors. The patient presented with classical features of Cushing syndrome, supported by laboratory evidence of hypercortisolemia and disrupted diurnal cortisol secretion. Imaging studies ruled out a pituitary adenoma, whereas colonoscopy identified a rectal malignancy. Immunohistochemical staining confirmed the presence of ectopic CRH syndrome. Despite prompt chemotherapy initiation, the patient's condition rapidly deteriorated, highlighting the aggressive nature and dismal prognosis associated with rectal large cell neuroendocrine carcinoma linked to ectopic CRH syndrome. This case underscores the importance of early recognition and comprehensive management to optimize patient outcomes.

Surgical Management and Long-Term Evaluation of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) arise from neuroendocrine cells and are a rare class of heterogenous tumors with increasing incidence. The diagnosis, staging, treatment, and prognosis of PNETs depend heavily on identifying the histologic features and biological mechanisms. Here, the authors provide an overview of the diagnostic workup (biomarkers and imaging), grade, and staging of PNETs. The authors also explore associated genetic mutations and molecular pathways and describe updated guidelines on surgical and systemic treatment modalities.

Efficacy of first-line chemotherapy based on primary site of tumor versus etoposide-platinum in advanced gastroenteropancreatic neuroendocrine carcinoma

Background

Gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs) constitute a rare and aggressive group of malignancies usually with widespread disease. There are limited studies on GEP-NECs, and therefore, we aim to acquire more information on the clinical features, treatment regimens, and prognosis.

Methods

Data from advanced GEP-NECs patients who had not previously received systemic treatment for advanced disease at The First Affiliated Hospital of Nanjing Medical University from 2010 to 2022 were retrospectively collected. Relationships between clinical-pathological features, treatment regimens, and prognosis were investigated using Kaplan-Meier curves and cox regression models.

Results

A total of fifty-four patients were enrolled in the study. The median age was 65.5 years and 79.6% were male. At diagnosis, 51.9% and 3.7% of patients developed liver and brain metastasis respectively. Sixteen (29.6%) patients received chemotherapy according to primary site of tumor (PST), while thirty-eight (70.4%) were treated with etoposide-platinum (EP) regimen, which based on the first-line treatment of advanced small cell lung cancer (SCLC). No significant differences on progression-free survival (PFS) and response rate were observed between these two groups. Univariate survival analysis showed that liver metastasis, elevated baseline serum carcinoembryonic antigen, elevated baseline serum neuron-specific enolase, elevated baseline serum lactate dehydrogenase, and elevated baseline serum neutrophil-to-lymphocyte ratio (NLR) were associated with shorter PFS. After multivariate analysis, elevated NLR was the only factor that remained significantly associated with shorter PFS (P=0.01).

Conclusions

GEP-NECs are aggressive neoplasms, of which elevated NLR is proven to be an independent negative predictor. Treatment regimens based on PST are not inferior to regiments based on SCLC (EP) for GEP-NECs patients. Large-scale, prospective randomized controlled trials are required to establish the standard of care.

Evaluating Prognosis of Gastrointestinal Metastatic Neuroendocrine Tumors: Constructing a Novel Prognostic Nomogram Based on NETPET Score and Metabolic Parameters from PET/CT Imaging

INTRODUCTION

The goal of this study is to compare the prognostic performance of NETPET scores, based on gallium-68 DOTANOC (68Ga-DOTANOC) and fluorine-18 fluorodeoxyglucose (18F-FDG) Positron Emission Tomography-Computed Tomography (PET-CT), and PET-CT metabolic parameters in metastatic gastrointestinal neuroendocrine tumors (GI-NET), while constructing and validating a nomogram derived from dual-scan PET-CT.

METHODS

In this retrospective study, G1-G3 GI-NET patients who underwent 68Ga-DOTANOC and 18F-FDG PET scans were enrolled and divided into training and internal validation cohorts. Three grading systems were constructed based on NETPET scores and standardized uptake value maximum (SUVmax). LASSO regression selected variables for a multivariable Cox model, and nomograms predicting progression-free survival (PFS) and overall survival (OS) were created. The prognostic performance of these systems was assessed using time-dependent receiver-operating characteristic (ROC) curves, concordance index (C-index), and other methods. Nomogram evaluation involved calibration curves, decision curve analysis (DCA), and the aforementioned methods in both cohorts.

RESULTS

In this study, 223 patients (130 males; mean age ±  SD: 52.6 ± 12 years) were divided into training (148) and internal validation (75) cohorts. Dual scans were classified based on NETPET scores (D1-D3). Single 68Ga-DOTANOC and 18F-FDG PET-CT scans were stratified into S1-S3 and F1-F3 based on SUVmax. The NETPET score-based grading system demonstrated the best OS and PFS prediction (C-index, 0.763 vs. 0.727 vs. 0.566). Nomograms for OS and PFS exhibited superior prognostic performance in both cohorts (all AUCs > 0.8).

