Consensus of clinical diagnosis and treatment for non-functional pancreatic neuroendocrine neoplasms with diameter<2 cm

In clinical practice,pancreatic neuroendocrine neoplasms(pNENs)with a diameter smaller than 2 cm are commonly referred to as small pNENs.Due to their generally favorable biological characteristics,the diagnosis and treatment of small pNENs differ from other pNENs and are somewhat controversial.In response to this,the Chinese Pancreatic Surgery Association,Chinese Society of Surgery,Chinese Medical Association have developed a consensus on the diagnosis and treatment of small pNENs,which is based on evidence-based medicine and expert opinions.This consensus covers various topics,including concepts,disease assessment,treatment selection,follow-up,and other relevant aspects.

Surgical management of pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms are a rare and complex group of neoplastic lesions that develop from pancreatic islet cells.Their incidence has dramatically increased during the last two decades.Due to its complex nature and pathophysiological behaviour,surgical management continues to evolve.Surgery remains the cornerstone of treatment for most non-functional and functional pancreatic neuroendocrine tumours,while lymphadenectomy remains a controversial subject.Different techniques,such as pancreas-preserving and minimally invasive approaches,continue to evolve and offer the same overall outcomes as open surgery.This comprehensive review describes in detail the current and most up-todate classification and staging of pancreatic neuroendocrine tumours,explores the rationale for nonsurgical and surgical management,and focuses on surgical treatment and more specifically,on minimally invasive approaches.

Pancreatic neuroendocrine tumors:Are tumors smaller than 2 cm truly indolent?

BACKGROUND Pancreatic neuroendocrine tumors(PNETs)are relatively rare but rank as the second most common pancreatic neoplasm.They can be functional,causing early metabolic disturbances due to hormone secretion,or non-functional and diagnosed later based on tumor size-related symptoms.Recent diagnoses of PNETs under 2 cm in size have sparked debates about their management;some practitioners advocate for surgical removal and others suggest observation due to the tumors’lower potential for malignancy.However,it is unclear whether managing these small tumors expectantly is truly safe.AIM To evaluate poor prognostic factors in PNETs based on tumor size(>2 cm or<2 cm)in surgically treated patients.METHODS This cohort study included 64 patients with PNETs who underwent surgical resection between 2006 and 2019 at a high-complexity reference hospital in Medellín,Colombia.To assess patient survival,quarterly follow-ups were conducted during the first year after surgery,followed by semi-annual con-sultations at the hospital's hepatobiliary surgery department.Qualitative variables were described using absolute and relative frequencies,and quantitative variables were expressed using measures of central tendency and their corresponding measures of dispersion.RESULTS The presence of lymph node involvement,neural involvement,and lymphovascular invasion were all associated with an increased risk of mortality,with hazard ratios of 5.68(95%CI:1.26–25.61,P=0.024),6.44(95%CI:1.43–28.93,P=0.015),and 24.87(95%CI:2.98–207.19,P=0.003),respectively.Neural involvement and lymphovascular invasion were present in tumors smaller than 2 cm in diameter and those larger than 2 cm in diameter.The recurrence rates between the two tumor groups were furthermore similar:18.2%for tumors smaller than 2 cm and 21.4%for tumors larger than 2 cm.Patient survival was additionally comparable between the two tumor groups.CONCLUSION Tumor size does not dictate prognosis;lymph node and lymphovascular involvement affect mortality,which high-lights that histopathological factors-rather than tumor size-may play a role in management.

