Cell-Free DNA and Clinical Characteristics in Patients with Small Intestinal or Pancreatic Neuroendocrine Tumors.

INTRODUCTION: Neuroendocrine tumors (NETs) are rare and characterized by a heterogeneous clinical course and an unmet need for better prognostic markers. Plasma cell-free DNA (cfDNA) has prognostic value in other malignancies but is not previously investigated in NETs. We studied cfDNA levels in patients with mainly low-grade small intestinal NET -(siNET) or pancreatic NET (pNET) and evaluated the prognostic potential of cfDNA. MATERIALS AND METHODS: We included 70 NET patients, siNET (n = 50) and pNET (n = 20). Plasma cfDNA levels were determined by droplet digital PCR for the beta-2-microglobulin gene every 6 months during a period of 3 years, including in a subgroup of 19 patients during peptide receptor radionuclide therapy (PRRT) therapy. RESULTS: cfDNA levels were higher in both siNET and pNET compared to a previously established healthy cohort (p < 0.0001). -cfDNA levels did not predict overall survival (crude hazard ratio [HR] 0.95 [0.57-1.58], p = 0.837, adjusted for smoking status HR 0.77 [0.51-1.17], p = 0.22). The impact of cfDNA level on progression-free survival showed different trends in siNET and pNET. There was no effect of PRRT treatment on cfDNA levels and no difference in cfDNA levels between patients with and without progressive disease after PRRT (ANOVA p = 0.66). cfDNA levels were significantly higher in never-smokers and previous smokers than in current smokers (p = 0.029). DISCUSSION/CONCLUSION: cfDNA levels are higher in NET patients than in healthy controls; however, there was no association with prognosis, and cfDNA levels were unaffected by PRRT. Our observations suggest that cfDNA levels are not associated with the disease course in low-grade NET in contrast to other malignancies.

Neuropilin-2 contributes to tumor progression in preclinical models of small intestinal neuroendocrine tumors.

The identification of novel regulators of tumor progression is a key challenge to gain knowledge on the biology of small intestinal neuroendocrine tumors (SI-NETs). We recently identified the loss of the axon guidance protein semaphorin 3F as a protumoral event in SI-NETs. Interestingly the expression of its receptor neuropilin-2 (NRP-2) was still maintained. This study aimed at deciphering the potential role of NRP-2 as a contributor to SI-NET progression. The role of NRP-2 in SI-NET progression was addressed using an approach integrating human tissue and serum samples, cell lines and in vivo models. Data obtained from human SI-NET tissues showed that membranous NRP-2 expression is present in a majority of tumors, and is correlated with invasion, metastatic abilities, and neovascularization. In addition, NRP-2 soluble isoform was found elevated in serum samples from metastatic patients. In preclinical mouse models of NET progression, NRP-2 silencing led to a sustained antitumor effect, partly driven by the downregulation of VEGFR2. In contrast, its ectopic expression conferred a gain of aggressiveness, driven by the activation of various oncogenic signaling pathways. Lastly, NRP-2 inhibition led to a decrease of tumor cell viability, and sensitized to therapeutic agents. Overall, our results point out NRP-2 as a potential therapeutic target for SI-NETs, and will foster the development of innovative strategies targeting this receptor. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The Lymph Node Ratio Optimizes Staging in Patients with Small Intestinal Neuroendocrine Tumors.