CONCLUSIONS

New classification based on NETPET score predicts patient OS/PFS best. PET-CT-based nomograms show accurate OS/PFS forecasts.

Comparison of the clinical features and long-term prognosis of gallbladder neuroendocrine carcinoma versus gallbladder adenocarcinoma: A propensity score-matched analysis

Gallbladder neuroendocrine carcinoma (GBNEC) is rare and characterized by a low degree of tumor differentiation. The clinical features of GBNEC versus gallbladder adenocarcinoma (GBADC) remain a subject of debate. A total of 201 GBADC and 36 GBNEC cases that underwent surgery resection between January 2010 and 2022 at the Department of Biliary Surgery, West China Hospital, Sichuan University were included. A 1:1 propensity score matching (PSM) was performed based on seven predefined variables: age, sex, the American Joint Committee on Cancer (AJCC) stage, resection status, perineural invasion (PNI), lymphovascular invasion (LVI), and degree of tumor differentiation. Compared with GBADC, GBNEC patients were younger (median age 56.0 vs 64.0 years; P = 0.001), and more patients presented with advanced stages of tumor (P = 0.003). Patients with GBNEC also had a higher rate of PNI (55.6% vs 22.4%; P < 0.001), and LVI (63.9% vs 45.80%; P = 0.658). Before PSM, GBNEC patients had inferior prognoses compared with GBADC patients with a shorter median overall survival (mOS) (15.02 vs 20.11 months; P = 0.0028) and a shorter median recurrence-free survival (mRFS) (10.30 vs 15.17 months; P = 0.0028). However, after PSM analyses, there were no differences in OS (mOS 18.6 vs 18.0 months; P=0.24) or RFS (mRFS 10.98 vs 12.02 months; P = 0.39) between the GBNEC and GBADC cases. After multivariate analysis, tumor diagnosis (GBNEC vs GBADC) was not identified as an independent risk factor for shorter RFS (P = 0.506) or OS (P = 0.731). Unfavorable pathological features, including advanced AJCC tumor stages, poor differentiation, presence of LVI, and positive resection margins (all P < 0.05), were independent risk factors for inferior OS and RFS. GBNEC is difficult to diagnose early and has a prognosis comparable to stage-matched poorly differentiated GBADC. Tumor diagnosis (either GBADC or GBNEC) was not an independent risk factor for the patient's OS. Unfavorable pathological features of the neoplasm are the main determinants.

Radiotherapy in the management of rare gastrointestinal cancers: A systematic review

The aim of this analysis is to assess radiotherapy's role and technical aspects in an array of rare gastrointestinal (GI) cancers for adult patients. Collection data pertaining to radiotherapy and digestive rare cancers were sourced from Medline, EMBASE, and Cochrane Library. Preoperative chemoradiotherapy improved outcomes for patients with esophageal undifferentiated carcinoma compared with esophageal salivary gland types of carcinomas. For rare gastric epithelial carcinoma, perioperative chemotherapy is the common treatment. Adjuvant chemoradiotherapy showed no benefice compared with adjuvant chemotherapy for duodenal adenocarcinoma. Small bowel sarcomas respond well to radiotherapy. By analogy to anal squamous cell carcinoma, exclusive chemoradiotherapy provided better outcomes for patients with rectal squamous cell carcinoma. For anal adenocarcinoma, neoadjuvant chemoradiotherapy, followed by radical surgery, was the most effective regimen. For pancreatic neuroendocrine tumors, chemoradiotherapy can be a suitable option as postoperative or exclusive for unresectable/borderline disease. The stereotactic body radiotherapy (SBRT) is a promising approach for hepatobiliary malignancy. Radiotherapy is a valuable option in gastrointestinal stromal tumors (GIST) for palliative intent, tyrosine kinase inhibitors (TKIs) resistant disease, and unresectable or residual disease. Involved field (IF) radiotherapy for digestive lymphoma provides good results, especially for gastric extranodal marginal zone lymphoma (MALT). In conclusion, radiotherapy is not an uncommon indication in this context. A multidisciplinary approach is needed for better management of digestive rare cancers.

Neuroendocrine Neoplasms: Epidemiology, Diagnosis, and Management

Neuroendocrine tumors have variety of biological and clinical characteristics. The classification of neuroendocrine neoplasm has evolved, and the newest 2019 World Health Organization classification outlines a well-differentiated high-grade G3 subtype, recognizing its differences from the poorly differentiated neuroendocrine carcinoma. ⁶⁸Ga-DOTAT PET has largely replaced somatostatin scintigraphy as the diagnostic workup choice for NENs. NETest, a multi-analyte liquid biopsy, is a promising recent development in the biochemical diagnosis. Management includes wait and watch approach, surgical resection, somatostatin analogs, ¹⁷⁷Lu DOTATATE therapy, chemotherapy, radiotherapy or immunotherapy combinations. Further clinical trials are necessary for determining the appropriate sequencing.

