Neuroendocrine tumors of the pancreas

Review of Merkel cell carcinoma with solitary pancreatic metastases mimicking primary neuroendocrine tumor of the pancreas

OBJECTIVE/BACKGROUND

Merkel cell carcinoma (MCC) but metastases to the pancreas are very rare. There are only a few cases of isolated metastases of MCC to the pancreas. Because of this rarity, it can be wrongly diagnosed as a neuroendocrine tumor of the pancreas(pNET), especially the poorly differentiated neuroendocrine carcinoma (PNEC) subtype, in which the treatment is vastly different than that of MCC with isolated metastases of the pancreas.

METHODS

An electronic search of the PubMed and google scholar databases was performed to obtain the literature on MCC with pancreatic metastases, using the following search terms: Merkel cell carcinoma, pancreas, and metastases. Results are limited to the following available article types: case reports and case series. We identified 45 cases of MCC with pancreatic metastases from the PubMed and Google Scholar database search and examined their potential relevance. Only 22 cases with isolated pancreatic metastases were taken for review including one case that we encountered.

RESULTS

The results from our review of cases of isolated pancreatic metastases of MCC were compared to the characteristics of the poorly differentiated pancreatic neuroendocrine tumor (PNEC). We found the following: (a) MCC with isolated pancreatic metastases occurred at an older age than PNEC and with male gender predominance (b) Most of the metastases occurred within 2 years of initial diagnosis of MCC (c) Resection of pancreatic mass was the first line treatment in case of resectable PNECs whereas resection of metastases was infrequently performed in MCC with pancreatic metastases.

Occurrence of Immune Thrombocytopenic Purpura Following Enucleation of a Neuroendocrine Tumor of the Head of the Pancreas

Neuroendocrine tumors are growths occurring in various organs including the pancreas which contain endocrine tissue. Pancreatic neuroendocrine tumors are rare in occurrence with an incidence of <1 per 100,000 individuals. But the incidence is rising and the said tumors are becoming more common in the world. Herein we report a case of a 49-year-old female with a background history of poorly controlled type 2 diabetes mellitus for 7 years, dyslipidemia, and bronchial asthma for 19 years on regular inhaler therapy presenting with a history of back pain for 3 months duration. With serial investigations, she was found to have a neuroendocrine tumor involving the head of the pancreas with no local infiltration and distant metastases. Whipple's procedure was performed after which she developed thrombocytopenia from post-operative day 1 itself. Following this, she was diagnosed as having immune thrombocytopenic purpura and being managed with oral corticosteroids, after which she made a successful recovery from the acute condition but with multiple relapses from time to time.

Pancreatic Vasoactive Intestinal Peptide-Producing Tumor as a Rare Cause of Acute Diarrhea and Severe Hypokalemia

Pancreatic vasoactive intestinal peptide-producing tumor (VIPoma) is a rare functional neuroendocrine tumor most commonly presenting with watery diarrhea and electrolyte abnormalities that include hypokalemia, hypercalcemia and metabolic acidosis. This type of tumor has usually insidious clinical behavior that is characterized by chronic secretory diarrhea, lasting usually from months to years before diagnosis, not responsive to usual medical or dietary treatment approaches. Given the resemblance of VIPoma with other more common causes of chronic watery diarrhea, the final diagnosis is often delayed and the tumors are usually large and metastatic at the time of detection. Our case of pancreatic VIPoma demonstrates an unusual clinical course for this type of tumor with acute refractory diarrhea and rapid deterioration of patient's clinical and biochemical status that required emergent in-hospital diagnosis and treatment. Our patient is a 45-year-old woman who presented with abrupt, watery diarrhea during the past 24 h before admission accompanied with severe hypokalemia as well as hyponatremia, hyperglycemia and hypercalcemia. Despite aggressive management with fluid administration and electrolyte replenishment, no significant improvement in patient's symptoms and electrolyte imbalance was observed. After exclusion of other causes of acute diarrhea from the medical history and the laboratory tests, the clinical suspicion of a functional neuroendocrine tumor was raised. After the establishment of final diagnosis of pancreatic VIPoma with biochemical tests and magnetic resonance imaging (MRI), somatostatin analogues were prescribed and the patient underwent distal pancreatectomy and splenectomy with no signs of lymph node and splenic metastases. Few days after the surgical resection of the tumor, the patient readmitted to our hospital with tarry stools and severe anemia. The abdominal computed tomography (CT) revealed a retroperitoneal cystic lesion. The gastrointestinal bleeding gradually recessed after endoscopic hemostasis of duodenal ulcer lesions whereas the cystic lesion (postoperative lymphocele) was successfully drained under CT-guidance before discharge. After almost 10 years postoperatively, the patient is still asymptomatic with no signs of relapse or metastasis of the disease in the periodic laboratory and imaging follow-up. In conclusion, pancreatic VIPoma can sometimes manifest symptoms of abrupt onset and rapid progression that require high clinical suspicion, appropriate diagnostic workup and aggressive management.

[Indications for the surgical management of pancreatic neoplasms]

Due to its rising incidence, pancreatic neoplasia, which mainly include adenocarcinomas, neuroendocrine and cystic neoplasia of the pancreas, is becoming increasingly relevant in everyday clinical practice.Based on a systematic literature search, a working group of pancreatic experts developed evidence-based recommendations for surgical indications in pancreatic neoplasia to improve the quality.There is a clear surgical indication for primary or secondary resectable pancreatic carcinomas without metastasis, for functionally active, symptomatic and functionally inactive neuroendocrine neoplasia of more than 2 cm in size and for cystic neoplasm with symptoms or signs of malignancy including all intraductal papillary-mucinous neoplasia (IPMN) of the main duct and mixed type, all mucinous-cystic neoplasia (MCN) > 4 cm and all solid pseudopapillary neoplasia (SPN). Surgery can be indicated for pancreatic carcinomas with isolated arterial vascular infiltration or for long periods of stable oligometastasis, regarding neuroendocrine neoplasias for metastasis or debulking surgery as well as for branch-duct IPMN with risk criteria and MCN <4 cm. There is no primary indication for surgery in locally advanced and metastatic pancreatic cancer or asymptomatic serous-cystic neoplasia (SCN).The indication for surgery should always be individualized taking into account age, comorbidities and patient wishes.

Surgical Outcomes, Long-Term Survivals and Staging Systems of World Health Organization G3 Pancreatic Neuroendocrine Tumors

Background: In 2017, the World Health Organization (WHO) defined a new category of pancreatic neuroendocrine neoplasms named G3 pancreatic neuroendocrine tumors (p-NETs), whose surgical outcomes, long-term survivals and staging systems have not been well documented. Methods: Data from eligible patients with G3 p-NETs defined using the WHO 2017 grading classification at our institute were retrospectively analyzed. Results: Our study enrolled 80 patients with WHO G3 p-NETs, including 50 women and 30 men. The accumulative 5-year overall survival (OS) of G3 p-NETs was 29.7%. The current staging system by the American Joint Committee on Cancer (AJCC) failed to discriminate the survival difference between Stage II and Stage III (p = 0.172), while notable differences with regard to the OS were statistically offered between each stage using the modified tumor−node−metastasis (mTNM) staging system (all p < 0.05). The OS of patients receiving surgical resection was significantly better than those with palliative operation (p < 0.05). Both the current AJCC system and proposed mTNM system were independent predictors for the OS of G3 p-NETs (p = 0.017 and p = 0.032, respectively). The 95% confidence intervals of the proposed mTNM staging system were smaller than that of the current AJCC system (0.626−8.217 and 0.329−10.013, respectively), indicating a relatively more accurate predictive ability. Conclusion: Our demonstration revealed that surgical resection was an independent predictor for the favorable prognosis of patients with G3 p-NETs. Moreover, the new mTNM staging system was more suitable and practical than the current AJCC system for stratifying G3 p-NETs into prognostic groups.

Clinical features and postoperative survival in patients with sporadic versus multiple endocrine neoplasia type 1-related pancreatic neuroendocrine tumors: An international cohort study

BACKGROUND

The optimal surgical management of pancreatic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1 is controversial. This study sought to compare clinicopathologic characteristics and outcomes of multiple endocrine neoplasia type 1-associated and sporadic pancreatic neuroendocrine tumors from a large multi-national database.