BACKGROUND: The effectiveness of the current Tumor, Lymph node, Metastases (TNM) staging system in small intestinal neuroendocrine tumors (SiNETs) is unsatisfactory. Current N classification only distinguishes between node-negative and node-positive status. We aim to refine the N classification for updated TNM stage. METHODS: During the period from 1988 to 2012, patients with non-metastatic -SiNETs were enrolled in the Surveillance, Epidemiology, and End Results database. Using the X-tile program, we calculated an optimal cutoff value for lymph node ratio (LNR) and proposed a novel Nr category. Survival outcomes were estimated using the Kaplan-Meier method and Cox regression model. Adjusted hazard ratio (HR) and cluster analysis were performed to differentiate TNrM stages. RESULTS: Patients with existing TNM stage I and II had equivalent survival prognosis (p = 0.214). Current N classification was not a significant predictor of patient survival (p = 0.372). Multivariate analyses identified the revised Nr classification, based on LNR of 0.6 optimal cutoff value, as an independent prognostic factor (p = 0.020). By incorporating the Nr classification, a revised TNrM, which categorized patients into 3 new stages was proposed: stage I (T1-2Nr0-1), stage II (T3Nr0-1), and stage III (TxNr2 or T4Nrx). TNrM stage had better stratification according to the survival outcome (primary cohort: stage I: reference, II: HR 3.852, 95% CI 1.731-8.575; III: HR 7.169, 95% CI 3.220-15.963, p < 0.001; validation cohort: stage I: reference, II: HR 2.034; III: HR 3.815; p < 0.001). CONCLUSIONS: The Nr classification more accurately stratifies SiNET patients than current N classification. The new TNrM staging system could improve the ability to predict survival outcome of SiNET patients.

Emergency surgery influences oncological outcome in small intestinal neuroendocrine tumors.

BACKGROUND AND AIMS: Patients with small intestinal neuroendocrine tumors (siNETs) frequently present emergently due to bowel ischemia or bowel obstruction. The influence of emergency surgery on the prognosis of siNET remains controversial. The aim of this study was to investigate the association between type of presentation (emergency/elective) and oncological outcome. METHODS: Clinicopathological data of patients who underwent bowel resection and were treated due to siNET at the Charité - Universitätsmedizin Berlin, Germany were analyzed retrospectively. RESULTS: A total of 165 patients underwent bowel resection for siNET. Of these, 22.4% (n = 37) were emergency and 77.6% (n = 128) were elective procedures. A preoperative known diagnosis was less common in patients with emergency surgery (48.6% vs 85.2%; p < 0.001) and complete resections of all tumor manifestations were performed less often (32.4% vs 50.8%; p = 0.049), while more completion operations had to be performed (24.3% vs 11.1%; p = 0.049). Overall survival (OS) and progression-free survival (PFS) of emergently operated patients were reduced (5-year OS: 85.2% vs 89.5% (p = 0.023); 5-year PFS: 26.7% versus 52.5% (p = 0.018)). In addition, emergency surgery was negatively associated with OS after multivariable regression analysis. CONCLUSION: Emergency surgery in siNET patients is associated with adverse oncological outcomes including shorter OS and PFS. Prevention of emergency conditions should be emphasized in advanced disease.

Influence of Lymphatic, Microvascular and Perineural Invasion on Oncological Outcome in Patients with Neuroendocrine Tumors of the Small Intestine.

For the histopathological work-up of resected neuroendocrine tumors of the small intestine (siNET), the determination of lymphatic (LI), microvascular (VI) and perineural (PnI) invasion is recommended. Their association with poorer prognosis has already been demonstrated in many tumor entities. However, the influence of LI, VI and PnI in siNET has not been sufficiently described yet. A retrospective analysis of all patients treated for siNET at the ENETS Center of Excellence Charité-Universitätsmedizin Berlin, from 2010 to 2020 was performed (n = 510). Patients who did not undergo primary resection or had G3 tumors were excluded. In the entire cohort (n = 161), patients with LI, VI and PnI status had more distant metastases (48.0% vs. 71.4%, p = 0.005; 47.1% vs. 84.4%, p < 0.001; 34.2% vs. 84.7%, p < 0.001) and had lower rates of curative surgery (58.0% vs. 21.0%, p < 0.001; 48.3% vs. 16.7%, p < 0.001; 68.4% vs. 14.3%, p < 0.001). Progression-free survival was significantly reduced in patients with LI, VI or PnI compared to patients without. This was also demonstrated in patients who underwent curative surgery. Lymphatic, vascular and perineural invasion were associated with disease progression and recurrence in patients with siNET, and these should therefore be included in postoperative treatment considerations.

