[Current WHO classification (2022) of neuroendocrine neoplasms]

CLINICAL ISSUE

After the first description of the "carcinoid tumors" by the pathologist Siegfried Oberndorfer in Munich, the classification system of neuroendocrine neoplasms (NENs) is still a challenge and an evolving concept.

METHODICAL INNOVATIONS

The new WHO classification system proposed a framework for universal classification.

ACHIEVEMENTS

The new WHO classification system recognizes two distinct families distinguished by genetic, morphology and clinical behaviour: Well differentiated NENs are defined as neuroendocrine tumor (NET G1, G2, G3), while poorly differentiated ones are defined as neuroendocrine carcinoma (NEC, G3) and further subdivided into small and large cell carcinoma. All NENs are characterized by the expression of synaptophysin and chromogranin A, Ki-67 and morphology.

MOLECULAR PATHOLOGY

The morphological NEN dichotomy is supported by genetic alterations. NECs show TP53 and RB1 alterations that are absent in NETs and are therefore useful for differentiating between NETs and NECs.

PRACTICAL RECOMMENDATIONS

All NENs are divided into well-differentiated neuroendocrine tumor (NET G1, G2, G3) or poorly differentiated neuroendocrine carcinoma (NEC, G3). They are categorized by morphology, mitotic count and immunohistochemistry with synaptophysin, chromogranin and Ki-67.

Treatment of poorly differentiated neuroendocrine carcinomas of rectum and anus with chemoradiotherapy: a single-centre evaluation

PURPOSE

Poorly differentiated neuroendocrine carcinoma (PDNEC) of the rectum and anus is a rare disease exhibiting aggressive biological behaviour, even if diagnosed early. Currently, there are no agreed standard treatment approaches and management of locally advanced (LA) and metastatic PDNEC usually follows treatments used in pulmonary neuroendocrine carcinomas because of the similarities with small cell lung cancer. The role of surgery in PDNEC is still debated and the benefit of chemoradiotherapy (CRT) is unknown. This report summarises the experiences of CRT application in anorectal PDNEC in a single Danish institution.

METHODS

All patients with PDNEC treated with concomitant CRT between May 2019 and January 2021 at a University hospital in Denmark were evaluated. Demographics, treatment and survival outcomes were collected and analysed.

RESULTS

Six patients were identified. Five patients received radiotherapy with 50.4 Gy/28 fractions, and four were eligible for curative resection after the CRT. Distant metastasis was observed in four patients at diagnosis. Two patients with synchronous liver metastases were treated with RFA, and one received a liver resection. The treatment was well tolerated with limited side effects. The median follow-up time was 17 months (range 10-36 months), and the median duration of response was 11.2 months (range 8.1 to 24.2 months). One patient achieved a complete response.

CONCLUSION

A multimodal treatment approach with CRT in advanced stages of PDNEC in a highly selected patient group is well tolerated and with a high chance of achieving local control and, combined with surgery, even complete response in a single case.

Exploring the molecular features and genetic prognostic factors of pulmonary high-grade neuroendocrine carcinomas

Molecular research on large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung cancer (SCLC) has progressed significantly. However, there are still fewer molecular markers related to prognostic/therapeutic strategies for these conditions compared to those for adenocarcinoma. We therefore investigated the molecular characteristics of neuroendocrine carcinomas (NECs). We enrolled patients surgically diagnosed with NECs between 2011 and 2019, with complete follow-up records. All were analyzed using whole exome sequencing and p53/Rb immunohistochemistry (IHC). A total of 92 cases, comprising 45 pure SCLC, 15 combined SCLC, 27 pure LCNEC, and 5 combined LCNEC, were included. TP53 (78.3%) and RB1 (34.8%) were the most common molecular alterations, followed by KMT2D, LRP1B, FAT3, NCOR2, SPTA1, and NOTCH1. The mutation frequency for EGFR was 10.9%. Sixteen patients with LCNEC who had TP53/RB1 co-alterations were SCLC-like, while the remaining were NSCLC-like. There was no statistically significant difference between the groups regarding overall survival (OS; p = 0.458) and progression-free survival (PFS; p = 0.157). The frequency of the loss of Rb expression by IHC in SCLC-like LCNEC was 100%. Significant pathway alterations unique to SCLC included Notch and AMPK, while HIF-1 was enriched exclusively in LCNEC. NCOR2 mutation was linked to worse OS (p = 0.029) and PFS (p = 0.015), while wild-type SPTA1 was associated with poor PFS (p = 0.018). IHC for Rb was reliable for predicting LCNEC molecular subtypes, indicating its clinical value. NCOR2 and SPTA1 alterations were identified as prognostic factors that may provide therapeutic targets for patients with NEC.