Percutaneous transhepatic intraportal biopsy using gastroscope biopsy forceps for diagnosis of a pancreatic neuroendocrine neoplasm:A case report

BACKGROUND Pancreatic neuroendocrine neoplasms(PNENs)are a rare group of neoplasms originating from the islets of the Langerhans.Portal vein tumor thrombosis has been reported in 33%of patients with PNENs.While the histopathological diagnosis of PNENs is usually based on percutaneous biopsy or endoscopic ultrasound-guided fine-needle aspiration(EUS-FNA),these approaches may be impeded by gastric varices,poor access windows,or anatomically contiguous critical structures.Obtaining a pathological diagnosis using a gastroscope biopsy forceps via percutaneous transhepatic intravascular pathway is an innovative method that has rarely been reported.CASE SUMMARY A 72-year-old man was referred to our hospital for abdominal pain and melena.Abdominal contrast-enhanced magnetic resonance imaging revealed a wellenhanced tumor(size:2.4 cm×1.2 cm×1.2 cm)in the pancreatic tail with portal vein invasion.Traditional pathological diagnosis via EUS-FNA was not possible because of diffuse gastric varices.We performed a percutaneous transportal biopsy of the portal vein tumor thrombus using a gastroscope biopsy forceps.Histopathologic examination revealed a pancreatic neuroendocrine neoplasm(G2)with somatostatin receptors 2(+),allowing systemic treatment.CONCLUSION Intravascular biopsy using gastroscope biopsy forceps appears to be a safe and effective method for obtaining a histopathological diagnosis.Although welldesigned clinic trials are required to obtain more definitive evidence,this procedure may help improve the diagnosis of portal vein thrombosis and related diseases.

Update on surgical treatment of pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms(PNENs) are rare and account for only 2%-4% of all pancreatic neoplasms. All PNENs are potential(neurendocrine tumors PNETs) or overt(neuroendocrine carcinomas PNECs) malignant,but a subset of PNETs is low-risk. Even in case of low-risk PNETs surgical resection is frequently required to treat hormone-related symptoms and to obtain an appropriate pathological diagnosis. Low-risk PNETs in the body and the tail are ideal for minimallyinvasive approaches which should be tailored to the individual patient. Generally,surgeons must aim for parenchyma sparing in these cases. In high-risk and malignant PNENs,indications for tumor resection are much wider than for pancreatic adenocarcinoma,in many cases due to the relatively benign tumor biology. Thus,patients with locally advanced and metastatic PNETs may benefit from extensive resection. In experienced hands,even multi-organ resections are accomplished with acceptable perioperative morbidity and mortality rates and are associated with excellent long term survival. However,poorly differentiated neoplasms with high proliferation rates are associated with a dismal prognosis and may frequently only be treated with chemotherapy. The evidence on surgical treatment of PNENs stems from reviews of mostly singlecenter series and some analyses of nation-wide tumor registries. No randomized trial has been performed to compare surgical and non-surgical therapies in potentially resectable PNEN. Though such a trial would principally be desirable,ethical considerations and the heterogeneity of PNENs preclude realization of such a study. In the current review,we summarize recent advances in the surgical treatment of PNENs.

Survival comparison between primary hepatic neuroendocrine neoplasms and primary pancreatic neuroendocrine neoplasms and the analysis on prognosis-related factors

Background:Primary hepatic neuroendocrine neoplasms(PHNENs)are extremely rare and few articles have compared the prognosis of PHNENs with other neuroendocrine neoplasms(NENs).This study aimed to investigate the different prognosis between PHNENs and pancreatic NEN(Pan NENs)and evaluate the relevant prognosis-related factors.Methods:From January 2012 to October 2016,a total of 44 NENs patients were enrolled and divided into two groups according to the primary tumor location which were named group PHNENs(liver;n=12)and group Pan NENs(pancreas;n=32).Demographic,clinical characteristics and survival data were compared between the two groups with Kaplan-Meier method and log-rank tests.Prognostic factors were analyzed using the Cox regression model.Results:The overall survival of group PHNENs and group Pan NENs were 25.4±6.7 months and 39.8±3.7 months,respectively(P=0.037).The cumulative survival of group Pan NENs was significantly higher than that of group PHNENs(P=0.029).Univariate analysis revealed that sex,albumin,total bilirubin,total bile acid,aspartate aminotransferase,alkaline phosphatase,α-fetoprotein and carbohydrate antigen 19-9,histological types,treatments and primary tumor site were the prognostic factors.Further multivariate analysis indicated that albumin(P=0.008),histological types NEC(P=0.035)and treatments(P=0.005)were the independent prognostic factors.Based on the histological types,the cumulative survival of patients with well-differentiated neuroendocrine tumor was significant higher than that of patients with poorly differentiated neuroendocrine carcinoma in group PHNENs(P=0.022),but not in group Pan NENs(P>0.05).According to the different treatments,patients who received surgery had significantly higher cumulative survival than those with conservative treatment in both groups(P<0.05).Conclusions:PHNENs have lower survival compared to Pan NENs.Histological types and treatments affect the prognosis.Surgical resection still remains the first line of treatment for resectable lesions and can significantly improve the survival.

