European Neuroendocrine Tumor Society (ENETS) 2022 Guidance Paper for Carcinoid Syndrome and Carcinoid Heart Disease

Psychiatric and cognitive function in patients with serotonin producing neuroendocrine tumors

Cognitive and psychiatric problems are common in cancer patients, but literature on patients with neuroendocrine tumors (NET) is scarce. In a subset of these patients, the tumor produces serotonin, causing physical symptoms known as carcinoid syndrome. This peripheral overproduction of serotonin may cause central depletion of its precursor tryptophan, potentially resulting in cognitive and psychiatric problems. Therefore, we investigated cognitive and psychiatric function in patients with a serotonin overproduction and the association with this serotonin overproduction. Eighty-one patients with a serotonin-producing metastatic ileal NET underwent standardized neuropsychological and psychiatric assessment. Blood and urine samples were collected to determine concentrations of serotonin, its precursor tryptophan, and metabolite (5-HIAA). Multivariate normative comparison was applied to determine the prevalence of cognitive impairment. Separate linear regressions of serotonin, tryptophan, and 5-HIAA concentrations on cognitive function, depressive symptoms, and anxiety symptoms were performed, corrected for age, sex, education, and/or duration of illness. We found an 11% prevalence of cognitive impairment and a 20% prevalence of psychiatric disorders. Cognitive function was not related to measures of peripheral serotonin production. Unexpectedly, depressive symptoms were significantly associated with lower serum serotonin concentrations and elevated serum tryptophan concentrations. Cognitive symptoms of anxiety were also associated with elevated tryptophan concentrations. Concluding, cognitive or psychiatric problems occur in a minority of patients with NET and cannot be explained by tryptophan depletion following tumor-related serotonin production.

Symptom Management for Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors: ASCO Guideline

PURPOSE

To develop a clinical practice guideline and recommendations for symptom management of patients with well-differentiated grade 1 to grade 3 metastatic gastroenteropancreatic neuroendocrine tumors.

METHODS

ASCO convened an Expert Panel to develop a clinical practice guideline by reviewing the literature for relevant guidelines, systematic reviews, randomized controlled trials (RCTs), and observational studies to develop recommendations for clinical practice.

RESULTS

The literature review identified eight guidelines, 19 systematic reviews, and three RCTs that informed the development of guideline recommendations.

RECOMMENDATIONS

Recommendations are included for carcinoid syndrome, carcinoid heart disease and carcinoid crisis, and functional pancreatic neuroendocrine tumor syndromes. Recommendations are provided for surgical management, liver-directed therapy, and systemic therapy options, as well as palliative care. Limited guidance is provided for sequencing of interventions.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

Mesenteric Fibrosis in Neuroendocrine Neoplasms: a Systematic Review of New Thoughts on Causation and Potential Treatments

PURPOSE OF REVIEW

Mesenteric fibrosis (MF) is a hallmark of small intestinal neuroendocrine neoplasms (SI-NEN) and is frequently associated with significant morbidity due to related complications such as intestinal obstruction, ischemia, and cachexia.

RECENT FINDINGS

Herein we performed a systematic review to discuss the development of MF in SI-NEN. The pathophysiological mechanisms acknowledged as causative for the development of MF include the major components of the tumor microenvironment, such as fibroblasts, endothelial and immune cells and the extracellular matrix, which are involved in a complex interplay activating several signaling pathways that promote profibrotic factors and induce both a desmoplastic reaction and tumor proliferation. Surgery remains the mainstay of treatment, while several medical management options of MF complicating SI-NEN available present rather limited efficacy. MF is a frequent characteristic of SI-NEN that requires particular attention and targeted management to avoid complications.

Martins R. Hypertension and Carcinoid Heart Disease as Initial Manifestations of Ovarian Carcinoid Tumor

Ovarian carcinoid tumors (OCTs) are rare and may cause carcinoid syndrome (CS) even in the absence of liver metastases. Carcinoid heart disease (CHD), which develops in up to 50% of patients with CS, substantially affects morbidity and mortality. While prognosis is generally favorable, maintaining clinical suspicion and early diagnosis is crucial to prevent the development of advanced heart failure or metastases. We present a case of a woman exhibiting asthenia, diarrhea, and de novo severe hypertension. Echocardiography revealed typical features of CHD. Elevated urinary levels of 5-hydroxyindoleacetic acid (5-HIAA) corroborated the diagnosis of CS. 68Ga-DOTANOC positron emission tomography computed tomography identified a suspicious left pelvic mass, which was subsequently confirmed by magnetic resonance imaging. Surgical resection of the tumor was performed, followed by tricuspid valve replacement surgery, confirming the diagnosis of OCT associated with CS and CHD. Postoperative follow-up revealed considerable clinical improvement, and the patient has remained free of recurrence. This case underscores the complex cardiovascular involvement in CS, with secondary hypertension as the initial symptomatic manifestation, which improved following resection of OCT. Additionally, it highlights the role of CS in the pathogenesis of severe tricuspid valve dysfunction, which ultimately required cardiac surgery.

Post-marketing Safety Evaluation of Lutathera (177Lu-DOTATATE): A Pharmacovigilance Analysis of FDA Adverse Event Reporting System

BACKGROUND

Lutathera, a key therapy for gastroenteropancreatic neuroendocrine tumors, has demonstrated efficacy, but its real-world safety profile remains unclear. This study aims to conduct a comprehensive analysis of the adverse events (AEs) associated with Lutathera using FDA Adverse Event Reporting System (FAERS) data.

PATIENTS AND METHODS

A retrospective pharmacovigilance analysis was conducted using FAERS data from Q4 2019 to Q3 2024. AE reports involving Lutathera were identified, and a case/non-case approach was employed to evaluate AE signals using disproportionality analysis methods, including the reporting odds ratio and information component (IC). Patient demographics, time to AE onset, and system organ class (SOC) involvement were analyzed.

RESULTS

After data processing, a total of 4284 AE reports associated with Lutathera were analyzed. The median time to AE onset was 113.5 days. Lutathera-related AEs exhibited a notably high mortality rate, reaching as much as 31.2%. Statistically significant signals were detected across 13 SOCs and multiple preferred terms (PTs). Among the SOCs, the most pronounced signals were observed in the category of endocrine disorders. The leading PTs included nonspecific disorders (IC025: 5.92), carcinoid syndrome (IC025: 5.69), and carcinoid crisis (IC025: 5.62). Moreover, several PTs not documented in the drug's labeling were reported, such as encephalitis, intestinal ischemia, and disseminated intravascular coagulation.

CONCLUSIONS

Our study utilized real-world data to identify multiple risk signals associated with Lutathera, providing additional evidence to support its rational use. However, due to the inherent limitations of the FAERS database, further research is warranted to validate these findings.

Perioperative management of a double valve replacement and coronary artery bypass graft in a patient with carcinoid syndrome; a case report and literature review

IntroductionCarcinoid tumors are rare neuroendocrine tumors; about 5% of patients develop the carcinoid syndrome. We present the case of a patient with carcinoid syndrome undergoing cardiac surgery.Case reportA 74-year-old patient with carcinoid heart disease and hepatic metastases underwent double valve replacement and CABG. The patient was on octreotide therapy and antihypertensive medication. An octreotide infusion was commenced perioperatively. Pharmaceutical agents that could potentially precipitate histamine release or exacerbate catecholamine secretion and carcinoid crises were avoided. Postoperatively, recovery was complicated by atrial fibrillation, chest infection, pleural effusions, acute kidney injury and delirium.DiscussionHepatic metastases cause systemic hormones' secretion, which cause a carcinoid crisis. Perioperative administration of octreotide is used, while vigilance is required to differentiate between hemodynamic effects related to the operation or disease specific factors.ConclusionNo carcinoid crisis was evident perioperatively. High vigilance with appropriate monitoring, aggressive management combined with meticulous choice of pharmaceutical agents led to this outcome.

Functioning neuroendocrine tumors (NET): Minimum requirements for a NET specialist

INTRODUCTION AND AIMS

Functioning neuroendocrine tumors (f-NETs) represent a minority of all NETs, however their management is challenging due to the impact on patients' survival and quality of life. In addition to f-NETs, paraneoplastic syndromes (PNS) are due to substances that are not related to the primary anatomical site, they can develop in different phases of NETs evolution, and might complicate the patient's clinical course. Dedicated guidelines are still scanty. We aim to review available literature on f-NETs to propose a useful tool for clinicians in order to improve the diagnostic process and the management.

