Health-Related Quality of Life for Long-Acting Octreotide versus Placebo in Patients with Metastatic Midgut Neuroendocrine Tumors in the Phase 3 PROMID Trial

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

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

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

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

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

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

Consideration of quality-of-life in the treatment decision-making for patients with advanced gastroenteropancreatic neuroendocrine tumors

INTRODUCTION

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a complex and heterogenous family of solid malignancies that originate from neuroendocrine tissue in the gastrointestinal tract or pancreas. Most patients diagnosed with GEP-NETs present with advanced or metastatic disease, and quality of life (QoL) is often an important priority when selecting treatments for these patients. Patients with advanced GEP-NETs often experience a substantial and persistent symptom burden that undermines their QoL. Addressing a patient's individual symptoms through judicious selection of treatment may improve QoL.

AREAS COVERED

The objectives of this narrative review are to summarize the impact of advanced GEP-NETs on patient QoL, assess the potential value of current treatments for maintaining or improving patient QoL, and offer a clinical framework for how these QoL data can be translated to inform clinical decision-making for patients with advanced GEP-NETs.

EXPERT OPINION

Patients with advanced GEP-NETs experience a significant and persistent symptom burden that impacts their daily lifestyle, activities, work life, and financial health, leading to erosion of their QoL. Ongoing and future studies incorporating longitudinal QoL assessments and head-to-head treatment evaluations will further inform the incorporation of QoL into clinical decision-making.

A practical proposal on treatment sequencing of metastatic well-differentiated neuroendocrine tumours

According to the neuroendocrine tumour (NET) characteristics, 3 to 7 different treatment options are available, corresponding to 6 to 5,040 theoretical different sequences. Even though each patient is unique and despite a large heterogeneity in NET characteristics, the present review aims to discuss the main sequences and addresses how one can propose the best sequence to treat metastatic NET (mNET) on a case-by-case basis. Each treatment must be discussed during dedicated multi-disciplinary meetings, and inclusions in clinical trials should be favoured. After a thorough characterization of patients and their mNET, and taking into account the availability of drugs, the first-line treatment should be chosen according to the treatment aim. The latter is determined based on three main topics (efficacy, safety, and patient preferences) that do not necessarily converge and must be defined a priori. At baseline, physicians should design an a priori full therapeutic sequence, which may evolve at each step depending on the response to previous treatment, the occurrence of chronic toxicities, and the patients' perception of the prior treatment. To improve knowledge in terms of effectiveness and risk of cumulative toxicities regarding the different sequences, real-world data using long follow-up durations are necessary; such issues will not be resolved by randomized clinical trials.

Association of Quality-of-Life Outcomes in Cancer Drug Trials With Survival Outcomes and Drug Class

Importance

Although quality of life (QOL) is an important clinical end point, cancer drugs are often approved based on overall survival (OS) or putative surrogate end points such as progression-free survival (PFS) without QOL data.

Objective

To ascertain whether cancer drug trials that show improvement in OS or PFS also improve global QOL of patients with cancer compared with the control treatment, as well as to assess how unchanged or detrimental QOL outcomes are reported in trial publications.

Design, Setting, and Participants

This retrospective cohort study included all patients with cancer in the advanced setting who were enrolled into phase 3 randomized clinical trials (RCTs) of cancer drugs reporting QOL data and published in English language in a PubMed-indexed journal in the calendar year 2019. The systematic search of PubMed was conducted in July 2020.

Main Outcomes and Measures

Association of QOL outcomes with OS and PFS, framing of unchanged QOL outcomes in trial publications, and the association of favorable framing with industry funding of the trials.

