Chromogranin A: a sensitive biomarker for the detection and post-treatment monitoring of gastroenteropancreatic neuroendocrine tumors

Advances in Management of Nonfunctional Pancreas Neuroendocrine Tumors

This article presents updates in the surgical management of non-functional sporadic pancreas neuroendocrine tumors NET, including considerations for assessment of biologic behavior to support decision-making, indications for surgery, and surgical approaches tailored to the unique nature of neuroendocrine tumors.

Clinical and Molecular Characteristics of Rare Malignant Tumors of Colon and Rectum

Simple Summary

Tumors of colon and rectum other than adenocarcinomas represent a neglected issue from clinical and laboratory points of view because of their rarity. In this review, we summarize and describe the rare histologic entities occurring in colon and rectum. Clinical and pathologic characteristics, prognostic behavior, treatments, and altered genes are reported to provide readers with a paramount and comparative perspective. In relation to this, we propose that improvements in registries and multidisciplinary research are warranted to ameliorate their management.

Abstract

The most frequent form of colorectal cancer is represented by adenocarcinoma being about 98% of tumor histological types. However, other rare histotypes can be found in colon and rectum (adenosquamous, goblet cell adenocarcinoma, lymphoma, medullary carcinoma, melanoma, mesenchymal, neuroendocrine, plasmacytoma, signet ring, squamous tumors). Altogether, these forms account for less than 2% of colorectal tumors. There are no specific diagnostic or therapeutic recommended approaches and most of the information available from literature derives from small and retrospective clinical series. In the present study, we provide a paramount and updated view on clinical and biologic characteristics of rare colorectal tumors.

A combination of fecal calprotectin and human beta-defensin 2 facilitates diagnosis and monitoring of inflammatory bowel disease

Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) show a large overlap in clinical presentation, which presents diagnostic challenges. As a consequence, invasive and burdensome endoscopies are often used to distinguish between IBD and IBS. Here, we aimed to develop a noninvasive fecal test that can distinguish between IBD and IBS and reduce the number of endoscopies.We used shotgun metagenomic sequencing to analyze the composition and function of gut microbiota of 169 IBS patients, 447 IBD patients and 1044 population controls and measured fecal Calprotectin (FCal), human beta defensin 2 (HBD2), and chromogranin A (CgA) in these samples. These measurements were used to construct training sets (75% of data) for logistic regression and machine learning models to differentiate IBS from IBD and inactive from active IBD. The results were replicated on test sets (remaining 25% of the data) and microbiome data obtained using 16S sequencing.Fecal HBD2 showed high sensitivity and specificity for differentiating between IBD and IBS (sensitivity = 0.89, specificity = 0.76), while the inclusion of microbiome data with biomarkers (HBD2 and FCal) showed a potential for improvement in predictive power (optimal sensitivity = 0.87, specificity = 0.93). Shotgun sequencing-based models produced comparable results using 16S-sequencing data. HBD2 and FCal were found to have predictive power for IBD disease activity (AUC ≈ 0.7).HBD2 is a novel biomarker for IBD in patients with gastro-intestinal complaints, especially when used in combination with FCal and potentially in combination with gut microbiome data.

Developing a Quantitative Ultrasound Image Feature Analysis Scheme to Assess Tumor Treatment Efficacy Using a Mouse Model

The aim of this study is to investigate the feasibility of identifying and applying quantitative imaging features computed from ultrasound images of athymic nude mice to predict tumor response to treatment at an early stage. A computer-aided detection (CAD) scheme with a graphic user interface was developed to conduct tumor segmentation and image feature analysis. A dataset involving ultrasound images of 23 athymic nude mice bearing C26 mouse adenocarcinomas was assembled. These mice were divided into 7 treatment groups utilizing a combination of thermal and nanoparticle-controlled drug delivery. Longitudinal ultrasound images of mice were taken prior and post-treatment in day 3 and day 6. After tumor segmentation, CAD scheme computed image features and created four feature pools including features computed from (1) prior treatment images only and (2) difference between prior and post-treatment images of day 3 and day 6, respectively. To predict tumor treatment efficacy, data analysis was performed to identify top image features and an optimal feature fusion method, which have a higher correlation to tumor size increase ratio (TSIR) determined at Day 10. Using image features computed from day 3, the highest Pearson Correlation coefficients between the top two features selected from two feature pools versus TSIR were 0.373 and 0.552, respectively. Using an equally weighted fusion method of two features computed from prior and post-treatment images, the correlation coefficient increased to 0.679. Meanwhile, using image features computed from day 6, the highest correlation coefficient was 0.680. Study demonstrated the feasibility of extracting quantitative image features from the ultrasound images taken at an early treatment stage to predict tumor response to therapies.

