Small Intestinal Neuroendocrine Tumors Research Articles

Plasma protein biomarkers for the detection of pancreatic neuroendocrine tumors and differentiation from small intestinal neuroendocrine tumors.

There is an unmet need for novel biomarkers to diagnose and monitor patients with neuroendocrine neoplasms. The EXPLAIN study explores a multi-plasma protein and supervised machine learning strategy to improve the diagnosis of pancreatic neuroendocrine tumors (PanNET) and differentiate them from small intestinal neuroendocrine tumors (SI-NET). At time of diagnosis, blood samples were collected and analyzed from 39 patients with PanNET, 135 with SI-NET (World Health Organization Grade 1-2) and 144 controls. Exclusion criteria were other malignant diseases, chronic inflammatory diseases, reduced kidney or liver function. Prosed Oncology-II (i.e., OLink) was used to measure 92 cancer related plasma proteins. Chromogranin A was analyzed separately. Median age in all groups was 65-67 years and with a similar sex distribution (females: PanNET, 51%; SI-NET, 42%; controls, 42%). Tumor grade (G1/G2): PanNET, 39/61%; SI-NET, 46/54%. Patients with liver metastases: PanNET, 78%; SI-NET, 63%. The classification model of PanNET versus controls provided a sensitivity (SEN) of 0.84, specificity (SPE) 0.98, positive predictive value (PPV) of 0.92 and negative predictive value (NPV) of 0.95, and area under the receiver operating characteristic curve (AUROC) of 0.99; the model for the discrimination of PanNET versus SI-NET providing a SEN 0.61, SPE 0.96, PPV 0.83, NPV 0.90 and AUROC 0.98. These results suggest that a multi-plasma protein strategy can significantly improve diagnostic accuracy of PanNET and SI-NET.

Survival of patients with small bowel neuroendocrine neoplasms in Auckland, Aotearoa New Zealand.

BackgroundSmall intestinal Neuroendocrine Neoplasms (SI‐NENs) are the most common primary malignancy of the small bowel. The aim of this study is to define the survival of patients with an SI‐NEN in Auckland, Aotearoa New Zealand (AoNZ).MethodsA retrospective study of all patients diagnosed with a jejunal or ileal SI‐NEN in the Auckland region between 2000 and 2012 was performed. The New Zealand NETwork! Registry was searched to identify the study cohort. Retrospective data collection was performed to collect stage, survival and follow up data.ResultsOne hundred and seven patients were included in the study. The mean age of patients was 62.8 years (SD 11.9). The 5 and 10‐year disease‐specific survival for all patients was 66.1% (95% CI 56.5–75.7%) and 61.8% (95% CI 51.8–71.8%), respectively. Ten‐year disease‐specific survival was 100% for stage I and II, 74% (95%CI 61.7–84.4%) for stage III and 33.9% (95%CI 16.9–35.6%) for stage IV SI‐NEN. Eleven of 40 (27.5%) patients with stage III disease had recurrence and 3 of 7 (42.8%) patients with stage IV disease had recurrence. In patients with stage IV disease, neither primary resection (HR 2.25, 95% CI 0.92–5.5) nor distant resection (HR 1.72, 95% CI 0.63–4.7) were significantly associated with a disease‐specific or overall survival benefit.ConclusionThis study demonstrates that stage at SI‐NEN diagnosis is associated with survival, but resection of the primary or distant metastases in patients with stage IV disease is not. There was no recurrence in patients with stage I or II disease after complete resection.

Survival effects of primary and metastatic surgical treatment in metastatic small intestinal tumors: A propensity score-matching study.