Advances in the Treatment of Gastroenteropancreatic Neuroendocrine Carcinomas: are we moving forward?

Poorly differentiated gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs) are aggressive neoplasms of challenging clinical management. A small proportion of patients with early-stage disease may achieve long-term survival, but the majority of patients present with rapidly lethal metastatic disease. Current standard of care still follows the treatment paradigm of small-cell lung cancer (SCLC), a far more common G3 NEN, although emerging molecular and clinical data increasingly question this approach. In this manuscript we will briefly summarize epidemiology and prognosis of GEP NECs to emphasize the very low incidence, aggressive nature and orphan status of this tumor entity. We will also discuss the current pathological classification and its limitations, as well as recent data on their differential biological background as compared to SCLC, and its potential implications for patients care. Then, we will review the standard of care of systemic therapy, basically focused on platinum-based cytotoxic chemotherapy, including some recent randomized trials providing evidence regarding efficacy of irinotecan vs etoposide platinum-doublets. Finally, we will present a comprehensive overview of novel therapeutic strategies in current clinical development, including recently reported data on immunotherapy, tumor-agnostic therapies (microsatellite instability, high tumor mutational burden, NTRK and RET gene fusions, BRAF or KRAS inhibitors) and additional treatment strategies targeting other tumor vulnerabilities (i.e. Notch pathway, novel targets for radioligand therapy), and provide some insights regarding unmet needs and future perspectives to improve patient's care and prognosis.

Primary Hepatic Neuroendocrine Carcinoma with Metastasis to the Mesentery: A Case Report

Primary hepatic neuroendocrine carcinomas (PHNECs) are extremely rare, with only about 90 cases having been reported in the English-language literature. Among all neuroendocrine neoplasms, primary hepatic neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs) are extremely rare, accounting for 0.3% of NETs and 0.28-0.46% of malignant liver tumors. Additionally, primary hepatic NECs occur infrequently. The clinical diagnosis of primary hepatic NEC remains challenging because of its rarity and the lack of information about its characteristic appearance on images. Consequently, pathological examination through the performance of a preoperative liver tumor biopsy is essential for diagnosis. Due to the lack of availability of substantial high-quality data, there is no standard therapy for primary hepatic NEC. We present the first case of PHNEC metastasized to the mesentery reported in the English-language literature.

Genomic characterization reveals distinct mutation landscapes and therapeutic implications in neuroendocrine carcinomas of the gastrointestinal tract

BACKGROUND

Neuroendocrine carcinomas of the gastrointestinal tract (GI-NECs) remain a disease of grim prognosis with limited therapeutic options. Their molecular characteristics are still undefined. This study aimed to explore the underlying genetic basis and heterogeneity of GI-NECs.

METHODS

Comprehensive genomic analysis using whole-exome sequencing was performed on 143 formalin-fixed, paraffin-embedded samples of surgically resected GI-NEC with a thorough histological evaluation. Mutational signatures, somatic mutations, and copy number aberrations were analyzed and compared across anatomic locations and histological subtypes. Survival analysis was conducted to identify the independent factors.

