Nothing But NET: A Review of Neuroendocrine Tumors and Carcinomas

Caracterización de pacientes con tumores neuroendocrinos en un hospital de referencia de alta complejidad

Introducción. Los tumores neuroendocrinos comprenden una amplia familia tumoral, siendo de mayor frecuencia aquellos localizados en el tracto gastrointestinal, los pulmones, el timo y el páncreas. Ocurren con poca frecuencia y cursan con un comportamiento biológico variable. El objetivo del presente estudio fue describir las características demográficas y clínicas de los pacientes con esta entidad en un hospital de alta complejidad. Métodos. Estudio descriptivo con revisión de historias clínicas correspondientes a pacientes con tumor neuroendocrino, cuya muestra histológica fue analizada en el Departamento de Patología del Hospital Pablo Tobón Uribe, Medellín, Colombia, entre 2010 y 2015. Se describen frecuencias de localización, grado de diferenciación y perfil de inmuno-histoquímica. Resultados. Se revisaron 111 historias, de las que el 51,5 % correspondió a pacientes masculinos, con una mediana de edad al momento del diagnóstico de 48 años. Las comorbilidades más frecuentes fueron: hipertensión arterial (38,6 %), hipotiroidismo (15,8 %) y diabetes mellitus (11,9 %). El antecedente de neoplasia estuvo presente en el 13,9 % de los casos. Un 59,4 % de las muestras correspondieron a tumores primarios, el 34,8 % estaban localizados en el páncreas. El hígado fue el órgano más comprometido por metástasis (73,3 %). De los tumores neuroendocrinos, el 27 % correspondió a tumores grado 1 del tracto gastrointestinal o del páncreas, el 36 % a grado 2 y el 27,9 % a grado 3. El 3,6 % correspondió a tumores pulmonares de grado bajo o intermedio y el 5,4 % a tumores pulmonares de alto grado. Los marcadores tumorales con mayor positividad fueron sinaptofisina (97,2 %), citoqueratinas AE1/AE3 (95 %), CD56 (91,3%) y cromogranina (87,8%). Discusión. Los tumores neuroendocrinos tienen características clínicas e histopatológicas diversas. Conocer las características de los pacientes afectados permite una aproximación de la epidemiología local aplicable a futuras investigaciones.  

Duodenal perforation as presentation of gastric neuroendocrine tumour: A case report

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Gastric neuroendocrine neoplasms (g-NENs) represent the most frequent digestive NENs and are increasingly recognized thanks to diffusion of upper gastrointestinal endoscopy.

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g-NENs can be sporadic or associated with multiple endocrine neoplasia type 1 (MEN-1) and present with a functional Zollinger-Ellison syndrome.

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We described a case of a 60 years old Caucasian male came to emergency room with diffuse abdominal pain and leukocytosis on blood tests.

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At the level of the pyloric portion we found irregularly thickened walls associated with a small fluid collection and bubbles of free air. On exploratory laparoscopy we found a large perforation (about 5 cm of size) in the first duodenum portion.

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Histological examination revealed a gastric NET perforation as a consequence of hypergastrinemia secondary to gastrinoma.

Introduction

Neuroendocrine tumors (NETs) represent uncommon neoplasms with different characteristics. They can be asymptomatic and benign or they can also proliferate and manifest themselves with neoplastic mass symptoms such as intestinal occlusion or with carcinoid syndrome. Gastric neuroendocrine neoplasms (g-NENs) are the most frequent digestive NENs while duodenal neuroendocrine neoplasms (d-NENs) may be sporadic or associated with multiple endocrine neoplasia type 1 (MEN-1) and present a functional syndrome (e.g. gastrinoma with Zollinger-Ellison syndrome).

Presentation of case

We report a case of duodenal perforation due to a unknown gastrinoma responsible of Zollinger-Ellison Syndrome. He underwent an emergency contrast enhanced CT abdominal scan that showed a perforation. We performed a distal gastrectomy. The histopathological examination revealed a g-NET configuring a possible picture of Zollinger-Ellison Syndrome.

Discussion

The management of NETs is diffulcult and controversial because of their rarity. It is useful to know the pathologic assessment of tumor differentiation and/or grade, evaluate surgical resectability and control the carcinoid syndrome symptoms.

Conclusion

This case report shows that gastric NETs can be found in cases of duodenal perforation. Our future goal is to evaluate the possibilities to diagnose the Zollinger Ellison Syndrome as early as possible and to treat it with targeted therapy in order to prevent its related complications.

Two neuroendocrine G protein-coupled receptor molecules, somatostatin and melatonin: Physiology of signal transduction and therapeutic perspectives

Recent studies have shown that G protein-coupled receptors (GPCRs), the largest signal-conveying receptor family, are targets for mutations occurring frequently in different cancer types. GPCR alterations associated with cancer development represent significant challenges for the discovery and the advancement of targeted therapeutics. Among the different molecules that can activate GPCRs, we focused on two molecules that exert their biological actions regulating many typical features of tumorigenesis such as cellular proliferation, survival, and invasion: somatostatin and melatonin. The modulation of signaling pathways, that involves these two molecules, opens an interesting scenario for cancer therapy, with the opportunity to act at different molecular levels. Therefore, the aim of this review is the analysis of the biological activity and the therapeutic potential of somatostatin and melatonin, displaying a high affinity for GPCRs, that interfere with cancer development and maintenance.

PCSK2 expression in neuroendocrine tumors points to a midgut, pulmonary, or pheochromocytoma-paraganglioma origin

Neuroendocrine tumors (NETs) are often diagnosed from the metastases of an unknown primary tumor. Specific immunohistochemical (IHC) markers indicating the location of a primary tumor are needed. The proprotein convertase subtilisin/kexin type 2 (PCSK2) is found in normal neural and neuroendocrine cells, and known to express in NETs. We investigated the tissue microarray (TMA) of 86 primary tumors from 13 different organs and 9 metastatic NETs, including primary tumor‐metastasis pairs, for PCSK2 expression with polymer‐based IHC. PCSK2 was strongly positive in all small intestine and appendiceal NETs, the so‐called midgut NETs, in most pheochromocytomas and paragangliomas, and in some of the typical and atypical pulmonary carcinoid tumors. NETs showing strong positivity were re‐evaluated in larger tumor cohorts confirming the primary observation. In the metastases, the expression of PCSK2 mirrored that of the corresponding primary tumors. We found negative or weak staining in NETs from the thymus, gastric mucosa, pancreas, rectum, thyroid, and parathyroid. PCSK2 expression did not correlate with Ki‐67 in well‐differentiated NETs. Our data suggest that PCSK2 positivity can indicate the location of the primary tumor. Thus, PCSK2 could function in the IHC panel determined from screening metastatic NET biopsies of unknown primary origins.

Beyond Traditional Morphological Characterization of Lung Neuroendocrine Neoplasms: In Silico Study of Next-Generation Sequencing Mutations Analysis across the Four World Health Organization Defined Groups

Simple Summary

Lung neuroendocrine neoplasms (LNENs) classes, as proposed by the World Health Organization 2015, do not provide properly prognostic and therapeutic indications. In fact, high-throughput molecular analysis, based on next-generation sequencing, identified novel molecular subgroups, associated with different genomic signatures, that could pave the way for alternative therapeutic approaches. The present review, coupled with in silico molecular analysis, could show the current genomic alterations state in actual LNENS groups. Interestingly our manuscript suggests that the molecular novelties could improve the LNENs therapeutics efficacy. In more detail, we reported the differences of gene alterations and mutational rate between LNENS, confirming the central pathogenetic role given by a different mutational rate in chromatin remodeling genes and tumor suppressors TP53-RB1. In conclusion, our results underlined that a further molecular layer is needed to improve the efficacy of LNENs medical treatment.

Abstract

Lung neuroendocrine neoplasms (LNENs) represent a rare and heterogeneous population of lung tumors. LNENs incidence rate has increased dramatically over the past 30 years. The current World Health Organization LNENs classification (WHO 2015), distinguished four LNENs prognostic categories, according to their morphology, necrosis amount and mitotic count: typical carcinoid (TC), atypical-carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC) and small cell lung cancer (SCLC). At present, due to their rarity and biological heterogeneity there is still no consensus on the best therapeutic approach. Next-generation-sequencing analysis showed that WHO 2015 LNENs classes, could be characterized also by specific molecular alterations: frequently mutated genes involving chromatin remodeling and generally characterized by low mutational burden (MB) are frequently detected in both TC and AC; otherwise, TP53 and RB1 tumor suppressor genes alterations and high MB are usually detected in LCNEC and SCLC. We provide an overview concerning gene mutations in each WHO 2015 LNENs class in order to report the current LNENs mutational status as potential tool to better understand their clinical outcome and to drive medical treatment.

[Theranostics and hybrid imaging for somatostatin receptor-expressing tumors]

CLINICAL/METHODICAL ISSUE

Conventional imaging tests like computed tomography (CT) cannot visualize somatostatin receptor (SSTR) expression on the tumor cell surface.

STANDARD RADIOLOGICAL METHODS

For imaging of SSTR-expressing tumors conventional morphological imaging tests such as CT or magnetic resonance imaging (MRI) are employed.