METHODS

Narrative review focused on f-NETs.

RESULTS

The most common f-NETs include insulinomas, gastrinomas and carcinoid syndrome (CS)- associated NETs. Symptoms related to hormone production may overlap with other common endocrine and gastrointestinal disorders, highlighting the pivotal role of multidisciplinary management. Somatostatin analogs (SSAs) represent the gold standard first-line treatment of most f-NETs, often followed by or combined with other treatments (surgery, liver-directed therapies, targeted therapies, peptide receptor radionuclide therapy). Paraneoplastic syndromes can develop in different phases of NET evolution and might complicate the patient's clinical course and response to therapy.

CONCLUSIONS

The management of hormonal syndromes is challenging and must be based on the multidisciplinary approach. Herein, we pointed out the minimal requirements for a NET specialist in the diagnosis and treatment of f-NETs. Efforts should be made to improve the awareness of functioning forms, to understand their pathogenesis and to improve their management.

British Society of Gastroenterology practice guidance on the management of acute and chronic gastrointestinal symptoms and complications as a result of treatment for cancer

BACKGROUND

Survival rates after a diagnosis of cancer are improving. Poorly managed gastrointestinal (GI) side effects can interfere with delivery of curative cancer treatment. Long-term physical side effects of cancer therapy impinge on quality of life in up to 25% of those treated for cancer, and GI side effects are the most common and troublesome.

AIM

To provide comprehensive, practical guidance on the management of acute and chronic luminal gastrointestinal symptoms arising during and after treatment for cancer METHODS: A multidisciplinary expert group including patients treated for cancer, divided into working parties to identify, and synthesise recommendations for the optimal assessment, diagnosis and appropriate interventions for luminal GI side effects of systemic and local cancer therapies. Recommendations were developed using the principles of the BMJ AGREE II reporting.

RESULTS

103 recommendations were agreed. The importance of the patient perspective and what can be done to support patients are emphasised. Key physiological principles underlying the development of GI toxicity arising from cancer therapy are outlined. Individual symptoms or symptom clusters are poor at distinguishing the underlying cause(s), and investigations are required if empirical therapy does not lead rapidly to significant benefits. Patients frequently have multiple GI causes for symptoms; all need to be diagnosed and optimally treated to achieve resolution. Investigations and management approaches now known to be ineffective or of questionable benefit are highlighted.

CONCLUSIONS

The physical, emotional and financial costs to individuals, their families and society from cancer therapy can be considerable. Identifying and signposting affected patients who require specialist services is the role of all clinicians. Progress in the treatment of cancer increasingly means that patients require expert, multidisciplinary supportive care providing effective and safe treatment at every stage of the cancer journey. Development of such expertise should be prioritised as should the education of health professionals and the public in what, when and how acute and chronic gastrointestinal symptoms and complications should be managed.

Simultaneous Transcatheter Pulmonary and Tricuspid Valve Replacement in Carcinoid Heart Disease

BACKGROUND

Neuroendocrine tumors can cause carcinoid heart disease, often presenting with pulmonary and tricuspid regurgitation. Valvular pathology and right heart failure can influence prognosis more than the tumor itself. Given high surgical risk, prolonged recovery, and limited life expectancy, interventional valve replacement is a strong alternative.

CASE SUMMARY

We present a patient with severe pulmonary and torrential tricuspid regurgitation caused by carcinoid heart disease. Despite stable neuroendocrine tumor control, the patient developed progressive right heart failure, requiring urgent valve therapy. Simultaneous transcatheter pulmonary and tricuspid valve replacements were performed, almost eliminating tricuspid and pulmonary regurgitation.

DISCUSSION

Right heart valve failure is frequent in carcinoid heart disease and significantly impacts outcomes. Although surgical valve replacement remains the standard, transcatheter approaches provide an effective, less invasive alternative for high-risk patients, offering symptom relief and excellent results.

TAKE-HOME MESSAGE

Simultaneous interventional valve replacement in carcinoid heart disease is feasible and effective.

Contemporary Management of Severe Carcinoid Heart Disease

BACKGROUND

Carcinoid heart disease (CHD), despite its rarity, is a serious complication of carcinoid syndrome (CS). Approximately 50% of patients with CS will develop CHD during the course of their disease. It predominantly affects the right-sided heart valves, leading to valve defect and right heart failure. In patients with advanced functional neuroendocrine tumors, diagnosing and managing CHD remains a challenge.

CASE SUMMARY

A 71-year-old male with a metastatic midgut neuroendocrine tumor and CS presented with worsening right heart failure. Despite initiating treatment appropriately, he deteriorated and ultimately died, highlighting the difficulty of CHD management in advanced cases.

REVIEW SUMMARY

Early detection and prompt management of CS are vital to prevent the progression to CHD. Therefore, a carefully planned sequential management approach should be developed for a generalized adaptation. Multidisciplinary care is vital, and new percutaneous interventions could provide promising options for high-risk patients.

TAKE-HOME MESSAGE

Routine screening of CHD in NET patients, timely intervention, and specialized multidisciplinary management are vital for improving outcomes in CHD.

Surgical and Oncologic Outcomes of Primary Tumor Resection in Patients with Small Intestinal Neuroendocrine Tumors: Results from a Single-Center Series Over a 15-Year Period

BACKGROUND

The role of prophylactic primary tumor resection (PTR) in patients with small intestinal neuroendocrine tumors (SI-NETs) and unresectable liver metastases is a matter of debate.

OBJECTIVE

We aimed to evaluate outcomes in patients with SI-NETs who underwent PTR, according to the presence of metastasis and symptoms from primary.

MATERIAL AND METHODS

Data from patients who underwent PTR for SI-NETs from a single referral center (2007-2023) were prospectively collected. Patients were divided into three groups: non-metastatic (M0) and metastatic with primary tumor-related symptoms (MS) or metastatic asymptomatic (MA). Kaplan-Meier curves for overall survival (OS) and event-free survival (EFS) were generated and compared by group. Univariate and multivariable Cox regression analyses were performed to assess the significance of risk factors.

RESULTS

Of 147 patients, 53 were M0, 23 were MS, and 71 were MA. Median follow-up was 26 months. The 5- and 10-year OS estimates were 100% and 100% in M0 patients, 82 and 21% in MS patients, and 89 and 80% in MA patients, respectively (p < 0.001). Median EFS was 91 months overall and 43,126 months and not reached for the MS, MA, and M0 groups, respectively (p < 0.001). In multivariable analysis, MS (hazard ratio [HR] 3.92, 95% confidence interval [CI] 1.71-9.52), functioning tumors (HR 1.98, 95% CI 1.03-3.81), and G2 grade (HR 3.20, 95% CI 1.64-6.85) were associated with a shorter EFS.

CONCLUSIONS

In this large retrospective series, the MS group had a significantly worse OS and EFS compared with M0 and MA. This finding suggests that prophylactic PTR might benefit SI-NET patients with unresectable liver metastases, as symptom development could impair long-term prognosis after surgery.

Assessment of response to PRRT including anatomical and molecular imaging as well as novel biomarkers

Peptide receptor radionuclide therapy (PRRT) is an effective treatment for both oncological and hormone control and is a widely accepted standard of care treatment for patients with neuroendocrine neoplasms (NEN). Its use is anticipated to increase significantly, and this demands accurate tools and paradigms to assess treatment response post PRRT. This article outlines the current role and future developments of anatomical, molecular imaging and biomarkers for response assessment to PRRT, highlighting the challenges and provides perspectives for the need to focus on a multimodality, multidisciplinary and individualised approach for patients with this complex heterogeneous disease.

The current status of somatostatin analogs in the treatment of neuroendocrine tumors and future perspectives

INTRODUCTION

Somatostatin analogs (SSAs) were developed as antisecretory agents to palliate hormonal symptoms in patients with functioning neuroendocrine tumors (NETs). Their antiproliferative activity has been established in the phase 3 PROMID and CLARINET trials. SSAs currently represent the standard first-line therapy for the majority of well-differentiated G1/G2 gastroenteropancreatic NETs as well as for pulmonary NETs.

