The association of a panel of biomarkers with the presence and severity of carcinoid heart disease: a cross-sectional study

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.

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.

Plasma or serum 5-hydroxyindoleacetic acid can be used interchangeably in patients with neuroendocrine tumours

5-hydroxyindole acetic acid, a metabolite of serotonin, is used in the diagnosis and monitoring of patients with neuroendocrine tumours, in particular patients with small intestinal neuroendocrine tumours associated with the carcinoid syndrome. Analysis of 5-hydroxyindole acetic acid was commonly performed in urine, but blood-based assays are now becoming available. The objective of this study was to assess how 5-hydroxyindole acetic acid compares in plasma and serum as a biochemical marker of neuroendocrine tumours. Twenty-four-hour urine, plasma and serum samples were obtained from 80 patients with neuroendocrine tumours and 30 healthy volunteers. We developed a liquid chromatography tandem mass spectrometry assay for plasma and serum 5-hydroxyindole acetic acid. Comparison was made between them, and their cut-off was determined using a receiver-operating characteristic curve. A close correlation was shown between plasma and serum 5-hydroxyindole acetic acid. At a cut-off of 135 nmol/l, a sensitivity of 91.2% with a specificity of 61.9% was obtained for both compared to the urinary assay. A statistically significant agreement was shown when plasma and serum 5-hydroxyindole acetic acid were compared with the currently used urine assay in patients with neuroendocrine tumours; κ = 0.675 (95% CI 0.49 to 0.86), p < 0.001 and healthy volunteers; 0.967 (95% CI 0.828 to 0.999), p = <0.001. In conclusion, 5-hydroxyindole acetic acid in plasma and serum were comparable, hence either sample type can be used interchangeably.

The role of N-terminal pro-brain natriuretic peptide, chromogranin A, and 5-hydroxyindoleacetic acid in screening for carcinoid heart disease

Carcinoid heart disease (CHD) is a serious complication for patients with neuroendocrine tumors (NETs), and early detection is crucial. We aimed to investigate N-terminal pro-brain natriuretic peptide (NT-proBNP), chromogranin A (CgA), and plasma 5-hydroxyindoleacetic acid (P-5-HIAA) as a screening tool for detection of CHD. We prospectively included patients with disseminated small intestinal NETs (SI-NETs) and performed transthoracic echocardiography (TTE), questionnaires, and biochemical assessment of NT-proBNP, CgA, and P-5-HIAA. The presence and severity of CHD was assessed using a scoring system based on echocardiographic characteristics. A total of 93 patients were included in the final analysis. Fifteen (16%) were diagnosed with CHD. The median NT-proBNP (219 ng/L vs. 124 ng/L, p = .05), CgA (3930 pmol/L vs. 256 pmoL/L, p < .0001), and P-5-HIAA (1160 nmol/L vs. 210 nmoL/L, p < .0001) were significantly higher in patients with CHD compared to non-CHD patients. For NT-proBNP, the area under the receiver operating characteristic (AUROC) curve for detection of CHD was 0.67 (95% CI: 0.50-0.84), and at a 260 ng/L cutoff level, the sensitivity and specificity were 46% and 79%. For CgA, the AUROC was 0.91 (95% CI: 0.84-0.97), and at a cutoff level of 598 pmol/L, the sensitivity and specificity were 100% and 69%. For P-5-HIAA, the AUROC was 0.89 (95% CI: 0.80-0.98), and at a cutoff level of 752 nmol/L, the sensitivity and specificity were 92% and 85%. In conclusion, CgA and P-5-HIAA proved excellent markers of CHD while NT-proBNP lacked the required diagnostic accuracy to be used as a screening tool.

NT-proBNP as a neuroendocrine tumor biomarker: beyond heart failure

Introduction

Neuroendocrine tumors (NETs) are rare neoplasms that occur in various locations throughout the body. Despite their usually benign character, they might manifest with distant metastases. N-terminal prohormone of brain natriuretic peptide (NT-proBNP) has previously been described as a useful biomarker in diagnosing carcinoid heart disease (CHD), a common advanced NETs manifestation. We observed plasma concentrations of NT-proBNP in metastatic midgut NETs over a 4-year period.

Objectives

We aimed to explore NT-proBNP concentrations in states of varying levels of cell proliferation and disease status. Our goal was to investigate NT-proBNP's role in predicting disease progression in relation to previous research and up-to-date scientific guidelines.

Patients and methods

We performed a retrospective multivariate analysis of NT-proBNP concentrations in 41 midgut NETs patients treated with somatostatin analogs, all with liver metastases. NT-proBNP concentrations were measured in every patient across 16 evenly distanced time points over a 48-month period and were compared to variables such as sex, age, grading, Ki-67, primary tumor location, and CT findings.

Results

NT-proBNP concentrations correlated positively with higher liver tumor burden, higher grading, high Ki-67 levels, and with progressive disease in CT. There were no differences in NT-proBNP levels with regard to primary location (ileum vs jejunum), sex, and age.

Conclusion

We conclude that NT-proBNP is a useful analyte for monitoring NETs progression, due to its increased concentration in scenarios implying increased cellular proliferation. These long-term follow-up results align with previous findings and suggest an additional role for NT-proBNP in diagnostic algorithms, beyond a CHD biomarker.

An Overview of Circulating Biomarkers in Neuroendocrine Neoplasms: A Clinical Guide

Neuroendocrine neoplasms (NENs) are a heterogeneous group of diseases that are characterized by different behavior and clinical manifestations. The diagnosis and management of this group of tumors are challenging due to tumor complexity and lack of precise and widely validated biomarkers. Indeed, the current circulating mono-analyte biomarkers (such as chromogranin A) are ineffective in describing such complex tumors due to their poor sensitivity and specificity. In contrast, multi-analytical circulating biomarkers (including NETest) are emerging as more effective tools to determine the real-time profile of the disease, both in terms of accurate diagnosis and effective treatment. In this review, we will analyze the capabilities and limitations of different circulating biomarkers focusing on three relevant questions: (1) accurate and early diagnosis; (2) monitoring of disease progression and response to therapy; and (3) detection of early relapse.

Outcome of carcinoid heart syndrome in patients enrolled in the SwissNet cohort

BACKGROUND

Carcinoid heart disease is a rare disease which develops in patients with functional neuroendocrine tumors in an advanced tumor state. Patients diagnosed with carcinoid heart disease have a poor longtime prognosis with respect to morbidity and mortality and long-term data on patient outcomes are lacking.

METHODS AND RESULTS

In this retrospective study, we analyzed outcomes of 23 patients with carcinoid heart disease enrolled into the SwissNet database. We observed that early diagnosis with echocardiographic surveillance of carcinoid heart disease during the course of the neuroendocrine tumor disease was beneficial to overall survival of patients.