RESULTS

In total, 143 GI-NECs were examined: the stomach, 87 cases (60.8%); the esophagus, 29 cases (20.3%); the colorectum, 20 cases (14.0%); and the small intestine, 7 cases (4.9%). Eighty-three (58.0%) and 60 (42.0%) cases were subclassified into small cell and large cell subtypes, respectively. GI-NECs showed distinct genetic alterations from their lung counterparts and non-neuroendocrine carcinomas in the same locations. Obvious heterogeneity of mutational signatures, somatic mutations, and copy number variations was revealed across anatomic locations rather than histological subtypes. Except for tumor protein p53 (TP53) and retinoblastoma 1 (RB1), the most frequently mutated genes in the stomach, esophagus, colorectum, and small intestine were low-density lipoprotein receptor-related protein 1B (LRP1B), notch receptor 1 (NOTCH1), adenomatosis polyposis coli (APC), catenin beta 1 (CTNNB1), respectively. Mutations in the WNT-β-catenin, NOTCH and erythroblastic leukemia viral oncogene B (ERBB) pathways were prevalently identified in gastric, esophageal, and colorectal NECs, respectively. Importantly, 104 (72.7%) GI-NECs harbored putative clinically relevant alterations, and non-gastric location and RB1 bi-allelic inactivation with copy number alterations were identified as two independent poor prognostic factors. Furthermore, we found that tumor cells in GI-NECs first gain clonal mutations in TP53, RB1, NOTCH1 and APC, followed by subsequent whole-genome doubling (WGD) and post-WGD clonal mutations in LRP1B, CUB and Sushi multiple domains 3 (CSMD3), FAT tumor suppressor homolog 4 (FAT4) and erb-b2 receptor tyrosine kinase 4 (ERBB4), and finally develop subclonal mutations.

CONCLUSIONS

GI-NECs harbor distinct genomic landscapes and demonstrate significant genetic heterogeneity across different anatomic locations. Moreover, potentially actionable alterations and prognostic factors were revealed for GI-NECs.

Primary Neuroendocrine Carcinoma of the Larynx: A Case Report

Neuroendocrine tumours can originate from any part of the body. The most common site in the head and neck is the larynx, accounts for less than 0.6%. The neuroendocrine carcinomas (NECs) of the larynx are rare tumours with high incidence of widespread metastases and poor prognosis. Here we report a 50-year-old male with localised primary moderately differentiated NEC of the larynx. He was treated with surgery followed by adjuvant chemotherapy and concurrent chemoradiation. He is free of his disease and is doing well.

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

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

Neuroendocrine neoplasms of the gallbladder: early detection and surgery is key to improved outcome

PURPOSE

Neuroendocrine neoplasms (NENs) of the gallbladder are very rare. As a result, the classification of pathologic specimens from gallbladder NENs, currently classified as gallbladder neuroendocrine tumors (GB-NETs) and carcinomas (GB-NECs), is inconsistent and makes nomenclature, classification, and management difficult. Our study aims to evaluate the epidemiological trend, tumor biology, and outcomes of GB-NET and GB-NEC over the last 5 decades.

METHODS

This is a retrospective analysis of the SEER database from 1973 to 2016. The epidemiological trend was analyzed using the age-adjusted Joinpoint regression analysis. Survival was assessed with Kaplan-Meier analysis and Cox regression was used to assess predictors of poor survival.

RESULTS

A total of 482 patients with GB-NEN were identified. Mean age at diagnosis was 65.2 ± 14.3 years. Females outnumbered males (65.6% vs. 34.4%). The Joinpoint nationwide trend analysis showed a 7% increase per year from 1973 to 2016. The mean survival time after diagnosis of GB-NEN was 37.11 ± 55.3 months. The most common pattern of nodal distribution was N0 (50.2%) followed by N1 (30.9%) and N2 (19.2%). Advanced tumor spread (into the liver, regional, and distant metastasis) was seen in 60.3% of patients. Patients who underwent surgery had a significant survival advantage (111.0 ± 8.3 vs. 8.3 ± 1.2 months, p < 0.01). Cox regression analysis showed advanced age (p < 0.01), tumor stage (P < 0.01), tumor extension (p < 0.01), and histopathologic grade (p < 0.01) were associated with higher mortality.

