Advancements in medical treatment for pancreatic neuroendocrine tumors:A beacon of hope

This editorial highlights the remarkable advancements in medical treatment strategies for pancreatic neuroendocrine tumors(pan-NETs),emphasizing tailored approaches for specific subtypes.Cytoreductive surgery and somatostatin analogs(SSAs)play pivotal roles in managing tumors,while palliative options such as molecular targeted therapy,peptide receptor radionuclide therapy,and chemotherapy are reserved for SSA-refractory patients.Gastrinomas,insul-inomas,glucagonomas,carcinoid tumors and VIPomas necessitate distinct thera-peutic strategies.Understanding the genetic basis of pan-NETs and exploring immunotherapies could lead to promising avenues for future research.This review underscores the evolving landscape of pan-NET treatment,offering renewed hope and improved outcomes for patients facing this complex disease.

Metformin and pancreatic neuroendocrine tumors:A systematic review and meta-analysis

BACKGROUND Most patients with advanced pancreatic neuroendocrine tumors(pNETs)die due to tumor progression.Therefore,identifying new therapies with low toxicity and good tolerability to use concomitantly with the established pNET treatment is relevant.In this perspective,metformin is emerging as a molecule of interest.Retrospective studies have described metformin,a widely used agent for the treatment of patients with type 2 diabetes mellitus(T2DM),to be effective in modulating different tumor-related events,including cancer incidence,recurrence and survival by inhibiting mTOR phosphorylation.This systematic review evaluates the role of T2DM and metformin in the insurgence and post-treatment outcomes in patients with pNET.AIM To systematically analyze and summarize evidence related to the diagnostic and prognostic value of T2DM and metformin for predicting the insurgence and posttreatment outcomes of pNET.METHODS A systematic review of the published literature was undertaken,focusing on the role of T2DM and metformin in insurgence and prognosis of pNET,measured through outcomes of tumor-free survival(TFS),overall survival and progression free survival.RESULTS A total of 13 studies(5674 patients)were included in this review.Analysis of 809 pNET cases from five retrospective studies(low study heterogeneity with I^(2)=0%)confirms the correlation between T2DM and insurgence of pNET(OR=2.13,95%CI=1.56-4.55;P<0.001).The pooled data from 1174 pNET patients showed the correlation between T2DM and post-treatment TFS in pNET patients(hazard ratio=1.84,95%CI=0.78-2.90;P<0.001).The study heterogeneity was intermediate,with I^(2)=51%.A few studies limited the possibility of performing pooled analysis in the setting of metformin;therefore,results were heterogeneous,with no statistical relevance to the use of this drug in the diagnosis and prognosis of pNET.CONCLUSION T2DM represents a risk factor for the insurgence of pNET and is a significant predictor of poor post-treatment TFS of pNET patients.Unfortunately,a few studies with heterogeneous results limited the possibility of exploring the effect of metformin in the diagnosis and prognosis of pNET.

Laparoscopic spleen-preserving total pancreatectomy for the treatment of low-grade malignant pancreatic tumors:Two case reports and review of literature

BACKGROUND Function-preserving pancreatectomy can improve the long-term quality of life of patients with benign or low-grade malignant tumors,such as intraductal papillary mucinous neoplasms(IPMNs)and mucinous cystic neoplasms.However,there is limited literature on laparoscopic spleen-preserving total pancreatectomy(LSpTP)due to technical difficulties.CASE SUMMARY Patient 1 was a 51-year-old male diagnosed with IPMN based on preoperative imaging,showing solid nodules in the pancreatic head and diffuse dilation of the main pancreatic duct with atrophy of the distal pancreas.We performed L-SpTP with preservation of the splenic vessels,and the postoperative pathology report revealed IPMN with invasive carcinoma.Patient 2 was a 60-year-old male with multiple cystic lesions in the pancreatic head and body.L-SpTP was performed,and intraoperatively,the splenic vein was injured and required ligation.Postoperative pathology revealed a mucinous cystic tumor of the pancreas with low-grade dysplasia.Both patients were discharged on postoperative day 7,and there were no major complications during the perioperative period.CONCLUSION We believe that L-SpTP is a safe and feasible treatment for low-grade malignant pancreatic tumors,but more case studies are needed to evaluate its safety,efficacy,and long-term outcomes.

