The prognostic role of WHO classification, urinary 5-hydroxyindoleacetic acid and liver function tests in metastatic neuroendocrine carcinomas of the gastroenteropancreatic tract

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.

Biochemical Markers for Neuroendocrine Tumors: Traditional Circulating Markers and Recent Development-A Comprehensive Review

Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms presenting unique challenges in diagnosis and management. Traditional markers such as chromogranin A (CgA), pancreatic polypeptide (PP), and neuron-specific enolase (NSE) have limitations in terms of specificity and sensitivity. Specific circulating markers such as serotonin and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) and various gastrointestinal hormones such as gastrin, glucagon, somatostatin, and vasoactive intestinal peptide (VIP) have a role in identifying functional NENs. Recent advances in molecular and biochemical markers, also accounting for novel genomic and proteomic markers, have significantly improved the landscape for the diagnosis and monitoring of NENs. This review discusses these developments, focusing on both traditional markers such as CgA and NSE, as well as specific hormones like gastrin, insulin, somatostatin, glucagon, and VIP. Additionally, it covers emerging genomic and proteomic markers that are shaping current research. The clinical applicability of these markers is highlighted, and their role in improving diagnostic accuracy, predicting surgical outcomes, and monitoring response to treatment is demonstrated. The review also highlights the need for further research, including validation of these markers in larger studies, development of standardized assays, and integration with imaging techniques. The evolving field of biochemical markers holds promise for improving patient outcomes in the treatment of NENs, although challenges in standardization and validation remain.

Recent advances and future challenges in the diagnosis of neuroendocrine neoplasms

Neuroendocrine neoplasms (NEN) are a heterogeneous group of malignancies with increasing incidence, whose diagnosis is usually delayed, negatively impacting on patients' prognosis. The latest advances in pathological classifications, biomarker identification and imaging techniques may provide early detection, leading to personalized treatment strategies. In this narrative review the recent developments in diagnosis of NEN are discussed including progresses in pathological classifications, biomarker and imaging. Furthermore, the challenges that lie ahead are investigated. By discussing the limitations of current approaches and addressing potential roadblocks, we hope to guide future research directions in this field. This article is proposed as a valuable resource for clinicians and researchers involved in the management of NEN. Update of pathological classifications and the availability of standardized templates in pathology and radiology represent a substantially improvement in diagnosis and communication among clinicians. Additional immunohistochemistry markers may now enrich pathological classifications, as well as miRNA profiling. New and multi-analytical circulating biomarkers, as liquid biopsy and NETest, are being proposed for diagnosis but their validation and availability should be improved. Radiological imaging strives for precise, non-invasive and less harmful technique to improve safety and quality of life in NEN patient. Nuclear medicine may benefit of somatostatin receptors' antagonists and membrane receptor analogues. Diagnosis in NEN still represents a challenge due to their complex biology and variable presentation. Further advancements are necessary to obtain early and minimally invasive diagnosis to improve patients' outcomes.

Established and novel circulating neuroendocrine tumor biomarkers for diagnostic, predictive and prognostic use

The management of neuroendocrine tumors (NETs) represents a clinical challenge due to heterogeneity of their clinical behaviour, molecular biology and response to treatment. Over the years, several circulating biomarkers have been developed for the early diagnosis and follow-up of NETs. The specific secretory products of tumors associated with a secretory syndrome (functioning tumors) may be used as diagnostic and/or prognostic biomarkers while the most common non-specific circulating biomarkers, that may be increased in both functioning and non-functioning tumors, are chromogranin A and the neuron specific enolase. However, the diagnostic accuracy as well as the prognostic and predictive value of these biomarkers are limited and novel techniques of multianalyte analysis of regulators of tumor biology have been developed. The NETest has been most extensively studied and proved to be useful in NET diagnosis, early detection of post-operative recurrence and prediction of response to treatment but further investigation establishing higher level of evidence is required for implementation in clinical practice.

Small bowel neuroendocrine tumours - casting the net wide

PURPOSE OF REVIEW

Our aim is to provide an overview of small bowel neuroendocrine tumours (NETs), clinical presentation, diagnosis algorithm and management options. We also highlight the latest evidence on management and suggest areas for future research.

RECENT FINDINGS

Dodecanetetraacetic acid (DOTATATE) scan can detect NETs with an improved sensitivity than when compared with an Octreotide scan. It is complimentary to small bowel endoscopy that provides mucosal views and allows the delineation of small lesions undetectable on imaging. Surgical resection is the best management modality even in metastatic disease. Prognosis can be improved with the administration of somatostatin analogues and Evarolimus as second-line therapies.

SUMMARY

NETs are heterogenous tumours affecting most commonly the distal small bowel as single or multiple lesions. Their secretary behaviour can lead to symptoms, most commonly diarrhoea and weight loss. Metastases to the liver are associated with carcinoid syndrome.

Circulating Neuroendocrine Tumor Biomarkers: Past, Present and Future

Neuroendocrine tumors are a heterogeneous group of neoplasms originating from the diffuse endocrine system. Depending on primary location and hormonal status, they range in terms of clinical presentation, prognosis and treatment. Functional tumors often develop symptoms indicating an excess of hormones produced by the neoplasm (exempli gratia insulinoma, glucagonoma and VIPoma) and can be diagnosed using monoanalytes. For non-functional tumors (inactive or producing insignificant amounts of hormones), universal biomarkers have not been established. The matter remains an important unmet need in the field of neuroendocrine tumors. Substances researched over the years, such as chromogranin A and neuron-specific enolase, lack the desired sensitivity and specificity. In recent years, the potential use of Circulating Tumor Cells or multianalytes such as a circulating microRNA and NETest have been widely discussed. They offer superior diagnostic parameters in comparison to traditional biomarkers and depict disease status in a more comprehensive way. Despite a lot of promise, no international standards have yet been developed regarding their routine use and clinical application. In this literature review, we describe the analytes used over the years and cover novel biomarkers that could find a use in the future. We discuss their pros and cons while showcasing recent advances in the field of neuroendocrine tumor biomarkers.