CONCLUSION

Gallbladder NENs are a rare histopathological variant of gallbladder cancer that is showing a rising incidence in the USA. In addition to tumor staging, surgical resection significantly impacts patient survival, when patients are able to undergo surgery irrespective of tumor staging. Advanced age, tumor extension, and histopathological grade of the tumor were associated with higher mortality.

Poorer prognosis for neuroendocrine carcinoma than signet ring cell cancer of the colon and rectum (CRC-NEC): a propensity score matching analysis of patients from the Surveillance, Epidemiology, and End Results (SEER) database

PURPOSE

Colorectal neuroendocrine carcinomas (CRC-NECs) are rare, comprising < 1% of colorectal cancers. This study aimed to assess the incidence, clinicopathologic characteristics, prognostic factors, and treatment outcomes of CRC-NEC.

METHODS

We analysed the Surveillance, Epidemiology, and End Results (SEER) database to identify patients from 20 to 74 years old diagnosed with CRC-NEC or common CRC (non-NEC) during 2004-2013. Log-rank testing was conducted to assess survival differences. A competing-risks regression model was used to adjust for covariate effects in the propensity score-matched (PSM) cohort, and adjusted hazard ratios (HRs) were calculated for the raw and PSM cohorts.

RESULTS

We identified 67,484 patients (344 CRC-NEC and 67,140 non-NEC). Lymph node metastasis (LNM) was more common in CRC-NEC (75.29%, n = 259) than in non-NEC (51.53%, n = 34,600) (P < 0.001); 56.40% (n = 194) of CRC-NECs were located on the right side, while 18.31% (n = 63) were located on the left side, with a statistically significant difference in distribution (P < 0.001) compared to that in non-NEC CRC. Multivariate analysis indicated that a left-side location was an independent adverse prognostic factor for CRC-NEC (P = 0.043). CRC-NEC had the poorest cancer-specific survival (median CSS, 9.0 months) among assessed cancers, even poorer than that of signet ring cell cancer (median CSS, 24.0 months). However, both radical operation (P = 0.007) and chemotherapy (P = 0.008) were beneficial for CSS.

CONCLUSION

NEC is a rare and extremely aggressive tumour with a poor prognosis. Right-side NEC has a better prognosis than left-side NEC. Early diagnosis, radical surgery, and chemotherapy are imperative for improving survival.

Targeting Galectin-1 by Aflibercept Strongly Enhances Its Antitumor Effect in Neuroendocrine Carcinomas

BACKGROUND

Galectin-1 (Gal-1) plays major roles in cancer by modulating different processes leading to tumor development and progression. In the last years, it has been suggested as a promising target for anticancer therapy. Recently, aflibercept has shown high affinity for Gal-1. Here, we investigated how aflibercept could exert its antitumor activity via Gal-1-driven pathways in neuroendocrine carcinomas (NECs).

METHODS AND RESULTS

NEC tumor xenografts were used to assess the effect of aflibercept on Gal-1 functions. Aflibercept induced a significant reduction of Gal-1 at epithelial, stromal, and extracellular localizations in lung NEC, whereas this was not observed in colon NECs, which displayed low expression of Gal-1. Additionally, aflibercept significantly reduced p-VEGFR2 protein, extracellular matrix remodeling, epithelial-mesenchymal transition, and activation of cancer-associated fibroblast hampering cell invasion in lung NEC but not in colon NEC. Gal-1 screening in human NECs confirmed that pulmonary and pancreatic tumors displayed higher levels of Gal-1 than colon NECs, becoming good candidates to benefit from aflibercept treatment.

CONCLUSIONS

The lack of validated predictive markers of aflibercept is a weakness for guaranteeing the best treatment management with this drug. This work provides new mechanistic insight of aflibercept depending on Gal-1. Thus, in tumors overexpressing Gal-1, aflibercept has not only an antiangiogenic effect but also prevents Gal-1-mediated tumor-stroma cross talk. The stronger aflibercept effect in tumors with high levels of Gal-1 points out this protein as a molecular marker to predict the efficacy of this agent not only for NECs but also for other tumors with high levels of this protein.

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.