METHODICAL INNOVATIONS

Molecular imaging of SSTR expression on the tumor cell surface, in particular by using (whole body) single photon emission computed tomography (SPECT) and positron emission tomography (PET), are considered the current standard of care. Only the use of CT enables for exact localization of putative sites of disease (hybrid imaging).

PERFORMANCE

Hybrid SPECT/CT and PET/CT are of utmost importance for staging and monitoring of treatment efficacy. SSTR-PET is superior to SPECT and the PET radiotracer ⁶⁸Ga-DOTATATE has been approved in multiple countries. In addition, SSTR positivity revealed by SPECT or PET pave the way for a peptide receptor radionuclide therapy (PRRT). Such a theranostic approach enables for systemic or locoregional radiation with β‑emitting radionuclides, which are linked to the identical amino acid peptide used for PET or SPECT imaging. The prospective, randomized Netter‑1 trial has shown significant benefit for patients receiving PRRT.

ACHIEVEMENTS

A combined use of conventional and functional imaging tests is superior to conventional imaging alone and allows for identification of suitable candidates for a theranostic approach.

PRACTICAL RECOMMENDATIONS

In case of clinical suspicion or after having obtained histological evidence, hybrid SSTR-SPECT/CT or -PET/CT should be performed, preferably in a dedicated molecular imaging center.

Prospective Analysis of the Impact of 68Ga-DOTATOC Positron Emission Tomography-Computerized Axial Tomography on Management of Pancreatic and Small Bowel Neuroendocrine Tumors

OBJECTIVES

A prospective clinical trial evaluated the effect of Ga-DOTATOC positron emission tomography-computerized axial tomography (PET-CT) on change in management of patients with lung, pancreatic, and small bowel neuroendocrine tumors. The primary eligibility criterion was a histologically proven tumor with positive somatostatin receptor subtype 2A immunohistochemistry. The primary and secondary end points were change in patient management and safety.

METHODS

Referring physicians completed questionnaires pre- and post-Ga-DOTATOC PET-CT, stating current and planned patient management, respectively, with tumor board adjudication of final management decisions. Change in management was categorized as follows: no change; minor change (additional imaging, supportive care); or major change (octreotide/lanreotide therapy, tumor biopsy, surgery, peptide receptor radiotherapy, chemotherapy, biological therapy, liver embolization).

RESULTS

A major change in management was recommended for 54 (47.37%) of 114 subjects and a minor change for 6 (5.26%) of 114 subjects, with no change for 54 (47.37%) of 114 subjects. Grade 1 adverse events were observed in 26 of 114 subjects (nausea, headache, back pain, diarrhea); one grade 2 (petechiae) and one grade 3 (abdominal pain) adverse event were observed. No grade 2 or 3 adverse events were related to study drug and none required intervention.

CONCLUSIONS

Imaging with Ga-DOTATOC PET-CT has a significant impact on management of patients with neuroendocrine tumors.

Effect of Octreotide Long-Acting Release on Tregs and MDSC Cells in Neuroendocrine Tumour Patients: A Pivotal Prospective Study

Octreotide long-acting repeatable (LAR) is largely used to treat functional and/or metastatic neuroendocrine neoplasms (NENs). Its effect in controlling carcinoid syndrome and partially reduce tumour burden is attributable to the ability of octreotide to bind somatostatin receptors (SSTRs) on the tumour and metastasis, regulating growth hormone secretion and cell growth. Notably, SSTRs are also expressed, at different levels, on Tregs. Tregs, together with myeloid-derived suppressor cells (MDSCs), are key components in the anti-tumour immunoregulation. This is the first prospective study aimed to explore the impact of Octreotide (OCT) LAR on the immune system, with a particular focus on Tregs and MDSC cells. Here, we show that circulating Tregs are elevated in NENs patients compared to healthy donors and that treatment with OCT LAR significantly decrease the level of total Tregs and of the three functional Tregs populations: nTregs, eTregs and non-Tregs. Furthermore, OCT LAR treatment induces a functional impairment of the remaining circulating Tregs, significantly decreasing the expression of PD1, CTLA4 and ENTPD1. A trend in circulating MDSC cells is reported in patients treated with OCT LAR. The results reported here suggest that the effect of OCT LAR on Tregs could tip the balance of the patients' immune-system towards a durable anti-tumour immunosurveillance with consequent long-term control of the NENs disease.

Gastrointestinal neuroendocrine tumors in 2020

Gastrointestinal neuroendocrine tumors are rare slow-growing tumors with distinct histological, biological, and clinical characteristics that have increased in incidence and prevalence within the last few decades. They contain chromogranin A, synaptophysin and neuron-specific enolase which are necessary for making a diagnosis of neuroendocrine tumor. Ki-67 index and mitotic index correlate with cellular proliferation. Serum chromogranin A is the most commonly used biomarker to assess the bulk of disease and monitor treatment and is raised in both functioning and non-functioning neuroendocrine tumors. Most of the gastrointestinal neuroendocrine tumors are non-functional. World Health Organization updated the classification of neuroendocrine tumors in 2017 and renamed mixed adenoneuroendocrine carcinoma into mixed neuroendocrine neoplasm. Gastric neuroendocrine tumors arise from enterochromaffin like cells. They are classified into 4 types. Only type I and type II are gastrin dependent. Small intestinal neuroendocrine tumor is the most common small bowel malignancy. More than two-third of them occur in the terminal ileum within 60 cm of ileocecal valve. Patients with small intestinal neuroendrocrine tumors frequently show clinical symptoms and develop distant metastases more often than those with neuroendocrine tumors of other organs. Duodenal and jejuno-ileal neuroendocrine tumors are distinct biologically and clinically. Carcinoid syndrome generally occurs when jejuno-ileal neuroendocrine tumors metastasize to the liver. Appendiceal neuroendocrine tumors are generally detected after appendectomy. Colonic neuroendocrine tumors generally present as a large tumor with local or distant metastasis at the time of diagnosis. Rectal neuroendocrine tumors are increasingly being diagnosed since the implementation of screening colonoscopy in 2000. Gastrointestinal neuroendocrine tumors are diagnosed and staged by endoscopy with biopsy, endoscopic ultrasound, serology of biomarkers, imaging studies and functional somatostatin scans. Various treatment options are available for curative and palliative treatment of gastrointestinal neuroendocrine tumors.

[Gastroenteropancreatic neuroendocrine neoplasms-Heterogeneity, management and perspectives of treatment and research]

The term neuroendocrine neoplasms (NEN) encompasses a molecularly and biologically very heterogeneous group of tumors, which have in common their origin in neuroendocrine cells. The also very heterogeneous subgroup of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) is the best classified and investigated group. This article provides a systematic review of the current classification, diagnostics and treatment options of GEP-NEN. In order to achieve a better overview, it was consciously decided not to use an approach based on the primary localization. Instead, a thematic organization according to classification, clinical phenotype, diagnostics and treatment was chosen.

A Rare Case of Primary Neuroendocrine Carcinomas in the Ear and Throat and Review of Literatures

The neuroendocrine carcinomas (NECs) of the head and neck are rare. The purpose of this article is to explore the diagnosis and treatment of NECs in the ear and larynx. We report a case of a patient with NECs found in the ear and throat simultaneously, and the relevant literatures are reviewed. It is difficult to identify which is the original site. There is no specific clinical manifestation of NECs in the ear and throat, and carcinoid syndrome is a rare situation. Surgery is still the preferred treatment for this disease. For patients with metastasis, radiotherapy and/or chemotherapy are required.

How I treat neuroendocrine tumours

Neuroendocrine tumours (NETs) constitute a heterogeneous group of neoplasms characterised by variable endocrine activity and somatostatin receptor expression, with the latter allowing the use of targeted therapeutic concepts. Currently accepted treatment strategies for advanced well-differentiated NET include somatostatin analogues octreotide and lanreotide, peptide receptor radionuclide therapy using radiolabelled somatostatin analogues, mammalian target of Rapamycin inhibitor everolimus, tyrosine kinase inhibitor sunitinib, interferon alpha and classical cytostatic, such as streptozotocin-based and temozolomide-based treatment. Indication, use and approval of these treatments differ based on primary tumour origin, grading and symptomatic burden and require an optimised multidisciplinary cooperation of medical oncologists, endocrinologists and nuclear medicine specialists. Interestingly, hot topics in oncology including immunotherapy and use of next-generation-sequencing techniques currently play a minor role for the treatment of NETs. The recent revision of the WHO classification including the recognition of the novel NET G3 category allows for potentially more tailored treatment strategies in the near future. However, this new entity also poses a therapeutic challenge as only limited data are currently available. The present article aims to provide an overview on our personal treatment concepts for advanced NETs with a focus on tumours of gastroenteropancreatic origin.