CONCLUSION

Through nationwide patient enrollment, the SwissNet registry is a powerful data tool to identify, follow-up and evaluate long-term patient outcomes in patients with rare neuroendocrine tumor driven pathologies including carcinoid heart syndrome with observational methods enabling better therapy optimization to improve patient`s long-term perspectives and survival. In line with the current ESMO recommendations, our data proposes that heart echocardiography should be included as part of the general physical assessment in patients with newly diagnosed NET.

Diagnosis and management of neuroendocrine tumours

Neuroendocrine tumours (NETs) represent a heterogenous group of tumours, with diversity in their primary tumour sites, functional status (ie hormone secreting or non-functional) and degrees of aggressiveness (ranging from well-differentiated, grade 1 neuroendocrine tumours to poorly differentiated grade 3, neuroendocrine carcinomas). The most common sites are the lung, small bowel, pancreas and appendix. Clinical presentation is variable, ranging from incidental lesions detected on cross-sectional imaging, small bowel obstruction, carcinoid syndrome or other syndromic presentations (eg hypoglycaemia resulting from insulinoma) through to florid carcinoid heart disease. Diagnosis relies on biochemical markers, computed tomography (CT), magnetic resonance imaging (MRI) and somatostatin-receptor based functional imaging. Treatment comprises surgery where curative resection is possible through to approaches where disease stabilisation is the key, involving somatostatin analogues, peptide receptor radionuclide therapy (PRRT), everolimus, sunitinib, liver-directed therapies and sometimes chemotherapy. Although local and systemic complications can occur, they are associated with reasonable 5- and 10-year survival rates, respectively.

Elevated Serotonin and NT-proBNP Levels Predict and Detect Carcinoid Heart Disease in a Large Validation Study

Carcinoid heart disease (CHD) is a rare fibrotic cardiac complication of neuroendocrine tumors. Besides known biomarkers N-Terminal pro-B-type natriuretic peptide (NT-proBNP) and serotonin, activin A, connective tissue growth factor (CTGF), and soluble suppression of tumorigenicity 2 (sST2) have been suggested as potential biomarkers for CHD. Here, we validated the predictive/diagnostic value of these biomarkers in a case-control study of 114 patients between 1990 and 2021. Two time-points were analyzed: T0: liver metastasis without CHD for all patients. T1: confirmed CHD in cases (CHD+, n = 57); confirmed absence of CHD five or more years after liver metastasis in controls (CHD−, n = 57). Thirty-one (54%) and 25 (44%) females were included in CHD+ and CHD− patients, respectively. Median age was 57.9 years for CHD+ and 59.7 for CHD- patients (p = 0.290). At T0: activin A was similar across both groups (p = 0.724); NT-proBNP was higher in CHD+ patients (17 vs. 6 pmol/L, p = 0.016), area under the curve (AUC) 0.84, and the most optimal cut-off at 6.5 pmol/L. At T1: activin A was higher in CHD+ patients (0.65 vs. 0.38 ng/mL, p = 0.045), AUC 0.62, without an optimal cut-off value. NT-pro-BNP was higher in CHD+ patients (63 vs. 11 pmol/L, p < 0.001), AUC 0.89, with an optimal cut-off of 27 pmol/L. Serotonin (p = 0.345), sST2 (p = 0.867) and CTGF (p = 0.232) levels were similar across groups. This large validation study identified NT-proBNP as the superior biomarker for CHD. Patients with elevated serotonin levels and NT-proBNP levels between 6.5 and 27 pmol/L, and specifically >27 pmol/L, should be monitored closely for the development of CHD.

Role of Cardiac Biomarkers in Cancer Patients

Simple Summary

Cardiac biomarkers have proved increasingly useful in the various branches of cardiology, not sparing the field of cardio-oncology. With specific reference to the latter subject, they have been investigated as predictors and/or diagnostic and monitoring tools, as well as prognostic factors, with the purpose of allowing the early prevention of many cardiovascular complications related to the direct action of some cancer types or related to the toxicity of its treatments. However, despite this great potential and excellent cost-effectiveness, their usefulness in some areas still seems to be limited due to lack of sufficient specificity or sensitivity. In fact, in clinical practice, while their use is nowadays standard in some circumstances, evidence does not yet support their routine use in other cases.

Abstract

In patients with cancer—and especially some specific subtypes—the heart can be pathologically affected due to the direct action of the tumor or its secretion products or due to the toxicity of some oncological treatments. Cardiac biomarkers have been investigated as inexpensive and easily accessible tools for prediction, early diagnosis, monitoring, or prognosis of various forms of cancer-related cardiac diseases. However, their clinical usefulness was not always clearly demonstrated in every area of cardioncology. For the identification of anthracycline related cardiotoxicity in the very early stages troponins proved to be more efficient detectors than imaging methods. Nevertheless, the lack of a standardized dosage methodology and of cardiotoxicity specific thresholds, do not yet allow to outline the precise way to employ them in clinical routine and to incorporate them into appropriate diagnostic or managing algorithms. Cardiac biomarkers proved also effective in patients with primary cardiac amyloidosis, in which both troponins and natriuretic peptides were able to predict adverse outcome, and carcinoid heart disease, where a precise diagnostic cut-off for N-terminal prohormone of brain natriuretic peptide (NT-proBNP) was identified to screen patients with valvular involvement. Likewise, NT-proBNP proved to be an excellent predictor of postoperative atrial fibrillation (POAF). On the contrary, evidence is still not sufficient to promote the routine use of cardiac biomarkers to early diagnose myocarditis due to immune check points inhibitors (ICIs), radiotherapy induced cardiotoxicity and cardiac complications related to androgenetic deprivation. In this review we present all the evidence gathered so far regarding the usefulness and limitations of these relatively inexpensive diagnostic tools in the field of cardio-oncology.

Interventional Strategies in Cancer-induced Cardiovascular Disease

PURPOSE OF REVIEW

To highlight the range of illnesses and procedures that the interventional onco-cardiologists face in their daily practice, along with the recent additions to anti-cancer therapies and their related cardiotoxicity.

RECENT FINDINGS

Immune checkpoint inhibitors (ICI) are not devoid of cardiotoxicity as thought earlier and lead to an increased incidence of myocarditis. Transcatheter valve replacement has been shown to be a safer alternative to surgical replacement in cancer patients. Interventional onco-cardiology is a novel field that addresses cardiovascular diseases in the setting of cancer. Traditionally excluding cancer patients from clinical trials has led to a dearth of information needed to tackle cardiac conditions like Takotsubo cardiomyopathy, malignant pericardial effusions, and radiation-induced vascular diseases encountered either exclusively or predominantly in this high-risk population. This review discusses the various treatment options available in the interventional armamentarium with a particular focus on ICI-myocarditis and transcatheter aortic valve replacement in cancer patients.