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.

Strong Antitumor Activity of Bevacizumab and Aflibercept in Neuroendocrine Carcinomas: In-Depth Preclinical Study

BACKGROUND

Neuroendocrine carcinoma (NEC) is a rare and very aggressive tumor. It has been greatly understudied, and very little is known about optimal treatment strategy for patients with this disease. The purpose of this study was to evaluate in vivo whether anti-vascular endothelial growth factor (VEGF) drugs could be a therapeutic alternative for these tumors with a poor prognosis.

METHODS

We have developed 2 xenograft models using either human cell line derived from lung (H460) or from colon (COLO320) NEC to assess the effect of 2 antiangiogenic drugs, aflibercept and bevacizumab, on tumor growth and their pathological characteristics. Additionally, tumors were subjected to immunohistochemistry staining and proteins were measured with Western blot and ELISA.

RESULTS

Both aflibercept and bevacizumab showed significant antitumor activity (p < 0.001). In the H460 model, aflibercept resulted in 94% tumor growth inhibition (TGI) and bevacizumab treatment resulted in 72.2% TGI. Similarly, in the COLO320 model, aflibercept and bevacizumab resulted in 89.3 and 84% TGI, respectively. Moreover, antitumor activity occurs early after treatment initiation. Using Tumor Control Index score, which address the kinetics of tumor growth in a way comparable to the methods used in human clinical studies, we confirmed that both drugs inhibit significantly tumor growth. When tumor stabilization was evaluated, aflibercept shows higher ability to stabilize NEC tumors than bevacizumab.

CONCLUSION

Results derived from this study strongly support anti-VEGF therapies, especially aflibercept, as a novel therapeutic option in NECs. Further studies are necessary, but our observations encourage the evaluation of antiangiogenics in clinical trials combined with standard chemotherapy.

Chemotherapy in Resected Neuroendocrine Carcinomas of the Digestive Tract: A National Study from the French Group of Endocrine Tumours

BACKGROUND

Neuroendocrine carcinomas (NECs) of the digestive tract are rare and aggressive tumours. In localised disease the treatment is surgery. Based on expert consensus, international guidelines recommend the administration of adjuvant chemotherapy combining etoposide and platinum derivatives, justified by the high risk of metastatic relapse. However, no clinical study has proven the benefit of neoadjuvant or adjuvant chemotherapy.

OBJECTIVES

We aimed to evaluate the effect of neoadjuvant +/- adjuvant and adjuvant therapy in this indication.

METHODS

We performed a retrospective observational French study to evaluate overall survival (OS) and disease-free survival (DFS), prognostic factors for survival, and chemotherapy toxicity.

RESULTS

Seventy-three patients had surgical resection of a localised digestive NEC between January 1, 2000 and December 31, 2016. The majority of patients presented colorectal (35%) tumours and the median Ki-67 value was 70%. Forty-three patients received chemotherapy, either perioperative (neoadjuvant +/- adjuvant) or adjuvant. The median OS and DFS for the whole population was 24 and 9 months, respectively. The median OS and DFS for patients receiving chemotherapy was 62 and 13 months, respectively. Positive postoperative node status and Ki-67 ≥80% had a negative prognostic impact on OS and DFS. Administration of chemotherapy had a positive prognostic impact on OS and DFS. Sixteen grade 3/4 toxicities were reported without toxic death.

CONCLUSIONS

Our results suggest a positive effect on survival of chemotherapy in resected digestive NECs, but further studies are needed to confirm these results.