AREAS COVERED

An update on the clinical applications of established SSAs for the treatment of NETs is provided. Perspectives on emerging nonpeptide SSAs such as paltusotine and innovative formulations of octreotide (CAM2029) are included.

EXPERT OPINION

SSAs represent the cornerstone of treatment for both functioning and nonfunctioning NETs. While standard-dose SSAs have a defined place in the therapeutic algorithm of well-differentiated NETs, uncertainties remain on how to best integrate above-label doses of SSAs in the treatment sequence, particularly when tumor control is the goal. Octreotide and lanreotide appear to be clinically interchangeable, and no signs of superiority of one agent over the other has been observed so far. Whether SSAs may be exploited in the maintenance setting following more aggressive treatments, whether continuing SSAs beyond-progression after first-line therapy could be an effective treatment strategy, and whether new-generation SSAs such as pasireotide could overcome resistance to established SSAs are key areas of investigation.

Laccase mimetics as sensing elements for amperometric assay of 5-hydroxyindoleacetic acid in urine

Monitoring of the levels of 5-hydroxyindole-3-acetic acid (5-HIAA) is of significant importance for diagnostics of carcinoid tumors. We propose simple catalytic electrochemical sensors for the determination of 5-HIAA in urine using laccase and its mimetics. Laccase-like nanozymes (LacNZs) were synthesized via a chemical reduction, and resulting PtMn and MnO2 nanoflowers (NFs) demonstrated laccase-like activity similar to the laccase from the Trametes zonata. In addition, these LacNZs showed enhanced stability under a wide range of pH (3.0-7.5), temperatures (4-70 °C), and ionic strengths (up to 500 mM NaCl). The developed PtMn NF/graphite electrode, similar to a laccase/graphite electrode, can detect 5-HIAA with a high sensitivity (25 000 ± 12 A·M-1·m-2 and 1900 ± 9 A·M-1·m-2, respectively) and have linear ranges of 0.3 - 15 μM and 2 - 50 μM. The sensors work at low working potentials with a detection limit of 0.16 and 1.4 μM, covering the normal and pathologic ranges of 5-HIAA (1 - 50 μM) content in urine. They have been successfully applied to 5-HIAA assay in urine samples of people with various diseases and revealed good recovery values and reproducibility. Additionally, the LacNZ-sensor has the best stability and can be used up to 20 days.

Radioligand therapy in the therapeutic strategy for patients with gastro-entero-pancreatic neuroendocrine tumors: a consensus statement from the Italian Association for Neuroendocrine Tumors (Itanet), Italian Association of Nuclear Medicine (AIMN), Italian Society of Endocrinology (SIE), Italian Association of Medical Oncology (AIOM)

PURPOSE

This paper outlines the consensus of the Italian Association for Neuroendocrine Tumors(Itanet), the Italian Association of Nuclear Medicine (AIMN), the Italian Society of Endocrinology (SIE), and the Italian Association of Medical Oncology (AIOM) on treating neuroendocrine neoplasms (NENs)with radioligand therapy (RLT).

METHODS

A list of 10 questions regarding using RLT ingastroenteropancreatic neuroendocrine tumors (GEP-NETs) was addressed after a careful review of theavailable literature. compiling information from the MEDLINE database, augmented with expert opinionsand recommendations, aligns with the latest scientific research and the author's extensive knowledge.The recommendations are evaluated using the GRADE system, showcasing the level of evidence andthe strength of the recommendations.

RESULTS AND CONCLUSIONS

Specifically, this paper focuses on thesubcategories of well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs) thatexpress somatostatin receptors and are considered suitable for RLT, according to internationalguidelines.

Neuroendocrine tumours and pregnancy: Real-world data from an European Neuroendocrine Tumour Centre of Excellence

Neuroendocrine neoplasms (NENs) arise from the diffuse endocrine system and have been considered to be rare. However, the incidence and prevalence of these tumours have increased in recent years, and they are being seen in younger patients including women in the reproductive age group. Due to the paucity of data, diagnostic and therapeutic strategies in managing such tumours during pregnancy can be challenging to both treating physicians and patients. This article describes the experience and outcomes of managing pregnant women with NEN at a European Neuroendocrine Tumour Society (ENETS) Centre of Excellence. In this retrospective analysis, we evaluated a total of 22 pregnancies in 18 pregnant women with concurrent diagnoses of NENs who were managed at Royal Free Hospital ENETS Centre of Excellence throughout their pregnancy. These were identified from our tumour registry of 3500 NEN patients between 2015 and 2023. Cross-sectional imaging (computed tomography (CT)/magnetic resonance imaging (MRI)), pre- and post-pregnancy, for each patient was reviewed by an experienced radiologist. Tumour growth rate (TGR) was calculated using the formula: TGR = 100 × [exp (TG) - 1]; TG. [3 × log (D2/D1)]/time (months), where D1 is the tumour size at date 1; D2 is the tumour size at date 2; and time (months) = (Date 2 - Date 1 + 1)/30.44. Tumour growth rate pre-conception (TGRpc) and tumour growth rate post-partum (TGRpp) were calculated for each patient. In a sub-group of patients, positivity for oestrogen and progesterone receptors were analysed on the tumour tissue to evaluate whether the presence of these receptors affected tumour progression during the pregnancy. We also reviewed the pregnancy outcome in patients treated with somatostatin analogues during pregnancy. We analysed the data of a total 22 pregnancy encounters in 18 women: 15 pregnancies (68%) preceded the diagnosis of the NEN, whereas the diagnosis of NEN was made during pregnancy or in the post-partum period in 5 (23%) and 2 (9%) pregnancies respectively. Eight patients (44%) had a diagnosis of a pancreatic NEN, whereas 5 (28%) were diagnosed with mid-gut NENs, and a further 5 at other sites. The majority of the patients (n = 12, 67%) had evidence of metastatic disease at the time of diagnosis. Most pregnancies had a successful outcome (n = 19, 86%), whereas 3 patients (14%) had miscarriages in the 1st trimester. Five patients in total of 6 pregnancies were treated with somatostatin analogues as monotherapy during the pregnancy, and all of them had stable disease after pregnancy. All of them delivered healthy babies without any side effects or complications due to therapy. The average TGRpc was -0.8% (n = 5) and the average TGRpp was +0.96% (n = 6); 2 patients who did not have suitable targets for calculation of TGRpc developed new lesions suggesting disease progression. Moreover, 2 of the 4 patients who have had both pre-conception and post-pregnancy scans showed an increase in TGRpp compared to TGRpc. The management of NENs during pregnancy should be multidisciplinary with an individualised approach to each patient. Somatostatin analogues appear to be safe during pregnancy, though further robust studies are needed. Pregnancy per se may accelerate tumour progression, and patients should be counselled regarding this possibility.

Biomarkers to Inform Prognosis and Treatment for Unresectable or Metastatic GEP-NENs

Importance

Evidence-based treatment decisions for advanced gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) require individualized patient-centered decision-making that accounts for patient and cancer characteristics.

Objective

To create an accessible guidance document to educate clinicians and patients on biomarkers informing prognosis and treatment in unresectable or metastatic GEP-NENs.

Methods

A multidisciplinary panel in-person workshop was convened to define methods. English language articles published from January 2016 to January 2023 in PubMed (MEDLINE) and relevant conference abstracts were reviewed to investigate prognostic and treatment-informing features in unresectable or metastatic GEP-NENs. Data from included studies were used to form evidence-based recommendations. Quality of evidence and strength of recommendations were determined using the Grading of Recommendations, Assessment, Development and Evaluations framework. Consensus was reached via electronic survey following a modified Delphi method.

Findings

A total of 131 publications were identified, including 8 systematic reviews and meta-analyses, 6 randomized clinical trials, 29 prospective studies, and 88 retrospective cohort studies. After 2 rounds of surveys, 24 recommendations and 5 good clinical practice statements were developed, with full consensus among panelists. Recommendations focused on tumor and functional imaging characteristics, blood-based biomarkers, and carcinoid heart disease. A single strong recommendation was made for symptomatic carcinoid syndrome informing treatment in midgut neuroendocrine tumors. Conditional recommendations were made to use grade, morphology, primary site, and urinary 5-hydroxyindoleacetic levels to inform treatment. The guidance document was endorsed by the Commonwealth Neuroendocrine Tumour Collaboration and the North American Neuroendocrine Tumor Society.