Immunohistochemical analysis of the Wnt/β-catenin signaling pathway in pancreatic neuroendocrine neoplasms

AIM: To investigate the role of the Wnt/β-catenin pathway in pancreatic neuroendocrine neoplasms(PanN ENs). METHODS: Tissue microarrays containing 88 PanN ENs were immunohistochemically labeled with antibodies to β-catenin, E-cadherin, adenomatous polyposis coli(APC), chromogranin and synaptophysin. One case had only metastatic tumors resected, whereas others(n = 87) received pancreatectomy with or without partial hepatectomy. Pathology slides, demographic, clinicopathologic, and follow up data were reviewed. Patients' demographics, clinicopathologic features, and immunohistochemical results from 87 primary tumors were compared between patients with low stage(stage Ⅰ/Ⅱ) and high stage(stage Ⅲ/Ⅳ) tumors. In addition, correlation of immunohistochemical results from primary tumors with disease-specific survival(DSS) was evaluated. RESULTS: Strong membranous β-catenin staining in the primary tumor was observed in all 13 stage Ⅲ/Ⅳ Pan NENs as compared to 47%(35/74) of stage Ⅰ/Ⅱtumors(P < 0.01). However, the strong membranous β-catenin staining was unassociated with tumor grade or DSS. Decreased membranous β-catenin staining was associated with decreased membranous E-cadherin labeling. Nuclear β-catenin staining was seen in 15%(2/13) of stage Ⅲ/Ⅳ Pan NENs as compared to 0%(0/74) of stage Ⅰ/Ⅱ tumors(P = 0.02). The case with metastasectomy only also showed nuclear β-catenin staining. Two of the three cases with nuclear β-catenin staining were familial adenomatous polyposis(FAP) patients. Lack of APC expression was seen in 70%(57/81) of the cases, including the 3 cases with nuclear β-catenin staining. Expression of E-cadherin and APC in primary tumor was not correlated with tumor grade, tumor stage, or disease specific survival. CONCLUSION: The Wnt/β-catenin pathway was altered in some PanN ENs, but did not Impact DSS. PanN ENs in FAP patients demonstrated nuclear β-catenin accumulation and loss of APC.

Advances in medical treatment for pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms(PanNENs)are rare neoplasms with strong heterogeneity that have experienced an increasing incidence rate in recent years.For patients with locally advanced or distant metastatic PanNENs,systemic treatment options vary due to the different differentiations,grades and stages.The available options for systemic therapy include somatostatin analogs,molecularly targeted agents,cytotoxic chemotherapeutic agents,immune checkpoint inhibitors,and peptide receptor radionuclide therapy.In addition,the development of novel molecularly targeted agents is currently in progress.The sequence of selection between different chemotherapy regimens has been of great interest,and resistance to chemotherapeutic agents is the major limitation in their clinical application.Novel agents and high-level clinical evidence continue to emerge in the field of antiangiogenic agents.Peptide receptor radionuclide therapy is increasingly employed for the treatment of advanced neuroendocrine tumors,and greater therapeutic efficacy may be achieved by emerging radiolabeled peptides.Since immune checkpoint inhibitor monotherapies for PanNENs appear to have limited antitumor activity,dual immune checkpoint inhibitor therapies or combinations of antiangiogenic therapies and immune checkpoint inhibitors have been applied in the clinic to improve clinical efficacy.Combining the use of a variety of agents with different mechanisms of action provides new possibilities for clinical treatments.In the future,the study of systemic therapies will continue to focus on the screening of the optimal benefit population and the selection of the best treatment sequence strategy with the aim of truly achieving individualized precise treatment of PanNENs.

