Prospective, randomized, multicenter trial on the antiproliferative effect of lanreotide, interferon alfa, and their combination for therapy of metastatic neuroendocrine gastroenteropancreatic tumors--the International Lanreotide and Interferon Alfa Study Group

New Treatments for the Carcinoid Syndrome

Neuroendocrine tumors, including carcinoids, are rare and insidiously growing tumors. Related to their site of origin, tumors can be functional, causing various forms of the carcinoid syndrome, owing to the overproduction of serotonin, histamine, or other bioactive substances. They often invade adjacent structures or metastasize to the liver and elsewhere. Treatment includes multimodal approaches, including cytoreductive surgery, locoregional embolization, cytotoxic therapy, peptide receptor radionuclide therapy, and various targeted therapies with goals of symptom relief and control of tumor growth. This article summarizes current and emerging approaches to management and reviews several promising future therapies.

The Genesis of the Neuroendocrine Tumors Concept: From Oberndorfer to 2018

The concept of neuroendocrine tumors (NETs) began in the 1900s with Oberndorfer's description of carcinoid tumors, followed by specific cytotoxic agents and the identification of somatostatin. NETs diagnosis was confirmed by World Health Organization classification. Histopathology included immunohistochemistry with specific antibodies. Imaging was refined with molecular imaging. Somatostatin is the leading agent for controlling clinical symptoms related to hormone production. Increasing interest in these tumors, previously thought rare, led to increased incidence and prevalence. Between 1960 and 1970, the true NET-concept was established with development of radioimmunoassays for peptides and hormones, and imaging with computerized tomography.

Chromogranin A: From Laboratory to Clinical Aspects of Patients with Neuroendocrine Tumors

Background. Neuroendocrine tumors (NETs) are characterized by having behavior and prognosis that depend upon tumor histology, primary site, staging, and proliferative index. The symptoms associated with carcinoid syndrome and vasoactive intestinal peptide tumors are treated with octreotide acetate. The PROMID trial assesses the effect of octreotide LAR on the tumor growth in patients with well-differentiated metastatic midgut NETs. The CLARINET trial evaluates the effects of lanreotide in patients with nonfunctional, well-, or moderately differentiated metastatic enteropancreatic NETs. Everolimus has been approved for the treatment of advanced pancreatic NETs (pNETs) based on positive PFS effects, obtained in the treated group. Sunitinib is approved for the treatment of patients with progressive gastrointestinal stromal tumor or intolerance to imatinib, because a randomized study demonstrated that it improves PFS and overall survival in patients with advanced well-differentiated pNETs. In a phase II trial, pasireotide shows efficacy and tolerability in the treatment of patients with advanced NETs, whose symptoms of carcinoid syndrome were resistant to octreotide LAR. An open-label, phase II trial assesses the clinical activity of long-acting repeatable pasireotide in treatment-naive patients with metastatic grade 1 or 2 NETs. Even if the growth of the neoplasm was significantly inhibited, it is still unclear whether its antiproliferative action is greater than that of octreotide and lanreotide. Because new therapeutic options are needed to counter the natural behavior of neuroendocrine tumors, it would also be useful to have a biochemical marker that can be addressed better in the management of these patients. Chromogranin A is currently the most useful biomarker to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy.

Somatostatin analogue-induced pancreatic exocrine insufficiency in patients with neuroendocrine tumors: results of a prospective observational study

BACKGROUND

Patients with advanced well-differentiated neuroendocrine tumours (Wd-NETs) are commonly treated with somatostatin analogues (SSAs). Some patients may develop SSA-related side effects such as pancreatic exocrine insufficiency (PEI).

METHODS

In this prospective, observational study, the frequency of SSA-induced PEI in 50 sequential patients with advanced Wd-NETs treated with SSAs was investigated. Toxicity was assessed monthly and faecal elastase-1 (FE1) and quality of life (QoL) were assessed 3-monthly.

RESULTS

The median age was 65.8 years, 58% were male and the majority (92%) of patients had metastatic disease; patients received 4-weekly long acting octreotide (60%) or lanreotide (40%). Twelve patients (24%) developed SSA-related PEI after a median of 2.9 months from SSA initiation; FE1 was a reliable screening tool for PEI, especially in symptomatic (abdominal bloating, flatulence and/or diarrhea) patients (risk ratio 8.25 (95% confidence interval 1.15-59.01)). Most of these patients (11/12; 92%) required PERT. Other SSA-related adverse events (any grade) included flatulence (50%), abdominal pain (32%), diarrhoea (30%) and fatigue (20%). Development of PEI did not significantly worsen overall QoL, however gastrointestinal symptoms and diarrhoea were increased.

CONCLUSION

This study demonstrated that PEI occurs at a higher rate than previously reported; clinicians need to diagnose and treat this SSA-related adverse-event which occurs in 1 in 4 patients with Wd-NETs treated with SSAs. Screening with FE1 in symtomatic patients is recommend.

Additional hepatic 166Ho-radioembolization in patients with neuroendocrine tumours treated with 177Lu-DOTATATE; a single center, interventional, non-randomized, non-comparative, open label, phase II study (HEPAR PLUS trial)

Background

Neuroendocrine tumours (NET) consist of a heterogeneous group of neoplasms with various organs of origin. At diagnosis 21% of the patients with a Grade 1 NET and 30% with a Grade 2 NET have distant metastases. Treatment with peptide receptor radionuclide therapy (PRRT) shows a high objective response rate and long median survival after treatment. However, complete remission is almost never achieved. The liver is the most commonly affected organ in metastatic disease and is the most incriminating factor for patient survival. Additional treatment of liver disease after PRRT may improve outcome in NET patients. Radioembolization is an established therapy for liver metastasis. To investigate this hypothesis, a phase 2 study was initiated to assess effectiveness and toxicity of holmium-166 radioembolization (¹⁶⁶Ho-RE) after PRRT with lutetium-177 (¹⁷⁷Lu)-DOTATATE.

Methods

The HEPAR PLUS trial (“HolmiumEmbolizationParticles forArterialRadiotherapyPlus¹⁷⁷Lu-DOTATATE inSalvage NET patients”) is a single centre, interventional, non-randomized, non-comparative, open label study. In this phase 2 study 30–48 patients with > 3 measurable liver metastases according to RECIST 1.1 will receive additional ¹⁶⁶Ho-RE within 20 weeks after the 4th and last cycle of PRRT with 7.4 GBq ¹⁷⁷Lu-DOTATATE. Primary objectives are to assess tumour response, complete and partial response according to RECIST 1.1, and toxicity, based on CTCAE v4.03, 3 months after ¹⁶⁶Ho-RE. Secondary endpoints include biochemical response, quality of life, biodistribution and dosimetry.

Discussion

This is the first prospective study to combine PRRT with ¹⁷⁷Lu-DOTATATE and additional ¹⁶⁶Ho-RE in metastatic NET. A radiation boost on intrahepatic disease using ¹⁶⁶Ho-RE may lead to an improved response rate without significant additional side-effects.

Trial registration

Clinicaltrials.gov NCT02067988, 13 February 2014. Protocol version: 6, 30 november 2016.

Predictors of Survival in 211 Patients with Stage IV Pulmonary and Gastroenteropancreatic MIBG-Positive Neuroendocrine Tumors Treated with 131I-MIBG

This retrospective analysis identifies predictors of survival in a cohort of patients with meta-iodobenzylguanidine (MIBG)-positive stage IV pulmonary and gastroenteropancreatic neuroendocrine tumor (P/GEP-NET) treated with ¹³¹I-MIBG therapy, to inform treatment selection and posttreatment monitoring. Methods: Survival, symptoms, imaging, and biochemical response were extracted via chart review from 211 P/GEP-NET patients treated with ¹³¹I-MIBG between 1991 and 2014. For patients with CT follow-up (n = 125), imaging response was assessed by RECIST 1.1 if images were available (n = 76) or by chart review of the radiology report if images could not be reviewed (n = 49). Kaplan-Meier analysis and Cox multivariate regression estimated survival and progression-free survival benefits predicted by initial imaging, biochemical response, and symptomatic response. Results: All patients had stage IV disease at the time of treatment. Median survival was 29 mo from the time of treatment. Symptomatic response was seen in 71% of patients, with the median duration of symptomatic relief being 12 mo. Symptomatic response at the first follow-up predicted a survival benefit of 30 mo (P < 0.001). Biochemical response at the first clinical follow-up was seen in 34% of patients, with stability of laboratory values in 48%; response/stability versus progression extended survival by 40 mo (P < 0.03). Imaging response (20% of patients) or stability (60%) at the initial 3-mo follow-up imaging extended survival by 32 mo (P < 0.001). Additionally, multiple ¹³¹I-MIBG treatments were associated with 24 mo of additional survival (P < 0.05). Conclusion: Therapeutic ¹³¹I-MIBG for metastatic P/GEP-NETs appears to be an effective means of symptom palliation. Imaging, biochemical, and symptomatic follow-up help prognosticate expected survival after ¹³¹I-MIBG therapy. Multiple rounds of ¹³¹I-MIBG are associated with prolonged survival.