Molecular factors, diagnosis and management of gastrointestinal tract neuroendocrine tumors: An update

The prevalence of gastrointestinal neuroendocrine tumors (GI-NETs) is increasing, and despite recent advances in their therapy, it remains inadequate in patients with advanced well-differentiated neuroendocrine tumors. These tumors present many challenges concerning the molecular basis and genomic profile, pathophysiology, clinicopathological features, histopathologic classification, diagnosis and treatment. There has been an ongoing debate on diagnostic criteria and clinical behavior, and various changes have been made over the last few years. Neuroendocrine carcinoma of the gastrointestinal system is a rare but highly malignant neoplasm that is genetically distinct from gastrointestinal system neuroendocrine tumors (NETs). The diagnosis and management have changed over the past decade. Emerging novel biomarkers and metabolic players in cancer cells are useful and promising new diagnostic tools. Progress in positron emission tomography-computerized tomography and scintigraphy with new radioactive agents (⁶⁴Cu-DOTATATE or ⁶⁸Ga-DOTATATE) replacing enough octreoscan, has improved further the current diagnostic imaging. Promising results provide targeted therapies with biological agents, new drugs, chemotherapy and immunotherapy. However, the role of surgery is important, since it is the cornerstone of management. Simultaneous resection of small bowel NETs with synchronous liver metastases is a surgical challenge. Endoscopy offers novel options not only for diagnosis but also for interventional management. The therapeutic option should be individualized based on current multidisciplinary information.

Metastatic rectal neuroendocrine carcinoma presenting with treatment-refractory immune thrombocytopenia: A case report and literature review

RATIONALE

Colorectal neuroendocrine cancer (CRNEC) accounts for < 1% of all colorectal cancers. It presents in advanced stages and carries a risk of poor survival. CRNEC may be diagnosed incidentally on imaging or routine endoscopy. When symptomatic, it may mimic colorectal adenocarcinoma. Syncope and immune thrombocytopenic purpura (ITP) have not previously been reported as clinical presentations.

PATIENT CONCERNS

A 57-year-old man with human immunodeficiency virus infection on treatment, seizure and stroke without residue presented for the evaluation of fall and syncope.

DIAGNOSIS

Physical examination revealed tachycardia, swelling, and ecchymosis of his proximal left lower extremity. Laboratory tests showed a new isolated thrombocytopenia of 26,000/mm3. Computed tomography for a trauma survey showed an incidental left posterior rectal wall mass. After hospital admission, his platelet count dropped to 14,000/mm3. A peripheral blood smear revealed low platelet count, no schistocytes or immature cells. ITP at a high risk for bleeding was diagnosed and treated with standard medical therapy but remained refractory. Bone marrow biopsy showed metastatic neuroendocrine carcinoma, likely from the rectum.

INTERVENTIONS

Patient received courses of high-dose dexamethasone and intravenous immunoglobulin. He also receive eleven units of platelet transfusion. A course of rituximab was administered. The platelet count response was suboptimal or short lived with drop to a nadir of 4000/mm3. However, after initiation of Eltrombopag, the thrombocytopenia resolved. Patient was started on etoposide, carboplatin, Atezolizumab. His hospital stay was complicated by neutropenia and sepsis, which was successfully treated.

OUTCOMES

He was discharged to subacute rehab in stable condition. About 4 months later, he was readmitted for severe thrombocytopenia, septic shock, and acute respiratory failure. Despite appropriate treatment, the patient deteriorated and expired.

CONCLUSION

CRNEC is a rare aggressive disease with dismal outcome that lacks standardized treatment. Metastasis to the bone marrow is uncommon and concomitant ITP has not been reported. We report a rare case of rectal neuroendocrine carcinoma metastatic to bone marrow associated with refractory ITP and review the relevant literature.

Enhancer of Zeste Homolog 2 (EZH2) Is a Marker of High-Grade Neuroendocrine Neoplasia in Gastroenteropancreatic and Pulmonary Tract and Predicts Poor Prognosis

Simple Summary

Neuroendocrine neoplasms most frequently arise in the gastroenteropancreatic and pulmonary tract and show an increasing incidence and prevalence. The prognosis and treatment depend on tumor proliferation and clinical behavior. Highly proliferating grade 3 neoplasms especially, show a wildly divergent therapy response and prognosis. In particular, it is crucial to securely separate the more indolent G3 tumors from the more aggressive carcinomas. Currently, this distinction is based on a combination of clinical, morphologic, immunohistochemical, and molecular biomarkers. However, none of these markers allow for a reliable distinction, and additional markers are needed. EZH2 has attracted increasing interest in different tumor entities. We aimed to analyze the expression of EZH2 in different neuroendocrine neoplasms and to correlate the expression with clinical parameters and survival. We demonstrate that EZH2 is nearly exclusively expressed in highly proliferative neoplasms and is a robust biomarker for identifying aggressive G3 tumors with poor prognosis.