Evaluation of a blood miRNA/mRNA signature to follow-up Lu-PRRT therapy for G1/G2 intestinal neuroendocrine tumors.

Background: 177Lu-oxodotreotide peptide receptor therapy (LuPRRT) is an efficient treatment for midgut neuroendocrine tumors (NETs) of variable radiological response. Several clinical, biological, and imaging parameters may be used to establish a relative disease prognosis but none is able to predict early efficacy or toxicities. We investigated expression levels for mRNA and miRNA involved in radiosensitivity and tumor progression searching for correlations related to patient outcome during LuPRRT therapy. Methods: Thirty-five patients received LuPRRT for G1/G2 midgut NETs between May 2019 and September 2021. Peripheral blood samples were collected prior to irradiation, before and 48 h after the second and the fourth LuPRRT, and at 6-month follow-up. Multiple regression analyses and Pearson correlations were performed to identify the miRNA/mRNA signature that will best predict response to LuPRRT. Results: Focusing on four mRNAs and three miRNAs, we identified a miRNA/mRNA signature enabling the early identification of responders to LuPRRT with significant reduced miRNA/mRNA expression after the first LuPRRT administration for patients with progressive disease at 1 year (p < 0.001). The relevance of this signature was reinforced by studying its evolution up to 6 months post-LuPRRT. Moreover, nadir absolute lymphocyte count within the first 2 months after the first LuPRRT administration was significantly related to low miRNA/mRNA expression level (p < 0.05) for patients with progressive disease. Conclusion: We present a pilot study exploring a miRNA/mRNA signature that correlates with early hematologic toxicity and therapeutic response 12 months following LuPRRT. This signature will be tested prospectively in a larger series of patients.

Identification of TIMP1-induced dysregulation of epithelial-mesenchymal transition as a key pathway in inflammatory bowel disease and small intestinal neuroendocrine tumors shared pathogenesis.

Inflammatory Bowel Disease (IBD) is believed to be a risk factor for Small Intestinal Neuroendocrine Tumors (SI-NET) development; however, the molecular relationship between IBD and SI-NET has yet to be elucidated. In this study, we use a systems biology approach to uncover such relationships. We identified a more similar transcriptomic-wide expression pattern between Crohn's Disease (CD) and SI-NET whereas a higher proportion of overlapping dysregulated genes between Ulcerative Colitis (UC) and SI-NET. Enrichment analysis indicates that extracellular matrix remodeling, particularly in epithelial-mesenchymal transition and intestinal fibrosis mediated by TIMP1, is the most significantly dysregulated pathway among upregulated genes shared between both IBD subtypes and SI-NET. However, this remodeling occurs through distinct regulatory molecular mechanisms unique to each IBD subtype. Specifically, myofibroblast activation in CD and SI-NET is mediated through IL-6 and ciliary-dependent signaling pathways. Contrarily, in UC and SI-NET, this phenomenon is mainly regulated through immune cells like macrophages and the NCAM signaling pathway, a potential gut-brain axis in the context of these two diseases. In both IBD and SI-NET, intestinal fibrosis resulted in significant metabolic reprogramming of fatty acid and glucose to an inflammatory- and cancer-inducing state. This altered metabolic state, revealed through enrichment analysis of downregulated genes, showed dysfunctions in oxidative phosphorylation, gluconeogenesis, and glycogenesis, indicating a shift towards glycolysis. Also known as the Warburg effect, this glycolytic switch, in return, exacerbates fibrosis. Corresponding to enrichment analysis results, network construction and subsequent topological analysis pinpointed 7 protein complexes, 17 hub genes, 11 microRNA, and 1 transcription factor related to extracellular matrix accumulation and metabolic reprogramming that are candidate biomarkers in both IBD and SI-NET. Together, these biological pathways and candidate biomarkers may serve as potential therapeutic targets for these diseases.

Does the dose matter? Antiproliferative efficacy and toxicity of everolimus in patients with neuroendocrine tumors - Experiences from a tertiary referral center.