METHODS

A multi-institutional, international database of patients with surgically resected pancreatic neuroendocrine tumors was analyzed. The cohort was divided into 2 groups: those with multiple endocrine neoplasia type 1 versus those with sporadic disease. Clinicopathologic comparisons were made. Overall and disease-free survival were analyzed. Propensity score matching was used to reduce bias.

RESULTS

Of 651 patients included, 45 (6.9%) had multiple endocrine neoplasia type 1 and 606 sporadic pancreatic neuroendocrine tumors. Multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors were more common in younger patients and associated with multifocal disease at the time of surgery and higher T-stage. Lymph node involvement and the presence of metastasis were similar. Total pancreatectomy rate was 5-fold higher in the multiple endocrine neoplasia type 1 cohort. Median survival did not differ (disease-free survival 126 months multiple endocrine neoplasia type 1 vs 198 months sporadic, P > .5). After matching, survival remained similar (overall survival not reached in either cohort, disease-free survival 126 months multiple endocrine neoplasia type 1 vs 198 months sporadic, P > .5). Equivalence in overall survival and disease-free survival persisted even when patients who underwent subtotal and total pancreatectomy were excluded.

CONCLUSION

Multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors are more common in younger patients and are associated with multifocality and higher T-stage. Survival for patients with multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors is comparable to those with sporadic pancreatic neuroendocrine tumors, even in the absence of radical pancreatectomy. Consideration should be given to parenchymal-sparing surgery to preserve pancreatic function.

Are We Undertreating Black Patients with Nonfunctional Pancreatic Neuroendocrine Tumors? Critical Analysis of Current Surveillance Guidelines by Race

BACKGROUND

Pancreatic neuroendocrine tumor (PNET) survival outcomes differ by race. Current recommendations for surveillance of PNETs less than 2 cm in size are based on low malignant potential and low rates of lymph node metastases (LNM). We investigated whether these guidelines are universally applicable regardless of race.

STUDY DESIGN

A multi-institutional analysis of patients with resected, nonfunctional, sporadic PNETs was performed initially using the US Neuroendocrine Study Group dataset with the National Cancer Database as a validation dataset. Patients with distant metastatic disease were excluded from analysis.

RESULTS

A total of 453 (388 White and 65 Black) and 5,532 patients (4,772 White and 760 Black) were analyzed in the initial and validation datasets, respectively. White patients had a low incidence of LNM in tumors of less than 2 cm in both datasets (5% and 12%, respectively), which increased with tumor size. However, the incidence of LNM in Black patients was similar in the initial and validation datasets for tumors sized less than 2 cm (23% and 21%) and 2 to 3 cm (21% and 29%). Black patients had a significantly higher incidence of LNM in tumors less than 2 cm in size in the initial and validation datasets (p < 0.01) compared with White patients.

CONCLUSIONS

The current recommendation for surveillance of PNETs of less than 2 cm in size is likely based on a low rate of LNM seen in a predominantly White population. The incidence of LNM in Black patients with tumors less than 2 cm in size is clinically relevant and concerning. Current guidelines may not be universally applicable, and a more aggressive approach to resection in Black patients with small PNETs may be warranted.

Multimodal Management of Grade 1 and 2 Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (p-NETs) are rare tumors with a recent growing incidence. In the 2017 WHO classification, p-NETs are classified into well-differentiated (i.e., p-NETs grade 1 to 3) and poorly differentiated neuroendocrine carcinomas (i.e., p-NECs). P-NETs G1 and G2 are often non-functioning tumors, of which the prognosis depends on the metastatic status. In the localized setting, p-NETs should be surgically managed, as no benefit for adjuvant chemotherapy has been demonstrated. Parenchymal sparing resection, including both duodenum and pancreas, are safe procedures in selected patients with reduced endocrine and exocrine long-term dysfunction. When the p-NET is benign or borderline malignant, this surgical option is associated with low rates of severe postoperative morbidity and in-hospital mortality. This narrative review offers comments, tips, and tricks from reviewing the available literature on these different options in order to clarify their indications. We also sum up the overall current data on p-NETs G1 and G2 management.

Is There a Role for Biomarkers in Surveillance of Pancreatic Neuroendocrine Neoplasms in Von Hippel-Lindau Disease?

Von Hippel-Lindau (VHL) disease is an autosomal dominant disorder characterized by the development of multi-organ neoplasms. Among the manifestations of VHL are pancreatic neuroendocrine neoplasms (panNENs). In order to detect these lesions in a timely manner, patients are enrolled in a surveillance program, in accordance with the several existing VHL guidelines. However, these guidelines remain unclear about the role of biomarkers in diagnosing panNENs, despite the benefits a biomarker may offer regarding early detection of new lesions, thereby possibly limiting radiation exposure, and improving quality of life. The aim is to determine which biomarkers might be available in VHL patients and to assess their clinical relevance in diagnosing panNENs in VHL patients.

We searched the databases of PubMed/Medline, Embase, and Web of Science to identify relevant articles. Seven studies assessing the diagnostic or prognostic value of biomarkers were included. The results from these studies were conflicting. Since no evident association between VHL-related panNENs and biomarkers was established in studies with larger study populations, currently biomarkers do not play a significant role in early detection or follow-up for panNENs in VHL patients. The absence of evidence underscores the need for specific research to address this unmet need.

Cdk5 drives formation of heterogeneous pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous population of neoplasms that arise from hormone-secreting islet cells of the pancreas and have increased markedly in incidence over the past four decades. Non-functional PanNETs, which occur more frequently than hormone-secreting tumors, are often not diagnosed until later stages of tumor development and have poorer prognoses. Development of successful therapeutics for PanNETs has been slow, partially due to a lack of diverse animal models for pre-clinical testing. Here, we report development of an inducible, conditional mouse model of PanNETs by using a bi-transgenic system for regulated expression of the aberrant activator of Cdk5, p25, specifically in β-islet cells. This model produces a heterogeneous population of PanNETs that includes a subgroup of well-differentiated, non-functional tumors. Production of these tumors demonstrates the causative potential of aberrantly active Cdk5 for generation of PanNETs. Further, we show that human PanNETs express Cdk5 pathway components, are dependent on Cdk5 for growth, and share genetic and transcriptional overlap with the INS-p25OE model. The utility of this model is enhanced by the ability to form tumor-derived allografts. This new model of PanNETs will facilitate molecular delineation of Cdk5-dependent PanNETs and the development of new targeted therapeutics.

Survival of Patients With Gastroenteropancreatic Neuroendocrine Tumors and Diabetes Mellitus

OBJECTIVES

Diabetes mellitus (DM) is associated with an increased risk of gastroenteropancreatic neuroendocrine tumors (GEP-NETs), but the association between DM and GEP-NET survival is unknown. We evaluated disease characteristics and survival in individuals with DM and GEP-NETs.

METHODS

Using the Surveillance, Epidemiology, and End Results registry linked to Medicare (SEER-Medicare) claims database, we examined sociodemographics, GEP-NET characteristics, and treatment in patients with and without DM before GEP-NET diagnosis. We compared survival using univariate and multivariate analyses.

RESULTS

We identified 1858 individuals with GEP-NETs: 478 (25.7%) with DM and 1380 (74.3%) without. Significant differences in race (P = 0.002) were found between the DM and non-DM groups. Compared with individuals without DM, those with DM had more gastric (9.7% vs 14.9%), duodenal (6.5% vs 10.0%), and pancreatic (17.0% vs 21.8%), and less jejunal/ileal (18.1% vs 12.8%) NETs (P < 0.0001). Patients with DM had earlier stages (stage I, 37.0%; stage IV, 30.8%) than those without (stage I, 30.6%; stage IV, 36.4%; P = 0.0012). We found no difference in survival (multivariate hazard ratio, 0.97; 95% confidence interval, 0.76-1.23) between groups.

CONCLUSIONS

Among patients with and without DM before GEP-NET diagnosis, we found differences in tumor location and stage, but not survival.