Sex differences in carcinoid syndrome: A gap to be closed

The incidence of neuroendocrine neoplasms and related carcinoid syndrome (CS) has markedly increased over the last decades and women seem to be more at risk than men for developing CS. Nevertheless, very few studies have investigated sex differences in clinical presentation and outcomes of CS. However, as per other tumours, sex might be relevant in influencing tumour localization, delay in diagnosis, clinical outcomes, prognosis and overall survival in CS. The present review was aimed at evaluating sex differences in CS, as they emerge from an extensive search of the recent literature. It emerged that CS occurs more frequently in female than in male patients with NENs and women seem to have a better prognosis and a slight advantage in overall survival and response to therapy. Moreover, the disease likely impacts differently the quality of life of men and women, with different psychological and social consequences. Nevertheless, sex differences, even if partially known, are deeply underestimated in clinical practice and data from clinical trials are lacking. There is urgent need to increase our understanding of the sex-related differences of CS, in order to define tailored strategies of management of the disease, improving both the quality of life and the prognosis of affected patients.

Plasmatic and Urinary 5-Hydroxyindolacetic Acid Measurements in Patients With Midgut Neuroendocrine Tumors: A GTE Study

CONTEXT

Although 24-hour urinary 5-hydroxyindolacetic acid (24u5HIAA) is a key biomarker in midgut neuroendocrine tumors (NETs), it may be inaccurate and inconvenient.

OBJECTIVE

We compared the diagnostic performances of 24u5HIAA, overnight urinary 5HIAA (Ou5HIAA), and plasmatic 5HIAA (p5HIAA) in midgut NETs.

METHODS

This prospective, multicenter study included 80 patients with metastatic midgut NETs and 17 control patients with irritable bowel syndrome. 24u5HIAA, Ou5HIAA, and p5HIAA were measured in urine and plasma collected on 2 consecutive days following a specific recommended diet. Reproducibility of the biomarkers was evaluated by the Spearman test. Diagnostic performance was assessed by the area under the receiver operating characteristic curve (AUROC). Correlations with the main clinical features and declared observance to the specific diet were assessed using AUROC and logistic regression models.

RESULTS

The reproducibility of 24u5HIAA, Ou5HIAA, and p5HIAA were excellent (ρ = 0.916; 0.897; 0.978, respectively, P < .001) with significant discrimination between patients and controls (AUROC = 0.795, P < .001; 0.757, P = .001; 0.717, P = .005, respectively). All 3 markers were correlated with the presence of carcinoid syndrome (AUROC = 0.702, P = .006; 0.701, P = .006; 0.697, P = .007, respectively), carcinoid heart disease (AUROC = 0.896; 0.887; 0.923, P < .001, respectively, P < .001), and liver metastatic involvement greater than 30% (AUROC = 0.827; 0.807; 0.849, P < .001, respectively, P < .001), independent from other traditional prognostic factors. Biomarker levels were similar between patients with optimal or suboptimal diet observance.

CONCLUSION

Ou5HIAA and p5HIAA could be used as more convenient alternatives to 24u5HIAA in patients with metastatic midgut NETs. Prospective long-term studies with repeated dosages are needed.

Serotonin pathway in carcinoid syndrome: Clinical, diagnostic, prognostic and therapeutic implications

Carcinoid syndrome represents the most common functional syndrome that affects patients with neuroendocrine neoplasms. Its clinical presentation is really heterogeneous, ranging from mild and often misdiagnosed symptoms to severe manifestations, that significantly worsen the patient's quality of life, such as difficult-to-control diarrhoea and fibrotic complications. Serotonin pathway alteration plays a central role in the pathophysiology of carcinoid syndrome, accounting for most clinical manifestations and providing diagnostic tools. Serotonin pathway is complex, resulting in production of biologically active molecules such as serotonin and melatonin, as well as of different intermediate molecules and final metabolites. These activities require site- and tissue-specific catalytic enzymes. Variable expression and activities of these enzymes result in different clinical pictures, according to primary site of origin of the tumour. At the same time, the biochemical diagnosis of carcinoid syndrome could be difficult even in case of typical symptoms. Therefore, the accuracy of the diagnostic methods of assessment should be improved, also attenuating the impact of confounding factors and maybe considering new serotonin precursors or metabolites as diagnostic markers. Finally, the prognostic role of serotonin markers has been only evaluated for its metabolite 5-hydroxyindole acetic acid but, due to heterogeneous and biased study designs, no definitive conclusions have been achieved. The most recent progress is represented by the new therapeutic agent telotristat, an inhibitor of the enzyme tryptophan hydroxylase, which blocks the conversion of tryptophan in 5-hydroxy-tryptophan. The present review investigates the clinical significance of serotonin pathway in carcinoid syndrome, considering its role in the pathogenesis, diagnosis, prognosis and therapy.

Exploring the role of survivin in neuroendocrine neoplasms

Neuroendocrine tumors (NETs) are a heterogenous group of tumors. While most NETs have excellent prognosis, certain subsets have aggressive biology and have limited treatment options. We explored the role of survivin in NET as a prognostic and potentially therapeutic marker. Tissue microarrays of 132 patients were stained for survivin using immunohistochemistry (IHC) and correlated with outcomes. Using genomic database, we then correlated survivin (BIRC5) mRNA expression with radiosensitivity index (RSI) in 52 samples of NET. Finally, we studied the effect of radiation on survivin expression in human cell lines and the impact of knock-down of BIRC5 on cell proliferation and radiation sensitivity. We found that survivin positivity by IHC correlated with a shorter survival (overall survival 8.5 years vs. 18.3 years, p < 0.001). There was a positive correlation between BIRC5 expression and RSI (r = 0.234, p < 0.0001). Radiation exposure increased BIRC5 gene expression in a human carcinoid cell line. Knockout of BIRC5 using siRNA reduced proliferation of neuroendocrine cells but did not increase radiation sensitivity. We conclude that survivin expression in NET correlates with an inferior survival and survivin expression in human carcinoid cell lines increases after exposure to ionizing radiation.