Conclusions and Relevance

The study results suggest that select factors have sufficient evidence to inform care in GEP-NENs, but the evidence for most biomarkers is weak. This article may help guide management and identify gaps for future research to advance personalized medicine and improve outcomes for patients with GEP-NENs.

Serum and urinary 5-hydroxyindolacetic acid, serotonin, chromogranin A, and NT-proBNP for the detection of carcinoid heart disease

OBJECTIVE

The aim of this study was to evaluate the performance of different biomarkers for the detection of carcinoid heart disease (CHD) in neuroendocrine tumours (NETs), in particular serum 5-HIAA (s5HIAA).

DESIGN

An explorative ancillary study of the French CrusoeNET cohort.

METHODS

Patients managed in the Lyon-EURACAN Center of Excellence (CoE) were included when they were aged of at least 18 years, treated and followed for an advanced/metastatic ileum or lung NET, a NET irrespective of the primary location or from unknown primary location but with clinical CS, and/or elevation of urinary 5-HIAA (u5HIAA) twice greater than the upper limit of normal. All patients included had 1 available serum stored within the local biobank between January 2021 and April 2022. Echocardiography was performed by 1 of the 3 expert cardiologists of the Lyon-EURACAN-CoE.

RESULTS

We included 138 patients with NETs, mainly of the small intestine and lung, and 19 of them had a CHD. Analysis showed that s5HIAA was well correlated with u5HIAA (ρ = 0.824 [0.76-0.88], P < .0001) and was a good biomarker for CHD detection (receiver operating characteristic curve = 0.85 [0.75-0.94], P < .0001). Using a threshold value of 757 nmol/L, the sensitivity and specificity for the detection of CHD were 84% and 80%, respectively.

CONCLUSIONS

s5HIAA is highly sensitive and specific for CHD detection. It could be used as a pre-screening tool in centres where systematic and regular echocardiography by an expert cardiologist is not performed in this population.

The Value of Repeat 5-HIAA Measurements as a Predictor of Carcinoid Heart Disease: A Prospective 5-Year Follow-Up Study in Patients with Small Intestinal Neuroendocrine Tumors

Background: Small intestinal neuroendocrine tumors (SI-NETs) are characterized by carcinoid syndrome and carcinoid heart disease (CHD). The aim of the present study was to identify early risk markers for carcinoid heart disease and survival in a prospective median-term follow-up setting. Methods: We measured 5-HIAA and cumulative 5-HIAA exposure (Cum-5-HIAA) based on repeated measurements, proBNP, vascular function, hepatic tumor load, and transthoracic echocardiography (TTE) at baseline and during the median 5-year follow-up. Of 65 patients with SI-NETs, 54 patients underwent a prospective follow-up. In addition, survival was evaluated during the median follow-up of 6 years. Results: At baseline, three patients had CHD. During the median follow-up of 5 years, two patients (4%) developed CHD. Cum-5-HIAA and proBNP correlated with CHD (Westberg score, Spearman's ρ = 0.32 and 0.31, respectively). Cum-5-HIAA had a superior diagnostic capability, predicting CHD in receiver operator characteristic analysis with an AUC of 0.98 (95% CI: 0.94-1.00) and outperformed proBNP, chromogranin A (CgA), and individual serum 5-HIAA measurements (AUC = 0.75, 0.85, and 0.91, respectively). Minor changes in valve regurgitation were frequently detected but did not correlate with vascular function. Regurgitation increased or decreased in 29% of tricuspid and 30% of pulmonic valves. CHD, hepatic tumor load, serum 5-HIAA, and elevated aortic pulse wave velocity (PWV) were associated with increased mortality in SI-NET patients. Conclusions: Cum-5-HIAA is a promising biomarker for CHD risk and outperformed other biomarkers. CHD and hepatic tumor load are the strongest predictors of mortality. PWV is a novel predictor of survival. The incidence of CHD was low among the SI-NET patients, probably reflecting successful treatment regimens.

Exploring Carcinoid Syndrome in Neuroendocrine Tumors: Insights from a Multidisciplinary Narrative Review

Carcinoid syndrome (CS) is a rare condition associated with neuroendocrine tumors (NETs), particularly those originating in the gastrointestinal tract, which secrete bioactive substances like serotonin. The management of CS requires a multidisciplinary approach due to its complex clinical manifestations, including flushing, diarrhea, bronchospasm, and carcinoid heart disease. Optimal care involves collaboration between several professional figures like oncologists, endocrinologists, gastroenterologists, surgeons, and dietitians. Currently, a wide range of treatments are available, focused on both symptom control and tumor burden reduction. Somatostatin analogs (SSAs) are the first-line therapy for symptom relief. Still, in patients with progressive disease or refractory CS, other options include targeted therapies, peptide receptor radionuclide therapy (PRRT), liver-directed therapies, and surgical resection, when feasible. Furthermore, management of complications related to prolonged serotonin release and malnutrition as a result of exocrine pancreatic insufficiency, post-surgical conditions, vitamin deficit, and chronic diarrhea often requires early detection to mitigate symptoms and improve the quality of life in these patients. The complexity of CS necessitates individualized care and continuous coordination among specialists to optimize outcomes and enhance patient well-being.

Clinicopathological and epigenetic differences between primary neuroendocrine tumors and neuroendocrine metastases in the ovary

Currently, the available literature provides insufficient support to differentiate between primary ovarian neuroendocrine tumors (PON) and neuroendocrine ovarian metastases (NOM) in patients. For this reason, patients with a well-differentiated ovarian neuroendocrine tumor (NET) were identified through electronic patient records and a nationwide search between 1991 and 2023. Clinical characteristics were collected from electronic patient files. This resulted in the inclusion of 71 patients with NOM and 17 patients with PON. Histologic material was stained for Ki67, SSTR2a, CDX2, PAX8, TTF1, SATB2, ISLET1, OTP, PDX1, and ARX. DNA methylation analysis was performed on a subset of cases. All PON were unilateral and nine were found within a teratoma (PON-T+). A total of 78% of NOM were bilateral, and none were associated with a teratoma. PON without teratomous components (PON-T-) displayed a similar insular growth pattern and immunohistochemistry as NOM (p > 0.05). When compared with PON-T+, PON-T- more frequently displayed ISLET1 positivity and were larger, and patients were older at diagnosis (p < 0.05). Unsupervised analysis of DNA methylation profiles from tumors of ovarian (n = 16), pancreatic (n = 22), ileal (n = 10), and rectal (n = 7) origin revealed that four of five PON-T- clustered together with NOM and ileal NET, whereas four of five PON-T+ grouped with rectum NET. In conclusion, unilateral ovarian NET within a teratoma should be treated as a PON. Ovarian NET localizations without teratomous components have a molecular profile analogous to midgut NET metastases. For these patients, a thorough review of imaging should be performed to identify a possible undetected midgut NET and a corresponding follow-up strategy may be recommended.

Carcinoid heart disease in patients with advanced small-intestinal neuroendocrine tumors and carcinoid syndrome: a retrospective experience from two European referral centers

BACKGROUND

Up to 50% of patients with advanced small-intestinal neuroendocrine tumors (SI-NETs) and carcinoid syndrome (CS) develop carcinoid heart disease (CHD). However, the true frequency and prognostic markers for CHD in CS are lacking. We described the real-world management of patients in two NET referral centers in this clinical context and relationships between clinical features, including CHD and overall survival (OS).

PATIENTS AND METHODS

This is a retrospective analysis of patients with stage IV SI-NET and CS, treated at the European Institute of Oncology in Milan and Uppsala University in Sweden between 2015 and 2021. CHD was defined as at least one moderate right-sided heart valve defect. Median OS and cumulative incidence of CHD were estimated from the diagnosis of metastatic disease, and the association between clinical parameters with both OS and occurrence of CHD was evaluated.