ObjectiveTo analyze the effects of primary tumor resection and metastatic lesion resection on the survival of metastatic small intestinal tumors.MethodsThe research subjects were patients with metastatic small bowel tumors identified from 2004 to 2016 in the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching and Kaplan–Meier analyses were performed to analyze the effect of surgery on the prognosis.ResultsA total of 4,034 patients from the SEER database were analyzed. Both before and after the propensity score–matching analysis, the prognosis of patients who underwent primary tumor surgery and metastatic surgery was better than that of patients who did not undergo surgery; all were patients with metastatic small bowel adenocarcinoma (mSIA) or metastatic small intestinal neuroendocrine tumors (mSI-NETs) (all p < .005). Patients with mSIA and adequate lymph node dissection had a longer prognosis than mSIA patients with inadequate lymph node dissection, but this survival benefit was not present in mSI-NET patients. It made no difference in the prognosis of mSIA and mSI-NETs whether localized surgery or intestine-ectomy was performed. Patients with mSIA who underwent primary and metastatic excision plus chemotherapy had the best overall survival and cancer-specific survival rates, whereas mSI-NET patients who underwent primary and metastatic excision had the best overall survival and cancer-specific survival rates (all p < .001).ConclusionIn these carefully selected patients, primary tumor resection and/or metastatic lesion resection significantly improved the survival rates for patients with mSIA and mSI-NETs. The mSIA patients with resectable primary tumors seemed to require a sufficient number of lymph node dissections more than the patients with well-differentiated mSI-NETs.

Incidence and prognosis of patients with small intestinal neuroendocrine tumors in a population based nationwide study

Background & aimsSmall intestinal neuroendocrine tumours (SI-NETs) are the most frequent malignant tumours of the small intestine. Population based studies on SI-NETs are scarce. We aimed to examine the incidence, presentation of disease and prognosis of SI-NET and to determine patient prognosis in those undergoing emergency or elective surgery. MethodsThis was a retrospective population-based study. Information on all patients diagnosed with neuroendocrine tumours of the small intestine (excluding duodenum) from the beginning of the Icelandic Cancer Registry and the pathology departments in the country (1966–2017). Detailed phenotypic information was obtained from medical records on symptoms at diagnosis, treatment, recurrence and survival. ResultsA total of 113 patients with SI-NETs were identified, 3 patients were excluded due to lack of data and/or diagnostic error, leaving 110 patients for final analysis. The incidence of SI-NET was 0.78/100,000 and did not increase during the study period. A total of 42 % (n = 46) of patients were diagnosed incidentally. Long-term prognosis, after a landmark of 12 months, was better in patients who were diagnosed incidentally (HR 0.52; p = 0.03). Overall 89 % (n = 98) of cases underwent surgical resection of the primary tumor, 31 % (n = 30) patients acute or semi-acute surgery and 69 % (n = 68) elective surgery. Emergency surgery was associated with a 6-fold risk of death in the first 12 months after surgery (HR: 5.99; p = 0.01) and associated with more severe surgical complications. However, there was no difference in the long-term risk of death after the first 12 months (HR: 1.39; p = 0.27). ConclusionsThe incidence of SI-NETs has not changed significantly in the last decades. Incidentally diagnosed SI-NET was associated with a favorable long-term prognosis. Emergency surgery in patients with SI-NET was associated with a significantly worse short-term risk of mortality compared to those who underwent elective surgery.

Abstract 46: Independent clonal origins of synchronous primary tumors in multifocal ileal neuroendocrine tumor patients

Abstract Background: Small intestinal neuroendocrine tumors (SI-NETs) are the most common neoplasms of the small bowel, accounting for 40% of all small intestinal malignancies. Previous high-throughput sequencing studies have shown that SI-NETs have a low somatic mutation rate. Loss of heterozygosity (LOH) at chromosome 18 is the most frequent genomic alteration identified, occurring in ~60% of tumors, and the only recurrent mutations reported to date are loss-of-function mutations in CDKN1B in ~10% of tumors. Most previous studies have focused on sequencing a single primary tumor from each SI-NET patient, even though up to 50% of the patients are diagnosed with multiple synchronous tumors. Thus, the mechanisms by which multifocal SI-NETs arise remain elusive. A better understanding of their tumorigenesis is essential for the optimal treatment of the patients. Materials and Methods: We performed a comprehensive genomic profiling of 75 de-identified synchronous primary tumors, 15 metastases, and 18 normal ileal mucosa and/or whole blood specimens from 13 patients with multifocal ileal NETs using whole genome sequencing. Results: We observed lack of shared somatic variation among the multifocal ileal NET patients and between the synchronous primary tumors within each patient, indicating that these tumors develop independently. Although recurrent copy-number alterations were identified, additional chromosome mapping revealed that tumors from the same patient can gain or lose different parental alleles. In addition to the previously reported CDKN1B loss-of-function mutations, we identified potential driver gene alterations in TNRC6B in a subset of ileal NETs. We also observed two different metastatic dissemination patterns among patients with multiple metastases. Metastases were either clonal or independent, originating from one or several primary tumors. Conclusions: Our study demonstrates notable genomic diversity among multifocal ileal NETs, which corroborates previous literature suggesting that these tumors originate independently. We identified potential loss-of-function mutations in TNRC6B, a candidate tumor suppressor gene in a small subset of ileal NETs. Identification of different metastatic dissemination patterns has an important clinical implication, highlighting the need to carefully remove all synchronous primary tumors of the entire jejunum and ileum at the time of surgery. Lastly, our results indicate that the tumorigenesis of multifocal ileal NETs is not exclusively driven by genomic alterations, suggesting that SI-NETs could be also driven by epigenetic mechanisms, or arise from morphologically normal small intestine as a result of field cancerization. Also, the tumor microenvironment in the ileum may play a role in the growth and development of SI-NETs. Citation Format: NETTA MÄKINEN, Meng Zhou, Zhouwei Zhang, Yosuke Kasai, Elizabeth Perez, Grace E. Kim, Chrissie Thirlwell, Eric Nakakura, Matthew Meyerson. Independent clonal origins of synchronous primary tumors in multifocal ileal neuroendocrine tumor patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 46.