Pancreatic neuroendocrine tumors: Therapeutic challenges and research limitations

Pancreatic neuroendocrine tumors (PNETs) are known to be the second most common epithelial malignancy of the pancreas. PNETs can be listed among the slowest growing as well as the fastest growing human cancers. The prevalence of PNETs is deceptively low; however, its incidence has significantly increased over the past decades. According to the American Cancer Society’s estimate, about 4032 (> 7% of all pancreatic malignancies) individuals will be diagnosed with PNETs in 2020. PNETs often cause severe morbidity due to excessive secretion of hormones (such as serotonin) and/or overall tumor mass. Patients can live for many years (except for those patients with poorly differentiated G3 neuroendocrine tumors); thus, the prevalence of the tumors that is the number of patients actually dealing with the disease at any given time is fairly high because the survival is much longer than pancreatic ductal adenocarcinoma. Due to significant heterogeneity, the management of PNETs is very complex and remains an unmet clinical challenge. In terms of research studies, modest improvements have been made over the past decades in the identification of potential oncogenic drivers in order to enhance the quality of life and increase survival for this growing population of patients. Unfortunately, the majority of systematic therapies approved for the management of advanced stage PNETs lack objective response or at most result in modest benefits in survival. In this review, we aim to discuss the broad challenges associated with the management and the study of PNETs.

Patient Survey of the Physical, Emotional, and Informational Challenges for Patients Living with Neuroendocrine Tumors

Introduction

Patient surveys of disease burden on daily living rarely explore the impact that patient information sources can have on optimizing care.

Methods

To identify unmet needs/possible solutions for information and support to address the physical, emotional, and informational challenges that patients living with neuroendocrine tumors (NETs) may have, an online survey was conducted among patients recruited by the Carcinoid Cancer Foundation (US), Netzwerk Neuroendokrine Tumoren (NeT) e.V. (Germany), and Association de Patients porteurs de Tumeurs Endocrines Diverses (France); these organizations approved the survey questions.

Results

Between August 2015 and November 2015, 741 online surveys were completed in France (n  = 73), Germany (n  = 240), and the US (n = 428) during a 6-week period. Over 65% of patients were diagnosed ≤ 5 years ago. Across the three countries, multiple symptoms were experienced before diagnosis. These symptoms were consistent with those of functional tumors, most commonly diarrhea (40–47%) and flushing (12–45%). The most common emotion upon diagnosis was anxiety (20–67%). The greatest physical challenges for patients living with NETs included fatigue (26–66%), diarrhea (22–48%), pain/discomfort (13–40%), and sleep disturbance (16–35%), despite cancer management. Information sources classed as “very useful” included patient-association websites, disease awareness websites, and journals; “patients-like-me” case studies were most favored (43–67%) for future use as sources of information.

Conclusion

Patients with NETs face negative emotions and multiple physical challenges that require psychological support/coping strategies, and they seek reliable, personally relevant, easily understood information, including that from interactions with other patients.

Plain Language Summary

Plain language summary available for this article.

Electronic Supplementary Material

The online version of this article (10.1007/s40487-019-00103-2) contains supplementary material, which is available to authorized users.

Systemic Treatment Selection for Patients with Advanced Pancreatic Neuroendocrine Tumours (PanNETs)

Pancreatic neuroendocrine tumours (PanNETs) are rare diseases and a good example of how research is not only feasible, but also of crucial importance in the scenario of rare tumours. Many clinical trials have been performed over the past two decades expanding therapeutic options for patients with advanced PanNETs. Adequate management relies on optimal selection of treatment, which may be challenging for clinicians due to the fact that multiple options of therapy are currently available. A number of therapies already exist, which are supported by data from phase III studies, including somatostatin analogues and targeted therapies (sunitinib and everolimus). In addition, chemotherapy remains an option, with temozolomide and capecitabine being one of the most popular doublets to use. Peptide receptor radionuclide therapy was successfully implemented in patients with well-differentiated gastro-entero-pancreatic neuroendocrine tumours, but with certain questions waiting to be solved for the management of PanNETs. Finally, the role of immunotherapy is still poorly understood. In this review, the data supporting current systemic treatment options for locally advanced or metastatic PanNETs are summarized. Strategies for treatment selection in patients with PanNETs based on patient, disease, or drug characteristics is provided, as well as a summary of current evidence on prognostic and predictive biomarkers. Future perspectives are discussed, focusing on current and forthcoming challenges and unmet needs of patients with these rare tumours.

Goblet cell carcinoid of the rectum: a case report

BACKGROUND

Goblet cell carcinoid (GCC) is a neuroendocrine tumor usually found in the appendix. GCCs exhibit characteristic findings with mixed endocrine-exocrine features such as staining positive for neuroendocrine markers and producing mucin. The primary GCC of the rectum is exceedingly rare.

CASE PRESENTATION

A 77-year-old Japanese male presented with hematochezia. Anal tenderness and a hard mass in the anal canal were found on the digital rectal examination, and colonoscopy was performed. Colonoscopy showed an irregularly shaped mass in the anal canal. Biopsy showed mixed features including adenocarcinoma in situ, well-differentiated adenocarcinoma, and mucinous carcinoma with invasive proliferation. No metastatic lesions were found on the computed tomography scan. Pelvic magnetic resonance imaging scan showed extramural growth of a tumor on the ventral side of the rectum without invasion to the prostate. Laparoscopic abdominoperineal resection was performed. The final diagnosis was well-differentiated adenocarcinoma in the mucosa and goblet cell carcinoid from the submucosa to the adventitia of the rectum. The patient was discharged from the hospital on postoperative day 16. Six months after resection, a computed tomography scan revealed multiple metastatic lesions in the liver. Several chemotherapy regimens were given, and the patient has stable disease 27 months after surgery.

CONCLUSION

We present a patient with rectal GCC with metachronous liver metastases. Since GCC grows intramurally and is biologically aggressive compared to typical carcinoid lesions, the disease is usually diagnosed at an advanced stage. The development of optimal adjuvant chemotherapy is needed for those patients.

An Update on Gastroenteropancreatic Neuroendocrine Neoplasms: From Mysteries to Paradigm Shifts

Although neuroendocrine neoplasms (NEN) were once thought to be rare and mostly "benign" diseases, they are now being redefined in light of recently discovered molecular information. NENs constitute a spectrum of variably differentiated neoplasms, ranging from well-differentiated tumors with a protracted course over many years to very aggressive neuroendocrine carcinomas. Although the majority of NEN are non-functional lesions, some of these tumors, do produce a hormonal hypersecretion syndrome. Their reappraisal has led scientist to unveil previously unknown oncogenic pathways and connections that resulted in a new category in the International Classification of Diseases (ICD-11) and a revised version of the World Health Organization Classification (WHO 2018). Complex diseases like NEN require a multidisciplinary approach that includes the perspectives of endocrinologists, medical and surgical oncologists, radiation oncologists, imaging specialists and pathologists. There are currently virtually thousands of ongoing trials evaluating the efficacy and safety of several molecular targeted therapies. The purpose of this review was to critically evaluate recent information regarding the pathogenesis, diagnosis and treatment of NEN.

Assessment and State of Nutrition of Patients with Gastroenteropancreatic Neuroendocrine Neoplasms

Introduction: In recent decades, the number of gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) cases, associated with coexisting metabolic disorders, has been continuously increasing. Patients with progressing neoplastic disease are at a risk of malnutrition. To improve the quality of life of neuroendocrine neoplasms (NEN) patients, the therapeutic approach should be supported by a well-balanced diet. The aim of the study was to analyze the nutritional errors and deficits in a group of GEP-NET patients. Materials and methods: The study group included 26 GEP-NET patients; 13 men and 13 women. The mean age of women was 68.77 ± 8.0, and the mean age of men was 64.69 ± 8.1. Three interviews on consumption in the last 24 h were performed, in order to evaluate the quality and quantity of nutrition. The data was incorporated into a dietetics software, which allows one to calculate the number of over 58 micronutrients and macronutrients with the participation of 52 menus. Subsequently, the mean values were compared with the current nutritional standards. Results: An energy deficit was observed in the group of women—76.9%, and men—100%, as well as high fat consumption in 23.1% in both groups. The proportions of SFA/MUFA/PUFA were very negative, whereas the consumption of saccharose was too high. Vitamin D deficiency was observed in 100% of men and women. Moreover, both men and women experienced the deficiency of vitamin E, folates and niacin. The consumption of sodium and phosphorus was twice as high as recommended, and an insufficient supply of calcium was observed in 80% of women and 90% of men. The insufficient consumption of magnesium, iodine and potassium in a significant part of the studied group was observed. All participants consumed too much cholesterol and insufficient amounts of fiber. The healthy diet indicator (HDI) and diet quality index (DQI) scores were 3.1 ± 1.8 (HDI) and 3.7 ± 1.6 (DQI) for women, and 7.2 ± 2.6 (HDI) and 8.5 ± 2.4 (DQI) for men. Conclusions: When analyzing the nutrition of GEP-NET patients, we highlight that they do not have a proper diet, despite the fact that they changed the way they eat. Dietetics support and the development of official nutritional standards seem to be a necessary element in the therapy of GEP-NET patients.

Impact of Postoperative Chemotherapy on the Survival of Patients with High-Grade Gastroenteropancreatic Neuroendocrine Carcinoma

BACKGROUND

This study aimed to determine whether postoperative chemotherapy is associated with a survival benefit for patients with poorly differentiated neuroendocrine carcinoma (NEC) of the stomach, small bowel, or pancreas.