Pancreatic neuroendocrine tumours: Grade is superior to T, N, or M status in predicting outcome and selecting patients for chemotherapy:A retrospective cohort study in the SEER database

BACKGROUND

Pancreatic neuroendocrine tumours (pNETs) are a rare and heterogeneous group of tumours with an increasing incidence. Current staging criteria for pNETs remain limited and controversial. Meanwhile, the impact of chemotherapy on overall survival has not been fully defined.

OBJECTIVES

The current study aimed to explore epidemiologic trends of pancreatic neuroendocrine tumours (pNETs). To determine feasible improvements to staging criteria and investigate the relationship between chemotherapy and survival.

METHODS

A retrospective cohort study design was used to analyse annual cancer incidence rates, patient demographics, tumour site and stage, and treatment of pNETs. Data were obtained from the National Cancer Institute's SEER registry for all patients diagnosed with pNETs between January 1973 and December 2015.

RESULTS

Patients diagnosed after 2010 were more likely to present with age greater than 45 years, T0, T1 status, N0 status, M0 status, and well differentiation. Current AJCC staging criteria was applicable to patients with well differentiation, but not other differentiation. The revised system, defined by Grade, T, N, and M status, could robustly discriminate between survival curves. Chemotherapy was associated with significantly improved survival for patients with poorly differentiated and undifferentiated tumour grading.

CONCLUSIONS

Grade is superior to 'T', 'N', or 'M' status in predicting outcomes and selecting patients for chemotherapy. It is necessary and feasible to combine grade into current staging criteria.

Combined Volumetric and Density Analyses of Contrast-Enhanced CT Imaging to Assess Drug Therapy Response in Gastroenteropancreatic Neuroendocrine Diffuse Liver Metastasis

OBJECTIVE

We propose a computer-aided method to assess response to drug treatment, using CT imaging-based volumetric and density measures in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) and diffuse liver metastases.

METHODS

Twenty-five patients with GEP-NETs with diffuse liver metastases were enrolled. Pre- and posttreatment CT examinations were retrospectively analyzed. Total tumor volume (volume) and mean volumetric tumor density (density) were calculated based on tumor segmentation on CT images. The maximum axial diameter (tumor size) for each target tumor was measured on pre- and posttreatment CT images according to Response Evaluation Criteria In Solid Tumors (RECIST). Progression-free survival (PFS) for each patient was measured and recorded.

RESULTS

Correlation analysis showed inverse correlation between change of volume and density (Δ(V + D)), change of volume (ΔV), and change of tumor size (ΔS) with PFS (r = -0.653, P=0.001; r = -0.617, P=0.003; r = -0.548, P=0.01, respectively). There was no linear correlation between ΔD and PFS (r = -0.226, P=0.325).

CONCLUSION

The changes of volume and density derived from CT images of all lesions showed a good correlation with PFS and may help assess treatment response.

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 options for PNET liver metastases: a systematic review

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are rare pancreatic neoplasms. About 40-80% of patients with PNET are metastatic at presentation, usually involving the liver (40-93%). Liver metastasis represents the most significant prognostic factor. The aim of this study is to present an up-to-date review of treatment options for patients with liver metastases from PNETs.

METHODS

A systematic literature search was performed using the PubMed database to identify all pertinent studies published up to May 2018.

RESULTS

The literature search evaluated all the therapeutic options for patients with liver metastases of PNETs, including surgical treatment, loco-regional therapies, and pharmacological treatment. All the different treatment options showed particular indications in different presentations of liver metastases of PNET. Surgery remains the only potentially curative therapeutic option in patients with PNETs and resectable liver metastases, even if relapse rates are high. Efficacy of medical treatment has increased with advances in targeted therapies, such as everolimus and sunitinib, and the introduction of radiolabeled somatostatin analogs. Several techniques for loco-regional control of metastases are available, including chemo- or radioembolization.

CONCLUSIONS

Treatment of patients with PNET metastases should be multidisciplinary and must be personalized according to the features of individual patients and tumors.