Gamma-Aminobutyric Acid Levels in the Anterior Cingulate Cortex of Perimenopausal Women With Depression: A Magnetic Resonance Spectroscopy Study

Objective

The anterior cingulate cortex (ACC) is associated with the processing of negative emotions. Gamma-aminobutyric acid (GABA) metabolism plays an important role in the pathogenesis of mental disorders. We aimed to determine the changes in GABA levels in the ACC of perimenopausal women with depression.

Methods

We recruited 120 perimenopausal women, who were followed up for 18-24 months. After reaching menopause, the participants were divided into a control group (n = 71), an anxiety group (n = 30), and a depression group (n = 19). The participants were examined using proton magnetic resonance spectroscopy (MRS). TARQUIN software was used to calculate the GABA concentrations in the ACC before and after menopause. The relationship of the GABA levels with the patients' scores on the 14-item Hamilton Anxiety Scale and 17-item Hamilton Depression Scale was determined.

Results

GABA decreased with time. The postmenopausal GABA levels were significantly lower in the depression group than in the anxiety group and were significantly lower in both these groups than in the normal group. The postmenopausal GABA levels were significantly lower than the premenopausal levels in the normal, anxiety, and depression groups (P = 0.014, <0.001, and <0.001, respectively). The premenopausal GABA levels did not significantly differ between the normal vs. anxiety group (P = 0.907), normal vs. depression group (P = 0.495), and anxiety vs. depression group. The postmenopausal GABA levels were significantly lower in the depression group than in the anxiety group and were significantly lower in both these groups than in the normal group, normal vs. anxiety group (P = 0.022), normal vs. depression group (P < 0.001), and anxiety vs. depression group (P = 0.047).

Conclusion

Changes in GABA concentrations in the anterior cingulate cortex are related with the pathophysiological mechanism and symptoms of perimenopausal depression.

Measurement of urinary 5-HIAA: correlation between spot versus 24-h urine collection

BACKGROUND

The 24-h urinary output of 5-hydroxyindoleacetic acid (5-HIAA) is used to monitor disease progression and treatment responses of neuroendocrine neoplasms (NENs). Several conditions are required for 5-HIAA assay, involving urine collection/preservation and food/drug restrictions.

AIM

To evaluate the correlation between 5-HIAA concentration in a spot urine sample and the output in a 24-h urine collection, and whether spot urine specimens can replace 24-h collection.

METHODS

Patients with NENs or symptoms suggestive of NENs were asked to provide a separate spot urine at the end of the 24-h urine collection for 5-HIAA assessment. The upper reference limit for 24-h urinary 5-HIAA was 40 µmol/24 h. 5-HIAA measurements in spot urine samples were corrected for variation in urine flow rate by expressing results as a ratio to creatinine concentration.

RESULTS

We included 136 paired urinary samples for 5-HIAA assessment from 111 patients (100 NENs). The correlation between 5-HIAA values measured in 24-h and spot urines was r = +0.863 (P < 0.001) and r = +0.840 (P < 0.001) including only NEN patients. Using the 24-h urinary 5-HIAA as reference method, the AUC on ROC analysis for spot urinary 5-HIAA was 0.948 (95% CI, 0.914-0.983; P < 0.001), attaining a sensitivity of 83% and specificity of 95% using 5.3 mol/mmol as cut-off for the spot urine. The AUC among NEN patients alone was 0.945 (95% CI, 0.904-0.987; P < 0.001).

CONCLUSIONS

The ratio of 5-HIAA to creatinine in a spot urine could replace the measurement of 5-HIAA output in a 24-h urine collection, especially for follow-up of patients with known elevated 5-HIAA levels.

Predicting Survival of Small Intestine Neuroendocrine Tumors: Experience From a Major Referral Center

OBJECTIVE

Neuroendocrine tumors (NETs) comprise 41.8% of small intestine malignancies. The NET nomogram is a 15-item prognostic tool that includes relevant factors for guiding management decisions. This is the first external validation of this tool among American patients at a tertiary treatment center.

METHODS

Patients who underwent surgical intervention from 2005 to 2017 were screened by retrospective chart review. Nomogram scores were calculated following the methods outlined by Modlin et al (Neuroendocrinology. 2010;92:143-157). Validation assessed the association between nomogram scores and survival using Wilcoxon test and Cox regression.

RESULTS

Among the 121 patients selected, the NET nomogram significantly predicted survival as a continuous variable (P < 0.01) and when dichotomized using 83 points to distinguish low-risk versus high-risk groups (P < 0.01). However, the nomogram was not universally applicable as even at our specialty center, variables such as chromogranin A and urinary 5-hydroxyindoleacetic acid are not routinely collected, whereas others, like tumor grade, do not reflect the most recently updated classifications.

CONCLUSION

The NET nomogram accurately identified patients at low and high risk of death. However, revision to update prognosticators could improve its usefulness for predicting survival of small intestine NETs.