RESULTS

We included 165 patients, with 97% having low-intermediate-grade SI-NETs and 86% having synchronous liver metastases. Ninety-eight patients (59%) became refractory to full label dose of somatostatin analogues and 25% developed a CHD. At CHD diagnosis, baseline urine 5-hydroxyindoleacetic acid (24-h u5-HIAA) value and plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) value were known in 76% of patients. Moderate-to-severe tricuspid insufficiency was the most common alteration of CHD. Prognosis was significantly impaired by CHD (multivariable hazard ratio for OS = 2.85, P < 0.001). The median OS from the CHD diagnosis was 4.5 years [95% confidence interval (CI) 2.1-7.2 years], and the 5-year survival rate was 34% (95% CI 13% to 57%).

CONCLUSIONS

In our study population of SI-NET patients with CS, more than half had a refractory carcinoid syndrome (RCS) and one-quarter developed a CHD, with a negative impact on OS. Therefore, it is recommended to screen and monitor patients with CS for CHD, ideally with a combination of u5-HIAA, NT-proBNP values, and echocardiography at CS baseline, preferably in NET referral centers.

Management of functional neuroendocrine tumors

Functional neuroendocrine neoplasms (NENs) are those associated with specific symptoms related to the hormonal secretion of the NENs. Although less than 25 % of NENs are functional at diagnosis,1 the associated syndromes significantly increase the patient burden of disease. Management of hormonal NEN symptoms may involve tumor resection or other reduction strategies (e.g., chemotherapy, embolotherapy, etc), but also specific therapies directed at decreasing hormonal synthesis, secretion, or end-organ effects. In this review, we focus on specific symptomatic management of many of the NEN syndromes, which may be pursued in addition to management primarily directed at tumor bulk and growth. A continued focus on symptom management related to the hormonal secretions of NENs, in the context of other efforts to reduce tumor bulk and growth, could significantly improve patient wellbeing.

Mid-Treatment Response to 177-Lutetium Dotatate Predicts Overall Outcome in Patients With Advanced Neuroendocrine Tumors

PURPOSE

Patients with advanced, well-differentiated neuroendocrine tumors (WD-NETs) often require both peptide receptor radionuclide therapy (PRRT) and subsequent chemotherapy. However, no mid-PRRT predictors are available to identify patients who will not benefit from subsequent PRRT to limit their radiation exposure. Our aim is to characterize patients for whom subsequent PRRT is less efficacious on the basis of mid-PRRT evaluation.

MATERIALS AND METHODS

A retrospective study of patients with WD-NET who underwent ≥four PRRT cycles. Data gathered included demographics, tumor grade, stage, and response (partial response [PR], stable disease [SD], and progressive disease [PD]) on the basis of RECIST 1.1 criteria and 68Ga-dotatate positron emission tomography-computerized tomography pretreatment, after second and fourth treatment cycle, 6 months after fourth cycle, and at last follow-up.

RESULTS

Fifty-one patients (51.6% women; age at diagnosis 66.0 ± 1.65 years), with pancreatic NET (PNET; n = 24), small intestine NET (n = 13), or other NET (n = 14), received PRRT, resulting in PR (n = 21), SD (n = 23), and PD (n = 3). Of the patients reaching PR after PRRT, most reached PR after two treatments (70.4%), with only 11.8% PR occurring between subsequent cycles (P = .001). Furthermore, patients with PR at mid-treatment had higher PR rates after PRRT completion than those with SD (P = .007). Patients harboring PNET who achieved PR had a more pronounced reduction of tumor burden in additional cycles than patients who did not (25.6% v 1.5%; P = .03, respectively). On the multivariable model, adjusted for grade and primary site, PR at mid-treatment evaluation was associated with a 20.9 adjusted odds ratio for additional PR at PRRT completion (P = .002).

CONCLUSION

Mid-PRRT assessment predicts subsequent PRRT response in patients with WD-NET, especially those with PNET, informing personalized management and consideration of reduced bone marrow radiation exposure in high-risk patients.

Efficacy of Racecadotril in a Patient Affected by a Therapy-Refractory VIPoma and Carcinoid Syndrome

Neuroendocrine neoplasms (NENs) encompass a heterogeneous spectrum of tumors originating from the diffuse neuroendocrine cell system. Approximately 30% of NEN exhibit functional activity with clinical syndromes through hormone-mediated effects. Synchronous and metachronous functioning syndromes, resulting from the simultaneous release of distinct hormones, are exceptionally rare. Of note, hormonal excess syndromes can have a greater effect on patients' morbidity and mortality than the tumor mass itself. We present the case of a 49-year-old male patient affected by an oligo-metastatic ileal NEN, concurrently demonstrating vasointestinal peptide (VIP) and serotonin excretion, complicated by pulmonary tuberculosis. After the first cycle of Lutetium-177-DOTATATE peptide-radio-receptor therapy, the patient developed a severe watery diarrhea, hypokalemia, and achlorhydria (WDHA) syndrome, despite receiving high-dose somatostatin analogues, everolimus, and telotristat ethyl, without any surgical options. The WDHA syndrome necessitated intensive-care-unit (ICU) admission with continual intravenous administration of electrolytes and fluids. With limited alternatives, an off-label intervention using the enkephalinase inhibitor racecadotril was initiated. After 5 days of treatment, the WDHA syndrome exhibited sufficient control, facilitating the patient's discharge from the ICU. This case report underscores racecadotril as an individualized, off-label treatment strategy for patients with severe VIPoma and serotonin-driven WDHA syndrome, where conventional therapeutic avenues have been exhausted.

Theranostics in Neuroendocrine Tumors: Updates and Emerging Technologies

Advancements in somatostatin receptor (SSTR) targeted imaging and treatment of well-differentiated neuroendocrine tumors (NETs) have revolutionized the management of these tumors. This comprehensive review delves into the current practice, discussing the use of the various FDA-approved SSTR-agonist PET tracers and the predictive imaging biomarkers, and elaborating on Lu177-DOTATATE peptide receptor radionuclide therapy (PRRT) including the evolving areas of post-therapy imaging practices, PRRT retreatment, and the potential role of dosimetry in optimizing patient treatments. The future directions sections highlight ongoing research on investigational PET imaging radiotracers, future prospects in alpha particle therapy, and combination therapy strategies.

Neuroendocrine neoplasms of head and neck, genitourinary and gynaecological systems, unknown primaries, parathyroid carcinomas and intrathyroid thymic neoplasms: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up

•This Clinical Practice Guideline provides key recommendations for managing rare endocrine tumours. •Neuroendocrine neoplasms of different origins, parathyroid carcinoma and intrathyroid thymic neoplasms are included. •The guideline covers clinical imaging and pathological diagnosis, staging and risk assessment, treatment and follow-up. •The authors comprise a multidisciplinary group of experts from different institutions and countries in Europe. •Recommendations are based on available scientific data and the authors’ collective expert opinion.

Thyroid Malignancy and Cutaneous Lichen Amyloidosis: Key Points Amid RET Pathogenic Variants in Medullary Thyroid Cancer/Multiple Endocrine Neoplasia Type 2 (MEN2)

We aimed to provide an updated narrative review with respect to the RET pathogenic variants and their implications at the clinical and molecular level in the diagnosis of medullary thyroid cancer (MTC)/multiple endocrine neoplasia (MEN) type 2, particularly with respect to the presence of cutaneous lichen amyloidosis (CLA). We searched English-language, in extenso original articles with no timeline nor study design restriction that were published on PubMed. A traditional interplay stands for CLA and MTC in MEN2 (not MEN3) confirmation. While the connection has been reported for more than three decades, there is still a large gap in understanding and addressing it. The majority of patients with MEN2A-CLA have RET pathogenic variants at codon 634; hence, it suggests an involvement of this specific cysteine residue in both disorders (most data agree that one-third of C634-positive subjects have CLA, but the ranges are between 9% and 50%). Females seem more prone to MEN2-CLA than males. Non-C634 germline RET pathogenic variants included (at a low level of statistical evidence) the following: RET V804M mutation in exon 14 for MTC-CLA (CLA at upper back); RET S891A mutation in exon 15 binding OSMR variant G513D (familial MTC and CLA comprising the lower legs to thighs, upper back, shoulders, arms, and forearms); and C611Y (CLA at interscapular region), respectively. Typically, CLA is detected at an early age (from childhood until young adulthood) before the actual MTC identification unless RET screening protocols are already applied. The time frame between CLA diagnosis and the identification of RET pathogenic variants was between 5 and 60 years according to one study. The same RET mutation in one family is not necessarily associated with the same CLA presentation. In MTC/MEN2 subjects, the most affected CLA area was the scapular region of the upper back. Alternatively, another hypothesis highlighted the fact that CLA is secondary to long-term prurit/notalgia paresthetica (NP) in MTC/MEN2. OSMR p. G513D may play a role in modifying the evolutionary processes of CLA in subjects co-harboring RET mutations (further studies are necessary to sustain this aspect). Awareness in CLA-positive patients is essential, including the decision of RET testing in selected cases.