Results

A total of 45 phase 3 RCTs enrolling 24 806 participants (13 368 in the experimental arm and 11 438 in the control arm) met the inclusion criteria and were included in the study analyses. Improvement in global QOL with the experimental agent was reported in 11 (24%) RCTs. The RCTs with improved QOL were more likely to also show improved OS vs trials with unimproved QOL (7 of 11 [64%] trials vs 10 of 34 [29%] trials; χ2 = 4.13; P = .04); there was no such association observed for PFS (6 of 11 [55%] trials vs 17 of 34 [50%] trials, χ2 = 0.03; P = .87). Six trials reported worsening QOL, of which 3 (50%) were trials of targeted drugs, and 11 trials reported improvement in QOL, of which 6 (55%) were trials of immunotherapy drugs. Of the 34 trials in which QOL was not improved compared with controls, 16 (47%) reported these results in a positive frame, an observation statistically significantly associated with industry funding (χ2 = 6.35; P = .01).

Conclusions and Relevance

In this cohort study, a small proportion of RCTs of cancer drugs showed benefit in global QOL with the experimental agent. These results showed an association between QOL benefit and OS benefit but no such association with PFS benefit. Trials that failed to show improved QOL often reported their QOL outcomes more favorably. Non-immunotherapy-targeted drugs led to worse QOL more often than did cytotoxic agents.

Health-Related Quality of Life (HRQoL) in Neuroendocrine Tumors: A Systematic Review

Simple Summary

Neuroendocrine tumors (NETs) are a group of heterogenous neoplasms arising from the diffuse neuroendocrine system. Several therapies have been added to the treatment landscape that have improved long-term outcomes. Despite therapeutic advancements, the symptom burden of the disease remains high, impacting health-related quality of life (HRQoL). In this study, we reviewed the impact of different treatment modalities on HRQoL in NET patients. Through a thorough literature review, 61 out of 2375 publications met the inclusion criteria. All randomized phase III trials leading to drug approvals showed a lack of deterioration of HRQoL, and one showed improved QoL. Capturing and understanding patient-reported outcome data is of vital importance for both patients and physicians to make treatment-related decisions.

Abstract

Therapeutic advancements in neuroendocrine tumors (NETs) have improved survival outcomes. This study aims to review the impact of the current therapeutics on health-related quality of life (HRQoL) in NET patients. A literature review was performed utilizing PubMed, The Cochrane Library, and EMBASE, using the keywords “Carcinoid”, “Neuroendocrine tumor”, “NET”, “Quality of life”, “Chemotherapy”, “Chemoembolization”, “Radiofrequency ablation”, “Peptide receptor radionucleotide therapy”, “PRRT”, “Surgery”, “Everolimus”, “Octreotide”, “Lanreotide”, “Sunitinib”, and “Somatostatin analog”. Letters, editorials, narrative reviews, case reports, and studies not in English were excluded. Out of 2375 publications, 61 studies met our inclusion criteria. The commonly used instruments were EORTC QLQ-C30, FACT G, and EORTC- QLQ GI.NET-21. HRQoL was assessed in all pivotal trials that led to approvals of systemic therapies. All systemic therapies showed no worsening in HRQoL. The NETTER-1 study was the only study to show a statistically significant improvement in HRQoL in several domains. The trial examining sunitinib versus placebo in pancreatic NETs showed no change in QoL, except for worsening of diarrhea. In addition to clinical outcomes, patient-reported outcomes are a key element in making appropriate treatment decisions. HRQoL data should be readily provided to patients to assist in shared decision-making.

Treatment for gastrointestinal and pancreatic neuroendocrine tumours: a network meta-analysis

BACKGROUND

Several available therapies for neuroendocrine tumours (NETs) have demonstrated efficacy in randomised controlled trials. However, translation of these results into improved care faces several challenges, as a direct comparison of the most pertinent therapies is incomplete.

OBJECTIVES

To evaluate the safety and efficacy of therapies for NETs, to guide clinical decision-making, and to provide estimates of relative efficiency of the different treatment options (including placebo) and rank the treatments according to their efficiency based on a network meta-analysis.

SEARCH METHODS

We identified studies through systematic searches of the following bibliographic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library; MEDLINE (Ovid); and Embase from January 1947 to December 2020. In addition, we checked trial registries for ongoing or unpublished eligible trials and manually searched for abstracts from scientific and clinical meetings.