Surgical Management of Pancreatic Neuroendocrine Tumors

Surgical management of pancreatic neuroendocrine tumors (PNETS) is steadily evolving and is influenced by multiple factors. Sporadic PNETs are generally managed more aggressively than those occurring in the background of hereditary syndromes, and functioning PNETs are almost always resected if they are not metastatic. Localized nonfunctioning PNETs less than 2 cm can often be observed. Surgical resection for localized PNET greater than 2 cm comprises parenchymal sparing pancreas resections, such as enucleations, or formal anatomic resection, such as distal pancreatectomy or pancreaticoduodenectomy. PNETs commonly metastasize to the liver, and several systemic and liver-directed options to treat hepatic metastases are available.

Multifocality is not associated with worse survival in sporadic pancreatic neuroendocrine tumors

BACKGROUND AND OBJECTIVES

Pancreatic neuroendocrine tumors (pNETs) in patients with hereditary cancer syndromes are typically multifocal. In contrast, sporadic pNETs are usually unifocal and the incidence of multifocal sporadic pNETs is unknown. The primary aim of this study was to investigate the incidence of multifocality in sporadic pNETs and any associated effect on recurrence risk and survival.

METHODS

Patients who underwent resection of pNETs at Mayo Clinic from 2000 to 2019 were identified and clinical data were obtained from medical records. Syndromic disease was defined as pNETs arising in the setting of a hereditary cancer syndrome. Statistical comparisons were made using χ² , Fisher's exact, and Kruskal-Wallis tests and survival was assessed using the Kaplan-Meier method.

RESULTS

Six hundred and sixty-one patients with sporadic pNETs and fifty-nine with syndromic pNETs were identified. Multifocal disease was present in 4.8% of sporadic patients and 84.7% of syndromic patients (p < .001). Within patients with sporadic pNETs, clinicopathologic features and recurrence-free and overall survival were similar between patients with unifocal and multifocal disease.

CONCLUSIONS

Multifocal sporadic pNETs are rare and multifocality is not associated with worse survival or increased recurrence risk. Patients with multifocal sporadic pNETs can likely be safely managed with a combination of resection and observation as indicated for each tumor.

Diagnostic and Interventional Role of Endoscopic Ultrasonography for the Management of Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (PanNENs) are relatively rare, but their incidence has increased significantly in the last decades. Precise diagnosis and prognostic stratification are crucial for proper patient management. Endoscopic ultrasound (EUS) is the modality of choice for diagnosis of solid pancreatic tumors, showing a higher tumor detection rate than other imaging modalities, especially for small size lesions. EUS also serves as a guide for preoperative sampling and other interventions. EUS-tissue acquisition is a safe and highly accurate technique for cyto/histological diagnosis of PanNENs with a well-demonstrated correlation between Ki-67 proliferation index values and tumor grading on EUS and surgical specimens according to the WHO 2017 classification. Furthermore, the possibility of a preoperative EUS-guided fine needle tattooing or fiducial markers placement may help the surgeon to locate small and deep tumors, thus avoiding formal pancreatic resections in favor of parenchymal-sparing surgery. Finally, locoregional ablative treatments using either ethanol injection or radiofrequency ablation have been proposed in recent studies with promising results in order to control symptoms or reduce tumor burden in selected patients unfit for surgery with functioning or non-functioning PanNENs. This article review highlights the current role of EUS in PanNENs management, focusing on the present and future applications of EUS-guided interventions.

Development and comparison of novel bioluminescent mouse models of pancreatic neuroendocrine neoplasm metastasis

Pancreatic neuroendocrine neoplasms (pNENs) are slow growing cancers of increasing incidence that lack effective treatments once they become metastatic. Unfortunately, nearly half of pNEN patients present with metastatic liver tumors at diagnosis and current therapies fail to improve overall survival. Pre-clinical models of pNEN metastasis are needed to advance our understanding of the mechanisms driving the metastatic process and for the development of novel, targeted therapeutic interventions. To model metastatic dissemination of tumor cells, human pNEN cell lines (BON1 and Qgp1) stably expressing firefly luciferase (luc) were generated and introduced into NSG immunodeficient mice by intracardiac (IC) or intravenous (IV) injection. The efficiency, kinetics and distribution of tumor growth was evaluated weekly by non-invasive bioluminescent imaging (BLI). Tumors formed in all animals in both the IC and IV models. Bioluminescent Qgp1.luc cells preferentially metastasized to the liver regardless of delivery route, mimicking the predominant site of pNEN metastasis in patients. By comparison, BON1.luc cells most commonly formed lung tumors following either IV or IC administration and colonized a wider variety of tissues than Qgp1.luc cells. These models provide a unique platform for testing candidate metastasis genes and anti-metastatic therapies for pNENs.

Ferumoxytol-enhanced MR imaging for differentiating intrapancreatic splenules from other tumors

Objectives

Ferumoxytol is an ultra-small superparamagnetic iron oxide (USPIO) agent that is taken up by splenic tissue. This study describes our initial institutional experience of ferumoxytol-enhanced MRI (feMRI) for differentiating intrapancreatic splenules (IPS) from other pancreatic lesions.

Methods

In this retrospective study, patients with computed tomographic imaging that identified small enhancing lesions in the tail of the pancreas subsequently underwent feMRI for further characterization. The feMRI protocol included T2-weighted (T2w) imaging with and without fat suppression (FS), R2* mapping, diffusion-weighted imaging (DWI), and T1-weighted (T1w) imaging with FS, prior to contrast injection. Immediately after slow intravenous infusion with 3 mg/kg body weight ferumoxytol, T1w was repeated. Delayed imaging with all sequences were obtained 24–72 h after ferumoxytol administration.

Results

Seven patients underwent feMRI. In two patients, the pancreatic lesions were presumed as pancreatic neuroendocrine tumor (PNET) from feMRI and in the remaining 5 IPS. One of the two patients with PNET was symptomatic for NET. In another symptomatic patient with pathologically proven duodenal NET and suspected PNET, the pancreatic lesion was proven to be an IPS on feMRI. IPS demonstrated strong negative enhancement in feMRI on T2w and increased R2* values consistent with splenic tissue, while the presumed PNETs did not enhance. T2w FS was helpful on the pre-contrast images to identify IPS, while R2* did on post-contrast images. Neither DWI nor T1w contributed to differentiating PNETs from IPS.

Conclusions

This study demonstrates the potential utility of feMRI as a helpful adjunct diagnostic tool for differentiating IPS from other pancreatic lesions. Further studies in larger patient cohorts are needed.

Prognostic Impact of Tumor Size on Pancreatic Neuroendocrine Tumor Recurrence May Have Racial Variance

OBJECTIVE

The incidence of pancreatic neuroendocrine tumors (PNETs) has increased over the last decade. Black patients have worse survival outcomes. This study investigates whether oncologic outcomes are racially disparate at a single institution.

METHODS

Retrospective analysis was performed on 151 patients with resected PNETs between 2010 and 2019.

RESULTS

More White males and Black females presented with PNETs (P = 0.02). White patients were older (65 years vs 60 years; P = 0.03), more likely to be married (P < 0.01), and had higher median estimated yearly incomes ($28,973 vs $17,767; P < 0.01) than Black patients. Overall and disease-free survival were not different. Black patients had larger median tumor sizes (30 mm vs 23 mm; P = 0.02). Tumor size was predictive of recurrence only for White patients (hazard ratio, 1.02; P = 0.01). Collectively, tumors greater than 20 mm in size were more likely to have recurrence (P = 0.048), but this cutoff was not predictive in either racial cohort independently.

CONCLUSIONS

Black patients undergoing curative resection of PNETs at our institution presented with larger tumors, but that increased size is not predictive of disease-free survival in this population.

Predicting Metastasis Risk in Pancreatic Neuroendocrine Tumors Using Deep Learning Image Analysis

BACKGROUND

The prognosis of patients with pancreatic neuroendocrine tumors (PanNET), the second most common type of pancreatic cancer, varies significantly, and up to 15% of patients develop metastasis. Although certain morphological characteristics of PanNETs have been associated with patient outcome, there are no available morphology-based prognostic markers. Given that current clinical histopathology markers are unable to identify high-risk PanNET patients, the development of accurate prognostic biomarkers is needed. Here, we describe a novel machine learning, multiclassification pipeline to predict the risk of metastasis using morphological information from whole tissue slides.