Role of biomarker tests for diagnosis of neuroendocrine tumours

Neuroendocrine tumours (NETs) are neoplasms that arise from neuroendocrine cells. Neuroendocrine cells and their tumours can secrete a wide range of amines and polypeptide hormones into the systemic circulation. This feature has triggered widespread investigation into circulating biomarkers for the diagnosis of NETs as well as for the prediction of the biological behaviour of tumour cells. Classic examples of circulating biomarkers for gastroenteropancreatic NETs include chromogranin A, neuron-specific enolase and pancreatic polypeptide as well as hormones that elicit clinical syndromes, such as serotonin and its metabolites, insulin, glucagon and gastrin. Biomarker metrics of general markers for diagnosing all gastroenteropancreatic NET subtypes are limited, but specific hormonal measurements can be of diagnostic value in select cases. In the past decade, methods for detecting circulating transcripts and tumour cells have been developed to improve the diagnosis of patients with NETs. Concurrently, modern scanning techniques and superior radiotracers for functional imaging have markedly expanded the options for clinicians dealing with NETs. Here, we review the latest research on biomarkers in the NET field to provide clinicians with a comprehensive overview of relevant diagnostic biomarkers that can be implemented in dedicated situations.

Influence of carcinoid syndrome on the clinical characteristics and outcomes of patients with gastroenteropancreatic neuroendocrine tumors undergoing operative resection

BACKGROUND

The incidence, clinical characteristics, and long-term outcomes of patients with gastroenteropancreatic neuroendrocrine tumors and carcinoid syndrome undergoing operative resection have not been well characterized.

METHODS

Patients undergoing resection of primary or metastatic gastroenteropancreatic neuroendrocrine tumors between 2000 and 2016 were identified from an 8-institution collaborative database. Clinicopathologic and postoperative characteristics as well as overall survival and disease-free survival were compared among patients with and without carcinoid syndrome.

RESULTS

Among 2,182 patients who underwent resection, 139 (6.4%) had preoperative carcinoid syndrome. Patients with carcinoid syndrome were more likely to have midgut primary tumors (44.6% vs 21.4%, P < .001), lymph node metastasis (63.4% vs 44.3%, P < .001), and metastatic disease (62.8% vs 26.7%, P < .001). There was no difference in tumor differentiation, grade, or Ki67 status. Perioperative carcinoid crisis was rare (1.6% vs 0%, P < .01), and the presence of preoperative carcinoid syndrome was not associated with postoperative morbidity (38.8% vs 45.5%, P = .129). Substantial symptom improvement was reported in 59.5% of patients who underwent curative-intent resection, but occurred in only 22.7% who underwent debulking. Despite an association on univariate analysis (P = .04), carcinoid syndrome was not independently associated with disease-free survival after controlling for confounding factors (hazard ratio 0.97, 95% confidence interval 0.64-1.45). Preoperative carcinoid syndrome was not associated with overall survival on univariate or multivariate analysis.

CONCLUSION

Among patients undergoing operative resection of gastroenteropancreatic neuroendrocrine tumors, the prevalence of preoperative carcinoid syndrome was low. Although operative intervention with resection or especially debulking in patients with carcinoid syndrome was disappointing and often failed to improve symptoms, after controlling for markers of tumor burden, carcinoid syndrome was not independently associated with worse disease-free survival or overall survival.

Effect of Lanreotide Depot/Autogel on Urinary 5-Hydroxyindoleacetic Acid and Plasma Chromogranin A Biomarkers in Nonfunctional Metastatic Enteropancreatic Neuroendocrine Tumors

BACKGROUND

Urinary 5-hydroxyindoleacetic acid (5-HIAA) is an established biomarker in neuroendocrine tumors and carcinoid syndrome; however, its role in nonfunctional neuroendocrine tumors is not defined. We present post hoc data on urinary 5-HIAA and plasma chromogranin A (CgA) from the CLARINET study.

METHODS

Patients with well- or moderately differentiated, nonfunctioning, locally advanced or metastatic enteropancreatic neuroendocrine tumors were randomized to deep subcutaneous lanreotide depot/autogel 120 mg or placebo once every 28 days for 96 weeks. Tumor response, evaluated centrally (RECIST 1.0), and progression-free survival (PFS) were assessed by treatment and biochemical response, defined as (a) baseline >upper limit of normal (ULN, 41.6 μmol per day 5-HIAA; 98.1 μg/L CgA) and (b) ≥50% decrease from baseline and to ≤ULN value on study.

RESULTS

Forty-eight percent (82 of 171; lanreotide, n = 45; placebo, n = 37) and 66% (129 of 195; lanreotide, n = 65; placebo, n = 64) of randomized patients had 5-HIAA and CgA > ULN at baseline. Among patients with >ULN baseline values who did not progress after 96 weeks of treatment, significantly greater reductions in 5-HIAA and CgA were observed in lanreotide-treated versus placebo-treated patients throughout the study (all p < .05). PFS was significantly prolonged among 5-HIAA responders versus nonresponders (median not reached vs. 16.2 months, p < .0001; hazard ratio [HR] = 0.21, 95% confidence interval [CI], 0.09-0.48) and CgA responders versus nonresponders (median not reached vs. 16.2 months, p = .0070; HR = 0.30, 95% CI, 0.12-0.76), regardless of treatment arm. PFS was also significantly prolonged among lanreotide-treated 5-HIAA responders versus nonresponders (p = .0071) but was not significantly different among placebo-treated 5-HIAA responders versus nonresponders. There were no significant differences in PFS between lanreotide-treated CgA responders versus nonresponders or between placebo-treated CgA responders versus nonresponders.

CONCLUSIONS

The 5-HIAA findings are noteworthy because they occurred in patients with nonfunctioning enteropancreatic neuroendocrine tumors. Monitoring 5-HIAA and CgA may be useful when treating patients with nonfunctional neuroendocrine tumors.