SELECTION CRITERIA

We evaluated randomised controlled trials (RCTs) comparing two or more therapies in people with NETs (primarily gastrointestinal and pancreatic).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies and extracted data to a pre-designed data extraction form. Multi-arm studies were included in the network meta-analysis using the R-package netmeta. We separately analysed two different outcomes (disease control and progression-free survival) and two types of NET (gastrointestinal and pancreatic NET) in four network meta-analyses. A frequentist approach was used to compare the efficacy of therapies.

MAIN RESULTS

We identified 55 studies in 90 records in the qualitative analysis, reporting 39 primary RCTs and 16 subgroup analyses. We included 22 RCTs, with 4299 participants, that reported disease control and/or progression-free survival in the network meta-analysis. Precision-of-treatment estimates and estimated heterogeneity were limited, although the risk of bias was predominantly low. The network meta-analysis of progression-free survival found nine therapies for pancreatic NETs: everolimus (hazard ratio [HR], 0.36 [95% CI, 0.28 to 0.46]), interferon plus somatostatin analogue (HR, 0.34 [95% CI, 0.14 to 0.80]), everolimus plus somatostatin analogue (HR, 0.38 [95% CI, 0.26 to 0.57]), bevacizumab plus somatostatin analogue (HR, 0.36 [95% CI, 0.15 to 0.89]), interferon (HR, 0.41 [95% CI, 0.18 to 0.94]), sunitinib (HR, 0.42 [95% CI, 0.26 to 0.67]), everolimus plus bevacizumab plus somatostatin analogue (HR, 0.48 [95% CI, 0.28 to 0.83]), surufatinib (HR, 0.49 [95% CI, 0.32 to 0.76]), and somatostatin analogue (HR, 0.51 [95% CI, 0.34 to 0.77]); and six therapies for gastrointestinal NETs: 177-Lu-DOTATATE plus somatostatin analogue (HR, 0.07 [95% CI, 0.02 to 0.26]), everolimus plus somatostatin analogue (HR, 0.12 [95%CI, 0.03 to 0.54]), bevacizumab plus somatostatin analogue (HR, 0.18 [95% CI, 0.04 to 0.94]), interferon plus somatostatin analogue (HR, 0.23 [95% CI, 0.06 to 0.93]), surufatinib (HR, 0.33 [95%CI, 0.12 to 0.88]), and somatostatin analogue (HR, 0.34 [95% CI, 0.16 to 0.76]), with higher efficacy than placebo. Besides everolimus for pancreatic NETs, the results suggested an overall superiority of combination therapies, including somatostatin analogues. The results indicate that NET therapies have a broad range of risk for adverse events and effects on quality of life, but these were reported inconsistently. Evidence from this network meta-analysis (and underlying RCTs) does not support any particular therapy (or combinations of therapies) with respect to patient-centred outcomes (e.g. overall survival and quality of life).

AUTHORS' CONCLUSIONS

The findings from this study suggest that a range of efficient therapies with different safety profiles is available for people with NETs.

Health-related quality of life and treatment effects in patients with well-differentiated gastroenteropancreatic neuroendocrine neoplasms: A systematic review and meta-analysis

Introduction

Gastroenteropancreatic neuroendocrine neoplasms (GEPNENs) are often diagnosed in an advanced stage. As the optimal sequence of therapy remains largely unclear, all treatment‐related outcomes, including health‐related quality of life (HRQoL) prospects, should be assessed according to patients' preferences.

Methods

A targeted search was performed in PubMed and EMBASE to identify studies on treatment effect and HRQoL, measured using the EORTC QLQ‐C30 tool, in patients with advanced, well‐differentiated GEPNENs. Study quality was assessed, and meta‐analyses were performed for global health status/QOL and tumour response.