[Neuroendocrine neoplasms : Two families with distinct features unified in one classification (German version)]

All neuroendocrine neoplasms (NENs) are characterized by the expression of synaptophysin and chromogranin A (or B). Yet, they are not a homogeneous group of tumors. Paradigmatic for these tumors are the NENs of the gastroenteropancreatic (GEP) system. Two NEN families can be distinguished: predominantly well differentiated and low-proliferative NENs, called neuroendocrine tumors (NET), and poorly differentiated and high-proliferative NENs, called neuroendocrine carcinomas (NECs). Based on their proliferative activity, GEP NETs are further classified into G1, G2, and G3 tumors. NECs are per definition G3 carcinomas. The morphological NEN dichotomy is supported by differences in epidemiology, genetics, clinics, and prognosis, and potentially has its cause originating from different progenitor cells. Genetically, NECs are distinguished by TP53 and RB1 alterations, which are lacking in NETs and are helpful in the distinction of NETs from NECs. Comparison of the GEP NEN WHO classification with extragastroenteropancreatic NEN classifications commonly reveal differences in terminology and categorization. In addition, they lack a grading system. However, common to all NEN classifications is the recognition of two tumor families differing in histological differentiation and prognosis. This allows the construction of a uniform classification frame for all NENs.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: What is New in the 2017 WHO Blue Book for Tumours of the Hypopharynx, Larynx, Trachea and Parapharyngeal Space

Chapter 3 "Tumours of the hypopharynx, larynx, trachea, and parapharyngeal space" of the World Health Organization (WHO) Blue Book 2017 "Classification of Head and Neck Tumours" shows a shortened list of entities, especially due to reducing the number of benign and malignant soft tissue tumours, malignant melanoma and some others, which are transferred to more frequently affected regions of the head and neck. The basic concept of the new edition is to assimilate all advances concerning the discussed tumours in a shorter framework, appropriate for daily work. The main emphasis is on the most frequent lesions and tumors originating from the covering squamous epithelium. Laryngeal and hypopharyngeal conventional squamous cell carcinoma (CSCC), its variants and precursor lesions, occupy a major part of the chapter. New data on etiopathogenesis, with the focus on human papillomavirus (HPV) infection, are discussed in relation to the entities of the squamous epithelium. Although only a small fraction of these lesions are HPV-related, further studies are required for evaluation of the potential prognostic and therapeutic benefit of mRNA HPV determination. In contrast to earlier data, laryngeal and hypopharyngeal verrucous SCC, spindle cell SCC and basaloid SCC are not anymore considered as HPV-related tumours. New data on the pathogenesis of spindle cell SCC exhibiting divergent differentiation by epithelial-mesenchymal transition, are also briefly discussed. The most important innovation is brought by the section on precursor lesions, in which a unified two-tier classification, consisting of low- and high-grade dysplasia, is introduced. The proposed two-tier system can also be transformed into a three-tier classification for treatment purposes, with a distinction between carcinoma in situ and high-grade dysplasia. The reviewed morphological criteria of the proposed system are based on the amended Ljubljana classification. The section on laryngeal neuroendocrine carcinomas (NEC) represents a considerable improvement in terminology and classification. NEC are divided into well-, moderate- and poorly-differentiated neuroendocrine carcinoma. The latter is additionally divided into small cell NEC and large cell NEC (LCNEC). It is of extreme importance that LCNEC, which was associated in the WHO 2005 edition with atypical carcinoid/moderately differentiated neuroendocrine carcinoma, grade II, has now been transferred into the group of poorly differentiated NEC, grade III, displaying a specific morphology and poorer prognosis.

A Case of Poorly Differentiated Large-Cell Neuroendocrine Carcinoma of the Cecum: A Rare Malignancy, with Review of the Literature

Poorly differentiated neuroendocrine carcinomas (NECs) are rare tumors that can arise anywhere along the gastrointestinal tract. They often present in advanced stage and portend a poor prognosis when compared to adenocarcinomas of the same stage. Characterization of these tumors is best accomplished with tissue biopsy, as peripheral tumor markers commonly used in NECs are of little utility. Therapeutic strategies often involve chemotherapeutic regimens that have been used to treat small-cell lung cancer. Recent studies have shown that programmed death-ligand 1 (PD-L1) expression within poorly differentiated NECs is a poor prognostic indicator. However, PD-L1 expression may represent a possible target for immunotherapy drugs, often called checkpoint inhibitors, such as anti-PD-1 inhibitors.