Radical Resection in Entero-Pancreatic Neuroendocrine Tumors: Recurrence-Free Survival Rate and Definition of a Risk Score for Recurrence.

Surgery with radical intent is the only potentially curative option for entero-pancreatic neuroendocrine tumors (EP-NETs) but many patients develop recurrence even after many years. The subset of patients at high risk of disease recurrence has not been clearly defined to date. The aim of this retrospective study was to define, in a series of completely resected EP-NETs, the recurrence-free survival (RFS) rate and a risk score for disease recurrence. This was a multicenter retrospective analysis of sporadic pancreatic NETs (PanNETs) or small intestine NETs (SiNETs) [G1/G2] that underwent R0/R1 surgery (years 2000-2016) with at least a 24-month follow-up. Survival analysis was performed using the Kaplan-Meier method and risk factor analysis was performed using the Cox regression model. Overall, 441 patients (224 PanNETs and 217 SiNETs) were included, with a median Ki67 of 2% in tumor tissue and 8.2% stage IV disease. Median RFS was 101 months (5-year rate 67.9%). The derived prognostic score defined by multivariable analysis included prognostic parameters, such as TNM stage, lymph node ratio, margin status, and grading. The score distinguished three risk categories with a significantly different RFS (p<0.01). Approximately 30% of patients with EP-NETs recurred within 5 years after radical surgery. Risk factors for recurrence were disease stage, lymph node ratio, margin status, and grading. The definition of risk categories may help in selecting patients who might benefit from adjuvant treatments and more intensive follow-up programs.

Arterial function, biomarkers, carcinoid syndrome and carcinoid heart disease in patients with small intestinal neuroendocrine tumours

PurposeCarcinoid heart disease (CHD) is a life-threatening complication of carcinoid syndrome (CS) characterised by tricuspid regurgitation (TR). However, there is an unmet need for earlier diagnosis of CHD. We cross-sectionally assessed the prevalence and potential predictive or diagnostic markers for CS and CHD in a contemporary cohort of patients with small intestinal neuroendocrine tumours (SI-NETs).MethodsBiochemical characteristics, hepatic tumour load, measures of arterial and endothelial function, atherosclerosis, and transthoracic echocardiography were analysed in a prospective cross-sectional setting.ResultsAmong the 65 patients studied, 29 (45%) had CS (CS+ ), and 3 (5%) CHD. CS+ was characterised by significantly higher hepatic tumour load, S-5-HIAA and fP-CgA, higher frequency of diarrhoea and flushing, and more frequent PRRT compared to CS− (for all, P < 0.05). Central systolic, central mean, and central end-systolic blood pressures were significantly higher in CS+ than in CS− (for all, P < 0.05). Subjects with grades 2–4 TR had higher hepatic tumour burden, fP-CgA, and S-5-HIAA compared to those with grades 0–1 TR, but measures of vascular function did not differ. fP-CgA (P = 0.017) and S-5-HIAA (P = 0.019) but not proBNP increased significantly according to the severity of TR.ConclusionAlthough CS is common, the prevalence of CHD was found to be lower in a contemporary cohort of SI-NET patients than previously anticipated. Measures of arterial or endothelial function or carotid atherosclerosis do not identify subjects with mild TR. Echocardiography remains the most sensitive means to diagnose CHD in CS patients with high tumour burden and elevated CgA and 5-HIAA.