Update in carcinoid heart disease - the heart of the matter

Carcinoid heart disease (CHD) is a paraneoplastic cardiac manifestation occurring in patients with carcinoid syndrome (CS) and advanced neuroendocrine malignancy. In about 20-40% of patients with CS, chronic exposure to tumor-released circulating vasoactive peptides typically results in right-sided valvular fibrosis leading to valve dysfunction and right heart failure. CHD remains a significant cause of morbidity and mortality. The management of patients with CHD is complex, as both the systemic malignant disease and the heart involvement have to be addressed. Early diagnosis and timely surgical intervention in selected patients are of utmost importance and offer a survival benefit. In patients with advanced carcinoid heart disease, valve replacement surgery is the most effective option to alleviate cardiac symptoms and contribute to survival outcomes. A collaboration of a multidisciplinary team in centers with experience is required to provide optimal patient management. Here, we review the current literature regarding CHD presentation, pathophysiology, diagnostic tools, and available treatment strategies.

The Emerging Roles of Chromogranins and Derived Polypeptides in Atherosclerosis, Diabetes, and Coronary Heart Disease

Chromogranin A (CgA), B (CgB), and C (CgC), the family members of the granin glycoproteins, are associated with diabetes. These proteins are abundantly expressed in neurons, endocrine, and neuroendocrine cells. They are also present in other areas of the body. Patients with diabetic retinopathy have higher levels of CgA, CgB, and CgC in the vitreous humor. In addition, type 1 diabetic patients have high CgA and low CgB levels in the circulating blood. Plasma CgA levels are increased in patients with hypertension, coronary heart disease, and heart failure. CgA is the precursor to several functional peptides, including catestatin, vasostatin-1, vasostatin-2, pancreastatin, chromofungin, and many others. Catestatin, vasostain-1, and vasostatin-2 suppress the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in human vascular endothelial cells. Catestatin and vasostatin-1 suppress oxidized low-density lipoprotein-induced foam cell formation in human macrophages. Catestatin and vasostatin-2, but not vasostatin-1, suppress the proliferation and these three peptides suppress the migration in human vascular smooth muscles. Chronic infusion of catestatin, vasostatin-1, or vasostatin-2 suppresses the development of atherosclerosis of the aorta in apolipoprotein E-deficient mice. Catestatin, vasostatin-1, vasostatin-2, and chromofungin protect ischemia/reperfusion-induced myocardial dysfunction in rats. Since pancreastatin inhibits insulin secretion from pancreatic β-cells, and regulates glucose metabolism in liver and adipose tissues, pancreastatin inhibitor peptide-8 (PSTi8) improves insulin resistance and glucose homeostasis. Catestatin stimulates therapeutic angiogenesis in the mouse hind limb ischemia model. Gene therapy with secretoneurin, a CgC-derived peptide, stimulates postischemic neovascularization in apolipoprotein E-deficient mice and streptozotocin-induced diabetic mice, and improves diabetic neuropathy in db/db mice. Therefore, CgA is a biomarker for atherosclerosis, diabetes, hypertension, and coronary heart disease. CgA- and CgC--derived polypeptides provide the therapeutic target for atherosclerosis and ischemia-induced tissue damages. PSTi8 is useful in the treatment of diabetes.

Carcinoid Syndrome and Hyperinsulinemic Hypoglycemia Associated with Neuroendocrine Neoplasms: A Critical Review on Clinical and Pharmacological Management

The carcinoid syndrome (CS) and hyperinsulinemic hypoglycemia (HH) represent two of the most common clinical syndromes associated with neuroendocrine neoplasms (NENs). The former is mainly related to the serotonin secretion by a small bowel NEN, whereas the latter depends on an insulin hypersecretion by a pancreatic insulinoma. Both syndromes/conditions can affect prognosis and quality of life of patients with NENs. They are often diagnosed late when patients become strongly symptomatic. Therefore, their early detection and management are a critical step in the clinical management of NEN patients. A dedicated and experienced multidisciplinary team with appropriate therapeutic strategies is needed and should be encouraged to optimize clinical outcomes. This review aims to critically analyze clinical features, evidence and treatment options of CS and HH and therefore to improve their management.

Vigilance for carcinoid heart disease is still required in the era of somatostatin analogues: Lessons from a case series

AIM

Carcinoid heart disease (CHD) is a well-documented complication of neuroendocrine tumors (NETs) due to secreted hormones causing fibrosis. Somatostatin analogues (SSAs) can decrease hormonal secretion and inhibit tumor growth. The reported incidence of CHD has decreased as SSA use has increased. We describe a series of patients who have developed CHD even though they were treated with SSA therapy.

METHODS

Nine patients were seen in four centers in Australia and New Zealand. The average duration of follow-up from diagnosis was 39 months.

RESULTS

Three patients had Grade 1 and six Grade 2 disease by World Health Organization 2010 criteria. All patients had no CHD symptoms at baseline and started SSA therapy soon after diagnosis, yet developed significant, symptomatic cardiac dysfunction in their disease course. The median time from NET diagnosis to SSA initiation was 1 month, and median time from NET diagnosis to CHD diagnosis was 23 months (range 4-52). All patients who were tested had persistently increased hormonal levels (chromogranin A, urinary 5-hydroxyindolacetic acid).

CONCLUSIONS

The good symptomatic control afforded by SSAs should not lead to reduced vigilance in screening for CHD, especially in patients with persistently elevated hormonal assays. Clinicians should consider regular echocardiographic screening in patients with a secretory syndrome.

Carcinoid Heart Disease: Pathophysiology, Pathology, Clinical Manifestations, and Management

Carcinoid heart disease (CHD) is a rare and potentially lethal manifestation of an advanced carcinoid (neuroendocrine) tumor. The pathophysiology of CHD is related to vasoactive substances secreted by the tumor, of which serotonin is most prominent in the pathophysiology of CHD. Serotonin stimulates fibroblast growth and fibrogenesis, which can lead to cardiac valvular fibrosis. CHD primarily affects right heart valves, causing tricuspid and pulmonic regurgitation and less frequently stenosis of these valves. Left heart valves are usually spared because vasoactive substances such as serotonin are enzymatically inactivated in the lung vasculature. The pathology of CHD is characterized by plaque-like deposition of fibrous tissue on valvular cusps, leaflets, papillary muscles, chordae, and ventricular walls. Symptomatic CHD usually presents between 50 and 70 years of age, initially as dyspnea and fatigue. Echocardiography is the mainstay of imaging and demonstrates thickened right heart valves with limited mobility and regurgitation. Treatment focuses on control of the underlying carcinoid syndrome, targeting subsequent valvular heart disease and managing consequent heart failure. Surgical valve replacement and catheter-directed valve procedures may be effective for selected patients with CHD.