Advanced neuroendocrine tumours of the small intestine and pancreas: clinical developments, controversies, and future strategies

In this Review, we discuss clinical developments and controversies in the treatment of neuroendocrine tumours (NETs) that are relevant for clinicians and clinical researchers. We describe advances in genetics, blood-based biomarkers, functional imaging, and systemic therapy of advanced NETs and discuss results of recent phase 3 studies, systemic treatment of advanced disease with peptide receptor radionuclide therapy, biotherapy, chemotherapy, and molecularly targeted therapy, and the potential role of immunotherapy in the treatment of NETs. Suggested treatment algorithms for NETs of ileal or jejunal origin and of pancreatic origin are presented.

Current and emerging therapies for PNETs in patients with or without MEN1

Pancreatic neuroendocrine tumours (PNETs) might occur as a non-familial isolated endocrinopathy or as part of a complex hereditary syndrome, such as multiple endocrine neoplasia type 1 (MEN1). MEN1 is an autosomal dominant disorder characterized by the combined occurrence of PNETs with tumours of the parathyroids and anterior pituitary. Treatments for primary PNETs include surgery. Treatments for non-resectable PNETs and metastases include biotherapy (for example, somatostatin analogues, inhibitors of receptors and monoclonal antibodies), chemotherapy and radiological therapy. All these treatments are effective for PNETs in patients without MEN1; however, there is a scarcity of clinical trials reporting the efficacy of the same treatments of PNETs in patients with MEN1. Treatment of PNETs in patients with MEN1 is challenging owing to the concomitant development of other tumours, which might have metastasized. In recent years, preclinical studies have identified potential new therapeutic targets for treating MEN1-associated neuroendocrine tumours (including PNETs), and these include epigenetic modification, the β-catenin-wingless (WNT) pathway, Hedgehog signalling, somatostatin receptors and MEN1 gene replacement therapy. This Review discusses these advances.

The Zollinger-Ellison syndrome: is there a role for somatostatin analogues in the treatment of the gastrinoma?

PURPOSE

Analyze the role of somatostatin analogues (SSAs) in the treatment of sporadic and MEN1-related gastrinomas, trying to define whether recent trials have changed the landscape of gastrinoma therapy.

METHODS

We evaluate the rationale of SSA use in the treatment of gastrinomas, summarize the current literature concerning the effect of SSAs on the control of Zollinger-Ellison syndrome (ZES) and gastrinomas tumor progression and discuss their role in the most recent guidelines.

RESULTS

The medical treatment of gastrinoma and related ZES is aimed at controlling acid hypersecretion and tumor progression, in inoperable patients. The use of proton pump inhibitors (PPIs) to control the syndrome is a cornerstone in the ZES therapy. SSAs are not usually indicated for antisecretory purpose, because PPIs are considered the treatment of choice, due to their long lasting high efficacy and oral availability. The antiproliferative effect of SSAs has been established by two placebo-controlled trials that have clearly demonstrated a significant increase in progression free survival in patients affected by non-functioning well-differentiated advanced neuroendocrine tumors (NETs). The recent ENETS guidelines recommend the use of SSAs in advanced well differentiated NETs as antiproliferative agents.

CONCLUSIONS

The high sstr-expression in gastrinomas make them highly responsive to SSAs and support the use of such drugs to counteract the tumour growth in patients not amenable to surgical cure. Unfortunately, limited data, mainly case reports or small series, support the use of SSAs in advanced gastrinomas, therefore, it is difficult to quantify their ability to control tumour growth and disease progression.

PD-L1 expression and presence of TILs in small intestinal neuroendocrine tumours

BACKGROUND

The extent of resistance to immune surveillance in patients with well-differentiated (Wd) (grade 1/2) small-intestinal neuroendocrine tumours (Si-NETs) is unknown.

METHODS

Patients diagnosed with Wd Si-NETs (excluding appendix, which are considered to have a different biology to other midgut NETs) were eligible. Tumoural programmed death (PD)-ligand(L) 1 (PD-L1)/PD-L2/PD-1 and tumour infiltrating lymphocytes (TILs) [presence and phenotype] were analysed in archival tissue by immunohistochemistry (IHC); reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used for confirmation of IHC results.

RESULTS

Of 109 patients screened, 62 were eligible: 54.8% were male; median age was 63.7 years (95%-CI 59.7-67.2); disease stage II: 4.8%, III: 40.3% and IV: 54.8%; 41.9% were functional. Analysed samples (67.1% from primary tumours, 32.9% from metastases) were of grade 1 (67.1%) or 2 (32.86%) with a median Ki-67 of 2%. From the total of 62 eligible patients, 70 and 63 samples were suitable for IHC and RT-qPCR analysis, respectively. PD-L1 expression within tumour cells and TILs were identified in 12.8% and 24.3% of samples respectively; 30% of samples showed PD-L1 expression within tumour cells and/or TILs. PD-1 was present in TILs in 22.8% of samples. Majority of samples showed significant presence of CD4+ (focal 42.86%; moderate 2.86%) and CD8+ (focal 92.86%; moderate 4.29%) TILs. IHC findings were confirmed with RT-qPCR; which showed higher expression levels of PD-L1 (p-value 0.007) and PD-1 (p-value 0.001) in samples positive for IHC compared to negative-IHC.

CONCLUSIONS

Thirty-percent of patients express PD-L1 within tumour cells and/or TILs. Identification of presence of TILs was also significant and warrant the investigation of immunotherapy in this setting.

Immune checkpoint inhibitors in neuroendocrine tumors: A single institution experience with review of literature

This unique case series and review of literature suggests that immune checkpoint inhibitors may have clinical activity in neuroendocrine tumors.

Objective

Summarize advances of immuno-oncology in neuroendocrine tumors with the help of a case series.

Design

Case series and review of literature.

Intervention or Exposure

The patients were treated with immune checkpoint inhibitors (pembrolizumab or nivolumab).

Main Outcomes and Measuress

Life expectancy, quality of life, disease progression.

Results

Maximum durable response of 16 months in one of the patients so far. All patients showed improvement in quality of life before disease progression. Two out of four are still on therapy. None of the patients experienced immune checkpoint inhibitor associated side-effects. All patients had failed standard of care therapy prior to the initiation of immune checkpoint inhibitors and were on the verge of hospice.

Conclusions

Immune checkpoint inhibitors have revolutionized cancer management and the last 5 years have seen a rapid expansion in the indications for this class of drug. Neuroendocrine tumors, unfortunately, have been slow to catch on to the immuno-oncology, partly due to difficulties in establishing relevant preclinical neuroendocrine tumors models for immune-oncology studies. In this manuscript, we review the current status of immunotherapy in neuroendocrine tumors.

Management of Well-differentiated Gastroenteropancreatic Neuroendocrine Tumors (GEPNETs): A Review

PURPOSE

Neuroendocrine tumors (NETs) are heterogeneous tumors that arise from the neuroendocrine cells of the digestive tract and other organs, such as the lung, ovary, and thyroid glands. They can be well differentiated or poorly differentiated, and management of these tumors differs for each histologic subtype. We have performed a review of NETs and focused on management of well-differentiated gastroenteropancreatic neuroendocrine tumors (GEPNETs) and carcinoid syndrome.