METHODS

Digital images from surgically resected tissues from 89 PanNET patients were used. Pathologist-annotated regions were extracted to train a convolutional neural network (CNN) to identify tiles consisting of PanNET, stroma, normal pancreas parenchyma, and fat. Computationally annotated cancer or stroma tiles and patient metastasis status were used to train CNN to calculate a region based metastatic risk score. Aggregation of the metastatic probability scores across the slide was performed to predict the risk of metastasis.

RESULTS

The ability of CNN to discriminate different tissues was high (per-tile accuracy >95%; whole slide cancer regions Jaccard index = 79%). Cancer and stromal tiles with high evaluated probability provided F1 scores of 0.82 and 0.69, respectively, when we compared tissues from patients who developed metastasis and those who did not. The final model identified low-risk (n = 76) and high-risk (n = 13) patients, as well as predicted metastasis-free survival (hazard ratio: 4.71) after adjusting for common clinicopathological variables, especially in grade I/II patients.

CONCLUSION

Using slides from surgically resected PanNETs, our novel, multiclassification, deep learning pipeline was able to predict the risk of metastasis in PanNET patients. Our results suggest the presence of prognostic morphological patterns in PanNET tissues, and that these patterns may help guide clinical decision making.

Adrenocorticotropic Hormone-Producing Pancreatic Neuroendocrine Neoplasms: A Systematic Review

OBJECTIVE

Adrenocorticotropic hormone-producing pancreatic neuroendocrine neoplasm (ACTHoma) is an exceedingly rare type of pancreatic neuroendocrine neoplasm (pNEN) that often causes ectopic adrenocorticotropic hormone syndrome. These neoplasms have been found to be very aggressive and challenging to treat. The current systematic review aimed to analyze the clinical features, immunohistochemical characteristics, diagnosis, therapy, and prognosis of ACTHoma.

METHODS

A systematic review of the English- and Chinese-language literature was performed. PubMed, EMBASE, and Wanfang databases were searched to identify articles about ACTHoma in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines.

RESULTS

A total of 210 studies encompassing 336 patients diagnosed with ACTHoma were selected for the systematic review, including 16 Chinese patients.

CONCLUSION

ACTHoma was more common in women (66.4%), and the mean age was 44.7 years. Tumors were generally large, and the mean tumor size was 4.43 cm. The incidence of clinical manifestations was: hypokalemia, 69.3%; diabetes, 63.2%; weakness, 60.1%, hypertension, 56.4%; moon face 41.1%; and edema, 37.4%. These tumors are more commonly found in the tail of pancreas, and the most frequent site of metastasis was the liver. The pNENs or other functioning pNENs could evolve into ACTHoma. ACTHoma is a very rare disease, and the mean follow-up time was 28.3 months.

Differentiation between non-hypervascular pancreatic neuroendocrine tumors and mass-forming pancreatitis using contrast-enhanced computed tomography

BACKGROUND

Non-hypervascular pancreatic neuroendocrine tumors (PNETs) showed slight or iso-enhancement in contrast-enhanced computed tomography (CE-CT), which shared similar imaging findings with mass-forming pancreatitis (MFPs).

PURPOSE

To explore the value of CT imaging features in differentiating the two diseases.

MATERIAL AND METHODS

Fifty-one patients with histologically proved MFPs (n = 27) or non-hypervascular PNETs (n = 24) were included. Two radiologists reviewed CT imaging findings and clinical features. Logistic regression analysis was performed to identify relevant features in differentiating non-hypervascular PNETs and MFPs. Receiver operating characteristic (ROC) curve analysis was used to show the performance of the optimal parameters in differentiating non-hypervascular PNETs and MFPs.

RESULTS

A well-defined margin was more common in non-hypervascular PNETs (P < 0.05) than that in MFPs. MFPs often occurred in older people (P < 0.01) and the head-neck of the pancreas compared with non-hypervascular PNETs (P < 0.05). Metastases only presented in non-hypervascular PNETs (P < 0.05). CT values at venous phase and delay phase of MFPs were higher (P = 0.010 and P = 0.029) than those in non-hypervascular PNETs. Logistic analysis showed gender, tumor margin, CT values at venous phase, and tumor components were independent predictors in differentiating the two lesions. The area under the curve (AUC) was 0.938 with a sensitivity of 87.5% and specificity of 92.6% for combined predicators.

CONCLUSION

Gender, tumor margin, CT values at venous phase, and tumor components were useful predicators in differentiating non-hypervascular PNETs and MFPs.

Pancreatic collision tumor of ductal adenocarcinoma and neuroendocrine tumor-A rare case report

A collision tumor is composed of two adjacent histological distinct neoplasms without the histological admixture of cell types in the same organ or tissue. It is rare in pancreas. Herein we report an unusual case of a mixed malignant neuroendocrine tumor (NET) and ductal adenocarcinoma of pancreas in a 24 year old male who presented with history abdomen pain. A clinicoradiological diagnosis of chronic calcific pancreatitis with carcinoma body of pancreas was made. Distal pancreaticosplenectomy specimen showed a grey white, nodular growth measuring 2 x 2 x 1.2 cm on the cut surface of pancreas. Histopathology revealed a composite tumor consisting of ductal and neuroendocrine origin. Immunohistochemistry showed complementary staining for CK7 in adenocarcinoma and chromogranin A in NET areas confirming a collision tumor. Accurate evaluation of the radiologic pointers, histomorphologic evaluation to recognize and quantitate the individual components, appropriate immunohistochemical evaluation and correlation is essential for diagnosis.

Central Pancreatectomy with Roux-en-Y Pancreaticojejunal Anastomosis-Report of Two Cases

Background  Central pancreatectomy (CP), a partial resection of the pancreas, is indicated for the excision of neuroendocrine tumors (NETs) of the pancreas, when located at the neck or the proximal body. Specifically, CP is preferable in functional NET and in nonfunctional sized 1 to 2 cm or/with proliferation marker Ki67 < 20% (Grade I/II). Postoperative leakage from the remaining pancreas constitutes the most frequent complication of CP (up to 63%). The aim of our study was to share the experience of our center in CP for NET, with pancreaticojejunal anastomosis. Methods  In 1 year, we performed CP in two patients, following the aforementioned criteria. They presented with tumor of the body of the pancreas, which was found in random check with computed tomography, with negative hormonal blood tests and they underwent magnetic resonance imaging and endoscopic ultrasound/fine-needle biopsy/pathological examination. Results  The patients underwent CP with Roux-en-Y pancreaticojejunal anastomosis of the distal pancreatic stump and jejunal patch of the proximal pancreatic stump. Histological exam revealed NET sized 2.8 cm and 1.45 cm, Grade I and II, respectively. Postoperatively both patients developed small pancreatic leakage, which did not affect their physical condition and stopped after 20 and 30 days. No one needed pancreatic enzymes supplements or developed new-onset diabetes mellitus. Conclusion  CP provided adequate, functional remaining pancreatic tissue in both patients. Small leakages were treated conservatively and retreated without septic complications. As a result, CP might be considered as safe and effective technique for pancreatic neck/proximal body NET.

Distinct Clinical Characteristics in Young-Onset Pancreatic Neuroendocrine Tumor

BACKGROUND

We aimed to study the effect of socioeconomic differences and molecular characteristics on survival in patients with young-onset pancreatic neuroendocrine tumors (YOPNET) and typical-onset PNET (TOPNET).

METHODS

We identified the patients with YOPNET (<50 years) and TOPNET (≥50 years) who underwent definitive surgery diagnosed between 2004 and 2016 using the National Cancer Database. We evaluated overall survival (OS) using the Kaplan-Meier and Cox regression methods before and after propensity score matching. A publicly available genomic dataset was used to compare mutation frequencies among the two groups.