Carcinoid Heart Disease: a Comprehensive Review

PURPOSE OF REVIEW

Carcinoid heart disease is a rare disorder that is associated with significant morbidity and mortality. In this review of the literature, we will present current concepts in diagnosis and management of carcinoid heart disease.

RECENT FINDINGS

Recent expert consensus guidelines highlight the role of echocardiography and screening with NT-proBNP for the evaluation of carcinoid heart disease. Advances in medical therapy along with better surgical outcomes highlight the experience and expertise that has been gained in the treatment of carcinoid heart disease. Carcinoid heart disease occurs in patients with neuroendocrine tumors who have carcinoid syndrome. Serotonin appears to play a central role in the development of carcinoid heart disease. Cardiac biomarkers and multimodality imaging can be used to aid in screening and diagnosis. The mainstay of treatment of carcinoid heart disease is surgery.

The role of 5-hydroxyindoleacetic acid in neuroendocrine tumors: the journey so far

5-Hydroxyindole acetic acid (5-HIAA) is a surrogate marker for serotonin measurement and one of the first biochemical markers used in neuroendocrine tumors. In this review, we give a brief history of 5-HIAA and its precursor serotonin. We discuss its clinical utility and diagnostic performance in small intestinal neuroendocrine tumor and describe the challenges encountered during its analysis, historically performed in urine. The introduction of blood-based assays will help overcome some of the issues associated with its measurement in urine. The diagnostic performance of serum and plasma 5-HIAA has been shown to be comparable to that of urine 5-HIAA. Thus, analysis in either serum or plasma will provide a practical and convenient alternative to urine.

Spotlight on telotristat ethyl for the treatment of carcinoid syndrome diarrhea: patient selection and reported outcomes

Neuroendocrine tumors (NETs) are rare cancers with an associated prolonged survival in some patients. A proportion of patients diagnosed with NETs will present with carcinoid syndrome symptoms, characterized by diarrhea, flushing and/or wheezing. This review summarizes the current treatment options for carcinoid syndrome, focusing on the latest novel treatment option, telotristat ethyl. In addition, information on patient-reported outcomes and impact of carcinoid syndrome on quality of life (QOL) and improvement of following treatment with telotristat ethyl are reviewed. This article also provides an overview of the current QOL questionnaires for patients with NETs and addresses unmet needs in this field of patient-reported outcomes.

Carcinoid Syndrome: Updates and Review of Current Therapy

OPINION STATEMENT

Carcinoid syndrome (CS) is a complex disorder caused by functional neuroendocrine tumors (NETs). This debilitating disease is characterized by hyper-secretion of biologically active substances eliciting major hormonal symptoms burden and fibrotic changes that are often challenging for management. There have been a number of insights that have substantially advanced treatments since the introduction of somatostatin analogs (SSAs). Second-line treatments are needed in a substantial proportion of patients with advanced disease that have uncontrolled hormone secretion on the highest labeled doses of SSAs. International guidelines suggest several available options including dose escalation of SSAs, interferon alpha, everolimus, radionuclide therapy, liver-directed therapies, and the novel tryptophan hydroxylase 1 inhibitor, telotristat ethyl. The clear preference of one second-line therapy over the other is not stated since their relative and long-term efficacy are largely unknown, and standardized approach of hormonal response assessment is lacking in the literature. In the clinical setting, the treatment of CS is guided in conjunction with patients' performance status, tumor origin, grade, stage, and growth rate, with regard to both anti-hormonal, as well as anti-proliferative effect. There is an unmet need for further well-designed randomized placebo-controlled and head-to-head studies that systematically assess CS symptom control and biochemical response following a specific intervention.

Recent Trends in the Quantification of Biogenic Amines in Biofluids as Biomarkers of Various Disorders: A Review

Biogenic amines (BAs) are bioactive endogenous compounds which play a significant physiological role in many cell processes like cell proliferation and differentiation, signal transduction and membrane stability. Likewise, they are important in the regulation of body temperature, the increase/decrease of blood pressure or intake of nutrition, as well as in the synthesis of nucleic acids and proteins, hormones and alkaloids. Additionally, it was confirmed that these compounds can be considered as useful biomarkers for the diagnosis, therapy and prognosis of several neuroendocrine and cardiovascular disorders, including neuroendocrine tumours (NET), schizophrenia and Parkinson's Disease. Due to the fact that BAs are chemically unstable, light-sensitive and possess a high tendency for spontaneous oxidation and decomposition at high pH values, their determination is a real challenge. Moreover, their concentrations in biological matrices are extremely low. These issues make the measurement of BA levels in biological matrices problematic and the application of reliable bioanalytical methods for the extraction and determination of these molecules is needed. This article presents an overview of the most recent trends in the quantification of BAs in human samples with a special focus on liquid chromatography (LC), gas chromatography (GC) and capillary electrophoresis (CE) techniques. Thus, new approaches and technical possibilities applied in these methodologies for the assessment of BA profiles in human samples and the priorities for future research are reported and critically discussed. Moreover, the most important applications of LC, GC and CE in pharmacology, psychology, oncology and clinical endocrinology in the area of the analysis of BAs for the diagnosis, follow-up and monitoring of the therapy of various health disorders are presented and critically evaluated.

Carcinoid-syndrome: recent advances, current status and controversies

PURPOSE OF REVIEW

To review recent advances and controversies in all aspects of carcinoid-syndrome.

RECENT FINDINGS

Over the last few years there have been a number of advances in all aspects of carcinoid syndrome as well as new therapies. These include new studies on its epidemiology which demonstrate it is increasing in frequency; increasing insights into the pathogenesis of its various clinical manifestations and into its natural history: definition of prognostic factors; new methods to verify its presence; the development of new drugs to treat its various manifestations, both initially and in somatostatin-refractory cases; and an increased understanding of the pathogenesis, natural history and management of carcinoid heart disease. These advances have generated several controversies and these are also reviewed.

SUMMARY

There have been numerous advances in all aspects of the carcinoid-syndrome, which is the most common functional syndrome neuroendocrine tumors produce. These advances are leading to new approaches to the management of these patients and in some cases to new controversies.