The mTOR-inhibitor everolimus has been approved for the treatment of advanced neuroendocrine tumors (NETs) but is associated with relevant toxicities in clinical practice. Hence, optimal treatment sequencing and the impact of dose reductions have yet to be clarified. This retrospective analysis assessed patients with advanced, well-differentiated NET treated with everolimus at the Medical University of Vienna. The primary objective was to evaluate the efficacy of everolimus in a real-world cohort. A total of 52 patients treated with everolimus for advanced NET grade 1 (G1) or G2 (or typical or atypical carcinoid) 2010-2021 were included in this analysis. The most common sites of origin were pancreas (44%) and lung (29%). The initial dose was decided by the treating physician based on clinical assessment and 25 patients (48%) each were started at 10 mg/day and 5 mg/day. Median progression-free survival (PFS) following everolimus in the overall cohort was 9.8 months (95% CI: 4.3-15.3), with a statistically significant PFS difference (p = .03) between NET G1/typical carcinoids (42.9 months) and NET G2/atypical carcinoids (8.9 months). PFS was numerically but not significantly shorter in patients treated with a reduced dose (7.5 months vs. 12.4 months, p = .359). Even in this mixed full/half dose cohort, 93% developed treatment-related side effects (mostly grade I, no grade IV), 63% had dose reductions or interruptions, and five stopped due to toxicity. Median survival following treatment was 40.9 months (95% CI: 21.5-60.3) and no difference with regard to dosing was observed (p = .517). These data from an unselected patient cohort show long-term outcomes similar to those reported in the pivotal studies. Comparing everolimus starting dose, median PFS did not significantly differ for patients treated at a lower dose. While this finding is limited by the sample size and warrants prospective verification, initiating therapy at a reduced dose might be practicable and safe in a distinct subset of patients.

Urinary 5-Hydroxyindolacetic Acid Measurements in Patients with Neuroendocrine Tumor-Related Carcinoid Syndrome: State of the Art.

Carcinoid syndrome (CS), mostly associated with small intestinal neuroendocrine tumors (SI-NETs) or lung-related NETs, is characterized by symptoms related to hormonal secretion and long-term complications, including carcinoid heart disease (CHD), which is potentially life-threatening. In the early stages of the disease, symptoms are non-specific, which leads to delayed diagnoses. The availability of reliable tumor markers is crucial for a prompt diagnosis and proper management. This review summarizes available evidence on the role of 24 h urinary 5-hydroxyindolacetic acid (24u5HIAA), which is the urinary breakdown metabolite of serotonin, in the diagnosis/follow-up of NET-related CS, with a focus on its potential prognostic role, while eventually attempting to suggest a timeline for its measurement during the follow-up of NET patients. The use of 24u5HIAA is an established biomarker for the diagnosis of NETs with CS since it shows a sensibility and specificity of 100% and 85-90%, respectively. The downside of 24u5-HIAA is represented by the need for 24 h urine collection and the risk of confounding factors (foods and medication), which might lead to false positive/negative results. Moreover, 24u5HIAA is useful in the follow-up of NETs with CS since a shorter double time correlates to a higher risk of disease progression/disease-specific mortality. Furthermore, an elevation in 24u5-HIAA is correlated with a dismal prognosis because it is associated with an increased likelihood of CHD development and disease progression/mortality. Other potentially interesting biochemical markers have been proposed, including plasmatic 5HIAA, although further standardization and prospective studies are required to define their role in the management of NETs. Meanwhile, 24u5HIAA remains the most accurate CS biomarker.

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

BACKGROUND & AIMS: Small 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. METHODS: This 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. RESULTS: A 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). CONCLUSIONS: The 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.

Association of lymph node metastases, grade and extent of mesenteric lymph node dissection in locoregional small intestinal neuroendocrine tumors with recurrence-free survival.