Correlation between radiologic features on contrastenhanced CT and pathological tumor grades in pancreatic neuroendocrine neoplasms

Contrast-enhanced computed tomography(CT)contributes to the increasing detection of pancreatic neuroendocrine neoplasms(PNENs).Nevertheless,its value for differentiating pathological tumor grades is not well recognized.In this report,we have conducted a retrospective study on the relationship between the 2017 World Health Organization(WHO)classification and CT imaging features in 94 patients.Most of the investigated features eventually provided statistically significant indicators for discerning PNENs G3 from PNENs G1/G2,including tumor size,shape,margin,heterogeneity,intratumoral blood vessels,vascular invasion,enhancement pattern in both contrast phases,enhancement degree in both phases,tumor-to-pancreas contrast ratio in both phases,common bile duct dilatation,lymph node metastases,and liver metastases.Ill-defined tumor margin was an independent predictor for PNENs G3 with the highest area under the curve(AUC)of 0.906 in the multivariable logistic regression and receiver operating characteristic curve analysis.The portal enhancement ratio(PER)was shown the highest AUC of 0.855 in terms of quantitative features.Our data suggest that the traditional contrastenhanced CT still plays a vital role in differentiation of tumor grades and heterogeneity analysis prior to treatment.

Pancreatic Neuroendocrine Neoplasms: Correlation between MR Features and Pathological Tumor Grades

This study investigated the accuracy of MRI features in differentiating the pathological grades of pancreatic neuroendocrine neoplasms（PNENs）. A total of 31 PNENs patients were retrospectively evaluated, including 19 cases in grade 1, 5 in grade 2, and 7 in grade 3. Plain and contrastenhanced MRI was performed on all patients. MRI features including tumor size, margin, signal intensity, enhancement patterns, degenerative changes, duct dilatation and metastasis were analyzed. Chi square tests, Fisher＇s exact tests, one-way ANOVA and ROC analysis were conducted to assess the associations between MRI features and different tumor grades. It was found that patients with older age, tumors with higher TNM stage and without hormonal syndrome had higher grade of PNETs（all P〈0.05）. Tumor size, shape, margin and growth pattern, tumor pattern, pancreatic and bile duct dilatation and presence of lymphatic and distant metastasis as well as MR enhancement pattern and tumor-topancreas contrast during arterial phase were the key features differentiating tumors of all grades（all P〈0.05）. ROC analysis revealed that the tumor size with threshold of 2.8 cm, irregular shape, pancreatic duct dilatation and lymphadenopathy showed satisfactory sensitivity and specificity in distinguishing grade 3 from grade 1 and grade 2 tumors. Features of peripancreatic tissue or vascular invasion, and distant metastasis showed high specificity but relatively low sensitivity. In conclusion, larger size, poorlydefined margin, heterogeneous enhanced pattern during arterial phase, duct dilatation and the presence of metastases are common features of higher grade PNENs. Plain and contrast-enhanced MRI provides the ability to differentiate tumors with different pathological grades.

Risk factors for lymph node metastasis in patients with pancreatic neuroendocrine neoplasms