Echocardiography in functional midgut neuroendocrine tumors: When and how often

The management of patients with midgut neuroendocrine tumors (MNET) is rapidly evolving. Current preoperative detection rates of primary tumor sites are higher than ever and progression-free survival in patients with already advanced disease is expanding due to the implementation of novel efficacious treatment strategies. This survival benefit may potentially translate into a need for a multidisciplinary approach to an even more heterogenous variety of clinical conditions, among these, carcinoid syndrome (CS) and carcinoid heart disease (CHD). The latter often triggers substantial morbidity and mortality, hence a systematic screening, an accurate diagnosis, as well as effective interventions are critically important. The rarity of the disease has result in a relative lack of statistically powerful evidence, which in turn may have rendered significant variability between practices. In this regard, despite recent guidelines, the optimal follow-up of patients with CHD remain debatable to some authors, perhaps due to the preponderance of certain schools throughout the manuscript. Herein, we present a concise and practical guidance document on clinical screening and echocardiographic surveillance of patients with CHD based on a comprehensive review of the literature, and complemented by our experience at the Center for Carcinoid and Neuroendocrine Tumors at The Mount Sinai Hospital.

Urinary sampling for 5HIAA and metanephrines determination: revisiting the recommendations

CONTEXT

Biogenic amines such as 5-hydroxy-indole acetic acid (5HIAA) the main metabolite of serotonin or metanephrines (catecholamines metabolites) are used as biomarkers of neuroendocrine tumours.

OBJECTIVE

To re-evaluate the recommendations for urinary sampling (preservatives, diet, drugs, etc.) as many of the reported analytical interferences supporting these recommendations are related to obsolete assays.

METHODS

Bibliographic analysis of old and modern assays concerning preservation, extraction, assay and interferences.

RESULTS

5HIAA may degrade as soon as urine is excreted. Thus, acids as preservatives (hydrochloric or acetic acid) have to be immediately added. Care should be taken not to decrease the pH under 2. Urine preservative for metanephrine assays is not mandatory. Diets including serotonin-, tryptophan- and dopamine-rich foods have to be avoided depending on the biomarkers investigated (bananas, plantain, nuts, etc.). Tryptophan-rich over-the-counter formulas have to be prohibited when 5HIAA has to be assayed. Acetaminophen may interfere with electrochemical detection depending on high-pressure liquid chromatography (HPLC) parameters. No interference is known with mass spectrometric assays but with the one described for metanephrines determination. Some drugs interfere however with serotonin and catecholamines secretion and/or metabolism (monoamine oxidase inhibitors, serotonin or dopamine recapture inhibitors, etc.).

CONCLUSION

Revisited recommendations are provided for the diet, the drugs and the preservatives before HPLC coupled with electrochemical and mass spectrometry assays.

Incidence and prognostic value of serotonin secretion in pancreatic neuroendocrine tumours

BACKGROUND

Serotonin secretion occurs in approximately 1%-4% of patients with a pancreatic neuroendocrine tumour (PNET), but the incidence is not well defined. The aim of this study was to determine the incidence of serotonin secretion with and without carcinoid syndrome and the prognostic value for overall survival (OS).

METHODS

Data were collected from 255 patients with a PNET if 24-hours urinary 5-hydroxyindoleacetic acid excretion (5-HIAA) was assessed. Patients were diagnosed with serotonin secretion if 24-hours urinary 5-HIAA excretion was more than 3× the upper limit of normal (ULN) of 50 μmol/24 hours during follow-up. The effect of serotonin secretion on OS was estimated with uni- and multivariate analyses using a Cox regression.

RESULTS

Two (0.8%) patients were diagnosed with carcinoid syndrome, and another 20 (7.8%) had a serotonin-secreting PNET without symptoms. These patients mostly had ENETS stage IV disease with high chromogranin A (CgA). Serotonin secretion was a negative prognostic factor in univariate analysis (HR 2.2, 95% CI: 1.27-3.81), but in multivariate analysis, only CgA>10× ULN (HR: 1.81, 95% CI: 1.10-2.98) and neuron-specific enolase (NSE) >ULN (HR: 3.51, 95% CI: 2.26-5.46) were predictors for OS. Immunohistochemical staining for serotonin was positive in 28.6% of serotonin-secreting PNETs (one with carcinoid syndrome) and negative in all controls.

CONCLUSION

Carcinoid syndrome is rare in patients with a PNET, but serotonin secretion occurs often. This is a negative prognostic factor for OS, but after correction for CgA and NSE, it is no longer a predictor and probably only a "not-so innocent bystander" in patients with high tumour burden.

Diagnosing and Managing Carcinoid Heart Disease in Patients With Neuroendocrine Tumors: An Expert Statement

Carcinoid heart disease is a frequent occurrence in patients with carcinoid syndrome and is responsible for substantial morbidity and mortality. The pathophysiology of carcinoid heart disease is poorly understood; however, chronic exposure to excessive circulating serotonin is considered one of the most important contributing factors. Despite recognition, international consensus guidelines specifically addressing the diagnosis and management of carcinoid heart disease are lacking. Furthermore, there is considerable variation in multiple aspects of screening and management of the disease. The aim of these guidelines was to provide succinct, practical advice on the diagnosis and management of carcinoid heart disease as well as its surveillance. Recommendations and proposed algorithms for the investigation, screening, and management have been developed based on an evidence-based review of the published data and on the expert opinion of a multidisciplinary consensus panel consisting of neuroendocrine tumor experts, including oncologists, gastroenterologists, and endocrinologists, in conjunction with cardiologists and cardiothoracic surgeons.

Profiling of metastatic small intestine neuroendocrine tumors reveals characteristic miRNAs detectable in plasma

Background

Current diagnostic and prognostic blood-based biomarkers for neuroendocrine tumors are limited. MiRNAs have tumor-specific expression patterns, are relatively stable, and can be measured in patient blood specimens. We performed a multi-stage study to identify and validate characteristic circulating miRNAs in patients with metastatic small intestine neuroendocrine tumors, and to assess associations between miRNA levels and survival.

Methods

Using a 742-miRNA panel, we identified candidate miRNAs similarly expressed in 19 small intestine neuroendocrine tumors and matched plasma samples. We refined our panel in an independent cohort of plasma samples from 40 patients with metastatic small intestine NET and 40 controls, and then validated this panel in a second, large cohort of 120 patients with metastatic small intestine NET and 120 independent controls.