Results

The search yielded 1,322 records, and 20 studies were included, examining somatostatin analogues (SSA), peptide receptor radionuclide therapies (PRRT), chemotherapy, SSA‐based combination therapies, and targeted therapies. Global HRQoL was stable, and rates for disease stabilisation were moderate to high across all treatments. Meta‐analyses for global health status/QOL after SSA treatment were not significant (mean difference: –0.3 [95% CI: −1.3 to 0.7]). The highest pooled overall tumour response rate was 33% (95% CI: 24–45%) for PRRT. The highest pooled clinical benefit rate was 94% (95% CI: 65–99%) for chemotherapy.

Conclusion

All treatments appeared beneficial for disease stabilisation while maintaining stable global health status/QOL. High‐quality HRQoL reporting was lacking. HRQoL should be a central outcome next to well‐established outcomes.

177Lu-DOTATATE Plus Radiosensitizing Capecitabine Versus Octreotide Long-Acting Release as First-Line Systemic Therapy in Advanced Grade 1 or 2 Gastroenteropancreatic Neuroendocrine Tumors: A Single-Institution Experience

PURPOSE

To compare the efficacy and safety of ¹⁷⁷Lu-DOTATATE plus radiosensitizing capecitabine and octreotide long-acting release (LAR) as first-line systemic therapy in advanced well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

MATERIALS AND METHODS

Data of consecutive patients of advanced inoperable or metastatic grade 1 or 2 GEP-NETs treated with first-line ¹⁷⁷Lu-DOTATATE plus radiosensitizing capecitabine or octreotide LAR from September 2012 to December 2019 were collected and analyzed for response, toxicity, and survival outcomes.

RESULTS

Seventy-six patients (median age: 53 years; range 14-81 years) with treatment-naïve advanced grade 1 or 2 GEP-NETs were included. Thirty-six patients received a median cumulative dose of 27.3 GBq of ¹⁷⁷Lu-DOTATATE intravenously at 8-12 weeks' intervals along with 1,250 mg/m² oral capecitabine on days 0-14 of each cycle of ¹⁷⁷Lu-DOTATATE, whereas 40 patients were administered 30 mg octreotide LAR intramuscularly every 4 weeks. Using response evaluation criteria in solid tumor 1.1, the objective response rate was 38% in the ¹⁷⁷Lu-DOTATATE arm compared with 15% in the octreotide LAR arm (P = .025), whereas the disease control rates were 88% and 67% in ¹⁷⁷Lu-DOTATATE and octreotide LAR arms, respectively (P = .035). The median durations of progression-free survival in the ¹⁷⁷Lu-DOTATATE and octreotide LAR arms were 54 months and 16 months, respectively (P = .017), whereas the median overall survival was not reached and not significantly different across both the arms. Of the treatment-related adverse events, no major difference was observed in the occurrence of grade 3 or 4 toxicities between the two treatment arms.

CONCLUSION

First-line systemic ¹⁷⁷Lu-DOTATATE plus radiosensitizing capecitabine achieved better radiologic response and longer progression-free survival compared with octreotide LAR in patients with advanced grade 1 or 2 GEP-NETs. Future randomized controlled trials are, however, required to determine the best treatment sequence for the treatment-naïve patients with advanced GEP-NETs.

Peptide Receptor Radionuclide Therapy as First-Line Systemic Treatment in Advanced Inoperable/Metastatic Neuroendocrine Tumors

PURPOSE

Advanced inoperable/metastatic neuroendocrine tumors (NETs) pose a therapeutic challenge with limited treatment options. Peptide receptor radionuclide therapy (PRRT), being specific in targeting the somatostatin receptors, is a promising and viable option in this setting. In this study, we intended to evaluate the role of PRRT as the first-line systemic therapy in advanced inoperable/metastatic NETs.

METHODS

Data of consecutive patients of advanced inoperable/metastatic NETs treated with first-line Lu-DOTATATE at our center, from September 2012 to August 2019, were collected and analyzed.