We aimed to assess the prognostic impact of tumor- and patient-related parameters in patients with stage I-III small intestinal neuroendocrine tumors (SI-NETs), who underwent locoregional resective surgery (LRS) with curative intent. We included 229 patients with stage I-III SI-NETs diagnosed from June 15, 1993, through March 8, 2021, identified using the SI-NET databases from five European referral centers. Mean ± SD age at baseline was 62.5 ± 13.6 years; 111/229 patients were women (49.3%). All tumors were well-differentiated; 160 were grade 1 (G1) tumors, 51 were G2, two were G3 and 18 tumors were of unspecified grade (median Ki-67: 2%, range 1%-50%). One-hundred and sixty-three patients (71.2%) had lymph node (LN) involvement. The median number of retrieved lymph nodes was 10 (0-63), whereas the median number of positive LNs was 2 (0-43). After a mean ± SD follow-up of 54.1 ± 64.1 months, 60 patients experienced disease recurrence at a median (range) of 36.2 (2.5-285.1) months. The 5- and 10-year recurrence-free survival (RFS) rates were 66.6% and 49.3% respectively. In univariable analysis, there was no difference in RFS and overall survival (OS) between LN-positive and LN-negative patients (log-rank, p = .380 and .198, respectively). However, in stage IIIb patients who underwent mesenteric lymph node dissection (MLND) with a minimum of five retrieved LN (n = 125), five or more LN metastases were associated with shorter RFS (median RFS [95% CI] = 107.4 [0-229.6] vs. 73.7 [35.3-112.1] months; log-rank, p = .048). In addition, patients with G2 tumors exhibited shorter RFS compared to patients with G1 tumors (median RFS [95% confidence interval (CI)] = 46.9 [36.4-57.3] vs. 120.7 [82.7-158.8] months; log-rank, p = .001). In multivariable Cox-regression RFS analysis in stage IIIb patients, the Ki-67 proliferation index (hazard ratio = 1.08, 95% CI = 1.035-1.131; p < .0001) and the number of LN metastases (hazard ratio = 1.06, 95% CI = 1.001-1.125; p = .047) were independent prognostic factors for RFS. In conclusion, LRS with a meticulous MLND and a minimum number of five harvested LNs appears to be critical in the surgical management of SI-NET patients with locoregional disease. In patients who underwent LRS and MLND, the Ki-67 proliferation index and the LN metastases count were independent predictors of RFS.

Whole genome sequencing reveals the independent clonal origin of multifocal ileal neuroendocrine tumors.

BACKGROUND: Small intestinal neuroendocrine tumors (SI-NETs) are the most common neoplasms of the small bowel. The majority of tumors are located in the distal ileum with a high incidence of multiple synchronous primary tumors. Even though up to 50% of SI-NET patients are diagnosed with multifocal disease, the mechanisms underlying multiple synchronous lesions remain elusive. METHODS: We performed whole genome sequencing of 75 de-identified synchronous primary tumors, 15 metastases, and corresponding normal samples from 13 patients with multifocal ileal NETs to identify recurrent somatic genomic alterations, frequently affected signaling pathways, and shared mutation signatures among multifocal SI-NETs. Additionally, we carried out chromosome mapping of the most recurrent copy-number alterations identified to determine which parental allele had been affected in each tumor and assessed the clonal relationships of the tumors within each patient. RESULTS: Absence of shared somatic variation between the synchronous primary tumors within each patient was observed, 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 observed potential loss-of-function gene alterations in TNRC6B, a candidate tumor suppressor gene in a small subset of ileal NETs. Furthermore, we show that multiple metastases in the same patient can originate from either one or several primary tumors. CONCLUSIONS: Our study demonstrates major genomic diversity among multifocal ileal NETs, highlighting the need to identify and remove all primary tumors, which have the potential to metastasize, and the need for optimized targeted treatments.

Multiple Small Intestinal Neuroendocrine Tumors With Findings of Intestinal Obstruction.

Carcinoid tumors are one of the most common types of small intestinal neuroendocrine tumors (SI-NETs). However, SI-NETs that manifest as subacute intestinal obstruction are extremely rare. The annual occurrence rate of jejuno-ileal NETs is 0.28-0.8 per 100,000 people. In this report, we describe a case of subacute intestinal obstruction due to a mid-ileal stricture. The patient underwent laparotomy after evaluation and investigation. Mid-ileal growth was noted, and small bowel resection was performed with primary end-to-end anastomosis. Postoperative histopathology revealed the growth to be a well-differentiated NET.