Results

miRNA profiling of 19 matched small intestine neuroendocrine tumors and matched plasma samples revealed 31 candidate miRNAs similarly expressed in both tissue and plasma. We evaluated expression of these 31 candidate miRNAs in 40 independent cases and 40 normal controls, and identified 4 miRNAs (miR-21-5p, miR-22-3p, miR-29b-3p, and miR-150-5p) that were differently expressed in cases and controls (p<0.05). We validated these 4 miRNAs in a separate, larger panel of 120 cases and 120 controls. We confirmed that high circulating levels of miR-22-3p (p<0.0001), high levels of miR 21-5p, and low levels of miR-150-5p (p=0.027) were associated with the presence of metastatic small intestine NET. While levels of 29b-3p were lower in cases than in controls in both the initial cohort and the validation cohort, the difference in the validation cohort did not reach statistical significance. We further found that high levels of circulating miR-21-5p, high levels of circulating miR-22-3p and low levels of circulating miR-150-5p were each independently associated with shorter overall survival. A combined analysis using all three markers was highly prognostic for survival (HR 0.47, 95% CI 0.27-0.82).

Conclusions

Our study suggests that elevated circulating levels of miR-21-5p and miR-22-3p and low levels of miR-150-5p are characteristic in patients with metastatic small intestine neuroendocrine tumors, and further suggests that levels of these miRNAs are associated with overall survival. These observations provide the basis for further validation studies, as well as studies to assess the biological function of these miRNAs in small intestine neuroendocrine tumors.

Limited value for urinary 5-HIAA excretion as prognostic marker in gastrointestinal neuroendocrine tumours

OBJECTIVE

To determine if urinary 5-hydroxyindoleacetic acid (5-HIAA) excretion is of prognostic value for overall survival (OS) in patients with a gastrointestinal neuroendocrine tumour (NET) and to compare the prognostic value with patient characteristics, ENETS/WHO grading, ENETS TNM staging and biomarkers.

DESIGN AND METHODS

Data was collected from patients with a gastrointestinal NET or a NET with gastrointestinal metastases and available 5-HIAA excretion in 24-h urine samples. Laboratory results were stratified for urinary 5-HIAA and chromogranin A (CgA): <2× upper limit of normal (ULN), 2-10× ULN, or >10× ULN. For neuron-specific enolase (NSE), this was the reference range or >1× ULN. OS was compared using Kaplan-Meier and log-rank tests, and hazard ratios were calculated using Cox regression for univariate and multivariate analyses.

RESULTS

A total of 371 patients were included, 46.6% female with a mean age of 59.9 years. OS was shortest in patients with urinary 5-HIAA excretion >10× ULN vs reference range (median 83 months vs 141 months, P = 0.002). In univariate analysis, urinary 5-HIAA excretion >10× ULN was a negative predictor (HR 1.62, 95% CI: 1.09-2.39). However, in multivariate analysis, only age (HR 1.04, 95% CI: 1.01-1.08), grade 3 disease (HR 5.09, 95% CI: 2.20-11.79), NSE >1× ULN (HR 2.36, 95% CI: 1.34-4.14) and CgA >10× ULN (HR 3.61, 95% CI: 1.56-8.34) remained as the predictors.

CONCLUSION

Urinary 5-HIAA excretion >10× ULN is a negative predictor for OS. However, when added to other biomarkers and grading, it is no longer a predictor for OS. Therefore, it should only be determined to assess carcinoid syndrome and not for prognostic value.

Complications from carcinoid syndrome: review of the current evidence

Patients with well-differentiated neuroendocrine tumours may develop carcinoid syndrome (CS), which is characterised by flushing, abdominal cramps, diarrhoea, and bronchospasms. In this scenario, long-term secretion of vasoactive substances—serotonin, tachynins, and others, may induce fibrogenic responses in local or distant tissues, leading to complications such as carcinoid heart disease (CHD), mesenteric and/or retroperitoneal fibrosis. Rare cases of lung/pleural fibrosis and scleroderma have also been described. Despite it not being well described yet, current evidence suggests the pathogenesis of such fibrogenic complications relies on signalling through 5-HT_2B and TGF-β1. Medical management is still very limited and lacks prospective and randomised studies for definitive recommendations. Surgical procedures remain the best definitive treatment option for CHD and abdominal fibrosis. Recently, cognitive impairment has also been described as a potential consequence of CS. This review critically discusses the literature concerning the epidemiology, pathogenesis, clinical features, diagnosis, and treatment options for CS-related long-term complications.

Neuroendocrine tumours - Medical therapy: Biological

Somatostatin analogues (SSA) are well established antisecretory drugs that have been used as first line treatment for symptomatic control in hormonally active neuroendocrine tumours (NET) for three decades. Both available depot formulations of SSA, long-acting repeatable (LAR) octreotide and lanreotide autogel, seem similarly effective and well tolerated, although comparative trials in NET have not been performed. The importance of SSA as antiproliferative treatment has been increasingly recognized during recent years. Two placebo-controlled trials demonstrated significant prolongation of progression free survival under SSA treatment. However, objective response as assessed by imaging is rare. Interferon-α (IFNα) also has antisecretory and antiproliferative efficacy in NET. Due to the less favourable toxicity profile it mainly has a role as add-on option in the refractory setting, especially in carcinoid syndrome patients. Further studies are needed to evaluate the antiproliferative efficacy of the multiligand SSA pasireotide and the role of pegylated IFNα.

Neuroendocrine tumor biomarkers: From monoanalytes to transcripts and algorithms

The management of neuroendocrine neoplasia remains a perplexing problem because of the lack of knowledge of the biology of the disease, its late presentation, the relative insensitivity of imaging modalities and a paucity of predictably effective treatment options. A critical limitation is posed by the lack of accurate biomarkers to guide management, monitor the efficacy of therapy and provide a prognostic assessment of disease progress. Currently utilized monoanalyte biomarkers (e.g. chromogranin, serotonin, pancreastatin etc.) exhibit variable metrics, poor sensitivity, specificity, and predictive ability and are rarely used to guide clinical decision making. A National Cancer Institute Neuroendocrine Tumor summit conference held in 2007 noted biomarker limitations to be a crucial unmet need in the management of neuroendocrine tumors. Nevertheless little progress has been made in this field until recently with the consideration of blood transcript analysis, circulating tumor cells and miRNA measurement. Given the complexity and multidimensionality of the neoplastic process itself, the heterogeneity of neuroendocrine tumors (NET) as well as the interaction of the tumor microenvironment, it is not unexpected that no single (monoanalyte) biomarker has proven to be effective. This deduction reflects the growing recognition that use of a monoanalyte to define a multidimensional disease process has inherent flaws. Logic dictates that no single measured parameter can capture the pathobiological diversity of neoplasia and monoanalytes cannot define the multiple variables (proliferation, metabolic activity, invasive potential and metastatic propensity) that constitute tumor growth. Thus far, most biomarkers whether in tissue or blood/urine have been single analytes with varying degrees of sensitivity and specificity and in general have failed to exhibit robust metrics or lacked methodological rigor. Neuroendocrine (NE) disease represents an area of biomarker paucity since the individual biomarkers (gastrin, insulin etc) are not widely applicable to the diverse types of NE neoplasia (NEN). Broad spectrum markers such as CgA have limitations in sensitivity, specificity and reproducibility. This review serves to provide a general background of the evolution of NET biomarkers. It provides an assessment of their current and past usage and limitations in assessing their diagnostic, pathologic and prognostic aspects in respect of NET. It provides a view of the changing methodology of biomarker development and the application of biomathematical analyses to redefining detection and treatment. Finally, it presents a description and consensus on current advances in transcript analysis, miRNA measurement and circulating tumor cell identification.