METHODS

A PubMed search was performed to obtain articles on the management of well-differentiated NETs. Using the key words neuroendocrine tumors, carcinoid, pNET, octreotide, somatostatin analogues, and radiolabeled therapy, we reviewed Phase II and III trials that were published over the past 30 years. We also reviewed guidelines from the European Neuroendocrine Tumor Society, North America Neuroendocrine Tumor Society, and National Comprehensive Cancer Network in our search.

FINDINGS

NETs are usually slow-growing tumors that remain asymptomatic for a long duration and can be either nonfunctioning or functioning. Surgical resection is recommended for locoregional disease, impending obstruction, symptom control, and advanced disease. Nonsurgical treatment options include somatostatin analogues (SSAs), multikinase inhibitors, targeted therapy, chemotherapy, and radiolabeled SSAs. Carcinoid syndrome is mainly treated with SSAs.

IMPLICATIONS

Although GEPNETs are slow-growing tumors, most patients are diagnosed with metastatic disease, and therefore it is important that the management of each patient be discussed in a multidisciplinary setting to optimize the treatment strategy. Patients should be considered for clinical trials and refractory cases referred to a specialty center.

Advances and Current Concepts in the Medical Management of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare and heterogeneous group of tumors presenting as localised or metastatic disease and in a subset with distinct clinical syndromes. Treatment is aimed at controlling the functional syndrome, eradicating the tumor, and/or preventing further tumor growth. Surgery is the treatment of choice in removing the primary tumor and/or reducing tumor burden but cannot be applied to all patients. Somatostatin analogs (SS-analogs) obtain control of functional syndromes in the majority of GEP-neuroendocrine tumors (NETs); phase III trials have shown that SS-analogs can be used as first-line antiproliferative treatment in patients with slow-growing GEP-NETs. The role of the recently approved serotonin inhibitor, telotristat ethyl, and gastrin receptor antagonist, netazepide, is evolving. Streptozotocin-based chemotherapy has been used for inoperable or progressing pancreatic NENs but the orally administered combination of capecitabine/temozolomide is becoming more popular due to its better tolerability and potential effect in other GEP-NENs. Phase III trials have shown efficacy of molecular targeted therapies in GEP-NETs and of radionuclide treatment in patients with midgut carcinoid tumors expressing somatostatin receptors. Most patients will develop disease progression necessitating further therapeutic options. A combination of currently available treatments along with the molecular signature of each tumor will guide future treatment.

Somatostatin analogs in the treatment of neuroendocrine tumors: current and emerging aspects

INTRODUCTION

Neuroendocrine tumors (NETs) harbor somatostatin receptors and there is a strong rationale for using somatostatin analogs (SSAs) for treatment of NETs. Areas covered: This article discusses i) pharmacology of somatostatin and its analogs; ii) antisecretory and anti-proliferative effects of SSAs in NETs; iii) efficacy and safety of emerging therapeutic regimens with first generation SSAs administered at either high doses or in combination with antineoplastic drugs; iv) efficacy and safety of pasireotide and chimeric molecules; v) efficacy of radionuclide therapy of NETs using SSAs. Expert opinion: SSAs are the first-line medical therapy for functioning and non-functioning well-differentiated NETs. In patients not responder to first generation SSAs, the increase of drug dose over the conventional regimens, the combination of SSAs with other biotherapies or molecular targeted therapies, the switch to pasireotide or the use of SSAs in radionuclide therapy may improve the therapeutic success.

Optimizing Somatostatin Analog Use in Well or Moderately Differentiated Gastroenteropancreatic Neuroendocrine Tumors

BACKGROUND

Somatostatin analogues, aiming to control tumor secretion or growth, constitute the most attractive therapeutic option for patients with well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs). The objective of this article is to provide a comprehensive review of the current state-of-the-art knowledge gaps and potential opportunities for future development and optimization of this therapeutic modality.

METHOD

A contextualized systematic review with a narrative component was conducted using PubMed, The Cochrane Library, EMBASE, and Google Scholar. Titles were screened, and non-English, duplicate, or irrelevant entries were excluded. Selection criteria for articles included the following: publication in English between 1995 and 2016, patients with GEP-NETs, analysis of efficacy, safety, practical management considerations, predictive factors, and/or strategies for overcoming resistance, concerning somatostatin analogs.

RESULTS

Ninety-seven studies out of 2771 screened publications met the inclusion criteria (16 randomized clinical trials, 27 phase II trials, 3 phase I trials, 3 subgroup analyses of clinical trials, 1 open-label extension of a randomized trial, 1 phase IV trial, 32 observational studies, and 14 basic research articles). The nature and scope of literature was diverse with most articles dedicated to drug efficacy or indications of use (n = 49), pharmacological issues (n = 8), assessment or predictors of response (n = 4), practical management (n = 11), combination therapy or other means to overcome resistance (n = 19), receptors and signaling pathways (n = 3), and subgroup analyses (n = 3).

CONCLUSION

In this appraisal, we have found some practical aspects that can help to the optimization of somatostatin analog (SSA) therapy in patients with well-differentiated GEP-NETs. We have also identified areas of uncertainty in an effort to guide clinical research in the coming years.

Escalated-dose somatostatin analogues for antiproliferative effect in GEPNETS: a systematic review

BACKGROUND/PURPOSE

Somatostatin analogues are the cornerstone of systemic therapy for metastatic well-differentiated gastroenteropancreatic neuroendocrine tumours for both hormonal control and antiproliferative effect. Dose escalation of somatostatin analogues is often utilized in clinical practice, but small studies have yielded mixed results. The aim of this study was to systematically determine the efficacy and safety of escalated-dose somatostatin analogues in the above setting.

METHODS

Eligible trials (using more than 30 mg octreotide or 120 mg lanreotide/28 days) were identified from MEDLINE, EMBASE, other databases and conference proceedings. Demographics, disease control rate, objective response rate, biochemical response, improvement in symptoms and toxicity were abstracted. Trials were synthesized qualitatively.

RESULTS

Eighteen studies (1002 patients) were identified. The risk of bias was moderate for objective response outcomes, but high for the outcomes of symptom control and toxicity due to open-label trial designs. Disease control rates ranged from 30 to 100%, but response rates were modest (at 0-14%). Rates of biochemical improvement (27-100%) and symptom improvement (23-100%) ranged widely depending on the population studied and the definition of response. The most common toxicities were fatigue, diarrhoea, abdominal discomfort and cholelithiasis, with no severe or unexpected toxicities compared to standard-dose somatostatin analogues.

CONCLUSIONS

The current evidence indicates that escalated-dose somatostatin analogues are well-tolerated in patients with gastroenteropancreatic neuroendocrine tumours, with significant rates of disease control but low rates of tumour response. It was difficult to judge the exact rate of biochemical response or symptomatic improvement. There is a need for large, prospective studies investigating the role of escalated-dose somatostatin analogues in the treatment of metastatic gastroenteropancreatic neuroendocrine tumours.

Treatment Strategies for Metastatic Neuroendocrine Tumors of the Gastrointestinal Tract

OPINION STATEMENT

The therapeutic landscape of gastroenteropancreatic-neuroendocrine tumors (GEP-NETs) has evolved significantly in recent years. Current and emerging treatment options include somatostatin analogs, radiolabeled somatostatin analogs, the mTOR inhibitor everolimus, and the tyrosine kinase inhibitor sunitinib. Although high-quality data from phase III trials are lacking, cytotoxic agents are commonly used for the treatment of poorly differentiated neuroendocrine carcinomas and well-differentiated NETs originating in the pancreas. Hepatic-directed therapies are recommended for patients with slow-growing, liver-predominant disease but have never been compared to systemic agents. Telotristat ethyl, a novel serotonin synthesis inhibitor, has recently demonstrated efficacy in palliating diarrhea in patients with poorly controlled carcinoid syndrome. In the absence of definite predictive biomarkers, therapeutic decisions in most cases rely on clinical and pathological criteria. However, navigating the current therapeutic algorithm may be challenging, and future trials need to address several important questions: what is the best sequence of treatment? Is there a role for combination therapies in GEP-NETs? Are neoadjuvant, adjuvant, or maintenance strategies safe and effective? Do all NET patients require active treatment? What new molecular targets can be clinically exploited? A tight integration between basic and clinical research is needed to further advance the field of NETs.