Prognostic value of chromogranin A in patients with GET/NEN in the pancreas and the small intestine

The aim of this study was to evaluate the clinical usefulness of the chromogranin A (CgA) determination in patients with neuroendocrine neoplasms (NENs) of the digestive system and to analyse the association between concentration of the marker and progression-free survival (PFS) and overall survival (OS). Serum concentrations of CgA were determined before the treatment in 131 patients with NENs, including patients with tumours located in the pancreas, the small intestine, caecum, appendix and in the colon. No significant associations were identified in CgA concentrations between the control group and patients with NENs in appendix and colon. In patients with NENs of the pancreas and NENs of the small intestine and caecum, increased CgA levels were associated with lymph node involvement, distant metastases and a baseline liver involvement. Analyses revealed significantly higher CgA concentrations in patients with active disease compared to those without symptoms of NEN. In patients with NENs of the pancreas, CgA concentration was correlated with tumour grade and Ki67. Significantly higher CgA levels were also found in patients who died compared to those who lived. Analyses of PFS and OS revealed that CgA concentration was not a prognostic factor in patients with NENs of the pancreas. In patients with NENs of the small intestine and caecum, increased CgA concentrations are independent, poor prognostic factors for both PFS and OS. In conclusion, in patients with NENs in pancreas, CgA levels are associated with disease progression, while in patients with NENs in small intestine and caecum, its concentration is a predictive indicator for PFS and OS.

An observational analysis of insulinoma from a single institution

BACKGROUND

Insulinoma is the commonest functioning pancreatic neuroendocrine tumor causing hyperinsulinemic hypoglycemia.

AIM

This study is aimed to evaluate the clinical features, preoperative laboratory and imaging diagnosis and pathologic findings of insulinoma.

METHODS

Data of the patients from 2001 to 2016 diagnosed as insulinoma in Tongji Hospital, China were retrospectively extracted and analyzed.

RESULTS

A total of 40 patients were diagnosed as insulinoma with a male/female ratio of 0.68:1. The median onset age was 46.5 years. Nearly all the included patients presented neurological symptoms and 60% presented autonomic symptoms. More than 95% of the patients met the functional European Neuroendocrine Tumor Society criteria including glucose, insulin and C-peptide levels. The preoperative detection rates of ultrasonography, enhanced computed tomography, magnetic resonance imaging, and endoscopic ultrasonography were 60.50%, 84.95%, 80% and 83.3% respectively. The joint imaging examinations can markedly increase the detection rate. The mean tumor size was 1.89 ± 0.72 cm. Ki-67 index by histopathological diagnosis were all less than 20%. The positive rates of insulin, synaptophysin and chromogranin A were close to 100%.

CONCLUSION

Laboratory tests of glucose, insulin and C-peptide are reliable for preoperative diagnosis. Combination of the imaging examinations can improve the diagnosis.

Combined test of serum CgA and NSE improved the power of prognosis prediction of NF-pNETs

PURPOSE

Chromogranin A (CgA) and neuron-specific enolase (NSE) are important markers for neuroendocrine tumors; however, the clinical value of combining these markers has not been well studied. In this study, we investigated the utility of each marker individually and in combination for patients with nonfunctional pancreatic neuroendocrine tumors (NF-pNETs).

PATIENTS AND METHODS

In this study, NF-pNET patients and controls were recruited from December 2011 to March 2016; 784 serum samples from peripheral vein were collected. The clinical characteristics and biomarker values of all the individuals were recorded and analyzed. Tumor burdens were calculated by CT/MRI scan. Receiver-operating characteristic curves were constructed to assess the diagnostic predictive values; sensitivity and specificity were calculated to determine the cut-off value. Therapeutic responses reflected on the changes of the biomarkers' concentration were assessed by the RECIST criterion. Clinical relations between the prognosis and the biomarker values were also analyzed. Statistical significance was defined as P value less than 0.05.

RESULTS

Among the 167 NF-pNETs patients, 82 were males (49.1%) and the mean age was 50.0 (17.4). The mean CgA values of G1, G2 and G3 NF-pNENs were 75, 121 and 134 μg/L (P < 0.05), respectively. In NF-pNETs, CgA correlated with the WHO tumor grade (WHO G1 vs G2, P < 0.05); the linear regression relationships were found between the tumor burdens (both in pancreas and liver) and CgA concentration (P < 0.001); changes in CgA and NSE concentrations also reflect treatment response (P < 0.001).

CONCLUSION

CgA and NSE are important diagnostic and follow-up markers in patients with NF-pNETs. The combined monitoring of CgA and NSE possesses more accuracy than individual values of CgA and NSE at predicting prognosis and disease progression.

Diagnosis of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are relatively rare; however, the incidence has increased over the last few decades. They are classified as functional or non-functional tumors according to the presence of associated clinical symptoms. The majority are non-functional tumors. For classification and staging, the World Health Organization 2010 classification system is the most commonly accepted. Chromogranin A is the most sensitive marker but has insufficient specificity. In general, PNETs are hypervascular tumors, and multiphasic contrast-enhanced computed tomography is considered the first choice for imaging study. Multiphasic magnetic resonance imaging can detect PNETs smaller than 2 cm and small liver metastasis compared with other modalities. Somatostatin receptor scintigraphy is often used in cases where functional PNETs are suspected. Positron emission tomography (PET) scan with 18F-fluorodeoxyglucose cannot visualize PNETs, but PET with 68-Ga DOTATATE can. Endoscopic ultrasonography can characterize smaller PNETs using contrast and confirm histology through fine needle aspiration or biopsy. In this article, we review the characteristics of grading systems and diagnostic modalities commonly used for PNETs.