RESULTS

A total of 6259 patients with PNET were included, of which 27% were YOPNET. Patients with YOPNET were more likely to be Black, Hispanic, female, and have private insurance versus patients with TOPNET (all p < 0.001). Patients with YOPNET had a lower comorbidity score, but higher stage and tumor size (all p < 0.001). YOPNET was associated with a greater improved OS than TOPNET before and after propensity score matching (p < 0.001). On multivariable analysis, this survival difference persisted for YOPNET as an independent prognostic factor (unmatched p = 0.008; matched p = 0.01). For genomic analysis, patients with YOPNET had a lower rate of multiple endocrine neoplasia type-1 (MEN-1) mutation than patients with TOPNET (26% vs. 56%, p < 0.001).

CONCLUSIONS

YOPNET represents a disease with distinct clinical features. Patients with YOPNET who underwent definitive surgery had better OS than patients with TOPNET despite having higher stage and tumor size. YOPNET also had lower rate of MEN-1 mutation.

Significance of chromogranin A and synaptophysin in pancreatic neuroendocrine tumors

The two most commonly used immunohistochemical markers for neuroendocrine cells and their tumors are chromogranin A (CgA) and synaptophysin (SPY). CgA is a marker for neuroendocrine secretory granules of four pancreatic hormones and gastrin while SPY is a marker for synaptic vesicles in neuroendocrine cells, which release classic neurotransmitters such as acetylcholine and others. CgA is involved in synthesis and secretion of peptide hormones through exocytosis while the function of SPY is elusive. Thirty-five pancreatic neuroendocrine tumors (Pan-NETs) were studied, consisting of 14 insulinomas, 8 gastrinomas, 2 glucagonomas, 6 pancreatic polypeptidomas and 5 non-functioning tumors, and were immunostained for four pancreatic hormones, gastrin, CgA, and SPY. Majority of Pan-NETs were less immunostained for the endocrine hormones and CgA than the normal pancreatic endocrine cells. CgA immunostaining mostly correlates with each hormone staining in non-β-cell tumors, while SPY immunostaining recognizes endocrine cells diffusely in the cytoplasm. CgA immunostaining is less in insulinomas than in non-β-cell tumors, and CgA immunostaining may distinguish CgA-weaker insulinomas from CgA-stronger non-β-cell tumors. CgA immunostaining may be used as an independent marker for biological aggressiveness in non-β-cell Pan-NETs. The serum CgA levels are higher in subjects harboring non-β-cell tumors than those harboring insulinomas, and the serum CgA elevates in parallel to the increasing metastatic tumor mass. Thus, CgA positive immunostaining in Pan-NETs correlates with the elevated serum levels of CgA for diagnosing CgA-positive non-β-cell Pan-NETs and the increasing serum CgA levels indicate increasing metastatic tumor mass.

Transcriptomic analysis by RNA sequencing characterises malignant progression of canine insulinoma from normal tissue to metastatic disease

Insulinomas (INS) are the most common human and canine functioning pancreatic neuroendocrine tumours. The long-term prognosis for malignant INS is poor, because micrometastases are frequently missed during surgery. As human and canine malignant INS share clinical and histopathological features, dogs have been proposed as models for INS research. Using RNA-sequencing, we conducted a pilot study to better understand the underlying molecular mechanisms of canine INS. Normal canine pancreas and lymph node control tissues were compared with primary INS and INS-metastatic lymph nodes, revealing more than 3,000 genes differentially expressed in normal pancreas compared to primary INS. Only 164 genes were differentially expressed between primary INS and INS-metastatic lymph nodes. Hierarchical clustering analysis demonstrated similar genetic profiles in normal pancreas and early clinical stage primary INS, whereas late clinical stage primary INS resembled the genetic profile of INS-metastatic lymph nodes. These findings suggest that markers of malignant behaviour could be identified at the primary site of the disease. Finally, using the REACTOME pathways database, we revealed that an active collagen metabolism, extracellular matrix remodelling, beta-cell differentiation and non-beta-cell trans-differentiation might cause disease progression and hyperinsulinism in INS, identifying major pathways worthy of future research in this currently poorly controlled disease.

Sudden 'cure' of type two diabetes due to pancreatic insulinoma: A case report

Insulinomas are rare tumors of the islet cells of the pancreas and are the most common cause of endogenous hyperinsulinism. Although they usually present with symptoms of hypoglycemia, sometimes they can have vague symptoms. We present the case of a 62-year-old diabetic female who was diagnosed with a large insulinoma after being investigated for the 'cure' of her diabetes. We also review the literature regarding insulinomas in patients with diabetic. A 62-year-old, obese woman with type 2 diabetes mellitus was initially investigated for an unexplained normalization of her blood glucose levels after the cessation of antidiabetic medication due to an episode of severe hypoglycemia. She remained without antidiabetics for three months maintaining normoglycemia, and thereafter, she started experiencing frequent but less severe hypoglycemic episodes. She did not change her diet habits or level of activity and did not lose any weight. The patient underwent further investigation with a supervised 72 h fasting test, which resulted in the biochemical diagnosis of endogenous hyperinsulinism. Imaging studies revealed the presence of a large insulinoma in the head of the pancreas. Finally, the patient underwent a pylorus preserving Whipple procedure, which reversed the aforementioned 'normalization' of glucose levels and the underlying diabetes mellitus reappeared. Insulinomas are rare tumors causing hypoglycemia. Even more rarely are found in diabetic patients, making the diagnosis more challenging and probably delayed, as the symptoms are masked by the presence of diabetes, thereby leading to a more advanced disease diagnosis.

Pre- and intraoperative diagnostic requirements, benefits and risks of minimally invasive and robotic surgery for neuroendocrine tumors of the pancreas

Pancreatic neuroendocrine tumours (PanNET) are rare tumours, accounting for 1%-2% of all pancreatic neoplasms. These tumors are classified as functioning neuroendocrine tumours (F-PanNETs) or non-functioning (NF-PanNETs) depends on whether the tumour is associated with clinical hormonal hypersecretion syndrome or not. In the last decades, diagnosis of PanNETs has increased significantly due to the widespread of cross-sectional imaging. Whenever possible, surgery is the cornerstone of PanNETs management and the only curative option for these patients. Indeed, after R0 resection, the 5-year overall survival rate is around 90-100% for low grade lesions but significantly drops after incomplete resections. Compared to standard resections, pancreatic sparing surgery, i.e. enucleation and central pancreatectomy, significantly decreased the risk of pancreatic insufficiency. It should be performed in patients with good general condition and normal pancreatic function to limit the operative risk and enhance the benefit of surgery. Nowadays, due to many known advantages of minimally invasive surgery, there is an ongoing trend towards laparoscopic and robotic pancreatic surgery. The aim of this study is to describe the pre- and intraoperative diagnostic requirements for the management of PanNETs and the benefits and risks of minimally invasive surgery including laparoscopic and robotic approach in view of the recent literature.

A case report of three synchronous tumors in the same pancreatic specimen

It is known that Duodenal adenocarcinoma (DA) is a rare malignant solid tumor that cause occlusion symptoms with orthodox dysphagia when locally advanced. Pancreatic neuroendocrine tumors (PanNETs) account for about 2% of all pancreatic neoplasms. The combination of these two lesions, with the synchronous presence of ectopic pancreatic tissue (EPT) of the duodenum, has never been described in literature, to our knowledge. Here we report a case of combined DA, EPT and PanNET affecting a 71-year-old woman.

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Simultaneous presence of Duodenal adenocarcinoma pancreatic neuroendocrine tumor ectopic pancreatic tissue of duodenum.

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Biochemical tests did not reveal abnormalities: CA 19-9 was normal, CEA was 153 U/L.

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Ultrasonography confirmed a nodule dislocating pancreas investigated with contrast-enhanced CT and esophagogastroduodenoscopy.

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The association between duodenal adenocarcinomas, PanNET and ectopic pancreatic tissue (EPT) of the duodenum is really rare.

Gamma Emitters in Pancreatic Endocrine Tumors Imaging in the PET Era: Is there a Clinical Space for 99mTc-peptides?

