Identifying patients with undiagnosed small intestinal neuroendocrine tumours in primary care using statistical and machine learning: model development and validation study.

BACKGROUND: Neuroendocrine tumours (NETs) are increasing in incidence, often diagnosed at advanced stages, and individuals may experience years of diagnostic delay, particularly when arising from the small intestine (SI). Clinical prediction models could present novel opportunities for case finding in primary care. METHODS: An open cohort of adults (18+ years) contributing data to the Optimum Patient Care Research Database between 1st Jan 2000 and 30th March 2023 was identified. This database collects de-identified data from general practices in the UK. Model development approaches comprised logistic regression, penalised regression, and XGBoost. Performance (discrimination and calibration) was assessed using internal-external cross-validation. Decision analysis curves compared clinical utility. RESULTS: Of 11.7 million individuals, 382 had recorded SI NET diagnoses (0.003%). The XGBoost model had the highest AUC (0.869, 95% confidence interval [CI]: 0.841-0.898) but was mildly miscalibrated (slope 1.165, 95% CI: 1.088-1.243; calibration-in-the-large 0.010, 95% CI: -0.164 to 0.185). Clinical utility was similar across all models. DISCUSSION: Multivariable prediction models may have clinical utility in identifying individuals with undiagnosed SI NETs using information in their primary care records. Further evaluation including external validation and health economics modelling may identify cost-effective strategies for case finding for this uncommon tumour.

PREF-NET: a patient preference and experience study of lanreotide autogel administered in the home versus hospital setting among patients with gastroenteropancreatic neuroendocrine tumours in the UK.

PURPOSE: PREF-NET reported patients' experience of Somatuline® (lanreotide) Autogel® (LAN) administration at home and in hospital among patients with gastroenteropancreatic neuroendocrine tumours (GEP-NETs). METHODS: PREF-NET was a multicentre, cross-sectional study of UK adults (aged ≥ 18 years) with GEP-NETs receiving a stable dose of LAN, which comprised of (1) a quantitative online survey, and (2) qualitative semi-structured interviews conducted with a subgroup of survey respondents. The primary objective was the description of overall patient preference for home versus hospital administration of LAN. Secondary objectives included describing patient-reported opinions on the experience and associated preference for each administration setting, and the impact on healthcare utilisation, societal cost, activities of daily living and health-related quality of life (HRQoL). RESULTS: In the primary analysis (80 patients; mean age 63.9 years), 98.7% (95% confidence interval [CI]: 96.1-100.0) of patients preferred to receive LAN at home, compared with 1.3% (95% CI: 0.0-3.9) who preferred the hospital setting. Among participants, over half (60.3%) received their injection from a non-healthcare professional. Most patients (79.5% [95% CI: 70.5-88.4]) reported a positive effect on HRQoL after the switch from hospital to home administration. Qualitative interviews (20 patients; mean age 63.6 years) highlighted that patients preferred home administration because it improved overall convenience; saved time and costs; made them feel more comfortable and relaxed, and less stressed; and increased confidence in their ability to self-manage their treatment. CONCLUSION: Almost all patients preferred to receive LAN treatment at home rather than in hospital with increased convenience and psychological benefits reported as key reasons for this preference.

Matching-adjusted indirect treatment comparison of [177Lu]Lu-DOTA-TATE, everolimus and sunitinib in advanced, unresectable gastroenteropancreatic neuroendocrine tumours: Relative effectiveness of [177Lu]Lu-DOTA-TATE in gastroenteropancreatic neuroendocrine tumours.