Management and outcome of children with neuroendocrine tumors of the appendix in Spain: Is there room for improvement?

PURPOSE

Neuroendocrine tumors (NETs) are, after lymphomas, the most frequent gastrointestinal tumors in children, mainly located in the appendix. Best management remains unclear, given the absence of pediatric guidelines. We present the first Spanish series of pediatric patients with NETs.

PATIENTS AND METHODS

Retrospective study of all pediatric patients (<18 years) with NET treated in four oncology reference institutions in Spain between 1994 and 2015.

RESULTS

Seventeen patients were included. All patients presented with acute abdomen. TNM stage was T1a (82%) and T1b (12%). Extension study was heterogenous, with only 4 patients undergoing an OctreoScan. Four patients met criteria for second surgery (affected surgical margins or mesoappendix invasion), but it was only performed in two. Despite the diverse management, none of the patients relapsed during follow-up.

CONCLUSIONS

The disparity in diagnostic tests, second surgery criteria and follow-up shown in this study highlights the need for specific pediatric guidelines.

Advances in the diagnosis and treatment of pancreatic neuroendocrine neoplasms in Japan

Several new developments have occurred in the field of pancreatic neuroendocrine neoplasm (PNEN) recently in Japan. First, the utility of chromogranin A (CgA), useful for the diagnosis and monitoring of the treatment response of neuroendocrine neoplasm (NEN), has been demonstrated in Japan. For PNEN diagnosis and treatment, grading and correct histological diagnosis according to the WHO 2010 classification is important. Regarding the histological diagnosis, the advent of endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has enabled correct pathological diagnosis and suitable treatment for the affected tissue. Furthermore, EUS-FNA has also facilitates the assessment of the presence or absence of gene mutations. In addition, patients who have a well-differentiated neuroendocrine tumor (NET) showing a Ki-67 index of higher than 20 % according to the WHO 2010 classification, have also been identified, and their responses to treatment were found to be different from those of patients with poorly differentiated neuroendocrine carcinoma (NEC). Therefore, the concept of NET G3 was proposed. Additionally, somatostatin receptor type 2 is expressed in several cases of NET, and somatostatin receptor scintigraphy (¹¹¹In-octreoscan) has also been approved in Japan. This advancement will undoubtedly contribute to the localization diagnosis, the identification of remote metastasis, and assessments of the treatment responses of PNEN. Finally, regarding the treatment strategy for PNEN, the management of liver metastasis is important. The advent of novel molecular-targeted agents has dramatically improved the prognosis of advanced PNEN. Multimodality therapy that accounts for the tumor stage, degree of tumor differentiation, tumor volume, and speed of tumor growth is required.

Circulating Chromogranin A as A Marker for Monitoring Clinical Response in Advanced Gastroenteropancreatic Neuroendocrine Tumors

Chromogranin A (CgA), present in the chromaffin granules of neuroendocrine cells, is a useful biomarker for the diagnosis of patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs). This study was conducted to investigate the potential role of circulating CgA in monitoring clinical response in Chinese patients with advanced GEP-NETs. Eighty patients with advanced GEP-NETs treated in Peking University Cancer Hospital from September 2011 to May 2014 and 65 healthy individuals were included in this study. Serum CgA levels were analyzed for relationship with patient's baseline characteristics and clinical outcome. Median CgA levels were significantly higher in patients with advanced GEP-NETs than in healthy individuals (93.8 ng/mL vs. 37.1 ng/mL; P<0.01), as well as significantly higher in patients with carcinoid syndrome or liver metastasis than in those without carcinoid syndrome (298.8 ng/mL vs. 82.9 ng/mL; P = 0.011) or liver metastasis (137.0 ng/mL vs. 64.4 ng/mL; P = 0.023). A CgA cutoff value of 46.2 ng/mL was used in this study with a sensitivity of 78.8% and specificity of 73.8%. Patients with CgA levels higher than 46.2 ng/mL had a worse prognosis than patients with CgA levels lower than 46.2 ng/mL (P = 0.045). Notably, a weak correlation was observed between changes in serum CgA levels and clinical response to the IP regimen as well as SSAs. Our data also indicate that serum CgA could be a useful indicator of patient prognosis though there is more research required in order to validate such claims.