Gastrointestinal neuroendocrine tumors in 2020.

Gastrointestinal neuroendocrine tumors are rare slow-growing tumors with distinct histological, biological, and clinical characteristics that have increased in incidence and prevalence within the last few decades. They contain chromogranin A, synaptophysin and neuron-specific enolase which are necessary for making a diagnosis of neuroendocrine tumor. Ki-67 index and mitotic index correlate with cellular proliferation. Serum chromogranin A is the most commonly used biomarker to assess the bulk of disease and monitor treatment and is raised in both functioning and non-functioning neuroendocrine tumors. Most of the gastrointestinal neuroendocrine tumors are non-functional. World Health Organization updated the classification of neuroendocrine tumors in 2017 and renamed mixed adenoneuroendocrine carcinoma into mixed neuroendocrine neoplasm. Gastric neuroendocrine tumors arise from enterochromaffin like cells. They are classified into 4 types. Only type I and type II are gastrin dependent. Small intestinal neuroendocrine tumor is the most common small bowel malignancy. More than two-third of them occur in the terminal ileum within 60 cm of ileocecal valve. Patients with small intestinal neuroendrocrine tumors frequently show clinical symptoms and develop distant metastases more often than those with neuroendocrine tumors of other organs. Duodenal and jejuno-ileal neuroendocrine tumors are distinct biologically and clinically. Carcinoid syndrome generally occurs when jejuno-ileal neuroendocrine tumors metastasize to the liver. Appendiceal neuroendocrine tumors are generally detected after appendectomy. Colonic neuroendocrine tumors generally present as a large tumor with local or distant metastasis at the time of diagnosis. Rectal neuroendocrine tumors are increasingly being diagnosed since the implementation of screening colonoscopy in 2000. Gastrointestinal neuroendocrine tumors are diagnosed and staged by endoscopy with biopsy, endoscopic ultrasound, serology of biomarkers, imaging studies and functional somatostatin scans. Various treatment options are available for curative and palliative treatment of gastrointestinal neuroendocrine tumors.

Expression profiling of small intestinal neuroendocrine tumors identified pathways and gene networks linked to tumorigenesis and metastasis.

Small intestinal neuroendocrine tumors (SI-NETs) remain the most common subset in gastrointestinal neuroendocrine tumors and featured by aggressiveness. However, the molecular feature of SI-NETs remains largely unclear with key genes and pathways yet to be identified. The gene expression profile GSE65286 was retrieved for analysis. Artificial neural networks (ANNs) were constructed for the hub genes network models. A total of 613 differentially expressed genes (DEGs) were identified between normal (N) and primary tumor (T) groups, whereas 61 DEGs were identified between T and liver metastases (LM) groups. The top Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for the DEGs of N versus T were fat digestion and absorption pathway. For T versus LM the top KEGG pathways were complement and coagulation. In gene set enrichment analysis (GSEA), five gene sets, including Notch signaling, inflammatory response, coagulation, KRAS signaling, and allograft rejection were significantly enriched in the T group. The hub genes in the DEGs of T versus LM included albumin, fibrinogen gamma chain, alpha 2-HS glycoprotein, transferrin and GC, vitamin D binding protein. A distinct correlational alteration of hub genes was observed between T and LM groups. In ANN analysis, ALB and TF were the top predictors of metastasis. Moreover, the expression of ALB≤ showed the highest support to T whereas ALB>15.97 supports LM. TF≤7.54 showed the highest negative correlation to the T. This bioinformatics analysis provided insights on potential key pathways and genes networks involved in SI-NETs and established an ANN-based hub gene model for metastatic prediction.

Peritoneal Carcinomatosis in Well-Differentiated Small-Intestinal Neuroendocrine Tumors with Mesenteric Tumor Deposits.