Head-to-head comparisons of the efficacy of treatments for gastroenteropancreatic neuroendocrine tumours (GEP-NETs) have not yet been reported. This study used a series of matching-adjusted indirect comparisons to indirectly compare the effectiveness of [177Lu]Lu-DOTA-TATE to everolimus, sunitinib and best supportive care (BSC) for extending progression-free survival and overall survival in patients with advanced, unresectable gastrointestinal (GI)-NETs and P-NETs. The results of the main analysis suggest that after accounting for differences in key prognostic variables, the hazard of progression was 62% (hazard ratio [HR], 0.38; confidence interval [CI]95 0.25-0.58) and 65% (HR 0.35 CI95 0.21-0.59) lower in patients with GI-NETs treated with [177Lu]Lu-DOTA-TATE than in those treated with everolimus and BSC, respectively. Similarly, the hazard of progression was 64% (HR 0.36 CI95 0.18-0.70), 54% (HR 0.46 CI95 0.30-0.71) and 79-87% (HR 0.21 CI95 0.13-0.32; HR 0.13 CI95 0.08-0.22) lower in patients with P-NET treated with [177Lu]Lu-DOTA-TATE than in those treated with sunitinib, everolimus and BSC, respectively. The hazard of death was 58% (HR 0.42 CI95 0.25-0.72), 47% (HR 0.53 CI95 0.33-0.87) and 44-64% (HR 0.56 CI95 0.36-0.90; HR 0.34 CI95 0.20-0.57) lower in P-patients with NET treated with [177Lu]Lu-DOTA-TATE than in those treated with sunitinib, everolimus and BSC, respectively. While our results must be interpreted with caution given the non-randomised nature of the comparisons and the potential for residual confounding, the magnitude of the effect sizes we observe and their consistency across comparators suggest that [177Lu]Lu-DOTA-TATE may be a more effective treatment option than everolimus, sunitinib and BSC in advanced, unresectable GEP-NETs.

Circulating tumour cells and their association with bone metastases in patients with neuroendocrine tumours.

BACKGROUND: Bone metastases are associated with a worse outcome in patients with neuroendocrine tumours (NETs). Tumour overexpression of C-X-C chemokine receptor 4 (CXCR4) appears predictive of skeletal involvement. We investigated the role of circulating tumour cells (CTCs) and CXCR4 expression on CTCs as potential predictors of skeleton invasion. METHODS: Blood from patients with metastatic bronchial, midgut or pancreatic NET (pNET) was analysed by CellSearch. CXCR4 immunohistochemistry was performed on matched formalin-fixed paraffin-embedded (FFPE) samples. RESULTS: Two hundred and fifty-four patients were recruited with 121 midgut and 119 pNETs, of which 51 and 36% had detectable CTCs, respectively. Bone metastases were reported in 30% of midgut and 23% of pNET patients and were significantly associated with CTC presence (p = 0.003 and p < 0.0001). In a subgroup of 40 patients, 85% patients with CTCs had CTCs positive for CXCR4 expression. The proportion of CXCR4-positive CTCs in patients with bone metastases was 56% compared to 35% in those without (p = 0.18) it. Staining for CXCR4 on matched FFPE tissue showed a trend towards a correlation with CXCR4 expression on CTCs (p = 0.08). CONCLUSIONS: CTC presence is associated with bone metastases in NETs. CXCR4 may be involved in CTC osteotropism and present a therapeutic target to reduce skeletal morbidity.

Combination of cross-sectional and molecular imaging studies in the localization of gastroenteropancreatic neuroendocrine tumors.

Molecular imaging modalities exploit aspects of neuroendocrine tumors (NET) pathophysiology for both diagnostic imaging and therapeutic purposes. The characteristic metabolic pathways of NET determine which tracers are useful for their visualization. In this review, we summarize the diagnostic value of all available molecular imaging studies, present data about their use in daily practice in NET centers globally, and finally make recommendations about the appropriate use of those modalities in specific clinical scenarios. Somatostatin receptor scintigraphy (SRS) continues to have a central role in the diagnostic workup of patients with NET, as it is also widely available. However, and despite the lack of prospective randomized studies, many NET experts predict that Gallium-68 ((68)Ga)-DOTA positron emission tomography (PET) techniques may replace SRS in the future, not only because of their technical advantages, but also because they are superior in patients with small-volume disease, in patients with skeletal metastases, and in those with occult primary tumors. Carbon-11 ((11)C)-5-hydroxy-L-tryptophan (5-HTP) PET and (18)F-dihydroxyphenylalanine ((18)F-DOPA) PET are new molecular imaging techniques of limited availability, and based on retrospective data, their sensitivities seem to be inferior to that of (68)Ga-DOTA PET. Glucagon-like-peptide-1 (GLP-1) receptor imaging seems promising for localization of the primary in benign insulinomas, but is currently available only in a few centers. Fluorine-18 ((18)F)-fluorodeoxyglucose ((18)F-FDG) PET was initially thought to be of limited value in NET, due to their usually slow-growing nature. However, according to subsequent data, (18)F-FDG PET is particularly helpful for visualizing the more aggressive NET, such as poorly differentiated neuroendocrine carcinomas, and well-differentiated tumors with Ki67 values >10%. According to limited data, (18)F-FDG-avid tumor lesions, even in slow-growing NET, may indicate a more aggressive disease course. When a secondary malignancy has already been established or is strongly suspected, combining molecular imaging techniques (e.g. (18)F-FDG PET and (68)Ga-DOTA PET) takes advantage of the diverse avidities of different tumor types to differentiate lesions of different origins. All the above-mentioned molecular imaging studies should always be reviewed and interpreted in a multidisciplinary (tumor board) meeting in combination with the conventional cross-sectional imaging, as the latter remains the imaging of choice for the evaluation of treatment response and disease follow-up.