Somatostatin Analogs and Tumor Localization Do Not Influence Vitamin D Concentration in Patients with Neuroendocrine Tumors

Patients with neuroendocrine tumors (NETs), malignancies of rare but still rising incidence, may be a group at higher risk of vitamin D insufficiency. The gastrointestinal tumor prevalence and somatostatin analog (SSA) therapy may cause vitamin D malabsorption. The aim of this study was to evaluate the serum level of vitamin D in NET patients. A total of 36 NET patients were enrolled into the experimental group and 16 individuals were enrolled into the control group. All patients were further classified into subgroups according to primary tumor localization (gastropancreatic, lung, and other NETs) or therapy (with or without SSA treatment). The concentrations of total 25(OH)D were assayed with Electrochemiluminescence immunoassay (ECLIA). Serum concentration of 25(OH)D in NET patients did not differ significantly from that of the control group. However, the average level of 25(OH)D in both groups met the criteria of vitamin D deficiency. Importantly, SSA therapy did not aggravate vitamin D deficiency. Moreover, the concentration of 25(OH)D in the studied group was not significantly influenced by primary tumor localization, patient age, or season. Vitamin D deficiency is a widespread disorder affecting both NET patients and individuals without other health problems, and SSA and gastrointestinal tumor localization do not exacerbate this condition.

Chromogranin As a Biochemical Marker of Neuroendocrine Tumors

Comparative study of plasma chromogranin A levels was carried out in 227 patients with neuroendocrine tumors of various locations and 66 normal subjects, men and women, by standard ELISA. In patients with tumors of all locations (pancreas, stomach, small and large intestine, and lungs), the glycoprotein levels were significantly (p<0.000001) higher than in controls. The patients demonstrated high variability of chromogranin A levels; the maximum concentrations were detected in patients with neuroendocrine tumors of the stomach and lung. The highest median values of chromogranin A were found in patients with tumors of the small intestine, large intestine, and pancreas. A relationship between secretion of chromogranin A and dissemination and activity of the neuroendocrine tumor was detected, which was the maximum in patients with metastases in the liver and carcinoid syndrome. High diagnostic sensitivity of chromogranin A was shown: 85.8% for the total group of patients; specificity was 98.5%. These data confirmed high efficiency of chromogranin A as the marker of neuroendocrine tumors. Detection of this marker promotes more accurate diagnosis and evaluation of dissemination of the neuroendocrine tumors.

Pancreatic neuroendocrine tumors: Challenges in an underestimated disease

Pancreatic neuroendocrine tumours (PanNETs) are considered a relatively unusual oncologic entity. Due to its relative good prognosis, surgery remains the goal standard therapy not only in localized disease but also in the setting of locally or metastatic disease. Most of the patients are diagnosed in metastatic scenario, where multidisciplinary approach based on surgery, chemotherapies, liver-directed and/or molecular targeted therapies are commonly used. Owing to a deeper molecular knowledge of this disease, these targeted therapies are nowadays widely implemented, being the likely discovery of predictive biomarkers that would allow its use in other settings. This review is focused on describing the different classifications, etiology, prognostic biomarkers and multidisciplinary approaches that are typically used in PanNET.

Pancreatic Neuroendocrine Tumors: an Update

Pancreatic neuroendocrine tumors (pNETs) are rare and comprise only 1-2 % of all pancreatic neoplastic disease. Although the majority of these tumors are sporadic (90 %), pNETs can arise in the setting of several different hereditary genetic syndromes, most commonly multiple endocrine neoplasia type 1 (MEN1). The presentation of pNETs varies widely, with over 60 % having malignant distant disease at the time of initial diagnosis involving the liver or other distant sites. Functioning pNETs represent approximately 10 % of all pNETs, secrete a variety of peptide hormones, and are responsible for several clinical syndromes caused by profound hormonal derangement. Surgery remains the cornerstone of therapy and the only curative approach. It should be pursued for localized disease and for metastatic lesions amenable to resection. Multimodality therapies, including liver-directed therapies and medical therapy, are gaining increasing favor in the treatment of advanced pNETs. Their utility is multifold and spans from ameliorating symptoms of hormonal excess (functional pNETs) to controlling the local and systemic disease burden (non-functional pNETs). The recent introduction of target molecular therapy has promising results especially for the treatment of progressive well-differentiated G1/G2 tumor. In this review, we summarize the current knowledge and give an update on recent advancements made in the therapeutic strategies for pNETs.

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.

Update on pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) are relatively rare tumors comprising 1-2% of all pancreas neoplasms. In the last 10 years our understanding of this disease has increased dramatically allowing for advancements in the treatment of pNETs. Surgical excision remains the primary therapy for localized tumors and only potential for cure. New surgical techniques using laparoscopic approaches to complex pancreatic resections are a major advancement in surgical therapy and increasingly possible. With early detection being less common, most patients present with metastatic disease. Management of these patients requires multidisciplinary care combining the best of surgery, chemotherapy and other targeted therapies. In addition to surgical advances, recently, there have been significant advances in systemic therapy and targeted molecular therapy.