Cutting-Edge Imaging of Cardiac Metastases from Neuroendocrine Tumors: Lesson from a Case Series

With the increasing availability of high-performance medical imaging for the management of patients with neuroendocrine tumors (NETs), a progressive growth of asymptomatic and incidentally detected cardiac metastases (CMs) has been observed in the recent years. In clinical practice, CMs of NENs are often incidentally detected by whole-body 68Ga-labeled somatostatin analogs or 18F-fluorodihydroxyphenylalanine positron emission tomography/computed tomography, and afterwards accurately characterized by cardiac magnetic resonance (CMR) and/or gated cardiac computed tomography when CMR is contraindicated or not available. The interpreting physician should familiarize with the main imaging features of CM, a finding that may be encountered in NETs patients more than previously thought. Herein, we present a case series of four patients with CMs from small-intestine NETs highlighting strengths and weaknesses of a multimodality imaging approach in clinical practice.

Management of neuroendocrine neoplasms: conformity with guidelines in and outside a center of excellence.

PurposeTo improve neuroendocrine neoplasm (NEN) management, the European Neuroendocrine Tumor Society (ENETS) recognised 62 Centers of Excellence (CoE). This retrospective study compares conformity of patients’ initial management within vs outside an ENETS CoE with clinical practice guidelines (CPGs).MethodsPatients diagnosed with a NEN between August 2018 and July 2020 and presented in the Lyon-CoE Multidisciplinary Tumour Board (MDT) were included. Factors potentially associated with the conformity of initial management (work-up and first treatment) to CPG underwent univariate and multivariate analyses.ResultsAmong the 615 included patients, 170 (27.6%) were initially managed in the CoE and 445 (72.4%) were only presented at the CoE-MDT. Patients in the CoE group more often had intestinal or pancreatic primaries, metastatic disease (61.8% vs 33%), hereditary syndrome, and a functioning tumour. Work-up conformity was 37.1% in the CoE (vs 29.9%, P = 0.09); this was 95.8% for the first treatment (vs 88.7%, P = 0.01). After multivariate analysis, CPG conformity was significantly higher for patients managed in the CoE, for younger patients, for those having a grade 1–2 tumour, and a genetic syndrome. Pancreatic and small intestinal (SI) NET surgeries performed in the CoE had a higher splenic preservation rate during left pancreatectomy, better detection of multiple tumours in SI surgeries, and higher number of resected lymph nodes.ConclusionsGiven the widespread observance of CPG, not all patients require management in the CoE. Referral should be considered for more complex cases such as metastatic diseases, G2 tumours, or carcinoid syndromes. Finally, we should encourage the centralization of NET surgery.

Survival According to Therapy Regimen for Small Intestinal Neuroendocrine Tumors

Introduction: Scarce data exist for therapy regimens other than somatostatin analogues (SSA) and peptide receptor radiotherapy (PRRT) for siNET. We analyzed real world data for differences in survival according to therapy. Patients and methods: Analysis of 145 patients, diagnosed between 1993 and 2018 at a single institution, divided in treatment groups. Group (gr.) 0: no treatment (n = 10), gr 1: TACE and/or PRRT (n = 26), gr. 2: SSA (n = 32), gr. 3: SSA/PRRT (n = 8), gr. 4: chemotherapy (n = 8), gr. 5: not metastasized (at diagnosis), surgery only (n = 53), gr. 6 = metastasized (at diagnosis), surgery only (n = 10). Results: 45.5% female, median age 60 years (range, 27–84). A total of 125/145 patients with a resection of the primary tumor. For all patients, 1-year OS (%) was 93.8 (95%-CI: 90–98), 3-year OS = 84.3 (CI: 78–90) and 5-year OS = 77.5 (CI: 70–85). For analysis of survival according to therapy, only stage IV patients (baseline) that received treatment were included. Compared with reference gr. 2 (SSA only), HR for OS was 1.49 (p = 0.47) for gr. 1, 0.72 (p = 0.69) for gr. 3, 2.34 (p = 0.19) for gr. 4. The 5 y OS rate of patients whose primary tumor was resected (n = 125) was 73.1%, and without PTR was 33.3% (HR: 4.31; p = 0.003). Individual patients are represented in swimmer plots. Conclusions: For stage IV patients in this analysis (limited by low patient numbers in co. 3/4), multimodal treatment did not significantly improve survival over SSA treatment alone. A resection of primary tumor significantly improves survival.