Comparative analysis of international guidelines on the management of advanced non-functioning well-differentiated pancreatic neuroendocrine tumors

This review presents a comprehensive comparative analysis of international guidelines for managing advanced, non-functioning, well-differentiated pancreatic neuroendocrine tumors (panNETs). PanNETs, which represent a significant proportion of pancreatic neuroendocrine neoplasms, exhibit diverse clinical behaviors and prognoses based on differentiation, grading, and other molecular markers. The varying therapeutic strategies proposed by different guidelines reflect their distinct emphases and regional considerations, such as the ESMO guideline's focus on advanced disease management and the ENETS guidance paper's multidisciplinary approach. This review examines the most recent guidelines from ESMO, NCCN, ASCO, ENETS, and NANETS, analyzing the recommendations for first-line therapies and subsequent treatment pathways in different clinical scenarios. Significant variations are observed in the recommendations, particularly concerning the choice and sequence of systemic therapies, the role of tumor grading and the Ki-67 index in therapeutic decisions, and the integration of regional regulatory and clinical practices. The analysis highlights the need for a tailored approach to managing advanced NF panNETs, advocating for flexibility in applying guidelines to account for individual patient circumstances and the evolving evidence base. This work underscores the complexities of managing this patient population and the critical role of a multidisciplinary team in optimizing treatment outcomes.

Carcinoid Heart Disease

Carcinoid heart disease (CHD) is a rare cardiac complication that occurs most commonly in patients with advanced neuroendocrine tumors and is a known sequela of carcinoid syndrome. Neuroendocrine tumors most widely associated with CHD include tumors in the small bowel, followed by lung, large bowel, pancreatic, appendiceal, and ovarian neoplasms. Carcinoid syndrome is a paraneoplastic syndrome caused by the release of serotonin and other substances from neuroendocrine tumors. It results in a spectrum of symptoms, including diarrhea, flushing, bronchospasm, and symptoms of congestive heart failure. Without treatment and for patients with advanced heart failure, the prognosis of CHD can be less than a year. Management of CHD is often challenging as patients typically present late, and the disease can progress rapidly. Therefore, optimal management of these patients requires close collaboration among various specialties to quantify disease burden, delay the progression of valvular disease, and determine the most effective surgical and medical management strategies depending on the cardiac manifestations to improve quality of life and reduce mortality. This involves a collaborative team, including cardiology and oncology, and often involves many other disciplines, including hepatobiliary and cardiovascular surgeons, endocrinologists, anesthesiologists, and gastroenterologists.

Gastrointestinal side effects of somatostatin analogs in neuroendocrine tumors: a focused review

Neuroendocrine tumors (NETs) are a group of well-differentiated heterogeneous neoplasms characterized by slow progression and distinct clinical and biological behavior. In the majority of patients with NET, first-line treatment is represented by somatostatin analogs (SSAs) that, despite being drugs with high tolerability (even at high doses) and providing to carcinoid symptoms control and anti-proliferative effects, may present some side effects, with potential impact on quality of life and nutritional status. The most frequent side effects are represented by gastrointestinal events in particular alterations in bowel habits (diarrhea and constipation), abdominal pain, exocrine pancreatic insufficiency, and cholelithiasis. Considering the relative rarity of NETs, literature about frequency and standard clinical management of adverse events SSA-related is still lacking and heterogeneous. The aim of this review is to arm gastroenterologists and other physicians treating NET patients with essential knowledge on the side effects of SSAs. By identifying and managing these adverse events early, healthcare professionals can offer optimal care, avert foreseeable complications, and ensure the best outcomes for patients. Without such early recognition, there is a risk of diminishing the patient's quality of life and their ability to sustain treatment over time.

European Neuroendocrine Tumor Society (ENETS) 2024 guidance paper for the management of well-differentiated small intestine neuroendocrine tumours

Both the incidence and prevalence of well-differentiated neuroendocrine tumours from the small intestine (Si-NET) are gradually increasing. Most patients have non-functioning tumours with subtle GI symptoms and tumours are often discovered incidentally by endoscopy or at advanced disease stages by imaging depicting mesenteric lymph node and /or liver metastases while around 30% of the patients present with symptoms of the carcinoid syndrome. Adequate biochemical assessment and staging including functional imaging is crucial for treatment-related decision-making that should take place in an expert multidisciplinary team setting. Preferably, patients should be referred to specialised ENETS Centres of Excellence or centres of high expertise in the field. This guidance paper provides the current evidence and best knowledge for the management of Si-NET grade (G) 1-3 following 10 key questions of practical relevance for the diagnostic and therapeutic decision making.

The Clinicopathological Characteristics and Surgical Treatment of Gastrointestinal Neuroendocrine Neoplasm-A 10-Year Single-Center Experience

Background: Gastrointestinal neuroendocrine neoplasms (GI-NENs) represent a diverse group of tumors, with surgical resection being the gold standard for treatment. Materials and Methods: A retrospective analysis was conducted on 63 patients (32 women, 31 men) who underwent surgery for GI-NENs at the Department of Digestive Tract Surgery from January 2013 to June 2023. Tumors were classified by stage (localized, regionally advanced, metastatic). Results: Clinical symptoms were reported by 42 (66.7%) patients, with abdominal pain being the most common symptom, affecting 28 (44.4%) patients. The majority of tumors (44, 69.8%) originated in the midgut. The most frequently performed surgery was right hemicolectomy, carried out on 33 (52.4%) patients. Radical tumor resection was performed in 35 (55.6%) patients. Postoperative complications occurred in 12 (19%) patients, with male gender identified as an independent predictive factor for complications (p = 0.04). Non-functioning tumors were more common (33, 52.4%), and most tumors were classified as grade 1 histopathologically (49, 77.8%). Distant metastases were present in 29 (46%) patients. The overall two-year survival rate was 94.9%, with a five-year survival rate also estimated at 94.9%. Conclusions: GI-NENs are often diagnosed at advanced stages, frequently with distant or lymph node metastases, and predominantly arise in the midgut. Despite low postoperative morbidity and mortality, male gender may be a predictor of postoperative complications. Overall, the prognosis for GI-NENs is favorable, reflected in high overall survival rates.

Sarcopenia in Patients with Advanced Gastrointestinal Well-Differentiated Neuroendocrine Tumors

BACKGROUND

Neuroendocrine neoplasms (NENs) are slow-growing tumors. Sarcopenia is defined as the loss of muscle mass, strength, and physical performance. First-line NEN therapy is somatostatin analogs, which could be responsible for malabsorption conditions, such as pancreatic exocrine insufficiency (EPI) with underlying sarcopenia.

AIM

Evaluate the prevalence of sarcopenia in patients with NENs at diagnosis and during follow-up.

METHODS

A retrospective single-center study was conducted, including patients with advanced intestinal NENs G1/G2 (excluded pancreatic NENs). CT scans were analyzed at diagnosis and after 6 months of therapy, and the skeletal muscle index was assessed.

RESULTS

A total of 30 patients (F:M = 6:24) were enrolled, with the following primary tumor sites: 25 in the ileum, 1 stomach, 2 jejunum, and 2 duodenum. At diagnosis, 20 patients (66.6%) showed sarcopenic SMI values, and 10 patients (33.3%) showed non-sarcopenic SMI values. At follow-up, three more patients developed sarcopenic SMI values. Statistical significance in relation to the presence of sarcopenia was found in the group of patients with carcinoid syndrome (p = 0.0178), EPI (p = 0.0018), and weight loss (p = 0.0001).

CONCLUSION

Sarcopenia was present in 2/3 of the patients with advanced intestinal NENs at the diagnosis and during the follow-up. It is reasonable to consider this condition to improve clinical outcomes.