The North American Neuroendocrine Tumor Society Consensus Guidelines for Surveillance and Medical Management of Midgut Neuroendocrine Tumors

There have been significant developments in diagnostic and therapeutic options for patients with neuroendocrine tumors (NETs). Key phase 3 studies include the CLARINET trial, which evaluated lanreotide in patients with nonfunctioning enteropancreatic NETs; the RADIANT-2 and RADIANT-4 studies, which evaluated everolimus in functioning and nonfunctioning NETs of the gastrointestinal tract and lungs; the TELESTAR study, which evaluated telotristat ethyl in patients with refractory carcinoid syndrome; and the NETTER-1 trial, which evaluated Lu-DOTATATE in NETs of the small intestine and proximal colon (midgut). Based on these and other advances, the North American Neuroendocrine Tumor Society convened a multidisciplinary panel of experts with the goal of updating consensus-based guidelines for evaluation and treatment of midgut NETs. The medical aspects of these guidelines (focusing on systemic treatment, nonsurgical liver-directed therapy, and postoperative surveillance) are summarized in this article. Surgical guidelines are described in a companion article.

Is there still a role for the hepatic locoregional treatment of metastatic neuroendocrine tumors in the era of systemic targeted therapies?

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) frequently present with distant metastases at the time of diagnosis and the liver is the most frequent site of spreading. The early identification of metastatic disease represents a major prognostic factor for GEP-NENs patients. Radical surgical resection, which is feasible for a minority of patients, is considered the only curative option, while the best management for patients with unresectable liver metastases is still being debated. In the last few years, a number of locoregional and systemic treatments has become available for GEP-NEN patients metastatic to the liver. However, to date only a few prospective studies have compared those therapies and the optimal management option is based on clinical judgement. Additionally, locoregional treatments appear feasible and safe for disease control for patients with limited liver involvement and effective in symptoms control for patients with diffuse liver metastases. Considering the lack of randomized controlled trials comparing the locoregional treatments of liver metastatic NEN patients, clinical judgment remains key to set the most appropriate therapeutic pathway. Prospective data may ultimately lead to more personalized and optimized treatments. The present review analyzes all the locoregional therapy modalities (i.e., surgery, ablative treatments and transarterial approach) and aims to provide clinicians with a useful algorithm to best treat GEP-NEN patients metastatic to the liver.

Management of the hormonal syndrome of neuroendocrine tumors

Gastroenteropancreatic neuroendocrine tumors (GEP/NET) are unusual and rare neoplasms that present many clinical challenges. They characteristically synthesize store and secrete a variety of peptides and neuroamines which can lead to the development of distinct clinical syndrome, however many are clinically silent until late presentation with mass effects. Management strategies include surgery cure and cytoreduction with the use of somatostatin analogues. Somatostatin have a broad range of biological actions that include inhibition of exocrine and endocrine secretions, gut motility, cell proliferation, cell survival and angiogenesis. Five somatostatin receptors (SSTR1-SSTR5) have been cloned and characterized. Somatostatin analogues include octreotide and lanreotide are effective medical tools in the treatment and present selectivity for SSTR2 and SSTR5. During treatment is seen disapperance of flushing, normalization of bowel movements and reduction of serotonin and 5-hydroxyindole acetic acid (5-HIAA) secretion. Telotristat represents a novel approach by specifically inhibiting serotonin synthesis and as such, is a promising potential new treatment for patients with carcinoid syndrome. To pancreatic functionig neuroendocrine tumors belongs insulinoma, gastrinoma, glucagonoma and VIP-oma. Medical management in patients with insulinoma include diazoxide which suppresses insulin release. Also mTOR inhibitors may inhibit insulin secretion. Treatment of gastrinoma include both proton pump inhibitors (PPIs) and histamine H2 - receptor antagonists. In patients with glucagonomas hyperglycaemia can be controlled using insulin and oral blood glucose lowering drugs. In malignant glucagonomas smatostatin analogues are effective in controlling necrolytic migratory erythemia. Severe cases of the VIP-oma syndrome require supplementation of fluid losses. Octreotide reduce tumoral VIP secretion and control secretory diarrhoea.

Antiproliferative effect of somatostatin analogs in advanced gastro-entero-pancreatic neuroendocrine tumors: a systematic review and meta-analysis

A meta-analysis has systematically investigated the antineoplastic efficacy and safety of somatostatin analogs (SSAs) in advanced gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs). Randomized controlled trials (RCTs) reporting the hazard ratio (HR) for disease progression (DP) were evaluated. Response rate and risk ratio (RR) for adverse events were also analyzed. A total of 289 patients (143 receiving SSAs vs. 146 placebo) were evaluated from two RCTs. A significant benefit from SSAs in terms of disease control was observed (HR 0.41, 95% CI: 0.29 to 0.58, P < 0.01; I20%), response rate being 58.0% vs. 32.2%, respectively. The occurrence of adverse events significantly differed from the placebo arm only in terms of biliary stones (RR 3.79, 95% CI: 1.28 to 11.17, P = 0.02; I20%). In conclusion, SSAs showed an antiproliferative effect in advanced GEP-NETs, with a good safety profile.

Gastroenteropancreatic neuroendocrine tumors: recommendations of Turkish multidisciplinary neuroendocrine tumor study group on diagnosis, treatment and follow-up

Gastroenteropancreatic neuroendocrine tumors (GEPNETs) are a relatively rare, heterogeneous group of diseases in which important advances have been observed in the diagnosis and treatment as well as in our understanding of the biology and genetics of the disease in recent years. Given the insufficient scientific data available on evidence-based management of GEPNETs and the differences in circumstances in individual countries, a multidisciplinary study group was established to provide guidelines for the management of GEPNETS. This study group consisted of a medical oncologist, endocrinologist, surgeon, pathologist, gastroenterologist, and a nuclear medicine specialist, who aimed to prepare a practical guide in the light of existing scientific data and international guidelines, to be used in common clinical practice.

The Antiproliferative Role of Lanreotide in Controlling Growth of Neuroendocrine Tumors: A Systematic Review

BACKGROUND

Neuroendocrine tumors (NETs) are a heterogeneous group of tumors, with >50% of cases involving the gastrointestinal system or pancreas. Somatostatin analogs (SSAs) are used for treating NET-related secretory syndromes and, more recently, for their antiproliferative effects. We conducted a systematic review of published literature on the antiproliferative efficacy and safety of the SSA lanreotide Autogel in the management of NETs to gain a fuller understanding of the evidence and identify future areas of research.

METHODS

Searches were conducted in PubMed up to March 16, 2016, and in the proceedings of four congresses from 2013 to 2016.

RESULTS

Screening of 1,132 publications identified in the searches found 40 relevant publications, including 27 full-length publications and 13 congress abstracts. Twenty-four of these publications reported antiproliferative efficacy data for lanreotide Autogel. The CLARINET study showed that 120 mg lanreotide Autogel every 4 weeks improves progression-free survival (PFS) in patients with gastroenteropancreatic (GEP)-NETs, with grade 1 or grade 2 (Ki-67 <10%) disease, providing class I evidence of its antiproliferative effects. The CLARINET open-label extension study reported a median PFS of 32.8 months with lanreotide Autogel. Other smaller studies generally support CLARINET.

CONCLUSION

Current clinical evidence shows that lanreotide Autogel has good antiproliferative activity with favorable safety and tolerability in patients with GEP-NETs, suggesting it should be considered as an early first-line treatment in this population. Further studies are needed to assess the potential benefits of higher doses and the use of lanreotide Autogel in combination therapy and as maintenance therapy in the absence of disease progression following other therapies. The Oncologist 2017;22:272-285 IMPLICATIONS FOR PRACTICE: This review presents the current clinical evidence for the antiproliferative activity of lanreotide Autogel in patients with midgut or pancreatic neuroendocrine tumors (NETs) and shows its effectiveness, safety, and tolerability in these patient populations. By systematically presenting all the clinical evidence, the review adds to existing publications by discussing results in a broad range of settings. The review also indicates future directions for investigation of the use of lanreotide Autogel in NETs originating in other locations, in combination therapy, or as maintenance therapy in progressive disease.