BACKGROUND Although PNENs generally have a better prognosis than pancreatic cancers,some PNENs display malignant behavior including lymph node(LN)metastasis.Complete tumor resection can be the only potentially curative treatment for patients with resectable PNENs.However,the indications for LN dissection are still controversial.Over the last decade,minimally invasive surgery such as laparoscopic pancreatic surgery(LPS)has been increasingly performed for pancreatic tumors including PNENs.AIM To investigate the risk factors for LN metastasis in PNENs and to select appropriate patients for limited surgery by LPS.METHODS From April 2001 to December 2019,92 patients underwent pancreatic resection for PNENs at Kumamoto University Hospital.Finally,82 patients were enrolled in this study.Using perioperative factors,we examined the predictive factors for LN metastasis in PNENs.RESULTS Among the 82 patients,the percentage of LN metastasis according to the pathological findings was 12%(10/82 cases).The median tumor size was 12 mm(range:5-90 mm).The median tumor size in the LN-positive group(37 mm)was significantly larger than that in the LN-negative group(12 mm)(P=0.0001).Multivariate analyses revealed that larger tumor size(≥20 mm)was an independent risk factor for LN metastasis(odds ratio 16.8,P=0.0062).In patients with small tumors(≤10 mm),LN metastasis was not found.CONCLUSION Larger tumor size(≥20 mm)is an independent risk factor for LN metastasis in PNENs.In smaller PNENs(≤10 mm),we may be able to choose limited surgery without LN dissection.

Current update on imaging for pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms(panNEN)are a heterogeneous group of tumors with differing pathological,genetic,and clinical features.Based on clinical findings,they may be categorized into functioning and nonfunctioning tumors.Adoption of the 2017 World Health Organization classification system,particularly its differentiation between grade 3,well-differentiated pancreatic neuroendocrine tumors(panNET)and grade 3,poorly-differentiated pancreatic neuroendocrine carcinomas(panNEC)has emphasized the role imaging plays in characterizing these lesions.Endoscopic ultrasound can help obtain biopsy specimen and assess tumor margins and local spread.Enhancement patterns on computed tomography(CT)and magnetic resonance imaging(MRI)may be used to classify panNEN.Contrast enhanced MRI and diffusion-weighted imaging have been reported to be useful for characterization of panNEN and quantifying metastatic burden.Current and emerging radiotracers have broadened the utility of functional imaging in evaluating panNEN.Fluorine-18 fluorodeoxyglucose positron emission tomography(PET)/CT and somatostatin receptor imaging such as Gallium-681,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid–octreotate PET/CT may be useful for improved identification of panNEN in comparison to anatomic modalities.These new techniques can also play a direct role in optimizing the selection of treatment for individuals and predicting tumor response based on somatostatin receptor expression.In addition,emerging methods of radiomics such as texture analysis may be a potential tool for staging and outcome prediction in panNEN,however further investigation is required before clinical implementation.

Progress in immunotherapy for neuroendocrine neoplasm of the digestive system

Neuroendocrine neoplasms(NENs)are rare heterogeneous tumors that can develop in almost any organ,with the digestive organs,including the gastrointestinal tract and pancreas being the most commonly affected sites.Despite the fact that advances in initial therapies have progressed,there is presently no recognized effective treatment for advanced NEN.Immune checkpoint inhibitors(ICIs)have shown superior efficacy in treating several types of solid tumors.Despite their successful role in the treatment of partial NENs,such as small cell lung cancer,and Merkel cell carcinoma,the role of ICIs in most of the NENs remains limited.Nevertheless,due to their specific anti-tumor mechanisms and acceptable safety profile,ICIs are a promising avenue for further study in NENs therapy.Recent clinical trials have illustrated that combination therapy with ICI is more efficient than monotherapy,and multiple clinical trials are constantly ongoing to evaluate the efficacy and safety of these combination therapies.Therefore,the purpose of this review is to provide a comprehensive summary of the clinical progress of immunotherapy in NENs affecting the digestive system,with a specific emphasis on the application of programmed cell death protein 1/programmed death receptor ligand 1 inhibitor.Furthermore,this review has an exploration of the potential beneficiary population and the inherent value of utilizing immunotherapy in the management of NENs.