METHODS

Patients were identified in the National Cancer Database (NCDB) between 2004 and 2014. Inverse probability of treatment weighting (IPTW) was used to reduce selection bias. To compare the overall survival (OS) of patients in different treatment groups, IPTW-adjusted Kaplan-Meier curves and Cox proportional hazards models were used.

RESULTS

The inclusion criteria were met by 759 patients. The diagnosis was NEC of the stomach for 195 patients (25.7%), NEC of the small intestine for 278 patients (36.6%), and NEC of the pancreas for 286 patients (37.7%). Overall, 213 patients (28.1%) received postoperative chemotherapy after curative resection. For the patients who received chemotherapy, IPTW-adjusted survival showed no OS benefit. However, subgroup analysis demonstrated improved OS with observation (OB) for patients with NEC of the small intestine (hazard ratio [HR], 1.436; 95% confidence interval [CI] 1.13-1.823; P = 0.003), T3 or T4 primary tumor (HR, 1.258; 95% CI 1.08-1.465; P = 0.003), node-positive disease (HR, 1.238; 95% CI 1.040-1.475; P = 0.0165), or positive resection margin (HR, 1.4283; 95% CI 1.02-2.00; P = 0.038).

CONCLUSIONS

In this national database analysis, postoperative chemotherapy was not associated with improved survival for patients with poorly differentiated gastroenteropancreatic (GEP) NECs. These findings highlight the need for continued efforts to understand better which patients in this high-risk population will benefit from additional systemic therapy and the need for continued development of more effective therapies for these patients.

Tumour-to-liver ratio determined by [68Ga]Ga-DOTA-TOC PET/CT as a prognostic factor of lanreotide efficacy for patients with well-differentiated gastroenteropancreatic-neuroendocrine tumours

Abstract

Background

Lanreotide is a long-acting somatostatin analogue with proven antitumour effects against well-differentiated (WD) gastroenteropancreatic-neuroendocrine tumours (GEP-NETs). However, there are no globally established prognostic factors associated with the efficacy of lanreotide as a treatment for GEP-NETs. We investigated the prognostic value of [⁶⁸Ga]Ga-DOTA-TOC positron emission tomography (PET)/computed tomography (CT) somatostatin receptor imaging for patients with WD GEP-NETs treated with lanreotide.

Methods

In this retrospective study, we included 31 patients with unresectable or metastatic WD GEP-NETs who received lanreotide and underwent [⁶⁸Ga]Ga-DOTA-TOC PET/CT before receiving lanreotide. We captured the following clinicopathological variables: Eastern Cooperative Oncology Group (ECOG) performance status, primary tumour site, NET World Health Organization grade, existence of carcinoid symptoms, previous surgery, previous chemotherapy, and hepatic tumour volume assessed by CT or magnetic resonance imaging (MRI). We also assessed the following [⁶⁸Ga]Ga-DOTA-TOC PET/CT variables: Krenning score, tumour-to-liver ratio (TLR), maximum standardized uptake value (SUVmax), whole tumour volume (WTV), and total receptor expression (TRE, WTV multiplied by SUVmean). The associations between these markers and progression-free survival (PFS) with lanreotide were analysed.

Results

The mean age was 55.1 ± 15.5 years (range 16.0–81.0). The most common primary tumour site was the pancreas, followed by the stomach, and rectum. The median PFS interval with lanreotide was 14.4 months (range 1.3–34.9), with identified disease progression in 20 patients (64.5%). Among the [⁶⁸Ga]Ga-DOTA-TOC PET/CT variables, TLR (< 8.1 vs. ≥ 8.1; p = 0.013), SUVmax (< 42.9 vs. ≥ 42.9; p = 0.037), and WTV (≥ 58.9 cm³ vs. < 58.9 cm³; p = 0.030) were significantly associated with PFS in the univariate analyses, but only TLR (hazard ratio 3.182 [95% CI 1.189–8.514], p = 0.021) remained an independent factor for PFS in the multivariate analysis.

Conclusions

Low TLR, determined via [⁶⁸Ga]Ga-DOTA-TOC PET/CT, can be a factor of worse prognosis in patients with advanced WD GEP-NETs treated with lanreotide.

Immunotherapy of Ipilimumab and Nivolumab in Patients with Advanced Neuroendocrine Tumors: A Subgroup Analysis of the CA209-538 Clinical Trial for Rare Cancers

PURPOSE

Combination immunotherapy with anti-CTLA-4 and anti-PD-1 blockade has demonstrated significant clinical activity across several tumor types. Neuroendocrine tumors (NET) are a heterogeneous group of rare tumors with limited treatment options. CA209-538 is a clinical trial of combination immunotherapy with ipilimumab and nivolumab in rare cancers, including advanced NETs.

PATIENTS AND METHODS

CA209-538 is a prospective multicenter clinical trial in patients with advanced rare cancers. Patients received treatment with nivolumab at a dose of 3 mg/kg and ipilimumab at 1 mg/kg every three weeks for four doses, followed by nivolumab 3 mg/kg every two weeks and continued for up to 96 weeks, until disease progression or the development of unacceptable toxicity. Response was assessed every 12 weeks by RECIST 1.1. The primary endpoint was clinical benefit rate (CBR; complete remission + partial remission + stable disease).

RESULTS

Twenty-nine patients with advanced NETs received treatment. Three (10%) patients had low-, 13 (45%) had intermediate-, and 13 (45%) had high-grade tumors; lung was the most common primary site (39%). The objective response rate was 24% with a CBR of 72%; 43% of patients with pancreatic neuroendocrine neoplasms (NEN), and 33% of patients with atypical bronchial carcinoid achieved an objective response. The median progression-free survival was 4.8 months [95% confidence interval (CI): 2.7-10.5] and overall survival was 14.8 months (95% CI: 4.1-21.3). Immune-related toxicity was reported in 66% of patients with 34% experiencing grade 3/4 events.

CONCLUSIONS

Combination immunotherapy with ipilimumab and nivolumab demonstrated significant clinical activity in subgroups of patients with advanced NETs including patients with atypical bronchial carcinoid and high-grade pancreatic NENs.

p53-PHLDA3-Akt Network: The Key Regulators of Neuroendocrine Tumorigenesis

p53 is a well-known tumor suppressor gene and one of the most extensively studied genes in cancer research. p53 functions largely as a transcription factor and can trigger a variety of antiproliferative programs via induction of its target genes. We identified PHLDA3 as a p53 target gene and found that its protein product is a suppressor of pancreatic neuroendocrine tumors (PanNETs) and a repressor of Akt function. PHLDA3 is frequently inactivated by loss of heterozygosity (LOH) and methylation in human PanNETs, and LOH at the PHLDA3 gene locus correlates with PanNET progression and poor prognosis. In addition, in PHLDA3-deficient mice, pancreatic islet cells proliferate abnormally and acquire resistance to apoptosis. In this article, we briefly review the roles of p53 and Akt in human neuroendocrine tumors (NETs) and describe the relationship between the p53-PHLDA3 and Akt pathways. We also discuss the role of PHLDA3 as a tumor suppressor in various NETs and speculate on the possibility that loss of PHLDA3 function may be a useful prognostic marker for NET patients indicating particular drug therapies. These results suggest that targeting the downstream PHLDA3-Akt pathway might provide new therapies to treat NETs.

Molecular and Metabolic Imaging of Hepatic Neuroendocrine Tumors Following Radioembolization with 90Y-microspheres

Liver is the predominant site of metastatization for neuroendocrine tumors (NETs). Up to 75% of patients affected by intestinal NETs present liver metastases at diagnosis. For hepatic NET, surgery represents the most effective approach but is often unfeasible due to the massive involvement of multifocal disease. In such cases, chemotherapy, peptide receptor radionuclide therapy and loco-regional treatments may represent alternative therapeutic options. In particular, radioembolization with 90Y-microspheres has been introduced as a novel technique for treating hepatic malignant lesions, combining the principles of embolization and radiation therapy. In order to evaluate the response to 90Y-radioembolization, standard radiologic criteria have been demonstrated to present several limitations. 18Fluoro-deoxyglucose (FDG) Positron Emission Tomography (PET) is routinely used for monitoring the response to therapy in oncology. Nevertheless, NETs often present low glycolytic activity thus the conventional 18FDG PET may not be adequate for these tumors. For many years, somatostatin receptor scintigraphy (SRS) with 111In-pentetreotide has been used for diagnosis and staging of NETs. More recently, three 68Ga-DOTA-compounds have been developed and introduced for the imaging of NETs with PET technology. The aim of the present paper was to review the existing literature concerning the application of different metabolic and molecular probes for the imaging evaluation of hepatic NETs following 90Y-RE.

Pulmonary Neuroendocrine Tumor Presenting as a Left Pleural Effusion

The presence of a symptomatic and recurrent unilateral pleural effusion should alert physicians to consider thoracentesis with mindful use of biomarkers not only for therapeutic purposes, but also for diagnosis of both benign and malignant etiologies.