Refractory carcinoid syndrome: a review of treatment options

Carcinoid syndrome (CSy) is a constellation of symptoms that may commonly present in patients with well differentiated neuroendocrine tumors (NETs), with somatostatin analogs (SSAs) being the first-line option for symptom management. However, symptomatic progression eventually occurs and in this scenario of a refractory CSy; several treatment options have been studied such as dose escalation of SSA, interferon and liver-directed therapies. Nevertheless, recent phase III trials have contributed to the understanding and management of this condition. We performed a comprehensive review of interventional studies examining refractory CSy to provide the evidence for current treatment options and propose a treatment sequence.

New therapeutic approaches to metastatic gastroenteropancreatic neuroendocrine tumors: A glimpse into the future

Neuroendocrine (NE) gastroenteropancreatic tumors are a heterogeneous group of neoplasias arising from neuroendocrine cells of the embryological gut. Their incidence have increased significantly over the past 3 decades probably due to the improvements in imaging and diagnosis. The recent advances in molecular biology have translated into an expansion of therapeutic approaches to these patients. Somatostatin analogs, which initially were approved for control of hormonal syndromes, have recently been proven to inhibit tumor growth. Several new drugs such as antiangiogenics and others targeting mammalian target of rapamycin pathways have been approved to treat progressive pancreatic neuroendocrine tumors (NETs) although their role in non-pancreatic is still controversial. The treatment of NETs requires a coordinated multidisciplinary approach. The management of localized NETs primarily involves surgical resection followed by surveillance. However, the treatment of unresectable and/or metastatic disease may involve a combination of surgical resection, systemic therapy, and liver-directed therapies with the goal of alleviating symptoms of peptide release and controlling tumor growth. This article will review the current therapeutic strategies for metastatic gastroenteropancreatic NETs and will take a glimpse into the future approaches.

ENETS Consensus Guidelines for the Standards of Care in Neuroendocrine Neoplasms: Systemic Therapy - Biotherapy and Novel Targeted Agents

Systemic therapies established in the management of patients with neuroendocrine tumors (NETs) include somatostatin analogs and interferon-α, also referred to as biotherapy. Recent randomized controlled studies have extended the knowledge on the frequency of side effects associated with biotherapy. More recently, novel targeted drugs, such as the mammalian target of rapamycin inhibitor everolimus and the multiple tyrosine kinase inhibitor sunitinib, have been introduced in the management of NETs. Although targeted drugs are generally well tolerated, with most adverse events being of mild to moderate severity and manageable, novel targeted drugs exhibit a distinct adverse event profile that warrants guidance for appropriate diagnostic and therapeutic management. This is particularly important given the widespread and potentially long-term use of everolimus in a broad spectrum of NETs and of sunitinib in pancreatic NETs. This review will focus on the most relevant toxicities associated with biotherapy and novel targeted drugs and on their management. For each drug class indication, administration and dosing schedule, most frequent adverse events, actions and dose adjustments for adverse events as well as their monitoring are presented. This review further covers the evaluation of treatment effect, patient information, drug interactions, and information on pregnancy.

Everolimus in the management of metastatic neuroendocrine tumours

Neuroendocrine tumours are increasing in incidence and cause a variety of symptoms. The mammalian target of rapamycin (mTOR) pathway plays a key role in neuroendocrine tumour (NET) pathogenesis, leading to increased lipid synthesis, protein synthesis and cellular growth. Upregulation of this pathway is noted in both hereditary and sporadic NETs. This understanding has led to investigations of mTOR inhibitors as therapy for metastatic NETs. After promising preclinical findings, everolimus, an mTOR inhibitor, was trialled in the RADIANT-1-4 studies on patients with advanced, well differentiated NETs. RADIANT-3 and RADIANT-4 established the efficacy of everolimus in improving progression-free survival (PFS) for metastatic NET of pancreatic, lung and gastrointestinal origin, leading to the US Food and Drug Administration (FDA) approval for its use in tumour control in those settings. Everolimus treatment is generally well tolerated; common adverse events include stomatitis, diarrhoea, rash and hyperglycaemia. Although discontinuation rates are low, many patients may require dose modification to successfully continue therapy. The combination of everolimus with somatostatin analogues (SSAs) (such as octreotide or pasireotide) or other targeted agents such as bevacizumab has not produced additional incremental benefit, and dual biologic therapy is not used widely. Ongoing trials are investigating everolimus compared with chemotherapy, optimal sequencing of therapy and combination of everolimus with radiotherapy. Future research should concentrate on identification of predictive biomarkers for benefit from mTOR therapy and include quality of life as a measure.

Role of Fluorouracil, Doxorubicin, and Streptozocin Therapy in the Preoperative Treatment of Localized Pancreatic Neuroendocrine Tumors

INTRODUCTION

5-Fluorouracil, doxorubicin, and streptozocin (FAS) leads to a 39 % response rate in advanced pancreatic neuroendocrine tumors (pNETs). We sought to validate our hypothesis that preoperative FAS may facilitate resection of locoregionally advanced pNETs by reducing the anatomic extent of the primary tumor.

PATIENTS

All patients who received FAS between 2000 and 2012 as initial therapy for a localized pNET were reviewed. Tumor size and vascular relationships were compared on pretreatment and posttreatment imaging studies to quantify treatment response.

RESULTS

Twenty-nine patients received a median 4 cycles of FAS (range 2-15). Rates of RECIST progressive disease (PD), stable disease (SD), and partial response (PR) were 3, 90, and 7 %, respectively. An interface was observed between the tumor and a major mesenteric artery and/or vein in 19 (66 %) and 24 (83 %) patients, respectively; after therapy with FAS, 17 (59 %) and 22 (76 %) had persistent interface with artery and/or vein. Fourteen (48 %) patients underwent pancreatectomy, 7 (50 %) required vascular management, and 9 (64 %) operations were R0. The median overall survival of unresected and resected patients was 41 months (95 % CI, 16-66) and 112 months (95 % CI, 104-120) (P = 0.04).

CONCLUSIONS

Although patients receiving FAS for locoregionally advanced pNETs are unlikely to progress during systemic therapy, significant "downstaging" appears uncommon.

Systematic Review of the Role of Targeted Therapy in Metastatic Neuroendocrine Tumors

BACKGROUND

Targeted therapies [interferon (IFN), vascular endothelial growth factor (VEGF) inhibitors, and somatostatin analogs (SSA)] have become an integral part of the neuroendocrine tumor (NET) treatment paradigm. We systematically reviewed the available literature to assess the overall beneficial and negative effects of targeted therapy on progression-free survival (PFS), overall survival (OS), response rate (RR), and toxicity.

METHODS

Randomized controlled trials (RCT) were identified from MEDLINE, Embase, other major databases, and an electronic search of major conferences. Abstract review, quality assessment, and data abstraction were performed independently by 2 investigators. Meta-analyses were conducted using the generic inverse variance method with a random-effects model, with studies pooled according to drug class and/or control arm for clinical homogeneity.

RESULTS

Fifteen RCT [SSA, n = 2; mammalian target of rapamycin (mTOR)/VEGF inhibitors, n = 4; IFN, n = 3; targeted therapy added to everolimus, n = 2, and other, n = 4] investigating 2,790 patients were included. Overall, targeted agents improved PFS (HR 0.54; 95% CI 0.40-0.73) but not OS (HR 0.86; 95% CI 0.72-1.01). SSA improved PFS (HR 0.41; 95% CI 0.29-0.58) but not OS (HR 1.00; 95% CI 0.58-1.74). mTOR/VEGF inhibitors improved PFS (HR 0.48; 95% CI 0.32-0.72) but not OS (HR 0.82; 95% CI 0.58-1.17). Targeted therapies added to everolimus or IFN did not improve either PFS or OS. The RR overall was improved (OR 2.85; 95% CI 1.77-4.59) but toxicity was increased (meta-analysis not performed).

CONCLUSIONS

The addition of targeted therapies improves PFS but not OS in NET. The evidence is strongest for VEGF inhibitors and SSA. There is an ongoing need for well-designed RCT to inform the optimal use of targeted therapies in NET.