Comparison of imaging-based and pathological dimensions in pancreatic neuroendocrine tumors

AIM To establish the ability of magnetic resonance(MR) and computer tomography(CT) to predict pathologic dimensions of pancreatic neuroendocrine tumors(Pan NET) in a caseload of a tertiary referral center.METHODS Patients submitted to surgery for Pan NET at the Surgical Unit of the Pancreas Institute with at least 1 preoperative imaging examination(MR or CT scan) from January 2005 to December 2015 were included and data retrospectively collected. Exclusion criteria were: multifocal lesions, genetic syndromes, microadenomas or mixed tumors, metastatic disease and neoadjuvant therapy. Bland-Altman(BA) and Mountain-Plot(MP) statistics were used to compare size measured by each modality with the pathology size. Passing-Bablok(PB) regression analysis was used to check the agreement between MR and CT.RESULTS Our study population consisted of 292 patients. Seventy-nine(27.1%) were functioning Pan NET. The mean biases were 0.17 ± 7.99 mm, 1 ± 8.51 mm and 0.23 ± 9 mm, 1.2 ± 9.8 mm for MR and CT, considering the overall population and the subgroup of non-functioning-Pan NET, respectively. Limits of agreement(LOA) included the vast majority of observations, indicating a good agreement between imaging and pathology. The MP further confirmed this finding and showed that the two methods are unbiased with respect to each other. Considering ≤ 2 cm non-functioning-Pan NET, no statistical significance was found in the size estimation rate of MR and CT(P = 0.433). PBR analysis did not reveal significant differences between MR, CT and pathology.CONCLUSION MR and CT scan are accurate and interchangeable imaging techniques in predicting pathologic dimensions of Pan NET.

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

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

Medical treatment for gastro-entero-pancreatic neuroendocrine tumours

Gastro-entero-pancreatic neuroendocrine neoplasms(GEPNENs) represents a various family of rare tumours. Surgery is the first choice in GEP-NENs patients with localized disease whilst in the metastatic setting many other treatment options are available. Somatostatin analogues are indicated for symptoms control in functioning tumours. Furthermore they may be effective to inhibit tumour progression. GEP-NENs pathogenesis has been extensively studied in the last years therefore several driver mutations pathway genes have been identified as crucial factors in their tumourigenesis. GEP-NENs can over-express vascular endothelial growth factor(VEGF), basic-fibroblastic growth factor, transforming growth factor(TGF-α and-β), platelet derived growth factor(PDGF), insulin-like growth factor-1(IGF-1) and their receptors PDGF receptor, IGF-1 receptor, epidermal growth factor receptor, VEGF receptor, and c-kit(stem cell factor receptor) that can be considered as potential targets. The availability of new targeted agents, such as everolimus and sunitinib that are effective in advanced and metastatic pancreatic neuroendocrine tumours, has provided new treatment opportunities. Many trials combing new drugs are ongoing.

Pancreatic neuroendocrine tumors G3 and pancreatic neuroendocrine carcinomas: Differences in basic biology and treatment

In 2017 the World Health Organization revised the criteria for classification of pancreatic neuroendocrine neoplasms(p NENs) after a consensus conference at the International Agency for Research on Cancer. The major change in the new classification was to subclassify the original G3 group into well-differentiated pancreatic neuroendocrine tumors G3(p NETs G3) and poorly differentiated pancreatic neuroendocrine carcinomas(p NECs), which have been gradually proven to be completely different in biological behavior and clinical manifestations in recent years. In 2019 this major change subsequently extended to NENs involving the entire digestive tract. The updated version of the p NENs grading system marks a growing awareness of these heterogeneous tumors. This review discusses the clinicopathological, genetic and therapeutic features of poorly differentiated p NECs and compare them to those of well-differentiated p NETs G3. For p NETs G3 and p NECs(due to their lower incidence), there are still many problems to be investigated. Previous studies under the new grading classification also need to be reinterpreted. This review summarizes the relevant literature from the perspective of the differences between p NETs G3 and p NECs in order to deepen understanding of these diseases and discuss future research directions.