The Neuroendocrine Neoplasms of the Digestive Tract: Diagnosis, Treatment and Nutrition

Nuroendocrine neoplasms (NENs) are a group of rare neoplasms originating from dispersed neuroendocrine cells, mainly of the digestive and respiratory tract, showing characteristic histology and immunoprofile contributing to classification of NENs. Some NENs have the ability to produce biogenic amines and peptide hormones, which may be associated with clinical syndromes like, e.g., the carcinoid syndrome caused by unmetabolized overproduced serotonin, hypoglycemic syndrome in case of insulinoma, or Zollinger-Ellison syndrome accompanying gastrinoma. Diagnostics for these include ultrasound with endoscopic ultrasound (EUS), computed tomography (CT), magnetic resonance imaging (MRI), and positron-emission tomography/computed tomography (PET/CT). Different nuclear medicine procedures can also be used, like somatostatin analogues scintigraphy (SRS) and 68Ga-Dota-Peptide PET/CT, as well as biochemical methods to determine the level of general neuroendocrine markers, such as chromogranin A (CgA), 5-hydroxyindolacetic acid (5-HIAA), synaptopfysin and cell type-specific peptide hormones, and neurotransmitters like gastrin, insulin, serotonin, and histamine. NENs influence the whole organism by modulating metabolism. The treatment options for neuroendocrine neoplasms include surgery, somatostatin analogue therapy, radionuclide therapy, chemotherapy, molecular targeted therapies, alpha-interferon therapy, and inhibitors of serotonin production. In the case of hypersensitivity to biogenic amines, a diet that limits the main sources of amines should be used. The symptoms are usually connected with histamine, tyramine and putrescine. Exogenic sources of histamine are products that take a long time to mature and ferment. Patients with a genetic insufficiency of the diamine oxidase enzyme (DAO), and those that take medicine belonging to the group of monoamine oxidases (MAO), are particularly susceptible to the negative effects of amines. Diet plays an important role in the initiation, promotion, and progression of cancers. As a result of the illness, the consumption of some nutrients can be reduced, leading to nutritional deficiencies and resulting in malnutrition. Changes in metabolism may lead to cachexia in some patients suffering from NENs. The aim of this narrative review was to advance the knowledge in this area, and to determine possibilities related to dietary support. The authors also paid attention to role of biogenic amines in the treatment of patients with NENs. We can use this information to better understand nutritional issues faced by patients with gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), and to help inform the development of screening tools and clinical practice guidelines.

Blood-based next-generation sequencing analysis of neuroendocrine neoplasms

Background: Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms that span from well-differentiated neuroendocrine tumors (NETs) to highly aggressive neoplasms classified as neuroendocrine carcinomas (NECs). The genomic landscape of NENs has not been well studied. The aim of this study is to confirm the feasibility of next generation sequencing (NGS) testing circulating tumor DNA (ctDNA) in patients with NENs and characterize common alterations in the genomic landscape.

Results: Of the 320 NEN patients, 182 (57%) were male with a median age of 63 years (range: 8-93) years. Tumor type included pancreatic NET (N = 165, 52%), gastrointestinal NEC (N = 52, 16%), large cell lung NEC (N = 21, 7%), nasopharyngeal NEC (N = 16, 5%) and NEC/NET not otherwise specified (N = 64, 20%). ctDNA NGS testing was performed on 338 plasma samples; 14 patients had testing performed twice and 2 patients had testing performed three times. Genomic alterations were defined in 280 (87.5%) samples with a total of 1,012 alterations identified after excluding variants of uncertain significance (VUSs) and synonymous mutations. Of the 280 samples with alterations, TP53 associated genes were most commonly altered (N = 145, 52%), followed by KRAS (N = 61, 22%), EGFR (N = 33, 12%), PIK3CA (N = 30, 11%), BRAF (N = 28, 10%), MYC (N = 28, 10%), CCNE1 (N = 28, 10%), CDK6 (N = 22, 8%), RB1 (N = 19, 7%), NF1 (N = 19, 7%), MET (N = 19, 7%), FGFR1 (N = 19, 7%), APC (N = 19, 7%), ERBB2 (N = 16, 6%) and PTEN (N = 14, 5%).

Conclusions: Evaluation of ctDNA was feasible among individuals with NEN. Liquid biopsies are non-invasive methods that can provide personalized options for targeted therapies in NEN patients.

Patients and Methods: Molecular alterations in 338 plasma samples from 320 patients with NEN were evaluated using clinical-grade NGS of ctDNA (Guardant360^®) across multiple institutions. The test detects single nucleotide variants in 54-73 genes, copy number amplifications, fusions, and indels in selected genes.

Imaging DNA Damage Repair In Vivo After 177Lu-DOTATATE Therapy

Molecular radiotherapy using 177Lu-DOTATATE is a most effective treatment for somatostatin receptor-expressing neuroendocrine tumors. Despite its frequent and successful use in the clinic, little or no radiobiologic considerations are made at the time of treatment planning or delivery. On positive uptake on octreotide-based PET/SPECT imaging, treatment is usually administered as a standard dose and number of cycles without adjustment for peptide uptake, dosimetry, or radiobiologic and DNA damage effects in the tumor. Here, we visualized and quantified the extent of DNA damage response after 177Lu-DOTATATE therapy using SPECT imaging with 111In-anti-γH2AX-TAT. This work was a proof-of-principle study of this in vivo noninvasive biodosimeter with β-emitting therapeutic radiopharmaceuticals. Methods: Six cell lines were exposed to external-beam radiotherapy (EBRT) or 177Lu-DOTATATE, after which the number of γH2AX foci and the clonogenic survival were measured. Mice bearing CA20948 somatostatin receptor-positive tumor xenografts were treated with 177Lu-DOTATATE or sham-treated and coinjected with 111In-anti-γH2AX-TAT, 111In-IgG-TAT control, or vehicle. Results: Clonogenic survival after external-beam radiotherapy was cell-line-specific, indicating varying levels of intrinsic radiosensitivity. Regarding in vitro cell lines treated with 177Lu-DOTATATE, clonogenic survival decreased and γH2AX foci increased for cells expressing high levels of somatostatin receptor subtype 2. Ex vivo measurements revealed a partial correlation between 177Lu-DOTATATE uptake and γH2AX focus induction between different regions of CA20948 xenograft tumors, suggesting that different parts of the tumor may react differentially to 177Lu-DOTATATE irradiation. Conclusion:111In-anti-γH2AX-TAT allows monitoring of DNA damage after 177Lu-DOTATATE therapy and reveals heterogeneous damage responses.

The radiosensitizer Onalespib increases complete remission in 177Lu-DOTATATE-treated mice bearing neuroendocrine tumor xenografts

PURPOSE

177Lu-DOTATATE targeting the somatostatin receptor (SSTR) is utilized for treatment of neuroendocrine tumors (NETs). Onalespib, a heat shock protein 90 (HSP90) inhibitor, has demonstrated radiosensitizing properties and may thus enhance the effect of 177Lu-DOTATATE. Consequently, the aim of this study was to assess the potential of Onalespib in combination with 177Lu-DOTATATE in vivo and to examine the toxicity profiles of the treatments.

METHODS

177Lu-DOTATATE selectivity and distribution in NET xenografts were studied using biodistribution and autoradiography. Therapeutic effects of Onalespib in combination with 177Lu-DOTATATE were studied in NET xenografts. Histological analyses were used to assess molecular effects from treatment and to establish toxicity profiles.

RESULTS

Biodistribution and autoradiography confirmed the SSTR-selective tumor uptake of 177Lu-DOTATATE, which was unaffected by Onalespib treatment. Immunohistochemistry verified molecular responses to Onalespib therapy in the tumors. While Onalespib and 177Lu-DOTATATE monotherapies resulted in a 10% and 33% delay in tumor doubling time compared with control, the combination treatment resulted in a 73% delayed tumor doubling time. Moreover, combination treatment increased complete remissions threefold from 177Lu-DOTATATE monotherapy, resulting in 29% complete remissions. In addition, histological analyses demonstrated radiation-induced glomerular injury in the 177Lu-DOTATATE monotherapy group. The damage was decreased tenfold in the combination group, potentially due to Onalespib-induced HSP70 upregulation in the kidneys.

CONCLUSION

Treatment with Onalespib potentiated 177Lu-DOTATATE therapy of NET xenografts with a favorable toxicity profile. Utilizing Onalespib's radiosensitizing properties with 177Lu-DOTATATE may lead to better therapeutic results in the future and may reduce unwanted side effects in dose-limiting organs.