Improving the diagnosis and management of neuroendocrine tumors: utilizing new advances in biomarker and molecular imaging science.

Neuroendocrine tumors (NET) are malignant solid tumors that arise in hormone-secreting tissue of the diffuse neuroendocrine system or endocrine glands. Although traditionally understood to be a rare disease, the incidence and prevalence of NET have increased greatly in the past 3 decades. However, during this time, progress in diagnosis and outcome of NET has generally been modest. In order to achieve improved outcome in NET, a better understanding of NET biology combined with more reliable serum markers and better techniques to identify tumor localization and small lesions are needed. Although some NET biomarkers exist, sensitive and specific markers that predict tumor growth and behavior are generally lacking. In addition, the integration of new molecular imaging technologies in patient diagnosis and follow-up has the potential to enhance care. To discuss developments and issues required to improve diagnostics and management of NET patients, with specific focus on the latest advances in molecular imaging and biomarker science, 17 global leaders in the fields of NET, molecular imaging and biomarker technology gathered to participate in a 2-day meeting hosted by Prof. Kjell Öberg at the University of Uppsala in Sweden. During this time, findings were presented regarding methods with potential prognostic and treatment applications in NET or other types of cancers. This paper describes the symposium presentations and resulting discussions.

Outcomes and survival in patients with advanced intestinal neuroendocrine tumours on home parenteral nutrition, an international multicentre retrospective cohort study.

BACKGROUND AND AIMS: Only limited information is available on the use of home parenteral nutrition (HPN) in patients with advanced neuroendocrine tumours (NETs) causing intestinal failure (IF). This study aims to report the outcomes of the explore the use of HPN in this patient cohort, in the largest case series to date. METHODS: A retrospective study in the United Kingdom and the Netherlands was performed, using the UK National British Artificial Nutrition Survey (BANS) and local databases in the Netherlands. Data regarding age, sex, NET grading, staging, treatment, HPN characteristics and survival outcomes were collected. RESULTS: Data were collected on 41 patients (n = 18 males, 44%) with a median age of 65. Most primary tumours were in the small bowel (n = 35, 85%). The NETs were Grade 1 (n = 16, 39%), Grade 2 (n = 7, 17%), Grade 3 (n = 1, 2%). In 28 patients (n = 68%) there was stage IV disease with metastases located in the peritoneum, mesentery and or liver. There were two indications for HPN; short bowel syndrome (n = 27, 66%) and inoperable malignant bowel obstruction (n = 14, 34%). The median period on HPN was 11 months (interquartile range 4-25 months). 11 patients were still alive and receiving HPN treatment after 2 years, and 6 patients after 3 years. Six patients (22%) with short bowel syndrome (SBS) could be weaned from HPN. There was a statistically significant improved survival for patients with short bowel syndrome (median 24 months) compared to inoperable malignant bowel obstruction (median 7 months). The catheter-related bloodstream infection rate was comparable to other HPN patient cohorts at 1.0 per 1000 catheter days. CONCLUSION: This study shows that HPN can be used safely in patients with NET and IF to increase survival beyond that reasonably expected in the context of either short bowel syndrome or inoperable malignant bowel obstruction. Patients with short bowel syndrome are most likely to benefit. Further prospective studies are necessary to validate survival benefits and to demonstrate the effect of HPN on quality of life.