Functionality is not an independent prognostic factor for pancreatic neuroendocrine tumors

BACKGROUND Pancreatic neuroendocrine neoplasms(pNENs)that produce hormones leading to symptoms are classified as functional tumors,while others are classified as nonfunctional tumors.The traditional view is that functionality is a factor that affects the prognosis of pNEN patients.However,as the sample sizes of studies have increased,researches in recent years have proposed new viewpoints.AIM To assess whether functionality is an independent factor for predicting the prognosis of pNEN patients.METHODS From January 2004 to December 2016,data of patients who underwent surgery at the primary site for the treatment of pNENs from the Surveillance,Epidemiology,and End Results(SEER)database and West China Hospital database were retrospectively analyzed.RESULTS Contemporaneous data from the two databases were analyzed separately as two cohorts and then merged as the third cohort to create a large sample that was suitable for multivariate analysis.From the SEER database,age(P=0.006)and T stage(P<0.001)were independent risk factors affecting the survival.From the West China Hospital database,independent prognostic factors were age(P=0.034),sex(P=0.032),and grade(P=0.039).The result of the cohort consisting of the combined populations from the two databases showed that race(P=0.015),age(P=0.002),sex(P=0.032)and T stage(P<0.001)were independent prognostic factors.In the West China Hospital database and in the total population,nonfunctional pNETs and other functional pNETs tended to have poorer prognoses than insulinoma.However,functionality was not associated with the survival time of patients with pNETs in the multivariate analysis.CONCLUSION Functionality is not associated with prognosis.Race,age,sex,and T stage are independent factors for predicting the survival of patients with pNETs.

Pancreatic Neuroendocrine Tumors in the 21^stCentury—An Update

Pancreatic neuroendocrine tumors (PNETs) are rare, reported to account for less than 1% - 2% of all pancreatic tumors. This, however, is likely an underestimation, as improved radiologic techniques and heightened awareness have resulted in an increase in the detection of incidentalomas, with estimations of true prevalence as high as 10%. The term “PNET” is an umbrella name that encompasses a heterogeneous group of neoplasms each with distinct clinical presentations, diagnostic radiographic features, management principles, and tumor/patient outcomes. In this context, accurate diagnosis is challenging, and management guidelines remain unclear. A high degree of clinical suspicion is required for best patient management. This manuscript provides an update on PNETs in the 21st century, in which we re-examine the terminology, epidemiology, classification, etiopathogenesis, radiographic and histopathologic diagnostic features, management for localized and metastatic disease, as well as a review of features defining functional and non-functional PNETS, and finally deliberates on the prognosis and predictive features of this unpredictable and largely unfathomable neoplasm.

Pancreatic Neuroendocrine Tumors Are Characterized by Loss of Noxa Expression that Can be Recovered by the Proteasome Inhibitor Bortezomib

Prognosis in well-differentiated neuroendocrine carcinomas varies considerably and therapeutic targets for metastatic disease are urgently needed. cDNA microarray studies in our laboratory revealed a significantly lower expression level of the Noxa-gene in human pancreatic neuroendocrine neoplasms (PNENs) as compared to normal islet cells. To determine the validity of the downregulation of Noxa in PNENs, benign and malignant tumors from both sporadic and MEN1 patients were selected for expression analysis. To further verify the findings, neuroendocrine BON1 and QGP cell lines were tested for Noxa expression and its recovery by treatment with the proteasome inhibitor bortezomib. The expression of Noxa was significantly downregulated in 20 PNENs (p = 0.0036). There was no significant difference between MEN1 and sporadic tumors. However, the malignant tumors showed a more significant decrease as compared to benign tumors?(p = 0.0385) and the decrease in expression in tumors greater than 20 mm was very highly significant (p Noxa protein in the absence of the proteasome inhibitor, Bortezomib. After stimulation with the drug for 16 h, the expression was induced in both cell lines that are correlated with an increase in the level of c-MYC expression, cleaved caspase 3 and cell death. The low expression level of Noxa in PNENs contributes to the inability of these tumor entities to undergo apoptosis. The recovery of Noxa expression following treatment with the proteasome inhibitor, bortezomib, leading to caspase activation and cell death supports the use of such drugs for the treatment of these tumor entities.