Consensus Recommendations for the Diagnosis and Management of Pancreatic Neuroendocrine Tumors: Guidelines from a Canadian National Expert Group

Pancreatic neuroendocrine tumors (pNETs) are rare heterogeneous tumors that have been steadily increasing in both incidence and prevalence during the past few decades. Pancreatic NETs are categorized as functional (F) or nonfunctional (NF) based on their ability to secrete hormones that elicit clinically relevant symptoms. Specialized diagnostic tests are required for diagnosis. Treatment options are diverse and include surgical resection, intraarterial hepatic therapy, and peptide receptor radionuclide therapy (PRRT). Systemic therapy options include targeted agents as well as chemotherapy when indicated. Diagnosis and management should occur through a collaborative team of health care practitioners well-experienced in managing pNETs. Recent advances in pNET treatment options have led to the development of the Canadian consensus document described in this report. The discussion includes the epidemiology, classification, pathology, clinical presentation and prognosis, imaging and laboratory testing, medical and surgical management, and recommended treatment algorithms for pancreatic neuroendocrine cancers.

Serum chromogranin A is a useful marker for Japanese patients with pancreatic neuroendocrine tumors

Although chromogranin A (CGA) is a useful marker for pancreatic neuroendocrine tumors (pNET) in the West, its usefulness in Japanese populations is unclear. To assess this, we evaluated the serum CGA levels in 189 patients with various pancreatic diseases, including proven pNET (n = 69), pancreatic cancer (PC) (n = 50), chronic pancreatitis (CP) (n = 50) and autoimmune pancreatitis (AIP) (n = 20), and 112 normal controls (controls) using an ELISA kit. The mean CGA level of patients with pNET was significantly higher than any of the other groups (407.8 ± 984.6 ng/mL [pNET] vs 91.8 ± 101.8 ng/mL [PC], 93.6 ± 57.5 ng/mL [CP], 69.9 ± 52.4 ng/mL [AIP] and 62.5 ± 48.3 ng/mL [controls]). Limiting the analysis to patients not using proton pump inhibitors (PPI), the CGA level of patients with PC or CP was not significantly different compared with the controls. Discriminant analysis revealed that the best cut-off value of CGA to distinguish patients with pNET from the controls was 78.7 ng/mL, with a sensitivity and specificity of 53.6% and 78.6%, respectively. In patients with pNET, significant factors associating with elevated CGA levels were tumor classification, tumor size, and the presence of liver metastases in univariate analysis as well as PPI use and the presence of liver metastases in multivariate analysis. We show that CGA is a useful marker for diagnosing pNET in Japanese populations and for distinguishing patients with pNET from patients with other pancreatic diseases. The increased use of CGA in Japan will likely be a helpful tool in managing these patients, as found in the West.

Chromogranin A is a reliable serum diagnostic biomarker for pancreatic neuroendocrine tumors but not for insulinomas

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are a group of rare tumors. Chromogranin A (CgA) was considered as the most practical and useful serum tumor marker in PNET patients. But peripheral blood levels of CgA are not routinely tested in Chinese patients with PNETs. This study was to assess the diagnostic value of CgA in Chinese patients with PNETs especially in patients with insulinomas.

METHODS

Eighty-nine patients with PNETs including 57 insulinomas and 32 non-insulinoma PNETs as well as 86 healthy participants were enrolled in this study between September 2003 and June 2013. Serum levels of CgA were measured by ELISA method. Expression of CgA protein was detected in 26 PNET tissues including 14 insulinomas by immunohistochemical staining.

RESULTS

Serum levels of CgA in 89 PNET patients were significantly higher than that in healthy controls (P = 7.2 × 10-9). Serum levels of CgA in 57 patients with insulinomas (median 64.8 ng/ml, range 25-164) were slightly higher than the levels in healthy controls (median 53.4 ng/ml, range 39-94) but much lower than the levels in 32 patients with non-insulinoma PNETs (median 193 ng/ml, range 27-9021), P = 0.001. The serum CgA levels were reduced in 16 of 17 patients with insulinomas after tumor resection. ROC curve showed that CgA values at 60 ng/ml distinguished patients with insulinomas from healthy controls but its sensitivity and specificity were 66.7% and 73.3%, respectively. In contrast, CgA values at 74 ng/ml distinguished patients with non-insulinoma PNETs from healthy controls, and the sensitivity and specificity were 65.6% and 91.9%, respectively. Except for two insulinomas with negative staining of CgA, 12 insulinoma tissues showed positive staining of CgA.