Current understanding and approach to well differentiated lung neuroendocrine tumors: an update on classification and management

Neuroendocrine tumors (NETs) are rare neoplasms that can arise from any tissue. They are classified based on embryonic gut derivative (i.e. foregut, midgut and hindgut) with midgut tumors being the most common (e.g. gastrointestinal NET). The second most common category of NETs is that which arises from the lung. In fact, 25% of primary lung cancers are NETs, including small cell lung cancer (SCLC), which comprises 20% of all lung cancers. The remaining 5% are large cell neuroendocrine cancer (LCNEC, 3%), typical carcinoids (TCs, 1.8%), and atypical carcinoids (ACs, 0.2%). The less common TCs/ACs are well differentiated lung NETs. Their incidence has been increasing in more recent years and although these tumors are slow growing, advanced disease is associated with poor survival. There have been advances in classification of lung NETs that have allowed for more appropriate management upfront. They are cured by surgical resection when disease is limited. However, advanced and metastatic disease requires medical therapy that is ever changing and expanding. In this review, the aim is to summarize the current understanding and classification of well differentiated lung NETs (i.e. TCs and ACs), and focus on recent updates in medical management of advanced disease, along with a brief discussion on potential future discoveries.

Telotristat ethyl: a new option for the management of carcinoid syndrome

INTRODUCTION

Many patients with neuroendocrine tumour-related carcinoid syndrome treated with somatostatin analogues (SSA) won't achieve adequate symptom relief with the SSA alone; new treatment options are required. Telotristat ethyl is a tryptophan hydroxylase inhibitor, developed for the treatment of carcinoid syndrome. Areas covered: This review summarises the evidence supporting the role of telotristat ethyl in the management of carcinoid syndrome. Rationale, pharmacodynamics, pharmacokinetics, metabolism, clinical experience, efficacy and toxicity profiles are covered. Expert opinion: The efficacy of telotristat ethyl in producing a statistically-significant and clinically-meaningful reduction in daily bowel movements has been confirmed in phase III clinical trials. Two pivotal trials, TELESTAR and TELECAST, explored the role of telotristat ethyl in the management of patients with carcinoid syndrome refractory to SSAs focusing on patients with ≥4 and <4 daily bowel movements, respectively. In addition, benefit was confirmed in patient-reported outcomes. Based on activity and safe toxicity profile, telotristat ethyl is pending regulatory agencies evaluation and is likely to add to the armamentarium used to treat carcinoid syndrome. Long-term safety and efficacy data will be available from the ongoing TELEPATH study. The impact on carcinoid heart disease, mesenteric fibrosis and other long-term complications of carcinoid syndrome as well as its role earlier in patients' pathways remain investigational.

Management of controversial gastroenteropancreatic neuroendocrine tumour clinical situations with somatostatin analogues: results of a Delphi questionnaire panel from the NETPraxis program

BACKGROUND

There are clinical situations (CS) in which the use of somatostatin analogs (SSAs) in patients with neuroendocrine tumors (NET) is controversial due to lack of evidence. A Delphi study was conducted to develop common treatment guidelines for these CS, based on clinical practice and expert opinion of Spanish oncologists.

METHODS

A scientific committee identified 5 CS with a common core (c-c) [non-functioning NET, not susceptible of surgery/locoregional therapy, Ki67 < 10 % (except for CS5: >10 %), ECOG ≤ 2], and controversy regarding use of SSAs, and prepared a Delphi questionnaire of 48 treatment statements. Statements were rated on a 1 (completely disagree) to 9 (completely agree) scale. Responses were grouped by tertiles: 1-3: Disagreement, 4-6: Neutral, 7-9: Agreement. Consensus was reached when the responses of ≥2/3 participants were located in the same tertile as the median value of all reported responses for that statement.

RESULTS

Sixty five (81.2 %) of 80 invited oncologists with experience in the management of NETs answered a first round of the questionnaire and 57 (87.7 %) of those 65 answered a second round (mean age 43.5 years; 53.8 % women; median time of experience 9 years). Consensus was obtained in 42 (36 agreement and 6 disagreement) of the 48 statements (87.5 %). Regarding CS1 (Enteropancreatic NET, c-c, non-progressive in the last 3-6 months), overall, SSA treatment is recommended (a wait and see approach is anecdotal and reserved for fragile patients or with low tumor load or ki-67 < 2 %); CS2 (Pancreatic NET, c-c), overall, SSA monotherapy is recommended, except when high tumor load or tumor progression exists, where combination therapy would be considered; CS3 [Gastroenteropancreatic (GEP)-NET, c-c, in treatment with anti-proliferative dose of SSA and progressing], overall, SSA maintenance is recommended at the time of progression, with or without adding molecular targeted drugs; CS4 (GEP-NET, c-c, and negative octreoscan®), SSA in monotherapy is only considered in low-risk patients (low tumor load and Ki-67 < 5 %); CS5 [GEP-NET, c-c (ki67 > 10 %), and positive octreoscan®], monotherapy with SSA is mainly considered in patients with comorbidities.

CONCLUSION

Several recommendations regarding use of SSAs in controversial NET CS were reached in consensus and might be considered as treatment guideline.

Predictive factors of antiproliferative activity of octreotide LAR as first-line therapy for advanced neuroendocrine tumours

BACKGROUND

The antiproliferative activity of octreotide LAR in neuroendocrine tumours (NETs) has been demonstrated by small retrospective studies and confirmed by a prospective phase III trial (PROMID). However, there are limited data about the duration and predictors of response. The aim of our retrospective study was to determine the time to radiological progression (TTRP) of disease and the factors that were associated with better response.

METHODS

A total of 254 treatment naïve patients with advanced NETs and positive somatostatin receptor scintigraphy were included. Mean follow-up period was 42 months.

RESULTS

The location of primary was in the small bowel in 204, pancreas in 22, lungs in 14, rectum in 7 and unknown in 7 patients. Most tumours were well-differentiated, G1 (58%) and G2 (23%). The majority of patients commenced octreotide LAR due to functional symptoms (57%), radiological progression (10%) or in the presence of asymptomatic and stable disease on the basis of data from the PROMID trial (18.5%). Partial response occurred in 5%. For all patients, the median TTRP was 37 months (95% confidence interval, CI: 32-52 months). There was a statistically significant shorter TTRP in patients with pancreatic tumours, liver metastases and intermediate grade tumours. Extremely raised (>10 times the upper limit of normal) baseline chromogranin A levels were associated with an unfavourable outcome. In contrast, male sex, carcinoid heart disease and initiation of treatment in the presence of stable disease were predictive of a better response. Age, extra-hepatic metastases, presence of mesenteric desmoplasia, previous resection and functional status of the primary tumour did not affect response.

CONCLUSIONS

The duration of the antiproliferative effect of octreotide LAR seems to be longer than previously reported. This study has identified several predictors of response in a large cohort of patients with NETs on somatostatin analogue therapy.

Somatostatin analogues in functioning gastroenteropancreatic neuroendocrine tumours: literature review, clinical recommendations and schedules

OBJECTIVE

Neuroendocrine tumours (NETs) represent a heterogeneous group of neoplasms, which include functioning and non-functioning forms. Somatostatin analogues (SSAs) play a key role in the management of these tumours. Herein, we aimed at reviewing the current evidence about the role of SSAs in the treatment of gastro-entero-pancreatic (GEP)-NETs.

MATERIAL AND METHODS

An extensive bibliographical search was performed in PubMed using the following keywords: gastro-entero-pancreatic neuroendocrine tumours, somatostatin analogues, octreotide, lanreotide, in order to identify all the pertinent English-written articles published between 1990 and 2015.

RESULTS

SSAs have shown to help the symptomatic and biochemical improvement of patients with NETs and to exhibit a good safety profile. Recent studies have also reported a role for SSAs in tumour growth control, although the results are less impressive and the underlying mechanisms are not fully understood.

CONCLUSIONS

SSAs are well known as a symptomatic and, to lesser extent, anti-proliferative treatment in GEP-NETs. However, some issues, including optimal dosage, benefits and adverse events of combination with other molecules, and the role of new analogues, remain to be elucidated in further randomised studies.