Neuroendocrine tumours: what gastroenterologists need to know.

Gastroenterologists are intermittently involved in diagnosing and managing patients who have neuroendocrine tumours (NETs). However, few UK gastroenterologists have received extensive training about this topic. This article aims to provide a brief introduction to NETs; it is aimed at a general gastroenterologist audience. NETs present in diverse ways and many symptomatic patients unfortunately experience significant delays in diagnosis. Comprehensive evaluation of a patient with a possible NET involves assessing their symptoms, the tumour's primary organ of origin, its differentiation status, grade and stage, whether the NET is secreting hormones and whether there is any underlying hereditary predisposition. Such assessment often needs specialist investigations such as nuclear medicine scans. All these factors influence patient management and prognosis, so a patient's case and investigations should always be discussed by a fully constituted NET multidisciplinary team. Most localised tumours are considered for resection, but there are multiple treatment options for metastatic disease and many patients receive several different therapies during the course of their illness. The most common first line treatment in patients who have metastatic low grade NETs is monthly long acting somatostatin analogue injections. Prognosis is highly variable, but some patients who have inoperable metastases survive for many years on treatment with good quality of life. Gastroenterologists may also be involved in managing the non-tumour associated chronic gastrointestinal problems that some patients experience. Their involvement has been shown to improve patient-reported outcomes and quality of life.

Circulating tumour cells and tumour biomarkers in functional midgut neuroendocrine tumours.

CALM-NET was a phase IV exploratory study in the UK that aimed to evaluate if the presence of circulating tumour cells (CTCs) at baseline predicted symptomatic response in patients with midgut neuroendocrine tumours (NETs) treated with lanreotide autogel (LAN). Adults with functional, well/moderately differentiated (Ki-67 <20%) midgut NETs received LAN 120 mg/28 days for 1 year. CTCs were present in blood if enumeration was >0. Primary endpoint was the clinical value of baseline CTCs to predict symptomatic response (decrease in diarrhoea or flushing of ≥50% frequency, or ≥1 severity level). Other endpoints included progression-free survival (PFS) and correlations between plasma and urinary biomarkers (including 5-hydroxyindoleacetic acid [5-HIAA]). Fifty patients were enrolled; 40 completed the study. Baseline CTCs were present in 22 (45.8%) patients (missing baseline CTC status n = 2). Overall, 87.5% (95% confidence interval [CI]: 73.9; 94.5) of patients had a symptomatic response; a 5.9-fold higher odds of symptomatic response in patients without CTC versus patients with CTC at baseline was observed, although this was not statistically significant (odds ratio: 0.17 [95% CI: 0.02; 1.65], p = .126). One-year PFS rate was 66.4% (95% CI: 48.8; 79.2). Biomarker concentrations did not correlate to baseline CTC status. However, there was a strong correlation between plasma and urinary 5-HIAA (Spearman correlation coefficients ≥0.87 [p < .001], all time points). In conclusion, patients without CTC at baseline may be more likely to achieve a symptomatic response following LAN treatment than patients with CTC. Plasma 5-HIAA correlated with urinary 5-HIAA during LAN treatment. ClinicalTrials.gov identifier: NCT02075606.

Patient and Healthcare Provider Perspectives of First-Generation Somatostatin Analogs in the Management of Neuroendocrine Tumors and Acromegaly: A Systematic Literature Review.