OBJECTIVE: Well-differentiated small-intestinal neuroendocrine tumors (SI-NETs) tend to be biologically indolent. Despite this tendency, they have a predilection for metastasis. Peritoneal involvement is quite common as is unfortunately peritoneal carcinomatosis (PC). PC is a dreaded metastatic complication due to the significant morbidity it creates for patients as well as well as increasing their mortality risk. The risk factors for PC development in SI-NETs remain understudied; however, one such factor may be the presence of mesenteric tumor deposits (MTDs). METHODS: We performed a retrospective analysis on 208 well-differentiated SI-NET patient samples, the majority with mesenteric masses, from the pathology archives of Vanderbilt University Medical Center. We sought to explore whether MTD presence was associated with PC, what other patient determinants were associated with PC and prognostic implication of these determinants. RESULTS: Patients with MTDs had an OR of 3.9 (CI 1.6, 10.9) for PC compared to patients without MTDs in the analysis. Patients who developed PC fared more poorly than those who did not (p=0.044). CONCLUSION: Our analysis, to the best of our knowledge, is the first to demonstrate an association between MTD presence and PC in this patient subgroup. We believe this finding warrants prospective evaluation given the possible therapeutic implications of being able to stratify SI-NET patients by their risk for developing PC based upon MTD presence.

Survival and prognostic factors analysis of 151 intestinal and pancreatic neuroendocrine tumors: a single center experience.

BACKGROUND: Intestinal and pancreatic neuroendocrine tumors (IP-NETs) are rare tumors with heterogeneous outcomes. The aim of our study was to determine the clinical, therapeutic and pathological factors which impact the overall survival (OS) in IP-NETs. METHODS: All the patients diagnosed with IP-NETs at the Nantes University Hospital between October 1994 and October 2013 were retrospectively analysed. Patients with MEN-1 (Type 1 Multiple Endocrine Neoplasia) or Von Hippel-Lindau syndrome were excluded. Additionally, a prospective analysis of tumor grade (mitotic index and Ki67 index) was performed on tumor samples. OS was evaluated by Kaplan-Meier method and prognostic factors by log-rank test and Cox model. RESULTS: The study included 151 patients. Median age was 60 (range, 14-81). Primary tumor was pancreatic in 86 patients (56.95%) and intestinal in 65 patients (43.05%). Tumors were metastatic (synchronous or metachronous) in 72 patients (47.7%). The median OS was 157 months. For all IP-NETs, age >65 years (P<0.0001), Ki67 >5% (P=0.03), synchronous metastases (P=0.016), primary tumor size >25 mm (P=0.03) and emergency surgery (P=0.007) were independent poor prognostic factors. CONCLUSIONS: In this large series of patients with IP-NET, age >65 years, Ki67 >5%, primary tumor size >25 mm, synchronous metastases and emergency surgery for acute complications have been identified as independent poor prognostic factors.

Upfront surgery of small intestinal neuroendocrine tumors. Time to reconsider?

Small intestinal neuroendocrine tumors (SI-NETs) may demonstrate a widely variable clinical behavior but usually it is indolent. In cases with localized disease, locoregional resective surgery (LRS) is generally indicated with a curative intent. LRS of SI-NETs is also the recommended treatment when symptoms are present, regardless of the disease stage. Concerning asymptomatic patients with distant metastases, prophylactic LRS has been traditionally suggested to avoid possible future complications. Even the current European Neuroendocrine Tumor Society guidelines emphasize a possible effect of LRS in Stage IV SI-NETs with unresectable liver metastases. On the contrary, the 2017 National Comprehensive Cancer Network Guidelines on carcinoid tumors do not support the resection of a small, asymptomatic, relatively stable primary tumor in the presence of unresectable metastatic disease. Furthermore, a recent study revealed no survival advantage for asymptomatic patients with distant-stage disease who underwent upfront LRS. At the aforementioned paper, it was suggested that delayed surgery as needed was comparable with the upfront surgical approach in terms of postoperative morbidity and mortality, the length of the hospital stay and the rate of incisional hernia repairs but was associated with fewer reoperations for bowel obstruction. On the other hand, it is also important to note that some patients might benefit from a prophylactic surgical approach and our attention should focus on identifying this patient population.