IMPLICATIONS FOR PRACTICE

Current guidelines focus only on the monitoring of 5-hydroxyindoleacetic acid (5-HIAA) in the diagnosis and management of functional neuroendocrine tumors with carcinoid syndrome. The current post hoc analysis of patients with nonfunctional enteropancreatic neuroendocrine tumors in the CLARINET study demonstrated that measuring and following both 5-HIAA and chromogranin A as biomarkers of disease progression may be useful in the management of patients with nonfunctional neuroendocrine tumors.

Treatment with Lanreotide Depot Following Octreotide Long-Acting Release Among Patients with Gastroenteropancreatic Neuroendocrine Tumors

Objective: To examine patients with metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs) who receive sequential treatment with somatostatin analogs. Materials and Methods: This retrospective chart review examined lanreotide depot/autogel tolerability and efficacy among GEP-NET patients who received lanreotide after octreotide long-acting release (LAR) at Tufts University Medical Center. Information obtained included background patient characteristics, dosing, adverse events (AEs), radiologic response, and biochemical markers. Results: Patients (n = 16; 43-81 years; mean age, 64.25 years; 11 female) with nonfunctional, low-grade GEP-NETs receiving octreotide LAR 30-60 mg were transitioned to lanreotide because of patient decision (n = 6), disease progression (n = 6), AEs (n = 2), poor tolerance (n = 1), and injection discomfort/pain (n = 1). Lanreotide doses started at 120 mg (n = 13), 90 mg (n = 1), or 60 mg (n = 2); 8 patients received concomitant therapies, mostly liver-directed (radiofrequency ablation/radioembolization). AEs associated with lanreotide experienced by ≥2 patients were fatigue, diarrhea, nausea, hypertension, pancreatic enzyme deficiency, and hyperglycemia. Radiologic treatment responses of the combination of lanreotide with other therapeutic modalities included complete response (n = 1), partial response (n = 5), and stable disease (n = 9). One patient had radiologic progression. Serum serotonin and chromogranin levels decreased, but urinary 5-hydroxyindoleacetic acid levels appeared relatively unchanged. Conclusion: Among post-octreotide GEP-NET patients, including those with disease progression or poor octreotide tolerance, lanreotide alone or with concomitant therapies was well tolerated and associated with radiologic responses.

Prognostic Utility of 24-Hour Urinary 5-HIAA Doubling Time in Patients With Neuroendocrine Tumors

OBJECTIVE

New clinical prognostic tools are needed to select the population of patients with neuroendocrine tumors (NETs) that have a high risk of disease progression and disease-specific mortality (DSM). Biochemical biomarker doubling time (DT) is used clinically for prognosis prediction in several solid malignancies. The aim of the current study was to determine whether 24-hour urinary 5-hydroxyindoleacetic acid (5-HIAA) level DT has any prognostic utility in patients with NETs.

METHODS

Patients with NETs were enrolled in a prospective study with comprehensive biochemical analysis. The current analysis included 90 subjects with increasing 5-HIAA levels in two consecutive measurements. DT was calculated using the Schwartz equation. The primary outcome measures were DSM and disease progression.

RESULTS

5-HIAA DT of <434 days was associated with a higher rate of DSM ( P = .02), with positive and negative predictive values for DSM of 75 and 77%, respectively. The difference in DSM was accounted for mainly by patients with small intestine or unknown primary NET ( P = .01). In addition, a shorter 5-HIAA DT in patients with small intestine or unknown primary NET was associated with a higher risk of disease progression both in univariate ( P = .001) and multivariable analyses (hazard ratio, 15.8; 95% confidence interval, 1.3 to 198.0; P = .03).

CONCLUSION

5-HIAA DT may be used as a risk stratification tool in patients with small intestine NET or NET of unknown primary after it is validated in an independent cohort and can assist in identifying patients with a high risk for disease progression and DSM.

ABBREVIATIONS

CT = computed tomography; DSM = disease-specific mortality; DT = doubling time; 5-HIAA = 5-hydroxyindoleacetic acid; MRI = magnetic resonance imaging; NET = neuroendocrine tumor; NETUP = neuroendocrine tumor of unknown primary; PET = positron emission tomography; PFS = progression-free survival; PNET = pancreatic neuroendocrine tumor; ROC = receiver operating characteristic; SINET = small-intestine neuroendocrine tumor.

BIOCHEMICAL RESPONSES IN SYMPTOMATIC AND ASYMPTOMATIC PATIENTS WITH NEUROENDOCRINE TUMORS: POOLED ANALYSIS OF 2 PHASE 3 TRIALS

OBJECTIVE

Neuroendocrine tumors (NETs) are associated with elevated 5-hydroxyindoleacetic acid (5-HIAA) and chromogranin A (CgA) levels. This study aimed to analyze relationships between urinary 5-HIAA and plasma CgA levels and clinical outcomes.

METHODS

Centrally assessed biomarker levels and correlations with progression-free survival (PFS) and carcinoid syndrome (CS) symptom control were evaluated in a pooled analysis of CLARINET (96-week randomized, double-blind, placebo-controlled) and ELECT (16-week randomized, double-blind, placebo-controlled, 32-week initial open label and ≥2 year long-term extension open label) studies of adults with NETs, with (ELECT) or without (CLARINET) CS at 97 institutions. Patients were treated with subcutaneous lanreotide depot 120 mg monthly.

RESULTS

Of 319 pooled patients, 86% and 95% had baseline 5-HIAA and CgA data, respectively, with 47% and 74% having levels greater than the upper limit of normal (ULN). PFS was longer among patients who experienced a decrease in biomarker levels at week 12, with statistical significance reached in the CgA cohort (not reached vs. 14.4 months; P<.0001). A large proportion (87%) of patients without symptoms of CS in the CLARINET study had detectable levels of 5-HIAA (48% >ULN). In ELECT, patients with CS who received lanreotide and experienced a biochemical response (≥50% decrease from baseline) achieved greater symptom control.