Concept of reintervention with thorough lymphadenectomy after suboptimal resection of small-intestine neuroendocrine neoplasms: A multicentre preliminary study.

Complete surgical resection is the only hope to cure small intestine neuroendocrine neoplasms (SiNENs). However, inadequate lymphadenectomy or entire small bowel palpation for multiple primary tumours renders at least 20% of resections suboptimal. This study was undertaken to investigate reintervention outcomes after initial suboptimal resections (ISORs), and agreement between residual tumour identification on interval imaging and during reintervention. This retrospective, multicentre study included all patients undergoing reintervention within 18 months post ISOR. Disease-free survival (DFS) was defined as the time from reintervention resection date to recurrence or any-cause of death. The kappa coefficient assessed agreement rates between suspected residual tumour on interval imaging and its presence at reintervention. A total of 21 patients underwent reintervention for nonmetastatic SiNENs (median follow-up 2.3 [IQR 0.6-3.75] years). Residual tumour, suspected in 17/21 (81%) patients based on interval imaging, was found in 20/21 (95%) during reintervention. Interval imaging-intraoperative detection agreement was fair for residual primary tumours (kappa=0.28, 95% CI: 0.05-0.62; p= .09) and residual lymph node metastases (kappa=0.17, 95% CI: 0.28-0.62; p= .45). Reintervention achieved complete tumour clearance in 16/21 (76%) patients, among whom 5/16 (31%) developed liver metastases during follow-up. Median DFS was 70.6months (IQR 39.7-not reached). Reintervention post-ISOR can obtain tumour clearance and prolonged remission. It should be systematically discussed after suspected ISOR, even when postoperative imaging does not find any residual tumour. To maximize detection of potentially resectable residual disease, imaging modalities after "curative" surgery should be redefined.

Prevalence of malnutrition and nutrition-related complications in patients with gastroenteropancreatic neuroendocrine tumours.

Cross-sectional studies report that up to 25% of people with gastroenteropancreatic neuroendocrine tumours (GEP NET) are malnourished. However, the changes in nutritional status and dietary intake over time are unknown. The present study aimed to comprehensively describe the impact of a GEP NET on nutritional status and quality of life (QOL). Patients diagnosed with a GEP NET were recruited to this prospective longitudinal study on initial attendance to the NET Unit at two tertiary hospitals in Melbourne (VIC, Australia). Patient self-reported QOL measures (European Organisation for Research and Treatment Cancer QLC-C30 and QLC-GINET21) and nutritional outcomes (nutritional status, weight change, fat-free mass [FFM], dietary change, dietitian contact) were collected bi-monthly for six months. Sixty-one patients were recruited (66% male) with a mean ± SD age of 62 ± 12 years, predominantly diagnosed with small intestinal NET and Grade 1/2 disease. Commonly reported symptoms were fatigue (79%), abdominal discomfort (75%) and pain (68%). More patients were malnourished at baseline than at 6 months (29% vs. 13%). Over this 6months, 48% lost weight, 20% lost ≥ 5% of their body weight, and 62% lost FFM with an average FFM loss of 2.8kg (95% confidence interval=2.0, 3.6), consistent with altered body composition. Dietary change was reported by 56% at baseline and 53% at six months, but only 21% consulted a dietitian at baseline and 18% at 6 months. Clinically significant loss of weight and FFM affected many patients with a GEP NET; however, few patients were referred to/or received a consultation with a dietitian. Valid screening practices are needed to identify weight loss and nutrition issues in GEP NET patients, and to facilitate referral to dietitian services.