Serum and plasma 5-hydroxyindoleacetic acid as an alternative to 24-h urine 5-hydroxyindoleacetic acid measurement

BACKGROUND

Neuroendocrine tumours are slow growing tumours known to secrete a variety of vasoactive peptides which give rise to symptoms of the carcinoid syndrome. The diagnosis and monitoring of patients with neuroendocrine tumours is undertaken in many centres using 24 h urinary measurement of 5-hydroxyindoleacetic acid. However, 5-hydroxyindoleacetic acid can also be quantified in plasma and serum.

METHODS

We measured 5-hydroxyindoleacetic acid concentration in 134 paired EDTA plasma and urine samples from 108 patients with known neuroendocrine tumours and 26 healthy volunteers. We also compared 5-hydroxyindoleacetic acid concentrations in paired serum and plasma samples (n = 63), then analysed paired urine and serum samples (n = 97). Furthermore, we examined the impact of renal impairment on serum 5-hydroxyindoleacetic acid by analysing 5-hydroxyindoleacetic acid in patients without neuroendocrine tumours in different stages of chronic kidney disease, as indicated by the estimated glomerular filtration rate.

RESULTS

Plasma and urine 5-hydroxyindoleacetic acid had very similar diagnostic sensitivities and specificities, with areas under the curve on ROC analysis of 0.917 and 0.920, respectively. Serum and plasma 5-hydroxyindoleacetic acid values showed good correlation but serum results demonstrated a positive bias, indicating the necessity for different serum and plasma reference intervals. There was an inverse correlation between estimated glomerular filtration rate and serum 5-hydroxyindoleacetic acid concentration, with 5-hydroxyindoleacetic acid increasing once the estimated glomerular filtration rate falls below 60 mL/min/1.73 m(2).

CONCLUSION

The measurement of both serum and plasma 5-hydroxyindoleacetic acid can be used for the diagnosis and monitoring of patients with neuroendocrine tumours. Provided renal function is taken into consideration, either of these tests should be incorporated into standard practice as an alternative assay to urinary 5-hydroxyindoleacetic acid.

Telotristat etiprate, a novel serotonin synthesis inhibitor, in patients with carcinoid syndrome and diarrhea not adequately controlled by octreotide

Serotonin produced by neuroendocrine tumors is believed to be a principal cause of the diarrhea in carcinoid syndrome. We assessed the safety and efficacy of telotristat etiprate, an oral serotonin synthesis inhibitor, in patients with diarrhea associated with carcinoid syndrome. In this prospective, randomized study, patients with evidence of carcinoid tumor and ≥4 bowel movements (BMs)/day despite stable-dose octreotide LAR depot therapy were enrolled in sequential, escalating, cohorts of four patients per cohort. In each cohort, one patient was randomly assigned to placebo and three patients to telotristat etiprate, at 150, 250, 350, or 500 mg three times a day (tid). In a subsequent cohort, one patient was assigned to placebo and six patients to telotristat etiprate 500 mg tid. Patients were assessed for safety, BM frequency (daily diary), 24 h urinary 5-hydroxyindoleacetic acid (u5-HIAA), and adequate relief of carcinoid gastrointestinal symptoms (using a weekly questionnaire). Twenty-three patients were treated: 18 received telotristat etiprate and five received placebo. Adverse events were generally mild. Among evaluable telotristat etiprate-treated patients, 5/18 (28%) experienced a ≥30% reduction in BM frequency for ≥2 weeks, 9/16 (56%) experienced biochemical response (≥50% reduction or normalization in 24-h u5-HIAA) at week 2 or 4, and 10/18 (56%) reported adequate relief during at least 1 of the first 4 weeks of treatment. Similar activity was not observed in placebo-treated patients. Telotristat etiprate was well tolerated. Our observations suggest that telotristat etiprate has activity in controlling diarrhea associated with carcinoid syndrome. Further studies confirming these findings are warranted.

Serial surveillance of carcinoid heart disease: factors associated with echocardiographic progression and mortality

Background:

Carcinoid heart disease is a complication of metastatic neuroendocrine tumours (NETs). We sought to identify factors associated with echocardiographic progression of carcinoid heart disease and death in patients with metastatic NETs.

Methods:

Patients with advanced non-pancreatic NETs and documented liver metastases and/or carcinoid syndrome underwent prospective serial clinical, biochemical, echocardiographic and radiological assessment. Patients were categorised as carcinoid heart disease progressors, non-progressors or deceased. Multinomial regression was used to assess the univariate association between variables and carcinoid heart disease progression.

Results:

One hundred and thirty-seven patients were included. Thirteen patients (9%) were progressors, 95 (69%) non-progressors and 29 (21%) patients deceased. Baseline median levels of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) and plasma 5-hydroxyindoleacetic acid (5-HIAA) were significantly higher in the progressors. Every 100 nmol l⁻¹ increase in 5-HIAA yielded a 5% greater odds of disease progression (OR 1.05, 95% CI: 1.01, 1.09; P=0.012) and a 7% greater odds of death (OR 1.07, 95% CI: 1.03, 1.10; P=0.001). A 100 ng l⁻¹ increase in NT-proBNP did not increase the risk of progression, but did increase the risk of death by 11%.

Conclusions:

The biochemical burden of disease, in particular baseline plasma 5-HIAA concentration, is independently associated with carcinoid heart disease progression and death. Clinical and radiological factors are less useful prognostic indicators of carcinoid heart disease progression and/or death.