RESULTS

Forty-five patients (median age, 50 years; range, 14-72 years) with treatment-naive advanced NETs received a median cumulative dose of 27 GBq (range, 13.3-41.3 GBq; over 2-7 cycles) Lu-DOTATATE and 1250 mg/m capecitabine from days 0 to 14 of each PRRT cycle. Three patients were lost to follow-up, 2 had nonmeasurable lesions on CT, and hence, radiological response using Response Evaluation Criteria in Solid Tumors version 1.1 could be assessed in 40 patients. Twelve of 40 patients (30%) showed a partial response, whereas stable disease was observed in 22 of 40 patients (55%). Disease progression was limited to 6 of 40 patients (15%). Treatment-related adverse effects were minimal with grade 3/4 anemia, leukopenia, neutropenia, and hepatotoxicity observed in 2%, 2%, 4%, and 4% of the patients, respectively. Median progression-free survival was 48 months (95% confidence interval, 34.7-61.3 months).

CONCLUSIONS

Our results indicate the efficacy and safety of first-line PRRT in advanced NETs. Future randomized trials, comparing PRRT and somatostatin analogs in treatment-naive patients, are required to identify the definite sequence of treatment options for these patients.

Clinicopathological Features of Gastroesophageal Neuroendocrine Neoplasms

PURPOSE OF REVIEW

Gastroesophageal neuroendocrine neoplasms (NENs) are a rare entity. Recent 2019 WHO classifications reflect our understanding of tumor biology, namely, that distinct molecular characteristics underline tumor behavior and prognosis. Here, we reviewed the evidence for linking molecular findings with the clinicopathological features and treatment of gastroesophageal NENs.

RECENT FINDINGS

Degree of differentiation and Ki-67 proliferation index are required for accurate classification of neuroendocrine tumors and carcinomas but not sufficient to distinguish between the two entities. Resection remains the mainstay treatment for early-stage gastroesophageal neuroendocrine tumors. Additional perioperative therapy may benefit mitotically active tumors. There is a role for somatostatin analogues, especially in the setting of metastatic and symptomatic disease. New radiolabeled somatostatin analogues, immunotherapy, and embolization offer multimodality treatments for distant metastases. We need to understand the specific underlying biology of the various subtypes of gastroesophageal NENs to provide tailored treatment.

Quality of life in patients with gastroenteropancreatic tumours: A systematic literature review

BACKGROUND

Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are slow-growing cancers that arise from diffuse endocrine cells in the gastrointestinal tract (GI-NETs) or the pancreas (P-NETs). They are relatively uncommon, accounting for 2% of all gastrointestinal malignancies. The usual treatment options in advanced GEP-NET patients with metastatic disease include chemotherapy, biological therapies, and peptide receptor radionuclide therapy. Understanding the impact of treatment on GEP-NET patients is paramount given the nature of the disease. Health-related quality of life (HRQoL) is increasingly important as a concept reflecting the patients’ perspective in conjunction with the disease presentation, severity and treatment.

AIM

To conduct a systematic literature review to identify literature reporting HRQoL data in patients with GEP-NETs between January 1985 and November 2019.

METHODS

The PRISMA guiding principles were applied. MEDLINE, Embase and the Cochrane library were searched. Data extracted from the publications included type of study, patient population data (mid-gut/hind-gut/GI-NET/P-NET), sample size, intervention/comparators, HRQoL instruments, average and data spread of overall and sub-scores, and follow-up time for data collection.

RESULTS

Forty-three publications met the inclusion criteria. The heterogeneous nature of the different study populations was evident; the percentage of female participants ranged between 30%-60%, whilst average age ranged from 53.8 to 67.0 years. Eight studies investigated GI-NET patients only, six studies focused exclusively on P-NET patients and the remaining studies involved both patient populations or did not report the location of the primary tumour. The most commonly used instrument was the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 (n = 28) with consistent results across studies; the GI-NET-specific module Quality of Life Questionnaire-GINET21 was used in six of these studies. A number of randomised trials demonstrated no HRQoL changes between active treatment and placebo arms. The Phase III NETTER-1 study provides the best data available for advanced GEP-NET patients; it shows that peptide receptor radionuclide therapy can significantly improve GEP-NET patients’ HRQoL.