Background:

Pancreatic Neuroendocrine Tumors (PNETs) are rare neoplasms, sporadic or familial, even being part of a syndrome. Their diagnosis is based on symptoms, hormonal disorders or may be fortuitous. The role of Nuclear Medicine is important, mainly because of the possibility of a theranostic strategy. This approach is allowed by the availability of biochemical agents, which may be labeled with radionuclides suitable for diagnostic or therapeutic purposes, showing almost identical pharmacokinetics. The major role for radiopharmaceuticals is connected with radiolabeled Somatostatin Analogues (SSA), since somatostatin receptors are highly expressed on some of the neoplastic cell types.

Discussion:

Nowadays, in the category of radiolabeled SSA, although 111In-pentetreotide, firstly commercially proposed, is still used, the best choice for diagnosis is related to the so called DOTAPET radiotracers labeled with 68-Gallium (Ga), such as 68Ga-DOTATATE, 68Ga-DOTANOC, and 68Ga-DOTATOC. More recently, labeling with 64-Copper (Cu) (64Cu-DOTATATE) has also been proposed. In this review, we discuss the clinical interest of a SAA (Tektrotyd©) radiolabeled with 99mTc, a gamma emitter with better characteristics, with respect to 111Indium, radiolabeling Octreoscan ©. By comparing both pharmacokinetics and pharmacodynamics of Octreoscan©, Tektrotyd© and PET DOTA-peptides, on the basis of literature data and of our own experience, we tried to highlight these topics to stimulate further studies, individuating actual clinical indications for all of these radiotracers.

Conclusion:

In our opinion, Tektrotyd© could already find its applicative dimension in the daily practice of NETs, either pancreatic or not, at least in centers without a PET/CT or a 68Ga generator. Because of wider availability, a lower cost, and a longer decay, compared with respect to peptides labeled with 68Ga, it could be also proposed, in a theranostic context, for a dosimetry evaluation of patients undergoing Peptide Receptor Radionuclide Therapy (PRRT), and for non-oncologic indications of radiolabelled SSA. In this direction, and for a more rigorous cost/effective evaluation, more precisely individuating its clinical role, further studies are needed.

Diagnostic performance of endoscopic ultrasound-guided fine-needle aspiration for cystic and non-cystic pancreatic neuroendocrine tumors

Background and study aims  Pancreatic neuroendocrine tumors (P-NENs) are rare tumors with malignant potential. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been shown to be superior to other imaging methods in preoperative localization and diagnosis of P-NENs. The objective of this study was to describe the EUS features of non-metastatic cystic and non-cystic P-NENs seen at a referral center and to evaluate the performance of EUS-FNA in diagnosis of P-NENs. Patients and methods  All patients with histologically confirmed, non-metastatic P-NENs, which underwent EUS-FNA prior to surgical resection at the Moffitt Cancer Center between Jan 2005 and Dec 2012 were included. Clinical, endoscopic and pathologic information was abstracted from electronic medical records. Results  Thirty-nine patients, all with non-functional P-NENs, were included in this study. Thirteen tumors were cystic and 26 were solid. Among the cystic tumors, 50 % were partly cystic and partly solid, and 50 % were fully cystic. The cystic tumors were more commonly seen at the body/tail, and the solid tumors were more uniformly distributed. Fluid could be aspirated from 50 % of the cystic tumors, all with a carcinoembryonic antigen level < 192 ng/mL. With surgical pathology as the gold standard, overall sensitivity of EUS-FNA in diagnosing cystic tumors was 62.5 %, and for solid tumors, 95 % ( P  < 0.03). Conclusions  EUS-FNA is much more sensitive in diagnosing solid P-NENs than cystic PNETs. Our results indicate that EUS-FNA may have higher sensitivity for diagnosis of cystic P-NENs than the reported sensitivity of EUS-FNA for all pancreatic cystic tumors.

Improving the Theranostic Potential of Exendin 4 by Reducing the Renal Radioactivity through Brush Border Membrane Enzyme-Mediated Degradation

As highly expressed in insulinomas, the glucagon-like peptide-1 receptor (GLP-1R) is believed to be an attractive target for diagnosis, localization, and treatment with radiolabeled exendin 4. However, the high and persistent radioactivity accumulation of exendin 4 in the kidneys limits accurate diagnosis and safe, as well as effective, radiotherapy in insulinomas. In this study, we intend to reduce the renal accumulation of radiolabeled exendin 4 through degradation mediated by brush border membrane enzymes. A new exendin 4 ligand NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4 containing Met-Val-Lys (MVK) linker between the peptide and 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) chelator was synthesized and labeled with ⁶⁸Ga. The in vitro mouse serum stability and cell binding affinity of the tracer were evaluated. Initial in vitro cleavage of the linker was determined by incubation of a model compound Boc-MVK-Dde with brush border membrane vesicles (BBMVs) with and without the inhibitor of neutral endopeptidase (NEP). Further cleavage studies were performed with the full structure of NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4. Kidney and urine samples were collected in the in vivo metabolism study after intravenous injection of ⁶⁸Ga-NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4. The microPET images were acquired in INS-1 tumor model at different time points; the radioactivity uptake of ⁶⁸Ga-NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4 in tumor and kidneys were determined and compared with the control radiotracer without MVK linker. ⁶⁸Ga-NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4 was stable in mouse serum. The MVK modification did not affect the affinity of NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4 toward GLP-1R. The in vitro cleavage study and in vivo metabolism study confirmed that the MVK sequence can be recognized by BBM enzymes and cleaved at the amide bond between Met and Val, thus releasing the small fragment containing Met. MicroPET images showed that the tumor uptake of ⁶⁸Ga-NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4 was comparable to that of the control, while the kidney uptake was significantly reduced. As a result, more favorable tumor to kidney ratios were achieved. In this study, a novel exendin 4 analogue, NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4, was successfully synthesized and labeled with ⁶⁸Ga. With the cleavable MVK sequence, this ligand could be cleaved by the enzymes on kidneys, and releasing the fragment of ⁶⁸Ga-NOTA-Met-OH, which will rapidly excrete from urine. As the high and consistent renal radioactivity accumulation could be significantly reduced, NOTA-MVK-Cys⁴⁰-Leu¹⁴-Exendin 4 shows great potential in the diagnosis and radiotherapy for insulinoma.

RABL6A inhibits tumor-suppressive PP2A/AKT signaling to drive pancreatic neuroendocrine tumor growth

Hyperactivated AKT/mTOR signaling is a hallmark of pancreatic neuroendocrine tumors (PNETs). Drugs targeting this pathway are used clinically, but tumor resistance invariably develops. A better understanding of factors regulating AKT/mTOR signaling and PNET pathogenesis is needed to improve current therapies. We discovered that RABL6A, a new oncogenic driver of PNET proliferation, is required for AKT activity. Silencing RABL6A caused PNET cell-cycle arrest that coincided with selective loss of AKT-S473 (not T308) phosphorylation and AKT/mTOR inactivation. Restoration of AKT phosphorylation rescued the G1 phase block triggered by RABL6A silencing. Mechanistically, loss of AKT-S473 phosphorylation in RABL6A-depleted cells was the result of increased protein phosphatase 2A (PP2A) activity. Inhibition of PP2A restored phosphorylation of AKT-S473 in RABL6A-depleted cells, whereas PP2A reactivation using a specific small-molecule activator of PP2A (SMAP) abolished that phosphorylation. Moreover, SMAP treatment effectively killed PNET cells in a RABL6A-dependent manner and suppressed PNET growth in vivo. The present work identifies RABL6A as a new inhibitor of the PP2A tumor suppressor and an essential activator of AKT in PNET cells. Our findings offer what we believe is a novel strategy of PP2A reactivation for treatment of PNETs as well as other human cancers driven by RABL6A overexpression and PP2A inactivation.

Advanced MR Imaging Techniques for Pancreas Imaging

Advances in MR imaging with optimization of hardware, software, and techniques have allowed for an increased role of MR in the identification and characterization of pancreatic disorders. Diffusion-weighted imaging improves the detection and staging of pancreatic neoplasms and aides in the evaluation of acute, chronic and autoimmune pancreatitis. The use of secretin-enhanced MR cholangiography improves the detection of morphologic ductal anomalies, and assists in the characterization of pancreatic cystic lesions and evaluation of acute and chronic pancreatitis. Emerging MR techniques such as MR perfusion, T1 mapping/relaxometry, and MR elastography show promise in further evaluating pancreatic diseases.