Mismatch repair deficiency and MUTYH variants in small intestine-neuroendocrine tumors

Small intestine-neuroendocrine tumors (SI-NETs) are one of the most common tumors of the small bowel. Despite an increasing incidence, the exact mechanisms driving underlying pathology remain to be determined. Interestingly, recent studies linked the development of (SI-)NETs to both Lynch syndrome (LS) and MUTYH variants. If confirmed, these associations would have important consequences for treatment. In this study we therefore investigated the prevalence of mismatch repair (MMR) deficiency and MUTYH variants in 64 primary resected SI-NETs. Immunohistochemistry was used to assess the expression of the MMR genes, and competitive allele-specific PCR (KASPar) targeting two hotspot MUTYH variants [p.(Tyr179Cys), p.(Gly396Asp)] was performed to determine their prevalence in SI-NETs. Strikingly, all 64 SI-NETs stained positive for MSH6 and PMS2, indicating MMR proficiency. In addition, no MUTYH hotspot variant was found in any of the 64 SI-NETs. As such, these results do not support an association between SI-NET development and LS or MUTYH variants. In order to gain insight into SI-NET pathogenesis and optimally manage patients, future research should therefore focus on other candidate genes.

Orbital Metastasis: A Rare but Typical Location of Small Intestine Neuroendocrine Tumor on 18F-FDOPA PET/CT.

Orbital foci of increased uptake are sometimes visualized on 18F-FDOPA PET/CT, but the literature remains poor as to their nature. The orbit is indeed a rare site of metastatic involvement. Given this low probability of metastatic location, the question of an incidental benign finding may arise. We reviewed all 18F-FDOPA PET/CT examinations performed at our institution between January 2015 and May 2021: 4/149 patients presented at least 1 orbital focus of increased uptake, all of them presented a metastatic small intestine neuroendocrine tumor. Somatostatin receptor expression was confirmed using 68Ga-DOTATOC PET/CT supporting the hypothesis of genuine metastases.

Systematic Evaluation of the Immune Environment of Small Intestinal Neuroendocrine Tumors.

The immune tumor microenvironment and the potential therapeutic opportunities for immunotherapy in small intestinal neuroendocrine tumors (siNET) have not been fully defined. Herein, we studied 40 patients with primary and synchronous metastatic siNETs, and matched blood and normal tissue obtained during surgery. We interrogated the immune checkpoint landscape using multi-parametric flow cytometry. In addition, matched FFPE tissue was obtained for multi-parametric IHC to determine the relative abundance and distribution of T-cell infiltrate. Tumor mutational burden (TMB) was also assessed and correlated with immune infiltration. Effector tumor-infiltrating lymphocytes (TIL) had a higher expression of PD-1 in the tumor microenvironment compared with the periphery. In addition, CD8+ TILs had a significantly higher co-expression of PD-1/ICOS and PD-1/CTLA-4 (cytotoxic T lymphocyte antigen-4) and higher levels of PD-1 expression compared with normal tissue. IHC revealed that the majority of cases have ≤10% intra-tumoral T cells but a higher number of peri-tumoral T cells, demonstrating an "exclusion" phenotype. Finally, we confirmed that siNETs have a low TMB compared with other tumor types in the TCGA database but did not find a correlation between TMB and CD8/Treg ratio. Taken together, these results suggest that a combination therapy approach will be required to enhance the immune response, using PD-1 as a checkpoint immunomodulator backbone in combination with other checkpoint targeting molecules (CTLA-4 or ICOS), or with drugs targeting other pathways to recruit "excluded" T cells into the tumor microenvironment to treat patients with siNETs.

Aberrant tryptophan metabolism in stromal cells is associated with mesenteric fibrosis in small intestinal neuroendocrine tumors.