[Current developments in the treatment of neuroendocrine tumors]

BACKGROUND

Well-differentiated neuroendocrine tumors (NET) are rare malignancies that are clinically very heterogeneous. Accordingly, their treatment is also complex and dependent on various factors. With currently available systemic therapies, the prognosis is often favorable.

OBJECTIVES

This article aims to provide an overview of current treatment strategies for NET, addressing the most important NET locations.

METHODS

The current European guidelines and further relevant literature on the treatment of NET were reviewed for this purpose.

RESULTS

The therapeutic spectrum for NET is extremely broad: For NET of the stomach/duodenum, appendix, and rectum, endoscopic or surgical resection is often sufficient, and metastatic tumors are rare. NET of the pancreas, small intestine and lung should also undergo potentially curative resection in the early stages. In the metastatic stage, locoregional treatments such as surgery and liver tumor embolization play a role. Major advances have been made in drug therapy, with somatostatin analogs (octreotide and lanreotide), an mTOR inhibitor (everolimus), and a tyrosine kinase inhibitor (sunitinib) being widely used. Peptide receptor radionuclide therapy (PRRT) is also an invaluable option. In some cases, classic chemotherapy is indicated.

CONCLUSIONS

Many effective therapies are now available for NET. It is important to select the right therapy at the right time for each patient through interdisciplinary management.

Carcinoid crisis: The challenge is still there

Carcinoid crisis (CC) has classically been considered the extreme end of the spectrum of carcinoid syndrome (CS). However, this presumption and other aspects of CC remain poorly understood. Consequently, current clinical guidelines are based on a low quality of evidence. There is no standard definition of CC and its incidence is unknown. Patients with florid CS and elevated serotonin (or its derivatives) which develop CC have been reported during decades. Nevertheless, the hypothesis that CC is due to the sudden massive release of serotonin or other vasoactive substances is unproven. Many triggers of CC (surgery, anaesthesia, peptide receptor radionuclide therapy, tumour biopsy or liver-directed treatments) have been proposed. However, data from studies are heterogeneous and even contradictory. Finally, the role of octreotide in the prevention of CC has been questioned. Herein, we report a clinical case and perform a critical review of the evidence available today on this topic.

EndoBridge 2023: highlights and pearls

EndoBridge 2023 took place on October 20-22, 2023, in Antalya, Turkey. Accredited by the European Council, the 3-day scientific program of the 11th Annual Meeting of EndoBridge included state-of-the-art lectures and interactive small group discussion sessions incorporating interesting and challenging clinical cases led by globally recognized leaders in the field and was well attended by a highly diverse audience. Following its established format over the years, the program provided a comprehensive update across all aspects of endocrinology and metabolism, including topics in pituitary, thyroid, bone, and adrenal disorders, neuroendocrine tumors, diabetes mellitus, obesity, nutrition, and lipid disorders. As usual, the meeting was held in English with simultaneous translation into Russian, Arabic, and Turkish. The abstracts of clinical cases presented by the delegates during oral and poster sessions have been published in JCEM Case Reports. Herein, we provide a paper on highlights and pearls of the meeting sessions covering a wide range of subjects, from thyroid nodule stratification to secondary osteoporosis and from glycemic challenges in post-bariatric surgery to male hypogonadism. This report emphasizes the latest developments in the field, along with clinical approaches to common endocrine issues. The 12th annual meeting of EndoBridge will be held on October 17-20, 2024 in Antalya, Turkey.

What Is Carcinoid Syndrome? A Critical Appraisal of Its Proposed Mediators

Carcinoid syndrome (CS) is a debilitating disease that affects approximately 20% of patients with neuroendocrine neoplasms (NEN). Due to the increasing incidence and improved overall survival of patients with NEN over recent decades, patients are increasingly suffering from chronic and refractory CS symptoms. At present, symptom control is hampered by an incomplete understanding of the pathophysiology of this syndrome. This systematic review is the first to critically appraise the available evidence for the various hormonal mediators considered to play a causative role in CS. Overall, evidence for the putative mediators of CS was scarce and often of poor quality. Based on the available literature, data are only sufficient to agree on the role of serotonin as a mediator of CS-associated diarrhea and fibrosis. A direct role for tachykinins and an indirect role of catecholamines in the pathogenesis of CS is suggested by several studies. Currently, there is insufficient evidence to link histamine, bradykinin, kallikrein, prostaglandins, or motilin to CS. To summarize, available literature only sufficiently appoints serotonin and suggests a role for tachykinins and catecholamines as mediators of CS, with insufficient evidence for other putative mediators. Descriptions of CS should be revised to focus on these proven hormonal associations to be more accurate, and further research is needed into other potential mediators.

Theranostics in Neuroendocrine Tumors

ABSTRACT

Neuroendocrine tumors (NETs) are rare tumors that develop from cells of the neuroendocrine system and can originate in multiple organs and tissues such as the bowels, pancreas, adrenal glands, ganglia, thyroid, and lungs. This review will focus on gastroenteropancreatic NETs (more commonly called NETs) characterized by frequent somatostatin receptor (SSTR) overexpression and pheochromocytomas/paragangliomas (PPGLs), which typically overexpress norepinephrine transporter. Advancements in SSTR-targeted imaging and treatment have revolutionized the management of patients with NETs. This comprehensive review delves into the current practice, discussing the use of the various Food and Drug Administration-approved SSTR-agonist positron emission tomography tracers and the predictive imaging biomarkers, and elaborating on 177Lu-DOTATATE peptide receptor radionuclide therapy including the evolving areas of posttherapy imaging practices and peptide receptor radionuclide therapy retreatment. SSTR-targeted imaging and therapy can also be used in patients with PPGL; however, this patient population has demonstrated the best outcomes from norepinephrine transporter-targeted therapy with 131I-metaiodobenzylguanidine. Metaiodobenzylguanidine theranostics for PPGL will be discussed, noting that in 2024 it became commercially unavailable in the United States. Therefore, the use and reported success of SSTR theranostics for PPGL will also be explored.

Elevated sortilin expression discriminates functional from non-functional neuroendocrine tumors and enables therapeutic targeting

A subset of neuroendocrine tumors (NETs) can cause an excessive secretion of hormones, neuropeptides, and biogenic amines into the bloodstream. These so-called functional NETs evoke a hormone-related disease and lead to several different syndromes, depending on the factors released. One of the most common functional syndromes, carcinoid syndrome, is characterized mainly by over-secretion of serotonin. However, what distinguishes functional from non-functional tumors on a molecular level remains unknown. Here, we demonstrate that the expression of sortilin, a widely expressed transmembrane receptor involved in intracellular protein sorting, is significantly increased in functional compared to non-functional NETs and thus can be used as a biomarker for functional NETs. Furthermore, using a cell line model of functional NETs, as well as organoids, we demonstrate that inhibition of sortilin reduces cellular serotonin concentrations and may therefore serve as a novel therapeutic target to treat patients with carcinoid syndrome.

From biology to clinical practice: antiproliferative effects of somatostatin analogs in neuroendocrine neoplasms

Somatostatin analogs (SSA), specifically octreotide and lanreotide, have demonstrated antiproliferative effects in patients with neuroendocrine tumors (NET), a group of rare malignancies of diverse origin and presentation. A prominent feature of NET cells is the expression of G protein-coupled receptors called somatostatin receptors (SSTR). Although these SSTR are not uniformly present in NET, they can be instrumental in the diagnosis and treatment of NET. Apart from their application in nuclear imaging and radionuclide therapy, SSA have proven invaluable in the treatment of hormonal syndromes associated with certain NET (antisecretory effects of SSA), but it took more than two decades to convincingly demonstrate the antiproliferative effects of SSA in metastatic NET with the two pivotal studies PROMID and CLARINET. The current review summarizes three decades of SSA treatment and provides an overview of the clinical trial landscape for SSA monotherapy and combination therapy, including clinical implications and quality of life aspects, as well as ongoing fields of research.

A systematic review and meta-analysis of the diagnosis and surgical management of carcinoid heart disease

Introduction

Carcinoid heart disease (CHD), a complication of carcinoid syndrome (CS), is a rare condition that can lead to right sided valvular heart disease and has been traditionally associated with a poor prognosis. We conducted a systematic review and meta-analysis to explore the accuracy of biomarkers and echocardiography in diagnosing CHD amongst patients who are already known to have neuroendocrine tumours and to assess whether surgical management of CHD leads to a reduction in mortality.