CONCLUSION

This pooled analysis of two randomized, placebo-controlled trials demonstrated that 5-HIAA and CgA are secreted as biochemical biomarkers in many patients with NETs, regardless of clinical syndromes. Significant biochemical response was associated with improved clinical outcomes, as measured by improved PFS or improved CS symptom control.

ABBREVIATIONS

5-HIAA = 5-hydroxyindoleacetic acid; CgA = chromogranin A; CI = confidence interval; CLARINET = Controlled Study of Lanreotide Antiproliferative Response in Neuroendocrine Tumors; CS = carcinoid syndrome; ELECT = Evaluation of Lanreotide Depot/Autogel Efficacy and Safety as a Carcinoid Syndrome Treatment; HR = hazard ratio; ITT = intention-to-treat; NET = neuroendocrine tumor; PanNET = pancreatic NET; PFS = progression-free survival; PPI = proton pump inhibitor; SSA = somatostatin analogue; ULN = upper limit of normal.

Long-term Outcomes of Gastroenteropancreatic Neuroendocrine Tumors

OBJECTIVES

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare but have been increasing in incidence. Limited data on the long-term outcomes of patients with these tumors are available.

METHODS

In this study, we used population-based data from the National Cancer Institute to assess long-term disease-specific survival (DSS) of patients who have undergone surgery for nonmetastatic disease. All patients with NETs of the stomach, small intestine, colon, rectum, appendix, and pancreas diagnosed between 1988 and 2009 were identified from the Surveillance, Epidemiology and End Results registry. Staging was derived from Surveillance, Epidemiology and End Results data using the European Neuroendocrine Tumor Society guidelines. Cases with incomplete staging data were excluded, along with those with stage IV disease, or those who did not undergo surgical resection.

RESULTS

Kaplan-Meier analyses were constructed to determine DSS. Analyses were further stratified according to tumor site, stage at diagnosis, and tumor grade. Overall, 13,348 patients with GEP-NETs meeting the inclusion criteria were identified.

CONCLUSIONS

There were excellent outcomes for most GEP-NET patients, with a 20-year DSS of greater than 75% across all sites and stages. Pancreatic tumors had the worst outcomes, but DSS remains greater than 50% at 20 years.

Effect of hormone secretory syndromes on neuroendocrine tumor prognosis

The treatment of hormone hypersecretory syndromes caused by neuroendocrine tumors (NETs) can be a major challenge. NETs originating from the small intestine often secrete serotonin causing flushing, diarrhea and valve fibrosis, leading to dehydration or heart failure in severe cases. NETs from the pancreas can secrete a wider variety of hormones, like insulin, glucagon and gastrin leading to distinct clinical syndromes. Historically mortality in patients with functioning NETs was high due to the complications caused by the hypersecretion of hormones. This has been reduced with several drugs: proton-pump inhibitors decrease acid secretion caused by gastrinomas. Somatostatin analogs can inhibit the secretion of multiple hormones and these are now the cornerstone for treating patients with a gastroenteropancreatic NET. However, peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogs and everolimus can also decrease symptoms of hypersecretion and increase progression-free survival. Several factors affect the survival in patients with a functioning NET. Complications of hypersecretion negatively impact survival; however, secretion of hormones is also often a sign of a well-differentiated NET and due to the symptoms, functioning NETs can be detected in an earlier stage suggesting a positive effect on prognosis. The effect on survival is also dependent on the type of hormone being secreted. This review aims to study the effect of hormone secretion on the prognosis of NETs with the contemporary treatments options available today.

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.

Single institutional series of neuroendocrine tumors managed in the Australian Capital Territory

AIMS

Retrospective review of neuroendocrine tumors (NETs) treated within the Australian Capital Territory to describe the local epidemiology and assess prognostic clinicopathological factors.

METHODS

Patients with histologically proven non-pulmonary low to intermediate grade NETs were identified from our hospital clinical database. Data were analyzed according to epidemiological, clinical and histopathological characteristics.

RESULTS

Of the 107 included patients, the most common primary tumor site was jejunum/ileum (32%), followed by rectum (22%) and pancreas (11.2%). In total, 32% had distant metastases at presentation, most commonly in the liver. Most patients were symptomatic at diagnosis, while 22.4% of cases were found incidentally. Second malignancies, in particular of gastrointestinal origin, were diagnosed in 33.6%. Surgical debulking was the most common treatment (59.8%) while 18% had multimodality therapy. With a median follow-up of 25 months from diagnosis, about 78% of patients are still alive. Median time to first relapse was 15 months and the 5-year survival rate was 80% for NETs of jejunum/ileum. Univariate survival analysis revealed tumor location, high Ki67 index, raised plasma chromogranin A, and urine 5-hydroxyindoleacetic acid upon diagnosis to be associated with shorter 5-year survival.

CONCLUSION

The epidemiologic characteristics and long-term outcome in our series are comparable to other reported studies. This analysis presents some important prognostic factors which could be used for risk stratification in patients with NETs.

Application of AJCC/UICC and WHO-2010 classifications for GEP-NEN in Chinese patients

OBJECTIVE

To assess the prognostic value in Chinese patients of two new systems, the World Health Organization (WHO)-2010 and the American Joint Committee on Cancer and the Union for International Cancer Control (AJCC/UICC) systems, for the classification of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN).

METHODS

One hundred and three patients with GEP-NEN treated at the First Affiliated Hospital of Nanjing Medical University from January 2003 to December 2011 were included in the study. All patients were diagnosed pathologically and had complete follow-up data. Univariate and multivariate analyses of their clinicopathological characteristics were performed.