BackgroundIncreased levels of serotonin secretion are associated with mesenteric fibrosis (MF) in small intestinal neuroendocrine tumors (SI-NETs). However, the profibrotic potential of serotonin differs between patients, and in this study, we aimed to gain an understanding of the mechanisms underlying this variability. To this end, we analyzed the proteins involved in tryptophan metabolism in SI-NETs.MethodsProteomes of tumor and stroma from primary SI-NETs and paired mesenteric metastases of patients with MF (n = 6) and without MF (n = 6) were identified by liquid chromatography–mass spectrometry (LC-MS). The differential expression of proteins involved in tryptophan metabolism between patients with and without MF was analyzed. Concurrently, monoamine oxidase A (MAO-A) expression was analyzed in the tumor and stromal compartment by immunohistochemistry (IHC) and reported as intensity over area (I/A).ResultsOf the 42 proteins involved in tryptophan metabolism, 20 were detected by LC-MS. Lower abundance of ten proteins was found in mesenteric metastases stroma in patients with MF. No differential expression was found in primary SI-NETs. In patients with MF, IHC showed lower MAO-A expression in the stroma of the primary SI-NETs (median 4.2 I/A vs 6.5 I/A in patients without MF, P = 0.003) and mesenteric metastases (median 2.1 I/A vs 2.8 I/A in patients without MF, P= 0.019).ConclusionWe found a decreased expression of tryptophan and serotonin-metabolizing enzymes in the stroma in patients with MF, most notably in the mesenteric stroma. This might account for the increased profibrotic potential of serotonin and explain the variability in the development of SI-NET-associated fibrotic complications.

Long-term survival of metastatic small intestine neuroendocrine tumors: a meta-analysis.

This meta-analysis aims to evaluate the long-term survival and prognostic factors in patients with metastatic small intestine neuroendocrine tumors (siNETs). Patients with siNETs usually present with advanced disease, limiting curative treatment options. The overall survival seems favorable compared to other cancers, but differences in terminology, lack of consistent coding, conflicting results from smaller cohorts, and recent developments of new treatment options make (reliable) survival data difficult to achieve. Nevertheless, accurate survival data are essential for many facets of health care. A systematic literature search was performed using MEDLINE®(PubMed), EMBASE®, Web of Science, and Cochrane Library up to June 30, 2021. Studies were included if the overall survival data in patients with metastatic siNETs were reported. The results were pooled in a random-effects meta-analysis and are reported as hazard ratios and 95% CIs. Subgroup analyses and meta-regression were performed to assess the observed heterogeneity and the impact of important prognostic factors. After screening 9065 abstracts, there were 23 studies, published between 1995 and 2021, that met the inclusion criteria, with a total of 8636 patients. The weighted 5- and 10-year overall survival was 67 and 37%, respectively. Meta-regression identified younger age and primary tumor resection to be associated with better prognosis. Subgroup analyses showed similar results. This study confirms that in an advanced, metastatic setting, the weighted 5- and 10-year overall survival reveal a favorable prognosis, improving over the last few decades. Meta-regression showed that age at diagnosis is an important prognostic factor.

Predicting resectability of primary tumor and mesenteric lymph-node masses in patients with small-intestine neuroendocrine tumors.

Vascular infiltration may jeopardize resection of the primary tumor and mesenteric metastatic masses in small-intestine neuroendocrine tumors (SI-NETs). However, other factors may play a role in predicting resectability. After computed tomography (CT) scan, three radiological parameters were considered: (1) degree of superior mesenteric artery involvement (SMA) according to a previous classification (2) degree of superior mesenteric venous involvement (SMV) as either absent, peripheral or proximal (3) presence or not of mesenteric fibrosis retraction (MF). Pre-surgical parameters were matched to surgical outcome. Forty-nine consecutive patients were submitted to laparotomy. Of them, 37 had complete primary tumor and mesenteric masses resection. SMA (p = 0.001), SMV (p = 0.008), metastasis site (p = 0.001) and MF (p < 0.001) were all significantly associated with the likelihood to receive resection at univariate analysis. All the five patients with infiltration of SMV proximal to middle colic vein were unresectable. At multivariable analysis excluding SMA stage, the absence of MF (HR 13.1, I.C. 1.44-119; p = 0.002) was the only factor associated with the likelihood to receive primary tumor and mesentery radical surgery. SMA stage 3-up and/or signs of MF, as well as infiltration of SMV proximal to middle colic vein at CT scan are predictive of operative failure in patients with SI-NETs. The assessment of such factors should be always considered in the decision-making process of such patients especially in those with asymptomatic disease with synchronous unresectable liver metastases.

Performances of 18F-FDOPA PET/CT in the Preoperative Evaluation of the Peritoneal Cancer Index in Small Intestine Neuroendocrine Tumors.