INTRODUCTION: Somatostatin analogs (SSAs) are used to treat neuroendocrine tumors (NETs) and acromegaly. Two first-generation SSAs, octreotide long-acting release (OCT LAR) and lanreotide autogel/depot (LAN), are available. A systematic literature review (SLR) was conducted to investigate which characteristics beyond efficacy are most important in patient and healthcare practitioner (HCP) experience of LAN and OCT when used to treat acromegaly and NETs. METHODS: MEDLINE, Embase, the Cochrane Library, and Database of Abstracts of Reviews of Effect were searched from database inception to January 2019 with terms for first-generation SSAs, NETs, acromegaly, preferences, decision-making, and human factors. Key congresses in 2016-2018 and SLR bibliographies were hand-searched. Two independent reviewers screened articles at title/abstract and full-text stage. Publications fulfilling pre-specified inclusion criteria reported patient or HCP perspectives of LAN or OCT, or any factors affecting treatment perspectives for NETs or acromegaly. RESULTS: A total of 1110 unique records were screened, of which 21 studies were included, reporting from the perspectives of patients (n = 18) and/or HCPs (n = 9). Perspectives were collected using shared decision-making frameworks, questionnaires, informal patient opinion, and a Delphi panel. Where patient preference was specifically reported, LAN was preferred in 4/5 studies and OCT LAR in 1/5. Common factors underlying treatment experience included technical problems with injections and associated pain, emotional quality/anxiety of injections, time and convenience of treatment administration, and independence. Immediate aspects of injections appeared most important to patients, though the possibilities of extended dosing intervals and self-/partner-injection with LAN were also notable factors. CONCLUSIONS: Study outcomes favored LAN in this SLR, with factors surrounding injection administration most influential in treatment experience. The findings of this SLR provide a basis that could inform development of decision-making criteria, with patient and HCP treatment perspectives considered. Future studies should utilize a common method to report preference and associated drivers.

Is local excision sufficient in selected grade 1 or 2 type III gastric neuroendocrine neoplasms?

PURPOSE: Type III gastric neuroendocrine neoplasms (g-NENs) have historically been regarded as aggressive tumours, hence current guidelines advocate radical surgery with lymph node dissection. Data on the roles of endoscopic or less extensive surgical resections are more limited. The aim of our study is to evaluate the clinicopathological features and long-term outcomes of patients undergoing endoscopic or limited surgical resection for localised grade 1 or 2 type III g-NENs when compared to radical surgery. METHODS: Retrospective analysis of all patients diagnosed with a localised grade 1 or 2 type III g-NENs across six tertiary NEN centers between 2006 and 2019. RESULTS: Forty-five patients were diagnosed with a potentially resectable grade 1 or 2 type III g-NEN of whom 36 underwent either endoscopic or surgical resection. No statistically significant differences were found between the three resection groups in terms of patient age, tumour location, grade or size. Only tumour size was found to be significantly associated with poor clinical outcome (p = 0.012) and ROC curve analysis identified tumour size >10 mm as a negative predictor (AUC:0.8030, p = 0.0021). Tumours >10 mm were also more likely to be associated with lymph node metastases on imaging and histology (p = 0.039 and p = 0.026 respectively). CONCLUSIONS: Localised grade 1 or 2 type III g-NENs had a good prognosis in this series. Tumour size >10 mm was the most significant prognostic factor affecting patient outcome. Endoscopic resection or limited surgical resection is feasible and safe in small type III g-NENs which demonstrate favourable grade 1/2, well differentiated histology.

Prognostic Threshold for Circulating Tumor Cells in Patients With Pancreatic and Midgut Neuroendocrine Tumors.

BACKGROUND: Circulating tumor cells (CTCs) are detectable in patients with neuroendocrine tumors (NETs) and are accurate prognostic markers although the optimum threshold has not been defined. OBJECTIVE: This work aims to define optimal prognostic CTC thresholds in PanNET and midgut NETs. PATIENTS AND METHODS: CellSearch was used to enumerate CTCs in 199 patients with metastatic pancreatic (PanNET) (90) or midgut NETs (109). Patients were followed for progression-free survival (PFS) and overall survival (OS) for a minimum of 3 years or until death. RESULTS: The area under the receiver operating characteristic curve (AUROC) for progression at 12 months in PanNETs and midgut NETs identified the optimal CTC threshold as 1 or greater and 2 or greater, respectively. In multivariate logistic regression analysis, these thresholds were predictive for 12-month progression with an odds ratio (OR) of 6.69 (P < .01) for PanNETs and 5.88 (P < .003) for midgut NETs. The same thresholds were found to be optimal for predicting death at 36 months, with an OR of 2.87 (P < .03) and 5.09 (P < .005) for PanNETs and midgut NETs, respectively. In multivariate Cox hazard regression analysis for PFS in PanNETs, 1 or greater CTC had a hazard ratio (HR) of 2.6 (P < .01), whereas 2 or greater CTCs had an HR of 2.25 (P < .01) in midgut NETs. In multivariate analysis OS in PanNETs, 1 or greater CTCs had an HR of 3.16 (P < .01) and in midgut NETs, 2 or greater CTCs had an HR of 1.73 (P < .06). CONCLUSIONS: The optimal CTC threshold to predict PFS and OS in metastatic PanNETs and midgut NETs is 1 and 2, respectively. These thresholds can be used to stratify patients in clinical practice and clinical trials.