Kaposi's Sarcoma-Associated Herpesvirus Infection Induces the Expression of Neuroendocrine Genes in Endothelial Cells

Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with endothelial Kaposi's sarcoma (KS) in immunocompromised individuals. KS lesion cells exhibit many similarities to neuroendocrine (NE) cancers, such as highly vascular and red/purple tumor lesions, spindle-shaped cells, an insignificant role for classic oncogenes in tumor development, the release of bioactive amines, and indolent growth of the tumors. However, the mechanistic basis for the similarity of KS lesion endothelial cells to neuroendocrine tumors remains unknown. Next-generation sequencing and bioinformatics analysis in the present study demonstrate that endothelial cells latently infected with KSHV express several neuronal and NE genes. De novo infection of primary dermal endothelial cells with live and UV-inactivated KSHV demonstrated that viral gene expression is responsible for the upregulation of five selected NE genes (adrenomedullin 2 [ADM2], histamine receptor H1 [HRH1], neuron-specific enolase [NSE] [ENO2], neuronal protein gene product 9.5 [PGP9.5], and somatostatin receptor 1 [SSTR1]). Immunofluorescence and immunohistochemistry examinations demonstrated the robust expression of the NE genes HRH1 and NSE/ENO2 in KSHV-infected KS tissue samples and KS visceral tissue microarrays. Further analysis demonstrated that KSHV latent open reading frame K12 (ORFK12) gene (kaposin A)-mediated decreased host REST/NRSF (RE1-silencing transcription factor/neuron-restrictive silencer factor) protein, a neuronal gene transcription repressor protein, is responsible for NE gene expression in infected endothelial cells. The NE gene expression observed in KSHV-infected cells was recapitulated in uninfected endothelial cells by the exogenous expression of ORFK12 and by the treatment of cells with the REST inhibitor X5050. When the neuroactive ligand-activating receptor HRH1 and inhibitory SSTR1 were knocked out by CRISPR, HRH1 knockout (KO) significantly inhibited cell proliferation, while SSTR1 KO induced cell proliferation, thus suggesting that HRH1 and SSTR1 probably counteract each other in regulating KSHV-infected endothelial cell proliferation. These results demonstrate that the similarity of KS lesion cells to neuroendocrine tumors is probably a result of KSHV infection-induced transformation of nonneuronal endothelial cells into cells with neuroendocrine features. These studies suggest a potential role of neuroendocrine pathway genes in the pathobiological characteristics of KSHV-infected endothelial cells, including a potential mechanism of escape from the host immune system by the expression of immunologically privileged neuronal-site NE genes, and NE genes could potentially serve as markers for KSHV-infected KS lesion endothelial cells as well as novel therapeutic targets to control KS lesions.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) manipulates several cellular pathways for its survival advantage during its latency in the infected human host. Here, we demonstrate that KSHV infection upregulates the expression of genes related to neuronal and neuroendocrine (NE) functions that are characteristic of NE tumors, both in vitro and in KS patient tissues and the heterogeneity of neuroendocrine receptors having opposing roles in KSHV-infected cell proliferation. Induction of NE genes by KSHV could also provide a potential survival advantage, as the expression of proteins at immunologically privileged sites such as neurons on endothelial cells may be an avenue to escape host immune surveillance functions. The NE gene products identified here could serve as markers for KSHV-infected cells and could potentially serve as therapeutic targets to combat KSHV-associated KS.

Insulinoma-associated protein 1 (INSM1): a potential biomarker and therapeutic target for neuroendocrine tumors

BACKGROUND

Insulinoma-associated protein 1 (INSM1), a transcriptional regulator with a zinc-finger DNA-binding domain, has been validated as a cytoplasmic marker for neuroendocrine differentiation of tumor cells. Next to its abundant expression in the fetal pancreas, it is expressed in brain tumors, pheochromocytomas, medullary thyroid carcinomas, insulinomas and pituitary and small-cell lung carcinomas. INSM1 is not expressed in normal adult tissues and/or most non-neuroendocrine tumors. It regulates various downstream signaling pathways, including the Sonic Hedgehog, PI3K/AKT, MEK/ERK1/2, ADK, p53, Wnt, histone acetylation, LSD1, cyclin D1, Ascl1 and N-Myc pathways. Although INSM1 appears to be a subtle and specific biomarker for neuroendocrine tumors, its role in tumor development has remained unclear.

CONCLUSIONS

Here, we highlight INSMI expression, as well as its diagnostic significance and use as a therapeutic target in various neuroendocrine tumors. Targeting signaling pathways or gene expression alterations associated with INSM1 expression may be instrumental for the design of novel therapeutic strategies for neuroendocrine tumors.

Theranostic approaches in nuclear medicine: current status and future prospects

Introduction: Theranostics is an emerging field in which diagnosis and specific targeted therapy are combined to achieve a personalized treatment approach to the patient. In nuclear medicine clinical practice, theranostics is often performed utilizing the same molecule labeled with two different radionuclides, one radionuclide for imaging and another for therapy.Areas covered: The authors review the clinical applications of different radiopharmaceuticals in the field of interest, including the well-established use of radioactive iodine in differentiated thyroid cancer, radiolabeled metaiodobenzylguanidine (MIBG) in neuroblastoma and the clinical impact of peptide radionuclide receptorial therapy (PRRT) in the management of neuroendocrine tumors. Furthermore, the more cutting-edge and recently introduced theranostic approaches will be reviewed, such as the radioligand therapy with ¹⁷⁷Lu-prostate specific membrane antigen (PSMA) and targeted alpha therapy in castration-resistant prostate cancer. Finally, the main applications of PET for the imaging of biomarkers suitable for the non-radionuclide targeted therapy will be covered.Expert opinion: Theranostics is envisaging a revolutionary clinical approach which is deeply connected with the concept of personalized medicine and ruled by a 'patient-centered' vision. In this perspective, the theranostic applications will need well-trained specialists, capable to manage not only the technological aspects of the discipline, but also to deal with the more innovative oncological therapies in a multidisciplinary setting.

Primary Functioning Neuroendocrine Tumor of the Appendix with Hypoglycemia Syndrome: A Case Report and Review of Neuroendocrine Tumors

INTRODUCTION

Primary neuroendocrine tumors (NETs) of the appendix are uncommon, but when present are usually not hyperfunctioning. This case represents an extraordinarily rare primary hyperfunctioning NET of the appendix with a clinical presentation of symptomatic hypoglycemia in an otherwise healthy man.

CASE PRESENTATION

A previously healthy 34-year-old man was found to be symptomatically hypoglycemic in early 2018. After the workup, the apparent explanation was a tumor in his midappendix, for which he was referred to our surgical oncology service for resection. The patient's clinical course is described in detail, including imaging, as well as surgical and pathologic descriptions of the appendiceal NET.

DISCUSSION

A literature review demonstrates no other case series or reports of a primary hyperfunctioning NET of the appendix presenting with hypoglycemic crisis. The symptoms of tumor-induced hypoglycemia more typically arise with islet cell tumors, such as pancreatic NETs or insulinomas. We believe this case represents a nonislet cell tumor-induced hypoglycemia. This patient's elevated serum proinsulin level preoperatively implies secretion of proinsulin by the tumor. However, tumor-induced hypoglycemia caused by proinsulin has been described previously only in pancreatic tumors. This unique case adds knowledge to the possible glycemic endocrine effects of nonpancreatic NETs, specifically those that arise primarily in the appendix.

Competing Mortality in Patients With Neuroendocrine Tumors

OBJECTIVES

Patients with neuroendocrine tumors (NETs) are at increased risk of mortality from competing causes in light of the improvement in overall survival over recent decades. The purpose of this study was to explore the competing causes of deaths and the risk factors associated with competing mortality.

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results database was used to identify patients diagnosed with NETs between 1973 and 2015. Risk of competing mortality was estimated by the standardized mortality ratios (SMRs) and by using the Fine and Gray multivariate regression model.

RESULTS

Of the 29,981 NET patients, 42.5% of the deaths that occurred during follow-up were attributed to competing causes (83.9% from noncancer causes and 16.1% from second primary neoplasms). Overall SMR of competing mortality was 2.50 (95% confidence interval [CI]: 2.43-2.56). The SMR of noncancer causes was 2.65 (95% CI: 2.58-2.73), with the highest risk present within the first year of diagnosis. The SMR of second primary neoplasms was 1.91 (95% CI: 1.79-2.04), with the highest risk observed after 10-year postdiagnosis. A drastic rise in competing mortality was observed in the last decade between 2005 and 2015. Advanced age, black race, small intestinal and gastric NETs, and surgery were significantly associated with competing mortality. Female, pancreatic and recto-anal NETs, distant and regional spread, chemotherapy and radiotherapy were significantly associated with lower competing mortality.

CONCLUSIONS

Competing mortality plays an increasingly significant role over the years and may hamper efforts made to improve survival outcomes in NET patients.

The therapeutic efficacy of 177Lu-DOTATATE/DOTATOC in advanced neuroendocrine tumors: A meta-analysis

BACKGROUND

Somatostatin analog therapies showed great potential for patients suffering advanced neuroendocrine tumors (NETs). This study was aimed to evaluate the therapeutic efficacy of Lu-DOTATATE/DOTATOC (Lu-octreotate/octreotide) peptide receptor radionuclide therapy (PRRT) in advanced or inoperable NETs patients.

METHODS

Pubmed, Web of Science, Embase and Cochrane Library were searched from 1950 to April 2019. Eligible studies should include randomized or nonrandomized controlled trials (RCTs)-based investigations of Lu-octreotate/octreotide PRRT for NETs. All these studies were assessed with Response Evaluation Criteria in Solid Tumors (RECIST), RECIST 1.1, Southwest Oncology Group (SWOG) criteria or World Health Organization (WHO) criteria. Disease response rates (DRRs) and disease control rates (DCRs) were calculated according to each response criteria group. DRRs were defined as the percentages of patients with complete response (CR) + partial response (PR), while DCRs represented the percentages of patients with CR+ PR+ stable disease (SD). The pooled proportions were calculated with either a fixed-effects model or a random-effects model depending on the test for heterogeneity.