Peritoneal carcinomatosis (PC) concerns up to 30% of patients with a neuroendocrine tumor (NET), especially of the small intestine. Aggressive management of carcinomatosis seems to be justified, especially with regard to possible mechanical complications. 18F-FDOPA PET/CT is known to be the most sensitive imaging modality for the detection of small bowel NET metastases, yet its performance in the detection of PC is not well studied. The main objective of our study is to evaluate the performances of preoperative 18F-FDOPA PET/CT in the prediction of surgical peritoneal cancer index. All patients referred to our center for an 18F-FDOPA PET/CT from October 2017 to January 2021 were retrospectively screened. Images were analyzed by a blinded nuclear medicine physician, and peritoneal abnormalities were reported to comply with the surgical peritoneal cancer index standard. Per patient analysis and per region analysis were then conducted. Thirty-three patients were included; 6 patients (35 regions) presented a peritoneal carcinosis. Peritoneal Carcinomatosis Index (PCI) estimated on 18F-FDOPA PET/CT was significantly and strongly correlated to surgical PCI (r = 0.96, P < 0.001). Patient-based sensitivity, specificity, negative predictive value, and positive predictive value for 18F-FDOPA PET/CT were 100%, 93%, 100%, and 75%, respectively. The agreement between 18F-FDOPA and surgery regarding PC was excellent (Cohen κ = 0.82 on per patient analysis, 0.74 on per region analysis). A preoperative estimation of PCI is achievable based on 18F-FDOPA PET/CT for small intestine NET and could allow to optimize surgical procedures and patient selection.

Heterogeneity of Small Intestinal Neuroendocrine Tumors Metastasis: Biologic Patterns of a Series with Virchow's Node Involvement.

Simple SummaryVirchow’s node metastasis (VM) refers to the involvement of the left supraclavicular lymph nodes at the junction of the thoracic duct and the left subclavian vein. Generally, VM is considered by clinicians to be a strong indicator of metastatic abdominal malignancy, and its dismal prognostic significance has previously been described in patients with metastatic gastric and ovarian cancer. To date, comprehensive descriptions of patients with small intestinal neuroendocrine tumors (SI-NETs) and rare metastatic manifestations, including that of VM, are sparse. In the present study from two tertiary referral centers, the prevalence of the VM secondary to SI-NET primaries was found to be 3.9%. VM was more often encountered in patients with higher-grade tumors and established disseminated disease to distant para-aortic lymph nodes. However, the presence of VM did not yield any negative prognostic impact in patient outcomes when compared to age- and sex-matched patients of similar grade with distant metastases confined in the abdomenSmall intestinal neuroendocrine tumors (SI-NETs) may rarely metastasize to the left supraclavicular lymph nodes, also known as Virchow’s node metastasis (VM). Data on prevalence, prognostic significance, and clinical course of disease for SI-NET patients with VM is limited. In this retrospective analysis of 230 SI-NET patients treated at two tertiary referral centers, we found nine patients with VM (prevalence 3.9%). Among those, there were 5 females and median age at SI-NET and VM diagnosis was 61 and 65 years, respectively. Two patients had G1 tumors and five G2, while two tumors were of unspecified grade (median Ki67: 7%, range 2–15%). Four patients presented with synchronous VM, whereas five developed metachronous VM after a median of twenty-four months (range: 4.8–117.6 months). Hepatic metastases were present in seven patients, extrahepatic metastases (EM) in eight (six para-aortic distant lymph node metastases, one lung and one pancreatic metastasis), whereas peritoneal carcinomatosis (PC) in two patients. We used a control group of 18 age- and sex-matched SI-NET patients from the same cohort with stage IV disease but no extra-abdominal metastases. There was no difference in best-recorded response to first line treatment according to RECIST 1.1 as well as progression-free survival (PFS) between patients with VM and those in the control group (Chi-square test p = 0.516; PFS 71.7 vs. 106.9 months [95% CI 38.1–175.8]; log-rank p = 0.855). In addition, median overall survival (OS) of SI-NET patients with VM did not differ from those in the control group (138.6 [95% CI 17.2–260] vs. 109.9 [95% CI 91.7–128] months; log-rank p = 0.533). In conclusion, VM, although relatively rare in patients with SI-NETs, is more often encountered in patients with G2 tumors and established distant para-aortic lymph node metastases. The presence of VM in SI-NET patients does not seem to impact patients’ survival outcomes and treatment responses, when compared to age- and sex-matched SI-NET patients with stage IV disease confined in the abdomen.