Association Between Somatostatin Receptor Expression and Clinical Outcomes in Neuroendocrine Tumors

OBJECTIVE

Somatostatin receptors (SSTRs), products of gene superfamily SSTR1-5, are commonly expressed in neuroendocrine tumors (NETs). Somatostatin analogs (SSAs) bind to SSTRs and are used as therapeutic agents in patients with advanced NETs. We hypothesized that tumor SSTR expression status would be associated with clinical outcomes in NET.

METHODS

Expression of the 5 SSTRs was evaluated by immunohistochemistry, using tissue microarrays comprising 173 primary NETs, 24 matched metastases, and 22 metastatic NETs from 195 patients. Cox proportional hazards regression analysis was used to assess the association of SSTR expression status (high vs low) with clinical outcomes, adjusting for potential confounders.

RESULTS

High expression of SSTR2 was associated with longer overall survival (OS) in the cohort overall (multivariate hazard ratio, 0.42; 95% confidence interval, 0.21-0.84; P = 0.013). In a subgroup of patients with metastatic small intestine NET treated with SSAs and evaluable for progression, SSTR2 expression was associated with both longer progression-free survival (PFS) and OS. No associations with PFS or OS were observed with expression of other SSTRs.

CONCLUSIONS

Our study demonstrated that expression of SSTR2, but not other SSTRs, is associated with longer OS. In patients treated with SSAs, expression of SSTR2 is associated with longer PFS survival.

WOMEN IN CANCER THEMATIC REVIEW: Systemic therapies in neuroendocrine tumors and novel approaches toward personalized medicine

Neuroendocrine tumors (NETs) are a group of heterogenous neoplasms. Evidence-based treatment options for antiproliferative therapy include somatostatin analogues, the mTOR inhibitor everolimus, the multiple tyrosine kinase inhibitor sunitinib and peptide receptor radionuclide therapy with 177-Lu-octreotate. In the absence of definite predictive markers, therapeutic decision making follows clinical and pathological criteria. As objective response rates with targeted drugs are rather low, and response duration is limited in most patients, numerous combination therapies targeting multiple pathways have been explored in the field. Upfront combination of drugs, however, is associated with increasing toxicity and has shown little benefit. Major advancements in the molecular understanding of NET based on genomic, epigenomic and transcriptomic analysis have been achieved with prognostic and therapeutic impact. New insight into molecular alterations has paved the way to biomarker-driven clinical trials and may facilitate treatment stratification toward personalized medicine in the near future. However, an improved understanding of the complexity of pathway interactions is required for successful treatment. A systems biology approach is one of the tools that may help to achieve this endeavor.

Summary of emerging personalized medicine in neuroendocrine tumors: are we on track?

Neuroendocrine tumors (NETs) comprise a heterogeneous group of malignancies, with differences in prognosis and effective therapies. Traditionally, NETs have been characterized by tumor grade, site of primary tumor, functional status, and presence of underlying familial syndrome. However, increased feasibility and utilization of next-generation sequencing and other methodologies have revealed new genomic and epigenetic aberrations. In the last decade, treatment options available for metastatic well-differentiated gastroenteropancreatic (GEP) NETs have expanded, with approval of antiangiogenic and mTOR-directed targeted therapies, and our armamentarium of active therapies is likely to further increase. Cytotoxic therapies also are an important option for pancreatic NETs, and MGMT promoter methylation and protein expression may be an important biomarker for efficacy of alkylating agents. Peptide receptor radioligand therapy is an emerging treatment that uses functional imaging to personalize dosimetry to the tumor and avoid nephrotoxicity. Nevertheless, there is a critical need for further biomarkers, particularly multianalyte biomarkers, to aid in prognostication and predict efficacy of therapies.

Neurokinin A monitoring of response to interferon alpha in a patient with an advanced small bowel neuroendocrine tumour uncontrolled by somatostatin analogue therapy

A 52-year-old lady presented with a history of occasional, severe abdominal cramps, postprandial diarrhoea and weight loss. After routine gastrointestinal investigations, she was diagnosed with irritable bowel syndrome. Over six months, she developed occasional facial flushing prompting assessment of neuroendocrine tumour markers. Urinary 5HIAA, 5HT, chromogranin A and neurokinin A were significantly elevated. Scans showed extensive hepatic metastases but did not show the location of a primary tumour. Somatostatin analogue therapy was commenced but despite increasing doses, symptoms increased and biomarkers rose dramatically. Interferon alpha was introduced concomitant with somatostatin analogue therapy. Biomarkers were monitored regularly. Within six months, symptoms abated and biomarkers reduced, continuing to fall over the next year, close to reference range. To manage side-effects of interferon alpha, dose was reduced from time to time. During these short periods, neurokinin A showed significant transient increases (75-150 ng/L) and carcinoid symptoms returned. For more than seven years, and with the co-operation of the patient, a balance was achieved between interferon alpha side-effects and disease control. Scans showed tumour load to be stable. The patient survived for 10 years post diagnosis. She chose to discontinue interferon alpha and received peptide receptor radiation therapy in her final year. Throughout, neurokinin A remained the most sensitive monitor of her disease progression.

Medical management of secretory syndromes related to gastroenteropancreatic neuroendocrine tumours

Although recent epidemiological evidence indicates that the prevalence of non-functioning gastroenteropancreatic (GEP) neuroendocrine tumours (NETs) is rising, a significant number of GEP-NETs still present with symptoms related to the secretion of biologically active substances leading to the development of distinct clinical syndromes. In the past, these syndromes were associated with substantial morbidity and mortality due to the lack of specific therapies; however, since the introduction of long-acting somatostatin analogues and medications such as proton pump inhibitors, their control has been greatly improved. As a result, nowadays, the main cause of morbidity and mortality in GEP-NETs is mostly directly related to tumour growth and the extent of metastatic disease. However, in some patients with functioning tumours and extensive disease, control of the secretory syndrome still remains problematic, necessitating the employment of several cytoreductive techniques, which may not always be sufficient. Recently, new agents directed against tumour growth, or exerting increased binding activity to receptors expressed in these tumours, or interfering with the synthetic pathway of some of the compounds secreted by these tumours, have been developed. Since there are no specific guidelines addressing the totality of the management of the secretory syndromes related to GEP-NETs, this review aims at critically analysing the medical management of previously recognised secretory syndromes; it also addresses areas of uncertainty, assesses the newer therapeutic developments and also addresses recently described but poorly characterised secretory syndromes related to GEP-NETs.

Systemic treatment of gastroenteropancreatic neuroendocrine tumors (GEP-NETS): current approaches and future options

OBJECTIVE

To describe recent advances in the treatment of gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

METHODS

A review of the published English language literature on GEP-NET therapy with a focus on practice-changing clinical trials.

RESULTS

Somatostatin analog (SSA) treatment remains a cornerstone of GEP-NET therapy, primarily for patients with hormonally functional tumors and midgut carcinoids. The biologic agents everolimus and sunitinib have similar tumor-stabilizing effects in pancreatic NETs and are both approved to treat progressive low-intermediate-grade tumors. Their role in nonpancreatic NETs remains controversial. Cytotoxic chemotherapy is effective against pancreatic NETs, but modern prospective data is lacking. Radiolabeled SSAs will likely become more widely available once phase III randomized studies are completed.

CONCLUSIONS

New treatment options for GEP-NETs have become available and highlight the necessity of developing predictive biomarkers that will allow for appropriate and individualized therapy selection.

Update on medical treatment of small intestinal neuroendocrine tumors

INTRODUCTION

Small intestinal (SI) neuroendocrine tumors (NETs) are relatively rare tumors. Due to the lack of symptom or specific symptoms, SI-NETs are often diagnosed at an advanced stage, making therapy challenging. The management of patients with advanced stage SI-NETS requires a multidisciplinary approach that combines surgical and medical treatment including novel targeted molecular therapies.

AREAS COVERED

This article summarizes current strategies for the medical treatment of SI-NETS. Expert commentary: The treatment plan of advanced-stage SI-NETs should be tailored in a case-by-case manner with the adoption of a multidisciplinary approach that combines different treatment options, including biological targeted therapies. In particular, we believe that the identification of the optimal treatment sequence(s), correct treatment timing and the selection of patients eligible to different treatments need specific investigation in controlled clinical trials.