RESULTS

A total of 22 studies (1758 patients) were included in this meta-analysis: 8 studies with 478 patients met RECIST criteria, 10 studies with 1127 patients met RECIST 1.1 criteria, 5 studies with 459 patients met SWOG criteria, and 1 study with 40 patients met WHO criteria, and among these articles 1 study met both RECIST and RECIST 1.1 criteria and 1 met both RECIST 1.1 and SWOG criteria. The pooled DRRs were 33.0% (95% CI: 25.0%-42.0%, I = 65%), 35.0% (95% CI: 26.0%-45.0%, I = 91%) and 25.0% (95% CI: 14.0%-36.0%, I = 84%) according to RECIST, RECIST 1.1 and SWOG criteria, respectively. The pooled DCRs were 79.0% (95% CI: 75.0%-83.0%, I = 97%), 83.0% (95% CI: 78.0%-88.0%, I = 0) and 82.0% (95% CI: 75.0%-89.0%, I = 91%), respectively.

CONCLUSION

In advanced NETs patients, DRRs and DCRs were significantly elevated after initial treatment with Lu-DOTATATE PRRT, which shows that this treatment would be beneficial and promising for advanced or inoperable NETs patients.

Differential and prognostic MRI features of gallbladder neuroendocrine tumors and adenocarcinomas

OBJECTIVES

To identify MRI features that are helpful for the differentiation of gallbladder neuroendocrine tumors (GB-NETs) from gallbladder adenocarcinomas (GB-ADCs) and to evaluate their prognostic values.

METHODS

Between January 2008 and December 2018, we retrospectively enrolled patients who underwent MRI for GB malignancy. Two radiologists independently assessed the MRI findings and reached a consensus. Significant MRI features, which distinguish GB-NETs from GB-ADCs, were identified. Cox regression analyses were performed to find MRI features that were prognostic for overall survival.

RESULTS

There were 63 patients with GB-NETs (n = 21) and GB-ADCs (n = 42). Compared with GB-ADCs, GB-NETs more frequently demonstrated the following MRI features: well-defined margins, intact overlying mucosa, and thick rim contrast enhancement and/or diffusion restriction (ps < 0.001). Liver metastases were more common and demonstrated thick rim contrast enhancement and diffusion restriction in GB-NETs (ps < 0.001). Lymph node (LN) metastasis showed thick rim diffusion restriction more often in GB-NETs than in GB-ADCs (p = 0.009). On quantitative analysis, the sizes of the GB mass and metastatic LNs in GB-NETs were larger than those in GB-ADCs (p = 0.002 and p = 0.010, respectively). The ratio of apparent diffusion coefficient values between the lesion and the spleen was lower in the GB mass, liver metastases, and LN metastases of GB-NETs than those of GB-ADCs (p < 0.001, p = 0.017, and p < 0.001, respectively). Survival analysis revealed that a large metastatic LN (hazard ratio 1.737; 95% confidence interval, 1.112-2.712) was the only poor prognostic factor (p = 0.015).

CONCLUSION

Several MRI features aided in differentiating between GB-NETs and GB-ADCs. A large metastatic LN was associated with poor survival.

KEY POINTS

• Compared with gallbladder adenocarcinomas (GB-ADCs), neuroendocrine tumors (GB-NETs) and their metastases to the liver and lymph nodes more frequently demonstrated a thick rim appearance on contrast-enhanced MRI and diffusion-weighted images. • The ratio of apparent diffusion coefficient values between the lesion and the spleen was significantly lower for the primary mass, liver metastases, and lymph node metastases of GB-NETs than for those of GB-ADCs. • A large metastatic lymph node was the only poor prognostic factor for overall survival in patients with GB-NETs and GB-ADCs.

Molecular imaging and radionuclide therapy of neuroendocrine tumors

PURPOSE OF REVIEW

Neuroendocrine tumors are heterogeneous neoplasms with variable prognoses and clinical behaviors. The majority of well differentiated NETs express somatostatin receptors. Identification of these receptors has contributed to advancements in molecular and targeted radiotherapies.

RECENT FINDINGS

Molecular scans provide important diagnostic, staging, and prognostic data. Somatostatin-receptor imaging aids in selection of patients who are eligible for somatostatin-receptor-targeting therapies. Peptide receptor radionuclide therapy has recently demonstrated robust efficacy in a phase III study of progressive midgut NETs. Current studies are investigating novel receptor agonists and antagonists, new classes of radioactive isotopes, and radiosensitizing combination treatments.

SUMMARY

The sophistication of molecular imaging is improving and its importance is increasing as a diagnostic, predictive, and prognostic tool. Theranostics, the coupling of molecular imaging with receptor-targeted therapy, represents a novel approach to cancer treatment.

Carcinoid Tumor: Advances in Treatment Options

Small bowel neoplasms are rare, accounting for only 3%-6% of all gastrointestinal neoplasms. Carcinoid tumors represent a large portion of these (20%-30%), making them the second most common small bowel malignancy after adenocarcinoma. Gastrointestinal carcinoids constitute 70% of all neuroendocrine tumors, and out of those, 42% originate in the small bowel. They are predominantly seen in older patients around the age of 65 years. From 1973 to 2004, there has been more than a fourfold increase in the incidence of carcinoid tumors. This can be probably due to increased diagnostic accuracy rather than an actual increase in the number of new cases. The workup of a suspicious case of gastrointestinal bleeding consists of esophagogastroduodenoscopy and/or colonoscopy, and other imaging tests including video capsule endoscopy and balloon-assisted endoscopy. Management of the tumors is dependent on the size and location of the lesion. Treatment options include surgery, endoscopic removal of tumors, and various immunotherapy and chemotherapeutic agents.

Ca2+ Channel Toolkit in Neuroendocrine Tumors

Neuroendocrine tumors (NET) constitute a heterogeneous group of malignancies with various clinical presentations and growth rates but a common origin in neuroendocrine cells located all over the body. NET are a relatively low-frequency disease mostly represented by gastroenteropancreatic (GEP) and bronchopulmonary tumors (pNET); on the other hand, an increasing frequency and prevalence have been associated with NET. Despite great efforts in recent years, the management of NET is still a critical unmet need due to the lack of knowledge of the biology of the disease, the lack of adequate biomarkers, late presentation, the relative insensitivity of imaging modalities, and a paucity of predictably effective treatment options. In this context Ca2+ signals, being pivotal molecular devices in sensing and integrating signals from the microenvironment, are emerging to be particularly relevant in cancer, where they mediate interactions between tumor cells and the tumor microenvironment to drive different aspects of neoplastic progression (e.g., cell proliferation and survival, cell invasiveness, and proangiogenetic programs). Indeed, ion channels represent good potential pharmacological targets due to their location on the plasma membrane, where they can be easily accessed by drugs. The present review aims to provide a critical and up-to-date overview of NET development integrating Ca2+ signal involvement. In this perspective, we first give an introduction to NET and Ca2+ channels and then describe the different families of Ca2+ channels implicated in NET, i.e., ionotropic receptors, voltage-dependent Ca2+ channels, and transient receptor potential channels, as well as intracellular Ca2+ channels and their signaling molecules.

Evaluating hepatotoxic effects of chemotherapeutic agents with gadoxetic-acid-enhanced magnetic resonance imaging

PURPOSE

To evaluate the hepatotoxicity of different chemotherapeutic agents used to treat neuroendocrine tumours (NETs) with gadoxetic acid-enhanced magnetic resonance imaging (MRI).

MATERIAL AND METHODS

A total of 129 patients with NETs who underwent two or more serial gadoxetic-acid-enhanced MRI examinations between 2014 and 2018 and started chemotherapy in the beginning of that time period were retrospectively analysed. Linear mixed model analysis evaluating relative enhancement (RE) of the liver in the hepatobiliary phase with respect to time between MRI examinations, primary chemotherapy, hepatotoxicity score of preceding and subsequent chemotherapies as well as age and gender as fixed variables was performed. Binary logistic regression was used to verify whether the hepatotoxicity score predicts a significant impact of a chemotherapeutic regimen on RE and hence liver function.

RESULTS

Linear mixed model analysis of a total of 539 MRI examinations identified all chemotherapeutic agents with known hepatoxicity as a factor with a statistically significant negative impact on RE of the liver in gadoxetic-acid-enhanced MRI in addition to age. This result was confirmed by binary logistic regression analysis.

CONCLUSION

Our results confirm that gadoxetic acid-enhanced MRI can be used as an imaging-based liver function test for assessing hepatotoxicity of chemotherapeutic agents used for NETs. The findings underscore the known degrees of hepatotoxicity of the chemotherapeutic agents currently used in the treatment of NETs.

Clinicopathologic analysis of primary gastroenteropancreatic poorly differentiated neuroendocrine carcinoma; A ten year retrospective study of 68 cases at Moffit Cancer Center

Objective:

To assess clinicopathological characteristics of primary gastro-entero-pancreatic poorly differentiated neuroendocrine carcinomas (GEP-PDNECAs) and evaluate overall survival in patients treated with systemic platinum and etoposide therapy.

Methods:

A detailed retrospective review of clinico-pathologic data (1999-2009) on 68 consecutive adult patients with primary GEP-PDNECAs was carried out, from H Lee Moffit Cancer Center and Research Institute, Tampa, Florida; USA, based on electronic patient records, specialty consultation files, tumor registry, social security index and pathology archives. All available tumor slides were reviewed and subtyped by neuro-endocrine pathologists. Clinicopathologic data and patient survival were analyzed.