Differentiation of hypovascular pancreatic neuroendocrine tumors from pancreatic ductal adenocarcinoma using contrast-enhanced computed tomography

Hypovascular pancreatic neuroendocrine tumors (hypo-PNETs) are often misdiagnosed as pancreatic ductal adenocarcinoma (PDAC). However, the treatment options and prognosis of PNETs and PDAC are substantially different. This retrospective study differentiated hypo-PNETs from PDAC using contrast-enhanced CT (CE-CT). Clinical data and CE-CT findings, including tumor location, size, boundary, pancreatic duct dilatation, local invasion or metastases, tumor contrast enhancement, and tumor-to-pancreas enhancement ratio, were compared between 39 PDACs and 18 hypo-PNETs. At CT imaging, hypo-PNETs showed a higher frequency of a well-defined margin and lower frequencies of pancreatic duct dilatation and local invasion or metastasis when compared with PDAC (p < 0.05 for all). The mean attenuation of hypo-PNETs at the arterial and portal venous phase was significantly higher than that of PDAC (p < 0.001, p = 0.003, respectively). Similar results were observed in tumor-to-pancreas enhancement ratio. Tumor attenuation and tumor-to-pancreas enhancement ratio at the arterial phase showed the largest area under the curve (AUC) of 0.888 and 0.812 with 83.3–88.9% of sensitivity and 61.6–77.0% of specificity. Pancreatic duct dilatation, local invasion or metastasis, and tumor attenuation at the portal venous phase also showed acceptable AUC (0.703–0.748). Thus CE-CT features, especially the enhancement degree at the arterial phases, may be useful for differentiating hypo-PNETs from PDAC using CE-CT.

Endoscopic Ultrasound Assessment of Pancreatic Duct Diameter Predicts Neuroendocrine Tumors and Other Pancreas Masses

OBJECTIVES

Distinguishing neuroendocrine tumors (NETs) and other pancreas lesions from adenocarcinomas via endoscopic ultrasound (EUS) requires additional tissue for special staining and processing. Our aim was to determine if main pancreatic duct (PD) diameter on EUS helps to differentiate NET and other unusual tumors from adenocarcinoma.

METHODS

We evaluated 30 consecutive patients diagnosed with NET or other pancreas lesions by EUS with 90 matched patients who were found to have adenocarcinoma. Dilated PD was defined as greater than 3 mm. Multivariate logistic regression was used to evaluate associations between lesion type and PD diameter.

RESULTS

Among the 30 patients with NET/other pancreas lesions, 21 had NETs, 7 had metastases, and 2 had lymphomas. A dilated PD was demonstrated in only 3.3% of pancreatic NET/other lesions but present in 88.9% of cases of primary adenocarcinoma (P < 0.01). In multivariate analysis, a normal PD diameter and absence of clinical symptoms strongly predicted the presence of pancreatic NET/other versus adenocarcinoma (P < 0.01).

CONCLUSIONS

The absence of PD dilation upstream of the lesion suggests NET or other lesions rather than adenocarcinoma. This finding should prompt endosonographers to obtain additional tissue at the time of EUS to send for special studies.

Molecular Imaging to the Surgeons Rescue: Gallium-68 DOTA-Exendin-4 Positron Emission Tomography-Computed Tomography in Pre-operative Localization of Insulinomas

Background

Insulinoma is an islet-cell neoplasm that secretes insulin. It is usually localized to the pancreas and is often the most common cause of endogenous hyperinsulinemic hypoglycaemia in non-diabetic adult patients. Surgical excision with a curative intent is the standard modality of treatment, and it requires precise localization of tumor tissue. Ga-68 DOTA-exendin-4 PET/CT scan is a clinically reasonable and sensitive scan for the identification of insulinoma. The aim of this prospective cohort study was to determine the overall accuracy of Ga-68 DOTA-exendin-4 PET/CT scan in the detection of insulinoma.

Materials and Methods

Eight patients with fasting hyperinsulinemic hypoglycaemia with neuroglycopenic symptoms were enrolled in this study which was conducted during October 2016 to October 2017. Whole body PET/CT scan was performed on a Philips time of flight PET/CT scanner, 60 minutes after injection of Ga-68 DOTA-exendin-4 (and also Ga-68 DOTANOC). The imaging findings were compared to the histopathological diagnosis in six out of eight patients and to subsequent follow up in the remaining two patients who did not undergo surgery.

Results

The sensitivity of Ga-68 DOTA-Exendin-4 PET/CT scan in insulinoma detection was found to be 75%.

Conclusion

Ga-68 DOTA-Exendin-4 PET/CT scan is highly sensitive for identification and exact localization of insulinoma which can guide better surgical exploration. However, randomised controlled trials are needed to assess the accuracy of Ga-68 DOTA-Exendin PET/CT scan in localization of insulinoma.

mTOR kinase inhibition reduces tissue factor expression and growth of pancreatic neuroendocrine tumors

Essentials Tissue factor (TF) isoforms are expressed in pancreatic neuroendocrine tumors (pNET). TF knockdown inhibits proliferation of human pNET cells in vitro. mTOR kinase inhibitor sapanisertib/MLN0128 suppresses TF expression in human pNET cells. Sapanisertib suppresses TF expression and activity and reduces the growth of pNET tumors in vivo. SUMMARY: Background Full-length tissue factor (flTF) and alternatively spliced TF (asTF) contribute to growth and spread of pancreatic ductal adenocarcinoma. It is unknown, however, if flTF and/or asTF contribute to the pathobiology of pancreatic neuroendocrine tumors (pNETs). Objective To assess TF expression in pNETs and the effects of mTOR complex 1/2 (mTORC1/2) inhibition on pNET growth. Methods Human pNET specimens were immunostained for TF. Human pNET cell lines QGP1 and BON were evaluated for TF expression and responsiveness to mTOR inhibition. shRNA were used to knock down TF in BON. TF cofactor activity was assessed using a two-step FXa generation assay. TF promoter activity was assessed using transient transfection of human TF promoter-driven reporter constructs into cells. Mice bearing orthotopic BON tumors were treated with the mTORC1/2 ATP site competitive inhibitor sapanisertib/MLN0128 (3 mg kg-1 , oral gavage) for 34 days. Results Immunostaining of pNET tissue revealed flTF and asTF expression. BON and QGP1 expressed both TF isoforms, with BON exhibiting higher levels. shRNA directed against TF suppressed BON proliferation in vitro. Treatment of BON with sapanisertib inhibited mTOR signaling and suppressed TF levels. BON tumors grown in mice treated with sapanisertib had significantly less TF protein and cofactor activity, and were smaller compared with tumors grown in control mice. Conclusions TF isoforms are expressed in pNETs. Sapanisertib suppresses TF mRNA and protein expression as well as TF cofactor activity in vitro and in vivo. Thus, further studies are warranted to evaluate the clinical utility of TF-suppressing mTORC1/2 inhibitor sapanisertib in pNET management.

Systematic review of current prognostication systems for pancreatic neuroendocrine neoplasms

BACKGROUND

Pancreatic neuroendocrine neoplasms are a heterogenous group of rare tumors whose natural history remains poorly defined. Accurate prognostication of pancreatic neuroendocrine neoplasms is essential for guiding clinical decisions. This paper aims to summarize all the commonly utilized and recently proposed prognostication systems for pancreatic neuroendocrine neoplasms published in the literature to date.

METHODS

A systematic review of Pubmed, Scopus, and Embase databases, of the period from January 1, 2000-November 29, 2016, was conducted to identify all published articles reporting on prognostication systems of pancreatic neuroendocrine neoplasms.