CONCLUSION

CgA is a reliable serum diagnostic biomarker for PNETs but not for insulinomas.

Pancreatic neuroendocrine tumors: current opinions on a rare, but potentially curable neoplasm

Pancreatic neuroendocrine tumors (PNETs) share a unique genetic identity, functional behavior, and clinical course. Compared with tumors of the exocrine pancreas, they are rare and show a different biologic behavior and prognosis. On the basis of data from recent studies, all PNETs, outside of small insulinomas, should be considered potentially malignant and treated accordingly. Untreated tumors have a high possibility to grow locally into adjacent structures or spread to distant organs. Although surgical excision irrespective of tumor functioning or nonfunctioning state remains the cornerstone of therapy, providing the best disease-free and survival rates to date, the understanding of the genetic nature of the disease yields new 'targets' to consider in drug development. The aim of this review is to summarize all recent advances of genetic research and new drug development in terms of PNETs, especially their genetic identity and subsequent alterations leading to the development of near or total malignant activity, and the new medical treatment strategies of this potentially curable disease on the basis of therapeutical agents acting, where possible, at the genetic level.

New insights into the role of chronic inflammation and cytokines in the etiopathogenesis of gastroenteropancreatic neuroendocrine tumors

Although previously considered rare, recent epidemiological studies have revealed that the incidence (3.6/100,000) and prevalence (35/100,000) of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has increased over the past few decades. Despite the progress in the understanding of GEP-NET molecular biology, there is still little advance in the early diagnosis due to lack of specific tumor markers. As the tumors are mostly detected in their late stage, they are not well controlled by either biotherapy or conventional chemotherapy, and thus represent a significant clinical issue. Chronic inflammation has been implicated in the development of GEP-NETs. This review presents recent findings that link pro-inflammatory cytokines to the molecular basis of GEP-NET tumorigenesis, leading to a more personalized approach to disease management and therapy.

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.

Plasma levels of soluble HLA-E and HLA-F at diagnosis may predict overall survival of neuroblastoma patients

The purpose of this study was to identify the plasma/serum biomarkers that are able to predict overall survival (OS) of neuroblastoma (NB) patients. Concentration of soluble (s) biomarkers was evaluated in plasma (sHLA-E, sHLA-F, chromogranin, and B7H3) or serum (calprotectin) samples from NB patients or healthy children. The levels of biomarkers that were significantly higher in NB patients were then analyzed considering localized or metastatic subsets. Finally, biomarkers that were significantly different in these two subsets were correlated with patient's outcome. With the exception of B7H3, levels of all molecules were significantly higher in NB patients than those in controls. However, only chromogranin, sHLA-E, and sHLA-F levels were different between patients with metastatic and localized tumors. sHLA-E and -F levels correlated with each other but not chromogranin. Chromogranin levels correlated with different event-free survival (EFS), whereas sHLA-E and -F levels also correlated with different OS. Association with OS was also detected considering only patients with metastatic disease. In conclusion, low levels of sHLA-E and -F significantly associated with worse EFS/OS in the whole cohort of NB patients and in patients with metastatic NB. Thus, these molecules deserve to be tested in prospective studies to evaluate their predictive power for high-risk NB patients.

Imaging features of carcinoid tumors of the gastrointestinal tract

OBJECTIVE

Recent studies have provided a better understanding of the biologic behavior of gastrointestinal carcinoid tumors. This article focusing on imaging of gastrointestinal carcinoids will emphasize epidemiology, molecular biology, taxonomy, histopathology, and management.

CONCLUSION

Gastrointestinal carcinoids are a biologically heterogeneous group of tumors, with variable clinical presentation and biologic behavior. Imaging can play an important role in multidisciplinary identification and management of this disease.

[Drug therapy for neuroendocrine tumours]

The author aims to review the established medical treatment options of neuroendocrine tumours, which have expanded greatly in recent years and present the most important aspects to be considered in planning patients' management. Medical treatment is usually considered in advanced stages of these tumours, as well as in cases of hormone overproduction. Somatostatin analogues have been known to be effective in alleviating hormone excess syndromes, especially carcinoid syndrome for the past 25 years. There is a convincing evidence that the somatostatin analogue octreotide is useful as an antitumor agent, at least in well-differentiated small intestinal neuroendocrine tumours and probably also in those of pancreatic origin. Interferons may be also used and the indications for their use may be almost the same. Optimal patient selection is mandatory for the use of cytotoxic chemotherapy. Streptozotocin- and, recently, temozolomide-based chemotherapies should be considered in progressive phases of well differentiated (G1/G2) pancreatic neuroendocrine tumours. A cisplatin-etoposide combination is the first choice for the treatment of G3 neuroendocrine carcinomas of any origin. Recently, the mammalian target of rapamycin inhibitor everolimus and the combined tyrosine kinase inhibitor sunitinib were registered for the treatment of G1/G2 pancreatic neuroendocrine tumours. The most recent drug treatment recommendations and therapeutic algorithms to improve systemic therapy in patients with neuroendocrine tumours are summarized and novel drug candidates with particular potential for future management of these tumours are outlined.