Patient Survey of the Physical, Emotional, and Informational Challenges for Patients Living with Neuroendocrine Tumors.

INTRODUCTION: Patient surveys of disease burden on daily living rarely explore the impact that patient information sources can have on optimizing care. METHODS: To identify unmet needs/possible solutions for information and support to address the physical, emotional, and informational challenges that patients living with neuroendocrine tumors (NETs) may have, an online survey was conducted among patients recruited by the Carcinoid Cancer Foundation (US), Netzwerk Neuroendokrine Tumoren (NeT) e.V. (Germany), and Association de Patients porteurs de Tumeurs Endocrines Diverses (France); these organizations approved the survey questions. RESULTS: Between August 2015 and November 2015, 741 online surveys were completed in France (n = 73), Germany (n = 240), and the US (n = 428) during a 6-week period. Over 65% of patients were diagnosed ≤ 5 years ago. Across the three countries, multiple symptoms were experienced before diagnosis. These symptoms were consistent with those of functional tumors, most commonly diarrhea (40-47%) and flushing (12-45%). The most common emotion upon diagnosis was anxiety (20-67%). The greatest physical challenges for patients living with NETs included fatigue (26-66%), diarrhea (22-48%), pain/discomfort (13-40%), and sleep disturbance (16-35%), despite cancer management. Information sources classed as "very useful" included patient-association websites, disease awareness websites, and journals; "patients-like-me" case studies were most favored (43-67%) for future use as sources of information. CONCLUSION: Patients with NETs face negative emotions and multiple physical challenges that require psychological support/coping strategies, and they seek reliable, personally relevant, easily understood information, including that from interactions with other patients. Plain language summary available for this article.

Differential diagnosis of diarrhoea in patients with neuroendocrine tumours: A systematic review.

BACKGROUND: Approximately 20% of patients with neuroendocrine tumours (NETs) develop carcinoid syndrome (CS), characterised by flushing and diarrhoea. Somatostatin analogues or telotristat can be used to control symptoms of CS through inhibition of serotonin secretion. Although CS is often the cause of diarrhoea among patients with gastroenteropancreatic NETs (GEP-NETs), other causes to consider include pancreatic enzyme insufficiency (PEI), bile acid malabsorption and small intestinal bacterial overgrowth. If other causes of diarrhoea unrelated to serotonin secretion are mistaken for CS diarrhoea, these treatments may be ineffective against the diarrhoea, risking detrimental effects to patient quality of life. AIM: To identify and synthesise qualitative and quantitative evidence relating to the differential diagnosis of diarrhoea in patients with GEP-NETs. METHODS: Electronic databases (MEDLINE, Embase and the Cochrane Library) were searched from inception to September 12, 2018 using terms for NETs and diarrhoea. Congresses, systematic literature review bibliographies and included articles were also hand-searched. Any study designs and publication types were eligible for inclusion if relevant data on a cause(s) of diarrhoea in patients with GEP-NETs were reported. Studies were screened by two independent reviewers at abstract and full-text stages. Framework synthesis was adapted to synthesise quantitative and qualitative data. The definition of qualitative data was expanded to include all textual data in any section of relevant publications. RESULTS: Forty-seven publications (44 studies) were included, comprising a variety of publication types, including observational studies, reviews, guidelines, case reports, interventional studies, and opinion pieces. Most reported on PEI on/after treatment with somatostatin analogs; 9.5%-84% of patients with GEP-NETs had experienced steatorrhoea or confirmed PEI. Where reported, 14.3%-50.7% of patients received pancreatic enzyme replacement therapy. Other causes of diarrhoea reported in patients with GEP-NETs included bile acid malabsorption (80%), small intestinal bacterial overgrowth (23.6%-62%), colitis (20%) and infection (7.1%). Diagnostic approaches included faecal elastase, breath tests, tauroselcholic (selenium-75) acid (SeHCAT) scan and stool culture, although evidence on the effectiveness or diagnostic accuracy of these approaches was limited. Assessment of patient history or diarrhoea characteristics was also reported as initial approaches for investigation. From the identified evidence, if diarrhoea is assumed to be CS diarrhoea, consequences include uncontrolled diarrhoea, malnutrition, and perceived ineffectiveness of CS treatment. Approaches for facilitating differential diagnosis of diarrhoea include improving patient and clinician awareness of non-CS causes and involvement of a multidisciplinary clinical team, including gastroenterologists. CONCLUSION: Diarrhoea in GEP-NETs can be multifactorial with misdiagnosis leading to delayed patient recovery and inefficient resource use. This systematic literature review highlights gaps for further research on prevalence of non-CS diarrhoea and suitability of diagnostic approaches, to determine an effective algorithm for differential diagnosis of GEP-NET diarrhoea.