Abstract

Tumor grading is a robust prognostic predictor in patients with neuroendocrine neoplasms (NEN) and guides therapy, especially in tumors with high proliferation. NEN can be separated into well-differentiated and poorly differentiated types. The more aggressive NEN have been further separated into neuroendocrine tumors (NET G3) with a better prognosis and neuroendocrine carcinomas (NEC) with a worse prognosis. Despite this distinction’s tremendous clinical and therapeutic relevance, optimal diagnostic biomarkers are still lacking. In this study, we analyzed the protein expression and prognostic impact of Enhancer of Zeste Homolog 2 (EZH2) by immunohistochemistry in 219 tissue samples of gastroenteropancreatic (GEP-NEN) and pulmonary NEN (P-NEN). EZH2 was almost exclusively expressed in NEN with a proliferation rate above 20% (G3), while all low-grade tumors were nearly negative. Among high-grade NEN, 65% showed high and 35% low expression of EZH2. In this group, the high expression of EZH2 was significantly associated with poor overall survival and NEC histology. Interestingly, EZH2 seems to act independently of Polycomb Repressive Complex 2 (PRC2) in NEN. In conclusion, we propose EZH2 as a robust biomarker for distinguishing between NET G3 and NEC among gastroenteropancreatic and pulmonary NEN.

Survival Analysis in Gastrointestinal Neuroendocrine Carcinoma With Bone Metastasis at Diagnosis

Purpose

Gastrointestinal neuroendocrine carcinoma (NEC) with bone metastasis is rarely reported. The purpose of this study is to explore the prognosis and risk factors of such patients.

Patients and Methods

We retrospectively reviewed patients diagnosed as gastrointestinal NECs with bone metastasis at diagnosis from 2010 to 2016 by using the Surveillance, Epidemiology and End Results (SEER) database. Predictors of overall survival (OS) and cancer-specific survival (CSS) were analyzed by univariable and multivariable Cox analyses. Kaplan–Meier plots were constructed to show the correlation between independent predictors and survival.

Results

A total of 330 gastrointestinal NEC patients with bone metastasis at diagnosis were included for analysis. Over half of patients were male and older than 60 years old. The most common primary site of gastrointestinal NEC with bone metastasis was the pancreas. The prognosis of gastrointestinal NEC with bone metastasis (3-year OS and CSS rates: 16.7 and 17.0%) was very poor. On Cox multivariable analysis, age over 60 years old, no surgery, and lung metastasis were independent predictors of decreased OS and CSS.

Conclusions

We identified three independent factors associated with prognosis among gastrointestinal NEC patients with bone metastasis, namely age, surgery, and lung metastasis. For younger gastrointestinal NEC patients with bone metastasis, surgical resection of primary tumors as well as actively treating lung metastasis might be useful for prolonging survival.

Somatostatin and Its Receptor System in Colorectal Cancer

Somatostatin (SST)/somatotropin release-inhibiting factor (SRIF) is a well-known neuropeptide, widely distributed in the central and peripheral nervous systems, that regulates the endocrine system and affects neurotransmission via interaction with five SST receptors (SST1-5). In the gastrointestinal tract, the main SST-producing cells include intestinal enteroendocrine cells (EECs) restricted to the mucosa, and neurons of the submucosal and myenteric plexuses. The action of the SRIF system is based on the inhibition of endocrine and exocrine secretion, as well as the proliferative responses of target cells. The SST1–5 share common signaling pathways, and are not only widely expressed on normal tissues, but also frequently overexpressed by several tumors, particularly neuroendocrine neoplasms (NENs). Furthermore, the SRIF system represents the only peptide/G protein-coupled receptor (GPCR) system with multiple approved clinical applications for the diagnosis and treatment of several NENs. The role of the SRIF system in the histogenesis of colorectal cancer (CRC) subtypes (e.g., adenocarcinoma and signet ring-cell carcinoma), as well as diagnosis and prognosis of mixed adenoneuroendocrine carcinoma (MANEC) and pure adenocarcinoma, is poorly understood. Moreover, the impact of the SRIF system signaling on CRC cell proliferation and its potential role in the progression of this cancer remains unknown. Therefore, this review summarizes the recent collective knowledge and understanding of the clinical significance of the SRIF system signaling in CRC, aiming to evaluate the potential role of its components in CRC histogenesis, diagnosis, and potential therapy.