RESULTS

A total of 23 articles were included in our review, and a total of 25 classification systems were identified. There were 2 modifications of the World Health Organization 2004 criteria, 4 modifications of the World Health Organization 2010 criteria, 2 modifications of the American Joint Committee on Cancer 2010 staging system, 3 modifications of the European Neuroendocrine Tumor Society 2006 tumor, node, metastasis staging system, 7 novel categorial classification systems, and 2 novel proposed continuous classifications. The most commonly included variables included age, size of tumor, presence of distant and lymph node metastases, Ki-67 index, and mitotic count.

CONCLUSION

Numerous prognostication systems have been proposed for pancreatic neuroendocrine neoplasms, of which the most commonly used systems presently include the World Health Organization 2010 criteria and the two tumor, node, metastasis staging systems by the European Neuroendocrine Tumor Society and the American Joint Commission on Cancer. However, prognostication systems for pancreatic neuroendocrine neoplasms continue to evolve with time as more prognostication factors are identified. More validation and comparative studies are needed to identify the most effective prognostication system.

High-Grade Gastrointestinal Neuroendocrine Carcinoma Management and Outcomes: A National Cancer Database Study

BACKGROUND

High-grade neuroendocrine carcinomas are rare in the gastrointestinal tract. However, treatment patterns and outcomes have not been well described.

SUBJECTS, MATERIALS, AND METHODS

The National Cancer Database was analyzed. The primary objective was to describe the clinical outcomes and identify prognostic factors. Univariate and multivariate analyses were done to identify factors associated with patient outcome.

RESULTS

A total of 1,861 patients were identified between 2004 and 2013. The mean age was 63 years (standard deviation ±13). The majority of the patients (78.1%) were non-Hispanic whites. The most common primary sites were pancreas (pancreatic neuroendocrine tumor [PNET] = 19.4%), large intestine (18.1%), esophagus (17.8%), and rectum (15.5%). Stage at presentation was I (6.6%), II (10.5%), III (18%) and IV (64.6%). Only 1.6% of the patients had brain metastases. Surgical resection was the primary therapy in 27.9%, and their median overall survival (OS) was 13.3 months. Patients treated with palliative chemotherapy had a median OS of 11.2 months, compared with 1.7 months for untreated patients. The median OS for high-grade PNET was 6 months, compared with 9.9 months for other high-grade gastrointestinal neuroendocrine carcinomas (HG GI NEC). On univariable analysis, age < 65 years (hazard ratio [HR] 0.72; 0.66-0.8; p < .001) and treatment at an academic center (HR 0.88; 0.79-0.99; p < .034) were associated with improved survival. Multivariable analysis confirmed prognostic advantage of treatment at an academic center.

CONCLUSION

This is the largest series of HG GI NEC. Most patients present with metastatic disease, and overall survival remains poor. Treatment at an academic center, younger age, and use of chemotherapy were associated with improved survival. Multiagent chemotherapy was found to be associated with superior survival compared with single-agent chemotherapy, which was superior to no chemotherapy. Temporal sequences of chemotherapy, surgery, and radiation administration were not found to be associated with survival differences on multivariable analysis.

IMPLICATIONS FOR PRACTICE

Management of patients with high-grade gastrointestinal neuroendocrine carcinomas (HG GI NEC) is based on experience with small-cell lung cancer. In this retrospective review, most patients had advanced disease and pancreatic primary had worse outcomes. Treatment at an academic center, younger age, and use of chemotherapy are associated with improved survival. Patients with early-stage disease treated with resection alone had inferior outcomes compared with patients who received neoadjuvant or adjuvant therapy, suggesting that micrometastases contribute to poor surgical outcomes. The relatively high proportion of positive surgical margin favors downstaging with neoadjuvant therapy to improve resection and lower the risk of systemic recurrence.

PET/MR Imaging of the Pancreas

PET/MR imaging has the potential to markedly alter pancreatic care in both the malignant, and premalignant states with the ability to perform robust, high-resolution, quantitative molecular imaging. The ability of PET/MR imaging to monitor disease processes, potentially correct for motion in the upper abdomen, and provide novel biomarkers that may be a combination of MR imaging and PET biomarkers, offers a unique, precise interrogation of the pancreatic milieu going forward.

HDAC-Linked "Proliferative" miRNA Expression Pattern in Pancreatic Neuroendocrine Tumors

Epigenetic factors are essentially involved in carcinogenesis, tumor promotion, and chemoresistance. Two epigenetic key players are miRNAs and histone deacetylases (HDACs). As previously shown by own theoretical databank analysis, the crosstalk between miRNAs and HDACs is relevant in different human chronic diseases and cancerogenic pathways. We aimed to investigate a potential connection between the expression of a well-defined subset of "proliferation-associated" miRNAs and the expression of HDACs as well as clinical parameters in pancreatic neuroendocrine tumors (pNETs).

MATERIALS AND METHODS

Expression levels of miRNA132-3p, miRNA145-5p, miRNA183-5p, miRNA34a-5p, and miRNA449a in 57 pNETs resected between 1997 and 2015 were measured and linked to the immunohistochemical expression pattern of members of the four HDAC classes on human tissue microarrays. All pNET cases were clinically and pathologically characterized according to published guidelines. Correlation analysis revealed a significant association between expression of specific miRNAs and two members of the HDAC family (HDAC3 and HDAC4). Additionally, a linkage between miRNA expression and clinico-pathological parameters like grading, TNM-staging, and hormone activity was found. Moreover, overall and disease-free survival is statistically correlated with the expression of the investigated miRNAs. Overall, we demonstrated that specific miRNAs could be linked to HDAC expression in pNETs. Especially miRNA449a (associated with HDAC3/4) seems to play an important role in pNET proliferation and could be a potential prognostic factor for poor survival. These first data could help, to improve our knowledge of the complex interactions of the epigenetic drivers in pNETs for further therapeutic approaches.

Angiogenesis in pancreatic cancer: current research status and clinical implications

Pancreatic cancer is one of the most lethal malignancies worldwide. Although the standard of care in pancreatic cancer has improved, prognoses for patients remain poor with a 5-year survival rate of < 5%. Angiogenesis, namely, the formation of new blood vessels from pre-existing vessels, is an important event in tumor growth and hematogenous metastasis. It is a dynamic and complex process involving multiple mechanisms and is regulated by various molecules. Inhibition of angiogenesis has been an established therapeutic strategy for many solid tumors. However, clinical outcomes are far from satisfying for pancreatic cancer patients receiving anti-angiogenic therapies. In this review, we summarize the current status of angiogenesis in pancreatic cancer research and explore the reasons for the poor efficacy of anti-angiogenic therapies, aiming to identify some potential therapeutic targets that may enhance the effectiveness of anti-angiogenic treatments.

Prognostic factors of patients with gastroenteropancreatic neuroendocrine neoplasms

There is an increasing trend in the incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) worldwide. The aim of the present study was to identify the prognostic factors of patients with GEP-NENs. A cross-sectional, retrospective chart review study was conducted among patients with pathologically proven GEP-NENs between January 2003 and December 2016 at Kaohsiung Chung-Gung Memorial Hospital. A total of 97 patients who met the inclusion criteria were included (male/female = 56/41, age: 57.7 ± 15.4 years). The presentation, clinical characteristics, and disease outcomes were reviewed and analyzed. The most common primary site of the GEP-NENs was the rectum (49.5%), followed by the pancreas (17.5%), duodenum (11.3%), stomach (10.3%), colon (6.2%), and appendix (5.2%), and most GEP-NENs were hormonally nonfunctional (94.8%). There were 56 tumors classified as G1 neuroendocrine tumors (NETs), 9 as G2 NETs, and 14 as G3 neuroendocrine carcinoma (NEC). Metastasis was found in 15 patients (15%). Curative treatments, such as surgery or endoscopic resection, were performed in 83.5% of patients (n = 81). The mean overall survival duration was 107.2 ± 7.8 months. The estimated 3- and 5-year overall survival rates for all patients were 84% and 82%, respectively. Logistic regression analysis showed that large tumor size, non-rectal NENs, high histopathological grading, lymphatic metastases and distant metastases were associated with poor survival. This study suggested that the presence of lymphatic or distant metastases at diagnosis is an independent risk factor for poor prognosis in patients with GEP-NENs.