RESULTS

The 5-year survival rates were 95%, 74%, 24% and 15% based on the AJCC/UICC stages I to IV, and 92%, 62% and 29% according to WHO-2010 grades 1 to 3, respectively, in patients with GEP-NEN. A higher mortality was observed in patients with AJCC/UICC stage III and IV tumors compared with those at stage I-II, and patients with stage II compared with those with stage I, whereas there was no difference in survival between stage IV and III patients. Based on the WHO-2010 grading classification, patients with grade 3 tumors had the lowest survival rate than those with grade 1 and 2 tumors, followed by patients with grade 2 tumors.

CONCLUSION

The WHO-2010 and AJCC/UICC staging systems can effectively evaluate the prognosis of patients with GEP-NEN, although the latter might not accurately discriminate the prognosis of patients with local metastasis from those having distant metastasis.

Neuroendocrine Carcinomas of the Gastroenteropancreatic System: A Comprehensive Review

To date, empirical literature has generally been considered lacking in relation to neuroendocrine carcinomas (NECs), the highly malignant subgroup of neuroendocrine neoplasms. NECs are often found in the lungs or the gastroenteropancreatic (GEP) system and can be of small or large cell type. Concentrating on GEP-NECs, we can conclude that survival times are poor, with a median of only 4–16 months depending on disease stage and primary site. Further, this aggressive disease appears to be on the rise, with incidence numbers increasing while survival times are stagnant. Treatment strategies concerning surgery are often undecided and second-line chemotherapy is not yet established. After an analysis of over 2600 articles, we can conclude that there is indeed more empirical literature concerning GEP-NECs available than previously assumed. This unique review is based on 333 selected articles and contains detailed information concerning all aspects of GEP-NECs. Namely, the classification, histology, genetic abnormalities, epidemiology, origin, biochemistry, imaging, treatment and survival of GEP-NECs are described. Also, organ-specific summaries with more detail in relation to disease presentation, diagnosis, treatment and survival are presented. Finally, key points are discussed with directions for future research priorities.

Circulating tumor markers in patients with neuroendocrine tumors – a clinical perspective

Abstract: 

Neuroendocrine tumors (NETs) are uncommon malignancies with a very diverse presentation and prognosis. Patients with NETs frequently have circulating tumor biomarkers that may aid in the diagnosis and help with prognostication. The most commonly used and best studied marker is chromogranin A, which appears to reflect the tumor burden and is useful at the time of diagnosis, and to monitor for recurrence after resection as well as to assess response to systemic therapy. Despite being the best studied marker, chromogranin A has significant limitations. Multiple other biomarkers are in use, but most have not been studied well and need further validation before being recommended for clinical practice. We review both established and novel circulating biomarkers, and highlight some of the limitations of tumor marker use in patients with NETs.

Gastroenteropancreatic neuroendocrine neoplasms: historical context and current issues

The digestive organs contain a large number of neuroendocrine cells as part of the diffuse neuroendocrine system. Neuroendocrine tumors can occur in every digestive organ. It has long been recognized that this is a diverse group of tumors with very different clinical outcomes; however, well-recognized prognostic parameters had been elusive until recently. Over the years, there have been several different classification schemes, each with different strengths and weaknesses. In an effort to standardize the classification and grading criteria for gastroenteropancreatic neuroendocrine tumors, the current World Health Organization classification includes a histologic grade based on proliferative rate (mitotic rate and Ki67 index) and a TNM stage that varies from organ to organ. The prognostic value of both the grade and stage has been validated in multiple studies. However, several issues remain, including the lack of standardized methods to assess proliferative rate, potential discrepancies between the mitotic count and the Ki67 index; intratumoral heterogeneity in proliferative rate; and the need for refinement in proliferative cut-points to define the grades. More studies are needed to further improve the classification of neuroendocrine tumors, thus guiding optimal treatment for these tumors.

The use of biomarkers in neuroendocrine tumours

The incidence and prevalence of neuroendocrine tumours (NETs) arising from the gastrointestinal tract are increasing. At the time of diagnosis, histological grade, based on Ki-67 proliferation index on a tumour biopsy or specimen, offers prognostication but with often lengthy survival, this may not reflect current tumour biology later in the disease course. Biomarkers, including plasma chromogranin A, urinary 5-hydroxyindole acetic acid and pancreatic specific hormones (insulin, gastrin, vasoactive intestinal peptide), have a role in diagnosis but despite being incorporated into routine clinical practice, there is a lack of robust prospectively collected data investigating their prognostic and predictive value. Given the increasing number of treatment options available for NETs and prolonged survival, there is no agreement on the order of treatment for individual NET patients but the emergence of novel biomarkers and validation of existing ones, in addition to better understanding of the molecular biology, may help solve this clinical problem.

A comparison of Ki-67 and mitotic count as prognostic markers for metastatic pancreatic and midgut neuroendocrine neoplasms

Background:

The aim of this study was to compare mitotic count (MC) and Ki-67 proliferation index as prognostic markers in pancreatic and midgut neuroendocrine neoplasms (NENs).

Methods:

Two hundred eighty-five patients with metastatic NENs were recruited. Concordance between histological grade according to either Ki-67 or MC as defined by the European Neuroendocrine Tumour Society guidelines was assessed and the prognostic significance of Ki-67 or MC were evaluated.

Results:

There was a discrepancy of 44 and 38% in grade assignment when using Ki-67 or MC in pancreatic and midgut NENs, respectively. In multivariate analysis, grade using Ki-67, but not MC, was a significant prognostic factor in determining overall survival (hazard ratios: midgut G2 2.34, G3 15.1, pancreas G2 2.08, G3 11.3). The prognostic value of Ki-67 was improved using a modified classification (hazard ratios: midgut G2 3.02, for G3 22.1, pancreas G2 5.97, G3 33.8).