The eye of the beholder: orbital metastases from midgut neuroendocrine tumors, a two institution experience.

BACKGROUND: Metastases to the orbit occur rarely in midgut neuroendocrine tumor (NET) patients with only 20 cases reported to date. Patients typically present with bilateral involvement of the recti muscles and experience symptoms such as diplopia, proptosis, and decreased vision. Although orbital MRI remains the gold standard for imaging orbital disease, many orbital lesions are now detected on somatostatin-receptor (SSTR) based imaging such as 68Ga-DOTATATE PET-CT. CASE PRESENTATIONS: Patient 1 is a 72 year-old female with a well-differentiated G3 ileal NET who was incidentally diagnosed with orbital metastases during a hospitalization for pre-septal cellulitis in 2018. Her disease has been controlled with capecitabine rather than local therapy. Patient 2 is a 68 year-old male with a G2 ileal NET who was diagnosed with orbital involvement after developing left peri-orbital swelling in 2017. He was found to have bilateral rectus muscle involvement and was treated with image-guided radiation therapy (IGRT) to both orbits and achieved disease control. Patient 3 is a 63 year-old female with a well-differentiated G3 ileal NET who was incidentally diagnosed with bilateral orbital masses in her recti after undergoing a 68Ga-DOTATATE PET-CT in 2015. She was asymptomatic initially however has now developed diplopia. She will be starting 177Lu-DOTATATE peptide radionuclide receptor therapy (PRRT) shortly. Patient 4 is a 72 year-old male with a grade 2 ileal NET who was incidentally diagnosed with a left lateral rectus metastasis in 2007. This was monitored via surveillance MRI until it began to grow and became symptomatic in 2015. The patient received stereotactic radiation to the site and has been asymptomatic since. Patient 5 is a 61 year-old female with a grade 2 ileal NET who developed progressive diplopia in 2016. Bilateral orbital metastases were noted on orbital MRI and she completed IGRT to the sites shortly thereafter. In the setting of continued growth of the masses she was switched to chemotherapy with capecitabine which has controlled her orbital disease. CONCLUSIONS: NETs can metastasize to the orbits. Orbital disease now often is detected on SSTR-based imaging rather than orbital MRI; when found, it changes treatment approach and surveillance for patients.

Medical Therapy of Gastrointestinal Neuroendocrine Tumors.

Intestinal neuroendocrine tumors (NETs) constitute a heterogeneous group with duodenal, small intestinal, colonic and rectal NETs. They constitute more than half of all NETs, with the highest frequencies in the rectum, small intestine, and colon. The tumor biology varies with the location of the primary tumor as well as with the grade and staging of the tumor. Small intestinal NETs usually present low proliferation and are treated in the first line with somatostatin analogs according to current guidelines. If progression occurs, one can add interferon alpha or change the treatment to everolimus. Peptide receptor radionuclide therapy (PRRT) with Lutetium177-DOTATATE can be an option in the future after registration of the compound. Rectal tumors are usually small when they metastasize; they can be treated with somatostatin analogs but more so with PRRT, while another option is of course everolimus. Colonic NETs are more aggressive than the rest of intestinal NETs and will be treated with everolimus, sometimes in combination with somatostatin analogs based on positive scintigraphy. Another option is a cytotoxic agent such as streptozotocin plus 5-fluorouracil (5-FU) or temozolomide plus capecitabine. The most aggressive tumors, i.e. neuroendocrine carcinoma G3, are treated with a platin-based therapy plus etoposide; if they present with a lower proliferation, i.e. <50%, temozolomide plus capecitabine plus bevacizumab can also be attempted. Duodenal NETs are mostly treated similar to pancreatic NETs, either with cytotoxic agents, streptozotocin plus 5-FU, or temozolomide plus capecitabine, or with targeted agents such as everolimus.