CONCLUSION

HRQoL instruments offer a means to monitor patients’ general disease condition, disease progression and their physical and mental well-being. Instruments including the commonly used European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 and GINET21 lack, however, validation and a defined minimal clinical important difference specifically for GI-NET and P-NET patients.

Patient reported symptoms, coping and quality of life during somatostatin analogue treatment for metastatic small- intestinal neuroendocrine tumours

BACKGROUND

Patients with metastatic small-intestinal neuroendocrine tumours (NET) have been shown to have a reduced quality of life compared to the general population and many have disabling symptoms during somatostatin analogue (SSA) treatment. The aim of this prospective study was to document the patient-reported symptoms, coping and quality of life during SSA treatment and to measure patients' fat-soluble vitamin levels.

METHODS

Patients with metastatic small-intestinal NET on treatment with long-acting SSA were included. Data on patient characteristics, blood samples, questionnaires (EORTC-QLQ-C30 and GI.NET-21) and structured patient interviews were collected at inclusion and after 1 year.

RESULTS

Eighty-eight patients were included, 77 (88%) attended 1 year follow-up. Approximately 50% of patients reported symptoms, the most common symptoms at baseline and after 1 year follow-up were diarrhoea, flatulence, fatigue, abdominal discomfort and sore injection lumps. Diarrhoea and fatigue were reported as their main complaint, 23% had > 5 daily episodes of diarrhoea and 59% reported fatigue. However, patients reported a high perceived quality of life, high daily activity, coped with their symptoms and managed their daily life well. Deficiency of vitamin D (27%) and A (13%) were observed.

CONCLUSIONS

Patients with metastatic small-intestinal NET on SSA treatment reported a high frequency of symptoms. Minor improvements were seen after 1-year of follow-up, illustrating that many symptoms might be difficult to improve, or may not be recognised by the health service. Patients, however, generally reported a high quality of life. Care for NET patients on SSA treatment should include a regular systematic symptom registration and vitamin measurements.

Medical Management of Gastroenteropancreatic Neuroendocrine Tumors

The increased incidence and prevalence of neuroendocrine tumors (NETs) over the past few decades has been accompanied by an improvement in overall survival. There are differences in the management of small bowel NETs versus pNETs. The management of all patients with NETs must be individualized based on patient characteristics as well tumor-related factors. This article reviews the role of somatostatin analogues, historical results with chemotherapy in gastroenteropancreatic NETs (GEPNETs), and more recent evidence for the use of cytotoxic chemotherapy in GEPNETs. The article also discusses molecular targeted therapies approved for use in GEPNETs and some ongoing clinical trials.

Management of Small Bowel Neuroendocrine Tumors

Several important landmark trials have reshaped the landscape of non-surgical management of small bowel neuroendocrine tumors over the last few years, with the confirmation of the antitumor effect of somatostatin analogue therapy in PROMID and CLARINET trials as well as the advent of therapies with significant potential such as mammalian target of rapamycin inhibitor (mTor) everolimus (RADIANT trials) and peptide receptor radionuclide therapy (PRRT) with 177-Lutetium (NETTER-1 trial). This narrative summarizes the recommended management strategies of small bowel neuroendocrine tumors. We review the main evidence behind each recommendation as well as compare and contrast four major guidelines, namely the 2016 Canadian Consensus guidelines, the 2017 North American Neuroendocrine Tumor Society guidelines, the 2018 National Comprehensive Cancer Network guidelines, and the 2016 European Neuroendocrine Tumor Society guidelines. Different clinical situations will be addressed, from loco-regional therapy to metastatic unresectable disease. Carcinoid syndrome, which is mostly managed by somatostatin analogue therapy and the serotonin antagonist telotristat etiprate for refractory diarrhea, as well as neuroendocrine carcinoma will be reviewed. However, several questions remain unanswered, such as the optimal management of neuroendocrine carcinomas or the effect of combining and sequencing of the aforementioned modalities where more randomized controlled trials are needed.