Conclusion:

There is a lack of concordance between Ki-67 and MC in assigning tumour grade. Grade according to Ki-67 was a better prognostic marker than MC for metastatic pancreatic and midgut NENs. We suggest that Ki-67 alone should be used for grading pancreatic and midgut NENs and that the current threshold for classifying G1/G2 tumours should be revised from 2 to 5%.

Comparison of 24-h and overnight samples of urinary 5-hydroxyindoleacetic acid in patients with intestinal neuroendocrine tumors

Neuroendocrine tumors (NETs) arising in the small intestine are known to produce vasoactive substances, including serotonin, that may result in the carcinoid syndrome (flushing, diarrhea, bronchoconstriction, and carcinoid heart disease). Measurement of the serotonin breakdown product 5-hydroxyindoleacetic acid (5-HIAA) in urine is important in diagnosing and monitoring of patients with intestinal NETs. Our aim was to compare 5-HIAA measurement in 24-h urine sampling with overnight (∼8-h) sampling in patients with known NETs, or at follow-up of patients potentially cured for their NETs. Twenty-four-hour and overnight urine samples were collected from 34 patients and analyzed for urinary 5-HIAA (U5-HIAA) using HPLC. Comparison of the overnight sampling values with the 24-h values showed no difference, P=0.45, and there was a significant direct correlation between the two samples using linear regression (R=0.97, P<0.001). U5-HIAA sample collection during a nightly interval of ∼8 h appears to have the same accuracy as the 24-h collection in this group of patients.

Biochemical markers for gastroenteropancreatic neuroendocrine tumours (GEP-NETs)

Biochemical markers are applied in gastroenteropancreatic neuroendocrine tumours (GEP-NETs) for diagnostic, prognostic or predictive purposes. Chromogranin A is the most important general marker and it is recommended to be measured in every patient with a suspected NET, whereas Neuron Specific Enolase is elevated mainly in poorly differentiated NETs. Pancreatic Polypeptide is used in the diagnosis of pancreatic non-functioning NETs, whereas Chorionic Gonadotrophin has an adjunctive role. In the case of functioning tumours, specific markers should be sought and monitored during follow up. Endogenous hyperinsulinemia is suggested in the presence of non-suppressible insulin and proinsulin levels during hypoglycemia, whereas high fasting or stimulated gastrin levels along with elevated gastric acid output are diagnostic for the Zollinger-Ellison syndrome. Glucagon, vasoactive intestinal polypeptide (VIP) and somatostatin are markers for glucagonoma, VIP-oma and somatostatinoma syndromes respectively. In case of ectopic paraneoplastic syndrome, the relevant hormone serves as a diagnostic and prognostic marker.

CT and enhanced CT in diagnosis of gastrointestinal neuroendocrine carcinomas

OBJECTIVES

To enhance diagnosis of gastrointestinal neuroendocrine carcinomas using CT and contrast-enhanced CT images.

METHODS

A total of 44 patients with gastrointestinal neuroendocrine carcinomas, as confirmed by clinical pathology and immunohistochemistry in the Sixth Affiliated People's Hospital of Shanghai Jiao Tong University Shanghai China, were included in the study. CT and enhanced CT scanning were performed, and the resulting images were reviewed and analyzed.

RESULTS

Twenty-seven males and 17 females were enrolled. Gastrointestinal involvement included the following: 5 cases located in the middle or inferior segment of the esophagus; 5 in the gastric cardia, 15 in the body of stomach, 6 located in the gastric antrum; 5 located in the Vater papilla of the duodenum; and 8 located in the colon. Among the 44 cases 80%-90% of the lesions had homogeneous density. Totally 81.8% (36/44) cases demonstrated homogeneous enhancement in arterial phases, most of the cases (n = 33) moderately or obviously enhanced. Only 17.2% (8/44) cases appeared as heterogeneous enhancement. And 86.4% cases (n = 38) were further enhanced in the venous phase. The CT images also revealed some of the metastases. Some liver metastasis cases have obvious homogeneous enhancement.

CONCLUSIONS

CT and enhanced CT provide useful information regarding gastrointestinal neuroendocrine carcinomas' location, density, enhancement pattern, and some metastasis. These features are helpful to increase the diagnostic accuracy.

Nordic Guidelines 2010 for diagnosis and treatment of gastroenteropancreatic neuroendocrine tumours

The diagnostic work-up and treatment of patients with neuroendocrine tumours has undergone a major change during the last decade. New diagnostic possibilities and treatment options have been developed. These Nordic guidelines, written by a group with a major interest in the subject, summarises our current view on how to diagnose and treat these patients. The guidelines are meant to be useful in the daily practice for clinicians handling patients with neuroendocrine tumours.

Persistent low urinary excretion of 5-HIAA is a marker for favourable survival during follow-up in patients with disseminated midgut carcinoid tumours

Survival of patients with disseminated midgut carcinoid tumours varies. We investigated which factors predict survival at referral and during follow-up, with emphasis on urinary 5-hydroxyindolacetic acid (5-HIAA) levels. Between 1992 and 2003, 76 patients were studied; urine was prospectively collected over a 24 h period every 3 months in order to measure 5-HIAA levels. Uni- and multivariate analyses were performed. Median follow-up was 55 months with a median survival of 54 months. Prognostic factors for poor survival were high age, high gamma-glutamyltransferase levels and greatly increased 5-HIAA levels (>20 mmol/mol creatinine) The Hazard Ratio (HR) of a greatly increased 5-HIAA level was 3.33 (95% confidence interval (CI) 1.66-6.66, p=0.001). In a multivariate survival analysis with the 5-HIAA level as time dependent covariable, the HR for the 5-HIAA level was 1.007 (95% CI 1.004-1.010, p=0.000). In conclusion, patients with persistent moderately increased urinary 5-HIAA levels (< or =20 mmol/mol creatinine) have favourable outcome.