Management of neuroendocrine carcinomas of the pancreas (WHO G3): A tailored approach between proliferation and morphology

Neuroendocrine carcinomas (NEC) of the pancreas are defined by a mitotic count > 20 mitoses/10 high power fields and/or Ki67 index > 20%, and included all the tumors previously classified as poorly differentiated endocrine carcinomas. These latter are aggressive malignancies with a high propensity for distant metastases and poor prognosis, and they can be further divided into small- and large-cell subtypes. However in the NEC category are included also neuroendocrine tumors with a well differentiated morphology but ki67 index > 20%. This category is associated with better prognosis and does not significantly respond to cisplatin-based chemotherapy, which represents the gold standard therapeutic approach for poorly differentiated NEC. In this review, the differences between well differentiated and poorly differentiated NEC are discussed considering both pathology, imaging features, treatment and prognostic implications. Diagnostic and therapeutic flowcharts are proposed. The need for a revision of current classification system is stressed being well differentiated NEC a more indolent disease compared to poorly differentiated tumors.

From Mice to Men and Back: An Assessment of Preclinical Model Systems for the Study of Lung Cancers

INTRODUCTION

Studies of preclinical models are essential for determining the biology of lung cancers and testing new and novel therapeutic approaches. We review the commonly used preclinical models for lung cancers and evaluate their strengths and weaknesses.

METHODS

We searched the MEDLINE database via PubMed using combinations of the following medical subject headings: lung cancer; animal models, mice; cell line, tumor; cell culture, mice; transgenic, mice; SCID, transplantation; heterologous; and genetic engineering. We reviewed the relevant published articles.

RESULTS

Multiple examples of the three major preclinical models-tumor cell lines, patient-derived xenografts, and genetically engineered mouse models-exist and have been used by investigators worldwide, with more than 15,000 relevant publications. Each model has its strengths and actual or potential weaknesses. In addition, newer forms of these models have been proposed or are in use as potential improvements over the conventional models.

CONCLUSIONS

A large number and variety of models have been developed and extensively used for the study of all major types of lung cancer. While they remain the cornerstone of preclinical studies, each model has its individual strengths and weaknesses. These must be carefully evaluated and applied to the proposed studies to obtain the maximum usefulness from the models.

CT and MR findings in 16 cases of primary neuroendocrine carcinoma in the otolaryngeal region

Primary neuroendocrine carcinoma (NEC) is a rare malignancy in the otolaryngeal region. Computed tomography and magnetic resonance imaging findings in 16 patients with primary otolaryngeal NECs were summarized. Most of tumors occurred in the sinonasal cavity (n=9; 56.3%), then supraglottis (n=3; 18.8%). All sinonasal and one hard palate tumors were ill defined, and the other tumors were well defined. All lesions showed moderate to marked enhancement, but homogeneously in well-differentiated tumors while heterogeneously in most of poorly differentiated tumors. Most sinonasal tumors were poorly differentiated and invaded adjacent bones. Primary otolaryngeal NECs might have some distinct features related to their origin and differentiation.

Appropriateness of systemic treatments in unresectable metastatic well-differentiated pancreatic neuroendocrine tumors

AIM: To evaluate systemic treatment choices in unresectable metastatic well-differentiated pancreatic neuroendocrine tumors (PNETs) and provide consensus treatment recommendations.

METHODS: Systemic treatment options for pancreatic neuroendocrine tumors have expanded in recent years to include somatostatin analogs, angiogenesis inhibitors, inhibitors of mammalian target of rapamycin and cytotoxic agents. At this time, there is little data to guide treatment selection and sequence. We therefore assembled a panel of expert physicians to evaluate systemic treatment choices and provide consensus treatment recommendations. Treatment appropriateness ratings were collected using the RAND/UCLA modified Delphi process. After studying the literature, a multidisciplinary panel of 10 physicians assessed the appropriateness of various medical treatment scenarios on a 1-9 scale. Ratings were done both before and after an extended discussion of the evidence. Quantitative measurements of agreement were made and consensus statements developed from the second round ratings.