Diagnosis and management of gastrointestinal neuroendocrine tumors: An evidence-based Canadian consensus

The majority of neuroendocrine tumors originate in the digestive system and incidence is increasing within Canada and globally. Due to rapidly evolving evidence related to diagnosis and clinical management, updated guidance on the diagnosis and treatment of gastrointestinal neuroendocrine tumors (GI-NETs) are of clinical importance. Well-differentiated GI-NETs may exhibit indolent clinical behavior and are often metastatic at diagnosis. Some NET patients will develop secretory disease requiring symptom control to optimize quality of life and clinical outcomes. Optimal management of GI-NETs is in a multidisciplinary environment and is multimodal, requiring collaboration between medical, surgical, imaging and pathology specialties. Clinical application of advances in pathological classification and diagnostic technologies, along with evolving surgical, radiotherapeutic and medical therapies are critical to the advancement of patient care. We performed a systematic literature search to update our last set of published guidelines (2010) and identified new level 1 evidence for novel therapies, including telotristat etiprate (TELESTAR), lanreotide (CLARINET), everolimus (RADIANT-2; RADIANT-4) and peptide receptor radionuclide therapy (PRRT; NETTER-1). Integrating these data with the clinical knowledge of 16 multi-disciplinary experts, we devised consensus recommendations to guide state of the art clinical management of GI-NETs.

Update on management of midgut neuroendocrine tumors

Midgut neuroendocrine tumors are typically indolent but can be fatal when advanced. They can also cause significant morbidity due to the characteristic carcinoid syndrome. Somatostatin analogs continue to be the mainstay of treatment given their antiproliferative properties, as well as inhibitory effects on hormones that cause carcinoid syndrome. There have been several recent advances in the systemic therapy of these tumors including consolidation of somatostatin analogs as the cornerstone of therapy, completion of pivotal trials with mTOR inhibitors, and the establishment of novel approaches including peptide receptor radionuclide therapy and oral inhibitors of peripheral tryptophan hydroxylase in tumor and symptom control, respectively. In this review article, the recent advances are summarized and an updated approach to management is proposed.

Chemotherapy for advanced non-pancreatic well-differentiated neuroendocrine tumours of the gastrointestinal tract, a systematic review and meta-analysis: A lost cause?

BACKGROUND

Chemotherapy is well-established in the treatment of patients with well-differentiated neuroendocrine tumours (NETs) arising from the pancreas (pNETs); however, its role in patients with gastrointestinal non-pancreatic NETs (non-pNETs) is uncertain. This systematic review assesses the evidence for the role of chemotherapy in well-differentiated non-pNET patients.

METHODS

Eligible studies (identified using MEDLINE) were those reporting response and/or survival data for patients with well-differentiated non-pNETs receiving systemic chemotherapy. The primary end-point was overall-response (OR) rate; secondary end-points were progression-free survival (PFS), overall survival (OS), disease-stabilization (DS) and disease-control (DC) rates.

RESULTS

Of 6434 studies screened, 20 were eligible: one randomised phase III trial, 2 randomised phase II studies, 10 single-arm phase II trials and 7 retrospective analyses including a total of 264 patients (median of 11 patients per study, range 6-49); and employing multiple chemotherapy schedules. The mean "median PFS" and "median OS" were 16.9 months (95%-confidence interval (CI) 3.8-30.04) and 32.2 months (95%-CI 10.4-54.2), respectively. The non-weighted mean OR, DS and DC rates were 11.5% (95%-CI 5.8-17.2), 56.5% (95%-CI 38.1-74.9) and 70.7% (95%-CI 54.9-86.5), respectively. In studies including both pNETs and non-pNET patients, meta-analysis showed a lower OR-rate in the non-pNET patients when compared to pNETs [odds ratio (OR) 0.35 (95% CI 0.18-0.66)]; however significance was lost when high-risk bias studies were excluded in a sensitivity analysis [OR 0.45 (95% CI 0.19-1.07); p-value 0.07].

CONCLUSION

Studies were of evidence level-C with heterogeneous populations and treatments; and small patient numbers. Well-designed, prospective studies are needed to adequately evaluate the role of chemotherapy in this setting.

Pancreatic Neuroendocrine Tumor Control: Durable Objective Response to Combination 177Lu-Octreotate-Capecitabine-Temozolomide Radiopeptide Chemotherapy

BACKGROUND/METHODS

Thirty patients with advanced progressive grade 1 or 2 pancreatic neuroendocrine tumors (pNETs), treated on a prospective phase II single-center study, were followed up for up to 4 years after 4 cycles of 7.9 GBq 177Lu-octreotate combined with chemotherapy. Each 8-week cycle of treatment combined radiopeptide therapy with 14 days of capecitabine at 1,500 mg/m2 and 5 days of temozolomide at 200 mg/m2.

RESULTS

The overall response rate was 80% (95% CI 66-93), and there was complete remission in 13% (95% CI 4-30) and partial response in 70% (95% CI 52-83) of the cases. No patient manifested progressive disease on treatment. Median progression-free survival was 48 months. Median overall survival had not been reached at a median follow-up of 33 months. No patient was lost to follow-up, all but 1 received 4 cycles of outpatient therapy, and all were evaluated for response and toxicity. No one required hospital admission. The treatment was well tolerated, and no serious dose-limiting toxicities were seen. The commonest toxicity was transient nausea of grade 2 (33%) or 3 (7%). Hematological toxicity was limited to grade 3 thrombocytopenia (10%) and anemia (10%). There were no grade 4 adverse events, and no renal functional impairment was evident.

CONCLUSION

Combined 177Lu-octreotate-capecitabine-temozolomide radiopeptide chemotherapy is a well-tolerated, highly effective outpatient regimen for control of advanced progressive pNETs, achieving a durable objective response.

Neuroendocrine tumours - Medical therapy: Biological

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

Pancreatic neuroendocrine tumors: Nosography, management and treatment

Pancreatic neuroendocrine tumors (pNETs) represent about 7% of all NETs, 8.7% of gastroenteropancreatic NETs (GEP-NETs) and 1-2% of all pancreatic neoplasms. In the last two decades, the increased diagnosis of pNETs has generated great interest and the development of different classifications, grading and staging systems. Recently, several trials were performed in order to improve the knowledge of biomarkers and imaging and to provide an early diagnosis, but their role is still under debate. Nowadays, surgery represents the only curative approach for pNETs. Approximately 90% of pNETs are silent and non-functional; therefore, most patients are diagnosed in late stage and present metastatic (60%) or locally unresectable advanced disease (21%) with a poor prognosis. Not many therapeutic options are available for pNETs, with different treatments for G1-G2 and G3 tumors, because these diseases are still rare and trials are made up of few series of patients. At present, medical treatments is controversial. On these bases, we believe that a multidisciplinary team composed of surgeons, oncologists, endocrinologists, radiation oncologists, radiologists, pathologists and medicals nuclear is required. This paper presents a review of present state-of-the-art in the field of pNETs.

Role of Locoregional and Systemic Approaches for the Treatment of Patients with Metastatic Neuroendocrine Tumors

Although gastroenteropancreatic neuroendocrine tumors are often perceived as being indolent tumors, more than half of the patients will harbor liver metastases at the time of diagnosis. Gastroenteropancreatic neuroendocrine tumors have the potential to be aggressive and resistant to therapy, making the integration of both locoregional and systemic therapy even more critical in the treatment of patients with locally advanced or metastatic lesions. Over the last several years, significant advancements have been made in the surgical treatment, liver-directed therapy, and medical management of gastroenteropancreatic neuroendocrine tumors. While surgical resection is the cornerstone of therapy, cytoreductive surgery, orthotopic liver transplantation, local ablation, and intra-arterial therapy all improve the prognosis of patients suffering with locally advanced or metastatic disease. In addition, great strides have been made in the medical management of gastroenteropancreatic neuroendocrine tumors, particularly with the evolution of novel molecular targeted therapy, such as everolimus and sunitinib. Hence, gastroenteropancreatic neuroendocrine tumor is becoming a disease process requiring more of a multi-disciplinary approach with the integration of both locoregional and systemic therapies for improved outcomes.