Results:

Of 68 patients 41 were males and 27 females with a mean age of 42 years (range: 25-76 years). Regarding the site of origin, 39 patients were of the colorectal location, 19 from the pancreas, 04 from small intestines, 03 from stomach and 03 were multi-focal from colon, small intestine and pancreas. Sixty three of 68 (93%) patients presented with lymph node/distant metastases. Of 68 tumors 37 (54%) were classified as small cell carcinoma (SCCA), 16 (24%) large cell carcinoma (LCCA), 5 (7%) mixed small and large cell (MSLCCA) and 10 (15%) poorly differentiated carcinoma with neuroendocrine features (PDCA-NEF). Neuroendocrine differentiation was confirmed by positivity for chromogranin in 38/65 (55%), synaptophysin in 62/67 (92%) and CD56 in 17/21 (81%) cases. One neuroendocrine marker was positive in 22/68 (32%), 2 in 40/68 (59%) and all 3 were positive in 9/68 (13%) cases. Fifty-eight of 68 (85%) patients were treated with platinum and etoposide. Overall patient survival at 1, 3 5 and 10 years was 85%, 40%, 16% and 1.5% respectively. Patient survival was independent of age (r= 0.1022), sex (r= -0.909) and histologic tumor subtype (r=0.1028) (p= 0.128) but was related to distant metastases (r=0.306; p=0.0383).

Conclusions:

GEP-PDNECA occurred in many part of the GI tract, most commonly in the colorectal region. Positivity of neuroendocrine markers was variable, which helped to confirm neuro-endocrine differentiation and to avoid under-diagnosis of GEP-PDNECA, especially in metastatic setting. Overall prognosis of GEP-PDNECA patients following platinum and etoposide therapy in our series was relatively favorable but remained poor in the presence of distant metastases.

Exploring the current status of neuroendocrine tumours: a population-based analysis of epidemiology, management and use of resources

Background

Neuroendocrine tumours (NETs) are rare malignancies characterised by its capacity to synthesise and secrete monoamines, due to its neuroendocrine origin. Its varied locations and symptoms have traditionally been responsible for extended delays in their diagnosis. The interest of this study was to characterise the patient population diagnosed with NETs in Spain and to revise how the disease is managed, together with the hospitalisation costs of these patients.

Methods

The database included records of all patients diagnosed with a NET between 2010 and 2015. Admission records were used to evaluate hospitalisation, disease management data and costs, and single-patient files were used to characterise the population.

Results

Nine Thousand One Hundred Twenty patients were diagnosed with a neuroendocrine tumour between 2010 and 2015, with a 2 fold increase in the diagnosis rate over the study period. 42.25% of the patients were females, while 57.75% were males, and mean diagnosis age was 62.58 years (SD = 14.65). Considering all the registered neuroendocrine neoplasms, 46.86% of the patients had malignant well-differentiated NETs, 32.02% had a malignant poorly differentiated neuroendocrine carcinoma and 42.93% of patients developed metastatic NETs. In addition, 18.59% of patients were diagnosed with benign well-differentiated NETs. The most common tumour sites were the bronchus, lung and other sites, including pancreatic tumours; metastasis was found in the liver and distant lymph nodes. Pancreatic resection was the most common surgical procedure utilised in these patients, summing 19% of total expenses, the injection of an unspecified therapeutic substance (including targeted therapies) was registered in 11.40% of admissions, while chemotherapy was registered in only 6.85% of admissions. The annual healthcare cost of NETs was €15,373,961, corresponding to €9092 per patient.

Conclusions

The implementation of standard diagnosis procedures should be prioritised, with a focus on the pancreas and lung, and taking into account that 42.93% of the patients develop a metastatic tumour. The presence of comorbidities and multimorbidities should be considered in order to develop more efficient disease management protocols.

Metastatic retroperitoneal tumor from a non-functional neuroendocrine neoplasia of the left ethmoid-nose-orbitary region: Case report and short review of literature

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NENs are rare tumors with extremely variable behavior: they are difficult to diagnose, especially if biologically inactive.

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NENs can originate from any epithelial organ and present unusual metastases.

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NEN surgery is a valid treatment and a necessary tool for correct diagnosis.

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NEN classification is evolving and being discussed.

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Careful collection of anamnestic data and a correct analysis of patients’ symptoms can be a valuable resource.

Introduction

NeuroEndocrine Neoplasms (NENs) are rare and can originate from any epithelial organ. We describe a very rare case of retroperitoneal metastasis from a non-functioning neuroendocrine tumor of the ethmoid region and focus on the various issues related to NENs, from their nosological classification up to the most recent acquisitions in the diagnostic and therapeutic field.

Presentation of case

A woman presented with a mass in the right retroperitoneal area that infiltrated liver and kidney. The anamnestic data showed a previous undifferentiated small cell tumor of the left ethmoid-nasal-orbital region. The mass was removed surgically and the definitive histological examination revealed a non-functioning undifferentiated malignant small cell neoplasm.

Discussion

NENs represent a chapter of oncology whose systematization remains difficult. The lack of hormonal syndrome in Biologically Inactive Neuroendocrine Tumors (BINTs) may delay the diagnosis. Clinical manifestations relate to the size and location of the neoplasm. Small cell NeuroEndocrine Carcinoma (NEC) of the ethmoid-nose-orbital region is an extremely rare occurrence and generally the most frequent metastatic localization is represented by the larynx.

Conclusion

This case highlights the contradictions typical of NENs and only new scientific acquisitions in the histopathological field can help us in the future. Surgery remains the only possibility of treatment and diagnosis of large masses of inactive NENs. This is the only case in the world of metastasis from NEC of the nose-orbital region in the retroperitoneum.

hASH1 nuclear localization persists in neuroendocrine transdifferentiated prostate cancer cells, even upon reintroduction of androgen

Neuroendocrine prostate cancer (NEPC) is thought to arise as prostate adenocarcinoma cells transdifferentiate into neuroendocrine (NE) cells to escape potent anti-androgen therapies however, the exact molecular events accompanying NE transdifferentiation and their plasticity remain poorly defined. Cell fate regulator ASCL1/hASH1's expression was markedly induced in androgen deprived (AD) LNCaP cells and prominent nuclear localisation accompanied acquisition of the NE-like morphology and expression of NE markers (NSE). By contrast, androgen-insensitive PC3 and DU145 cells displayed clear nuclear hASH1 localisation under control conditions that was unchanged by AD, suggesting AR signalling negatively regulated hASH1 expression and localisation. Synthetic androgen (R1881) prevented NE transdifferentiation of AD LNCaP cells and markedly suppressed expression of key regulators of lineage commitment and neurogenesis (REST and ASCL1/hASH1). Post-AD, NE LNCaP cells rapidly lost NE-like morphology following R1881 treatment, yet ASCL1/hASH1 expression was resistant to R1881 treatment and hASH1 nuclear localisation remained evident in apparently dedifferentiated LNCaP cells. Consequently, NE cells may not fully revert to an epithelial state and retain key NE-like features, suggesting a "hybrid" phenotype. This could fuel greater NE transdifferentiation, therapeutic resistance and NEPC evolution upon subsequent androgen deprivation. Such knowledge could facilitate CRPC tumour stratification and identify targets for more effective NEPC management.

Histopathologist-level quantification of Ki-67 immunoexpression in gastroenteropancreatic neuroendocrine tumors using semiautomated method

The role of Ki-67 index in determining the prognosis and management of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has become more important yet presents a challenging assessment dilemma. Although the precise method of Ki-67 index evaluation has not been standardized, several methods have been proposed, and each has its pros and cons. Our study proposes an imaging semiautomated informatics framework [semiautomated counting (SAC)] using the popular biomedical imaging tool "ImageJ" to quantify Ki-67 index of the GEP-NETs using camera-captured images of tumor hotspots. It aims to assist pathologists in achieving an accurate and rapid interpretation of Ki-67 index and better reproducibility of the results with minimal human interaction and calibration. Twenty cases of resected GEP-NETs with Ki-67 staining that had been done for diagnostic purposes have been randomly selected from the pathology archive. All of these cases were reviewed in a multidisciplinary cancer center between 2012 and 2019. For each case, the Ki-67 immunostained slide was evaluated and five camera-captured images at 40 × magnification were taken. Prints of images were used by three pathologists to manually count the tumor cells. The digital versions of the images were used for the semiautomated cell counting using ImageJ. Statistical analysis of the Ki-67 index correlation between the proposed method and the MC revealed strong agreement on all the cases evaluates ( n = 20 ), with an intraclass correlation coefficient of 0.993, "95% CI: 0.984 to 0.997." The results obtained from the SAC are promising and demonstrate the capability of this methodology for the development of reproducible and accurate semiautomated quantitative pathological assessments. ImageJ features are investigated carefully and accurately fine-tuned to obtain the optimal sequence of steps that will accurately calculate Ki-67 index. SAC is able to accurately grade all the cases evaluated perfectly mating histopathologists' manual grading, providing reliable and efficient solution for Ki-67 index assessment.