RESULTS: Specialties represented were medical and surgical oncology, interventional radiology, and gastroenterology. Panelists had practiced for a mean of 15.5 years (range: 6-33). Among 202 rated scenarios, disagreement decreased from 13.2% (26 scenarios) before the face-to-face discussion of evidence to 1% (2) after. In the final ratings, 46.5% (94 scenarios) were rated inappropriate, 21.8% (44) were uncertain, and 30.7% (62) were appropriate. Consensus statements from the scenarios included: (1) it is appropriate to use somatostatin analogs as first line therapy in patients with hormonally functional tumors and may be appropriate in patients who are asymptomatic; (2) it is appropriate to use everolimus, sunitinib, or cytotoxic chemotherapy therapy as first line therapy in patients with symptomatic or progressive tumors; and (3) beyond first line, these same agents can be used. In patients with uncontrolled secretory symptoms, octreotide LAR doses can be titrated up to 60 mg every 4 wk or up to 40 mg every 3 or 4 wk.

CONCLUSION: Using the Delphi process allowed physician experts to systematically obtain a consensus on the appropriateness of a variety of medical therapies in patients with PNETs.

Long term outcomes of neuroendocrine carcinomas (high-grade neuroendocrine tumors) of the colon, rectum, and anal canal. J Visc Surg. 2014;151:3-7. [PMID: 24412088 DOI: 10.1016/j.jviscsurg.2013.12.007]

INTRODUCTION AND AIM

Neuroendocrine carcinomas (NEC) of the large intestine are rare and aggressive neoplasms. This study was designed to review the experience at a single institution and analyze the outcomes to improve our understanding of these tumors.

METHODS

The patients with NEC (high-grade neuroendocrine tumor) of the colon, rectum, and anal canal were identified from June 1993 to April 2011. Clinical features studied were patient demographics, presenting symptoms, tumor location, tumor stage, treatment status and length of follow-up.

RESULTS

Twenty-five patients were identified. Stages of the diseases were I (n=5), II (n=1), III (n=10) and IV (n=9). Locations of the tumors were: colon (36%); rectum (28%) and anal canal (36%). Rectal bleeding (36%) and pain (32%) were the most common symptoms but 16% of patients were asymptomatic. Among the patients with local or locally advanced disease, only five patients had surgery alone. The remainder of the patients underwent chemotherapy with/without radiation. Mean follow-up was 33.7 ± 8.4 months after diagnosis. NEC of the large bowel and anal canal has very distinctive pathologic features and a very poor prognosis. More than one third of the patients with NEC had metastatic disease at the time of diagnosis. When these tumors are in an advanced stage none of the treatment modalities impact on survival.

CONCLUSION

The present study showed the poor prognosis of these rare tumors.

Long term outcomes of neuroendocrine carcinomas (high-grade neuroendocrine tumors) of the colon, rectum, and anal canal

INTRODUCTION AND AIM

Neuroendocrine carcinomas (NEC) of the large intestine are rare and aggressive neoplasms. This study was designed to review the experience at a single institution and analyze the outcomes to improve our understanding of these tumors.

METHODS

The patients with NEC (high-grade neuroendocrine tumor) of the colon, rectum, and anal canal were identified from June 1993 to April 2011. Clinical features studied were patient demographics, presenting symptoms, tumor location, tumor stage, treatment status and length of follow-up.

RESULTS

Twenty-five patients were identified. Stages of the diseases were I (n=5), II (n=1), III (n=10) and IV (n=9). Locations of the tumors were: colon (36%); rectum (28%) and anal canal (36%). Rectal bleeding (36%) and pain (32%) were the most common symptoms but 16% of patients were asymptomatic. Among the patients with local or locally advanced disease, only five patients had surgery alone. The remainder of the patients underwent chemotherapy with/without radiation. Mean follow-up was 33.7 ± 8.4 months after diagnosis. NEC of the large bowel and anal canal has very distinctive pathologic features and a very poor prognosis. More than one third of the patients with NEC had metastatic disease at the time of diagnosis. When these tumors are in an advanced stage none of the treatment modalities impact on survival.

CONCLUSION

The present study showed the poor prognosis of these rare tumors.