Advancements in pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) have increased in incidence in the USA over the last 20 years. Although PanNETs are often misconceived as being indolent tumors as they have a far more favorable prognosis over pancreatic adenocarcinoma, roughly 60-70% of patients have metastatic disease at the time of diagnosis due to presentation late in the disease process. While improvements in imaging modalities allow for early detection and better tumor localization, recent advancements in basic science, as well as surgical and medical management of PanNETs have further improved the prognosis. The mainstay of therapy for localized PanNETs is surgical intervention, which has become safer and is slowly shifting towards a more minimally invasive approach. However, the prognosis still remains relatively bleak for patients with unresectable disease. Fortunately, novel molecular targeted therapies, such as everolimus and sunitinib, have recently come into the limelight and have shown significant promise for the treatment of locally advanced and metastatic disease.

Serum pancreastatin: the next predictive neuroendocrine tumor marker

BACKGROUND AND OBJECTIVES

Pancreastatin is a derived peptide of chromogranin A (CgA). Pancreastatin has the potential to be a diagnostic and predictive tumor marker in detecting NETs.

METHODS

Radioimmunoassay tests of pancreastatin and CgA were performed on 103 patient specimens collected at Mount Sinai Medical Center between 1/2010 and 7/2012. Patient demographics, diagnostic tests, surgical procedures, pathologic findings, adjuvant treatments, and survival were retrospectively reviewed. Statistical analysis utilized SPSS v20 software.

RESULTS

Mean pancreastatin levels were significantly higher in the 92 NETs patients than in the 11 non-NETs patients (227.261 vs. 59.727, P < 0.05). Twenty-seven of the 92 patients with elevated pancreastatin levels (mean = 240.67), had normal CgA levels (mean = 4.65). Pancreastatin had sensitivity and specificity of 64% (59/92), and 100% (11/11). CgA had lower sensitivity and specificity of 43% (40/92), and 64% (7/11). In all 27 instances the pancreastatin concentration was found to be sole indicator of NET disease. When controlling for the level of CgA for the entire sample, a statistically significant difference was not found in the mean pancreastatin levels between both patient groups (P = 0.139, R = 0.484).

CONCLUSION

Pancreastatin has greater sensitivity and specificity in diagnosing NETs than CgA. Further investigation of pancreastatin's diagnostic and predictive value is warranted.

Targeted therapies in neuroendocrine tumors (NET): clinical trial challenges and lessons learned

In the past 3 years, we have witnessed the completion of four randomized phase III studies in neuroendocrine tumors and the approval of two new drugs, everolimus and sunitinib, for the treatment of patients with well-differentiated pancreatic neuroendocrine tumors. These studies demonstrate a shift from case series and single-arm studies toward prospective, randomized controlled clinical trials and evidence-based therapy in the neuroendocrine tumor field. However, the clinical development of these agents also highlights the potential challenges awaiting other new drugs in this area. Herein, we discuss the strengths and weaknesses of the most recent phase II and phase III neuroendocrine tumor studies and discuss how limitations inherent in current trial design can lead to potential pitfalls. We also discuss how trial design can be improved, with the hope of increasing the number of drugs successfully developed to treat patients with neuroendocrine tumors.

Current concepts on gastric carcinoid tumors

Gastric carcinoid tumors (GCs) are rare lesions representing less than 10% of carcinoid tumors and less than 1% of all stomach neoplasms. There are three distinct types of gastric carcinoids; type I includes the vast majority (70–85%) of these neoplasms that are closely linked to chronic atrophic gastritis. Type II which accounts for 5–10 %, is associated with Zollinger-Ellison syndrome and often occurs in the context of multiple endocrine neoplasia type 1. Type III, finally, represents 15–25% of gastric carcinoids and is characterized by a far more aggressive course. The optimal clinical approach to GCs remains to be elucidated, depending upon type, size, and number of carcinoids. While there is universal agreement about the surgical treatment of type III GCs, current options for type I and II include simple surveillance, endoscopic polypectomy, surgical excision associated with or without surgical antrectomy, or total gastrectomy. Moreover, the introduction of somatostatin analogues could represent another therapeutic option.