Methods

A systematic literature search of MEDLINE, EMBASE, EBM Reviews, Google Scholar, ClinicalTrials.gov was conducted. All studies on patients with carcinoid heart disease (CHD) reporting on biomarkers, echocardiographic and surgical outcomes were included. The National Heart, Lung, and Blood Institute quality assessment tool was used to assess the methodological study quality. Data analysis was performed using Stata Statistical Software and R Studio, and individual meta-analyses were performed for biomarkers, echocardiographic findings, and surgical outcomes.

Results

A total of 36 articles were included in the systematic review analysis. N terminal pro-brain natriuretic peptide (NTproBNP) and 5-hydroxyindole acetate (5-HIAA) levels were higher in patients with CHD compared with those without CHD. 32% of CS patients had echocardiographic evidence of cardiac involvement, of which 79% involved tricuspid valve abnormalities. Moderate-severe tricuspid regurgitation was the most common echocardiographic abnormality (70% of patients). However, these analyses had substantial heterogeneity due to the high variability of cardiac involvement across studies. Pooled surgical mortality for CHD was 11% at 1 month, 31% at 12 months and 56% at 24 months. When assessing surgical outcomes longitudinally, the one-month surgical results showed a trend towards more recent surgeries having lower mortality rates than those reported in earlier years, however this was not statistically significant.

Discussion

There is not enough data in current literature to determine a clear cut-off value of NTproBNP and 5-HIAA to help diagnose or determine CHD severity. Surgical management of CHD is yet to show significant mortality benefit, and there are no consistent comparisons to medical treatment in current literature.

Plasma tryptophan pathway metabolites quantified by liquid chromatography-tandem mass spectrometry as biomarkers in neuroendocrine tumor patients

A good and accessible biomarker is of great clinical value in neuroendocrine tumor (NET) patients, especially considering its frequently indolent nature and long-term follow-up. Plasma chromogranin A (CgA) and 5-hydroxyindoleacetic acid (5-HIAA) are currently used as biomarkers in NET, but their sensitivity and specificity are restricted. 5-HIAA is the main metabolite of serotonin, an important neurotransmitter of the tryptophan pathway. The aim of this study is to estabish a sensitive and accurate method for the quantification of tryptophan pathway metabolites in plasma. We further aimed to evaluate its utility as a clinical tool in NET disease. We obtained plasma samples from NET patients and healthy controls recruited from the University Hospital of North Norway, Tromsø. Samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and eight metabolites of the tryptophan pathway were quantified. We included 130 NET patients (72/130 small intestinal [SI] NET, 35/130 pancreatic NET, 23/130 other origin) and 20 healthy controls. In the SI-NET group, 26/72 patients presented with symptoms of carcinoid syndrome (CS). We found that combining tryptophan metabolites into a serotonin/kynurenine pathway ratio improved diagnostic sensitivity (92.3%) and specificity (100%) in detecting CS patients from healthy controls compared with plasma 5-HIAA alone (sensitivity 84.6%/specificity 100%). Further, a clinical marker based on the combination of plasma serotonin, 5-HIAA, and 5OH-tryptophan, increased diagnostic capacity identifying NET patients with metastasized disease from healthy controls compared with singular plasma 5-HIAA, serotonin, or CgA. In addition, this marker was positive in 61% of curatively operated SI-NET patients compared with only 10% of healthy controls (p < .001). Our results indicate that simultaneous quantification of several tryptophan metabolites in plasma, using LC-MS/MS, may represent a clinically useful diagnostic tool in NET disease.

Does Telotristat Have a Role in Preventing Carcinoid Heart Disease?

Carcinoid heart disease (CHD) is a frequent and life-threatening complication in patients with carcinoid tumors. Its clinical management is challenging is some cases since serotonin-induced valve fibrosis leads to heart failure. Telotristat is an inhibitor of tryptophan-hydroxylase (TPH), a key enzyme in serotonin production. Telotristat use in patients with carcinoid syndrome and uncontrollable diarrhea under somatostatin analogs is approved, but its specific role in patients with CHD is still not clear. IN this context, we aimed to explore the effect of telotristat in heart fibrosis using a mouse model of serotonin-secreting metastasized neuroendocrine neoplasm (NEN). To this aim, four treatment groups (n = 10/group) were evaluated: control, monthly octreotide, telotristat alone, and telotristat combined with octreotide. Plasma serotonin and NT-proBNP levels were determined. Heart fibrosis was histologically evaluated after 6 weeks of treatment or when an individual mouse's condition was close to being terminal. Heart fibrosis was observed in all groups. Non-significant reductions in primary tumor growth were observed in all of the treated groups. Feces volume was increased in all groups. A non-significant decrease in feces volume was observed in the octreotide or telotristat-treated groups, while it was significantly reduced with the combined treatment at the end of the study compared with octreotide (52 g reduction; p < 0.01) and the control (44.5 g reduction; p = 0.05). Additionally, plasma NT-proBNP decreased in a non-significant, but clinically relevant, manner in the octreotide (28.2% reduction), telotristat (45.9% reduction), and the octreotide + telotristat (54.1% reduction) treatment groups. No significant changes were observed in plasma serotonin levels. A similar non-significant decrease in heart valve fibrosis was observed in the three treated groups. In conclusion, Telotristat alone and especially in combination with octreotide decreases NT-proBNP levels in a mouse model of serotonin-secreting metastasized NEN, when compared with the control and octreotide, but its effect on heart valve fibrosis (alone and in combination) was not superior to octreotide in monotherapy.

Diagnostic and Therapeutic Management of Primary Orbital Neuroendocrine Tumors (NETs): Systematic Literature Review and Clinical Case Presentation

BACKGROUND

The ocular involvement of neuroendocrine neoplasms (NENs) is uncommon and mainly represented by metastases from gastrointestinal and lung neuroendocrine tumors. Primary orbital NENs are even less common and their diagnostic and therapeutic management is a challenge.

METHODS

A systematic review of the literature was conducted from 1966 to September 2023 on PubMed to identify articles on orbital NENs and to summarize their clinical-pathological features, diagnosis and therapeutic management. Furthermore, we presented a case of a locally advanced retro-orbital primary neuroendocrine tumor that was referred to the certified Center of Excellence of Sant'Andrea Hospital, La Sapienza University of Rome, Italy.

RESULTS

The final analysis included 63 records on orbital NENs and 11 records focused on primary orbital NENs. The localization was mostly unilateral and in the right orbit; proptosis or exophthalmos represented the initial symptoms. The diagnostic work-up and therapeutic management was discussed and a diagnostic algorithm for the suspicion of primary orbital NENs was proposed.

CONCLUSIONS

A multidisciplinary approach is required for the management of primary orbital NENs, emphasizing the importance of early referral to dedicated centers for prompt differential diagnosis, tailored treatment, and an improved quality of life and survival.

Surgery as a Principle and Technical Consideration for Primary Tumor Resection of Small Bowel Neuroendocrine Tumors

Small bowel neuroendocrine tumors (SB-NETs) are increasingly identified and have become the most frequent entity among small bowel tumors. An increasing incidence, a high prevalence, and a prolonged survival with optimal modern multidisciplinary management makes SB-NETs a unique set of tumors to consider for surgical oncologists. The major goals of surgical treatment in the setting of SB-NET include control of tumor volume, control of endocrine secretion, and prevention of locoregional complications. Key considerations include assessment of multifocality and resection of mesenteric nodal masses with the use of mesenteric-sparing approaches and acceptance of R1 margins if necessary to clear disease while avoiding short bowel syndrome. A description through eight steps for consideration is presented to allow for systematic surgical planning and execution of resection. Moreover, some controversies and evolving considerations to the surgical principles and technical procedures remain. The role of primary tumor resection in the presence of (unresectable) liver metastasis is still unclear. Reports of feasibility of minimally invasive surgery are emerging, with undetermined selection criteria for appropriateness or long-term outcomes. Resection of SB-NETs should be considered in all patients fit for surgery and should follow principles to achieve surgical oncological control that is appropriate for the stage and tumor burden, considering the age and comorbidity of the individual patient.