A multianalyte PCR blood test outperforms single analyte ELISAs (chromogranin A, pancreastatin, neurokinin A) for neuroendocrine tumor detection

A critical requirement in neuroendocrine tumor (NET) management is a sensitive, specific and reproducible blood biomarker test. We evaluated a PCR-based 51 transcript signature (NETest) and compared it to chromogranin A (CgA), pancreastatin (PST) and neurokinin A (NKA). The multigene signature was evaluated in two groups: i) a validation set of 40 NETs and controls and ii) a prospectively collected group of NETs (n=41, 61% small intestinal, 50% metastatic, 44% currently treated and 41 age-sex matched controls). Samples were analyzed by a two-step PCR (51 marker genes) protocol and ELISAs for CgA, PST and NKA. Sensitivity comparisons included χ(2), non-parametric measurements, ROC curves and predictive feature importance (PFAI) analyses. NETest identified 38 of 41 NETs. Performance metrics were: sensitivity 92.8%, specificity 92.8%, positive predictive value 92.8% and negative predictive value 92.8%. Single analyte ELISA metrics were: CgA 76, 59, 65, and 71%; PST 63, 56, 59, and 61% and NKA 39, 93, 84, and 60%. The AUCs (ROC analysis) were: NETest: 0.96±0.025, CgA: 0.67±0.06, PST 0.56±0.06, NKA: 0.66±0.06. NETest significantly outperformed single analyte tests (area differences: 0.284-0.403, Z-statistic 4.85-5.9, P<0.0001). PFAI analysis determined NETest had most value (69%) in diagnosis (CgA (13%), PST (9%), and NKA (9%)). Test data were consistent with the validation set (NETest >95% sensitivity and specificity, AUC =0.98 vs single analytes: 59-67% sensitivity, AUCs: 0.58-0.63). The NETest is significantly more sensitive and efficient (>93%) than single analyte assays (CgA, PST or NKA) in NET diagnosis. Blood-based multigene analytic measurement will facilitate early detection of disease recurrence and can predict therapeutic efficacy.

Chromogranin A in diagnosing and monitoring patients with gastroenteropancreatic neuroendocrine neoplasms: a large series from a single institution

BACKGROUND/AIMS

Plasma chromogranin A (CgA) is the most widely used biochemical biomarker in the diagnostic workup and follow-up of gastroenteropancreatic neuroendo- crine neoplasms (GEP-NENs). Herein, we assessed the clinical utility of CgA in diagnosing and monitoring a large series of GEP-NENs.

PATIENTS AND METHODS

A total of 181 GEP-NEN patients (87 males, 94 females) with pancreatic (n = 81) and gastrointestinal neoplasms (n = 100) were included; 99 patients had grade (G)1 NENs (Ki-67 ≤2%), 57 G2 NENs (Ki-67 3-20%) and 25 G3 NENs (Ki-67 >20%); 81 patients had tumor-node-metastasis (TNM) stage I, 14 stage II, 17 stage III and 69 stage IV cancer. For every patient, CgA values were assessed at diagnosis and during follow-up.

RESULTS

At diagnosis, the CgA values were above the upper reference limit in 148 patients (82%); the median CgA levels were significantly higher in functioning than in nonfunctioning tumors (295 vs. 43 U/l; p = 0.0001) as well as significantly higher in patients with metastases than in those without metastases (324.5 vs. 42 U/l; p = 0.0001). In logistic regression analysis, baseline CgA levels were significantly associated with Ki-67 index (p < 0.0001) and TNM stage (p < 0.0001) independently of the age and sex of the patient and the primary site of the tumor. The overall 5- and 10-year survival rates were 74 and 64.5%, respectively. A low Ki-67 index, the type of treatment and an early CgA decrease after treatment were positively correlated with the survival rate. After radical surgery, 15/95 patients relapsed, and an increase in CgA values anticipated the clinical and objective disease recurrence after a period of 9-12 months.

CONCLUSIONS

In GEP-NENs, plasma CgA has a significant prognostic relevance.

Determination of the optimal echocardiographic scoring system to quantify carcinoid heart disease

BACKGROUND

Carcinoid heart disease (CHD) is an important complication of metastatic neuroendocrine disease, requiring regular monitoring to enable intervention prior to right heart failure. We aimed to identify the most appropriate echocardiographic scoring systems for the quantitative assessment of CHD.

METHODS

In this prospective study conducted between April and October 2012 in two European Neuroendocrine Tumor Society (ENETS) Centres of Excellence, patients with neuroendocrine tumours with liver metastases and/or carcinoid syndrome underwent transthoracic echocardiography and blood sampling for serum N-terminal pro-brain natriuretic peptide (NT-proBNP) and plasma 5-hydroxyindoleacetic acid (5-HIAA). Each patient was assessed according to six echocardiographic scoring systems. The individual scoring systems' feasibility, observer variability, sensitivity, specificity and correlation with the concentration biomarkers were determined.

RESULTS

100 patients were included; 21% had echocardiographic evidence of CHD. All scores discriminated highly between those with/without CHD, with no single score performing significantly better than another. The severity, determined using all of the scoring systems, correlated with the concentration of both biomarkers, but the strongest correlations were seen between the Bhattacharyya score and serum NT-proBNP.

CONCLUSION

All scoring systems are comparable in terms of sensitivity and specificity for the detection of CHD. There is a variation in the feasibility of the scoring systems due to varying complexity of the score components. All scores correlate with NT-proBNP and plasma 5-HIAA. The Westberg score appears to be the most optimal scoring system for use in screening of CHD whereas the more complex scoring systems are more suited to the patient with established disease who may require surgical intervention.

Neuroendocrine tumor biomarkers: current status and perspectives

The identification of accurate harbingers of disease status and therapeutic efficacy are critical requirements in precise diagnosis and effective management. Initially, tissue analysis was regarded as ideal but invasive strategies represent risk compared with peripheral blood sampling. Thus far, most biomarkers, whether in tissue or blood/urine, have been single analytes with varying degrees of sensitivity and specificity. Some analytes have not exhibited robust metrics or have lacked methodological rigor. Neuroendocrine disease represents an area of dire biomarker paucity since the individual biomarkers (gastrin, insulin, etc.) are not widely applicable to the diverse types of neuroendocrine neoplasia. Broad-spectrum markers such as chromogranin A have limitations in sensitivity, specificity and reproducibility. Monoanalytes cannot define the multiple variables (proliferation, metabolic activity, invasive potential, metastatic propensity) that constitute tumor growth. The restricted status of the neuroendocrine neoplasia field has resulted in a lack of comprehensive knowledge of the molecular and cellular biology of the disease, with tardy application of innovative technology. This overview examines limitations in current practice and describes contemporary viable strategies under evaluation, including the identification of novel analytes (gene transcripts, microRNA), circulating tumor cells and metabolic imaging agents that identify disease. Novel requirements are necessary to develop biomathematical algorithms for synchronous calibration of multiple molecular markers and predictive nomograms that interface biological variables to delineate disease progress or treatment efficacy. Optimally, the application of novel techniques and amalgamations of multianalyte assessment will provide a personalized molecular disease signature extrapolative of neuroendocrine neoplasia status and likelihood of progression and predictive of therapeutic opportunity.