Retrospective study on mixed neuroendocrine non-neuroendocrine neoplasms from five European centres.

BACKGROUND: Mixed neuroendocrine non-neuroendocrine neoplasm (MiNEN) is a rare diagnosis, mainly encountered in the gastro-entero-pancreatic tract. There is limited knowledge of its epidemiology, prognosis and biology, and the best management for affected patients is still to be defined. AIM: To investigate clinical-pathological characteristics, treatment modalities and survival outcomes of a retrospective cohort of patients with a diagnosis of MiNEN. METHODS: Consecutive patients with a histologically proven diagnosis of MiNEN were identified at 5 European centres. Patient data were retrospectively collected from medical records. Pathological samples were reviewed to ascertain compliance with the 2017 World Health Organisation definition of MiNEN. Tumour responses to systemic treatment were assessed according to the Response Evaluation Criteria in Solid Tumours 1.1. Kaplan-Meier analysis was applied to estimate survival outcomes. Associations between clinical-pathological characteristics and survival outcomes were explored using Log-rank test for equality of survivors functions (univariate) and Cox-regression analysis (multivariable). RESULTS: Sixty-nine consecutive patients identified; Median age at diagnosis: 64 years. Males: 63.8%. Localised disease (curable): 53.6%. Commonest sites of origin: colon-rectum (43.5%) and oesophagus/oesophagogastric junction (15.9%). The neuroendocrine component was; predominant in 58.6%, poorly differentiated in 86.3%, and large cell in 81.25%, of cases analysed. Most distant metastases analysed (73.4%) were occupied only by a poorly differentiated neuroendocrine component. Ninety-four percent of patients with localised disease underwent curative surgery; 53% also received perioperative treatment, most often in line with protocols for adenocarcinomas from the same sites of origin. Chemotherapy was offered to most patients (68.1%) with advanced disease, and followed protocols for pure neuroendocrine carcinomas or adenocarcinomas in equal proportion. In localised cases, median recurrence free survival (RFS); 14.0 mo (95%CI: 9.2-24.4), and median overall survival (OS): 28.6 mo (95%CI: 18.3-41.1). On univariate analysis, receipt of perioperative treatment (vs surgery alone) did not improve RFS (P = 0.375), or OS (P = 0.240). In advanced cases, median progression free survival (PFS); 5.6 mo (95%CI: 4.4-7.4), and median OS; 9.0 mo (95%CI: 5.2-13.4). On univariate analysis, receipt of palliative active treatment (vs best supportive care) prolonged PFS and OS (both, P < 0.001). CONCLUSION: MiNEN is most commonly driven by a poorly differentiated neuroendocrine component, and has poor prognosis. Advances in its biological understanding are needed to identify effective treatments and improve patient outcomes.

Early Changes in Circulating Tumor Cells Are Associated with Response and Survival Following Treatment of Metastatic Neuroendocrine Neoplasms.

PURPOSE: To investigate posttreatment circulating tumor cell (CTC) counts in patients with neuroendocrine neoplasms (NENs) as a predictive biomarker for disease progression and overall survival (OS). EXPERIMENTAL DESIGN: Patients with metastatic NENs commencing therapy were prospectively recruited (n = 138). Blood samples were obtained for evaluation of CTCs using the CellSearch platform and for chromogranin A (CgA) at baseline, three to five (median, 4.3) weeks and 10 to 15 (median 13.7) weeks after commencing therapy. Radiologic response and OS data were collected. RESULTS: There was a significant association between first posttreatment CTC count and progressive disease (PD; P < 0.001). Only 8% of patients with a favorable "CTC response" (0 CTCs at baseline and 0 at first posttreatment time-point; or ≥50% reduction from baseline) had PD compared with 60% in the unfavorable group (<50% reduction or increase). Changes in CTCs were strongly associated with OS (P < 0.001), the best prognostic group being patients with 0 CTCs before and after therapy; followed by those with ≥50% reduction in CTCs [hazard ratio (HR), 3.31]; with those with a <50% reduction or increase in CTCs (HR, 5.07) having the worst outcome. In multivariate analysis, changes in CTCs had the strongest association with OS (HR, 4.13; P = 0.0002). Changes in CgA were not significantly associated with survival. CONCLUSIONS: Changes in CTCs are associated with response to treatment and OS in metastatic NENs, suggesting CTCs may be useful as surrogate markers to direct clinical decision making.

A guide to midgut neuroendocrine tumours (NETs) and carcinoid syndrome.

Patients with midgut neuroendocrine tumours or carcinoid syndrome often face a delayed diagnosis. This article aims to highlight the different ways in which patients with midgut neuroendocrine tumours (NETs) present, the diagnostic approach to them, the current methods of management available and future considerations.

Circulating tumor cells as prognostic markers in neuroendocrine tumors.

PURPOSE: To determine the prognostic significance of circulating tumor cells (CTCs) in patients with neuroendocrine cancer. PATIENTS AND METHODS: In this single-center prospective study, 176 patients with measurable metastatic neuroendocrine tumors (NETs) were recruited. CTCs were measured using a semiautomated technique based on immunomagnetic separation of epithelial cell adhesion molecule-expressing cells. RESULTS: Overall, 49% patients had ≥ one CTC, 42% had ≥ two CTCs, and 30% had ≥ five CTCs in 7.5 mL blood. Presence of CTCs was associated with increased burden, increased tumor grade, and elevated serum chromogranin A (CgA). Using a 90-patient training set and 85-patient validation set, we defined a cutoff of < one or ≥ one as the optimal prognostic threshold with respect to progression-free survival (PFS). Applying this threshold, the presence of ≥ one CTC was associated with worse PFS and overall survival (OS; hazard ratios [HRs], 6.6 and 8.0, respectively; both P < .001). In multivariate analysis, CTCs remained significant when other prognostic markers, grade, tumor burden, and CgA were included. Within grades, presence of CTCs was able to define a poor prognostic subgroup. For grade 1, HRs were 5.0 for PFS (P = .017) and 7.2 for OS (P = .023); for grade 2, HRs were 3.5 for PFS (P = .018) and 5.2 for OS (P = .036). CONCLUSION: CTCs are a promising prognostic marker for patients with NETs and should be assessed in the context of clinical trials with defined tumor subtypes and therapy.

Molecular pathogenesis of neuroendocrine tumors: implications for current and future therapeutic approaches.

The treatment landscape and biologic understanding of neuroendocrine tumors (NET) has shifted dramatically in recent years. Recent studies have shown that somatostatin analogues have the potential not only to control symptoms of hormone hypersecretion but also have the ability to slow tumor growth in patients with advanced carcinoid. The results of clinical trials have further shown that the VEGF pathway inhibitor sunitinib and the mTOR inhibitor everolimus have efficacy in patients with advanced pancreatic NETs. The efficacy of these targeted therapies in NET suggests that the molecular characterization of NETs may provide an avenue to predict both which patients may benefit most from the treatment and to overcome potential drug resistance. Recent genomic studies of NETs have further suggested that pathways regulating chromatin remodeling and epigenetic modification may play a key role in regulating NET growth. These observations offer the potential for new therapeutic and diagnostic advances for patients with NET.