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.

Prediction of the lymphatic,microvascular,and perineural invasion of pancreatic neuroendocrine tumors using preoperative magnetic resonance imaging

BACKGROUND Significant correlation between lymphatic,microvascular,and perineural invasion(LMPI)and the prognosis of pancreatic neuroendocrine tumors(PENTs)was confirmed by previous studies.There was no previous study reported the relationship between magnetic resonance imaging(MRI)parameters and LMPI.AIM To determine the feasibility of using preoperative MRI of the pancreas to predict LMPI in patients with non-functioning PENTs(NFPNETs).METHODS A total of 61 patients with NFPNETs who underwent MRI scans and lymphadenectomy from May 2011 to June 2018 were included in this retrospective study.The patients were divided into group 1(n=34,LMPI negative)and group 2(n=27,LMPI positive).The clinical characteristics and qualitative MRI features were collected.In order to predict LMPI status in NF-PNETs,a multivariate logistic regression model was constructed.Diagnostic performance was evaluated by calculating the receiver operator characteristic(ROC)curve with area under ROC,sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV)and accuracy.RESULTS There were significant differences in the lymph node metastasis stage,tumor grade,neuron-specific enolase levels,tumor margin,main pancreatic ductal dilatation,common bile duct dilatation,enhancement pattern,vascular and adjacent tissue involvement,synchronous liver metastases,the long axis of the largest lymph node,the short axis of the largest lymph node,number of the lymph nodes with short axis>5 or 10 mm,and tumor volume between two groups(P<0.05).Multivariate analysis showed that tumor margin(odds ratio=11.523,P<0.001)was a predictive factor for LMPI of NF-PNETs.The area under the receiver value for the predictive performance of combined predictive factors was 0.855.The sensitivity,specificity,PPV,NPV and accuracy of the model were 48.1%(14/27),97.1%(33/34),97.1%(13/14),70.2%(33/47)and 0.754,respectively.CONCLUSION Using preoperative MRI,ill-defined tumor margins can effectively predict LMPI in patients with NF-PNETs.

Close relationship between mediators of inflammation and pancreatic cancer:Our experience

In this editorial,we focus specifically on the mechanisms by which pancreatic inflammation affects pancreatic cancer.Cancer of the pancreas remains one of the deadliest cancer types.The highest incidence and mortality rates of pancreatic cancer are found in developed countries.Trends of pancreatic cancer incidence and mortality vary considerably worldwide.A better understanding of the etiology and identification of the risk factors is essential for the primary prevention of this disease.Pancreatic tumors are characterized by a complex microenvironment that orchestrates metabolic alterations and supports a milieu of interactions among various cell types within this niche.In this editorial,we highlight the foundational studies that have driven our understanding of these processes.In our experimental center,we have carefully studied the mechanisms of that link pancreatic inflammation and pancreatic cancer.We focused on the role of mast cells(MCs).MCs contain pro-angiogenic factors,including tryptase,that are associated with increased angiogenesis in various tumors.In this editorial,we address the role of MCs in angiogenesis in both pancreatic ductal adenocarcinoma tissue and adjacent normal tissue.The assessment includes the density of c-Kit receptor-positive MCs,the density of tryptase-positive MCs,the area of tryptasepositive MCs,and angiogenesis in terms of microvascularization density.

Pancreatic neuroendocrine tumors:A review of serum biomarkers,staging,and management

Pancreatic neuroendocrine tumors(pNETs)are a heterogeneous group of tumors with complicated treatment options that depend on pathological grading,clinical staging,and presence of symptoms related to hormonal secretion.With regard to diagnosis,remarkable advances have been made:Chromogranin A is recommended as a general marker for pNETs.But other new biomarker modalities,like circulating tumor cells,multiple transcript analysis,microRNA profile,and cytokines,should be clarified in future investigations before clinical application.Therefore,the currently available serum biomarkers are insufficient for diagnosis,but reasonably acceptable in evaluating the prognosis of and response to treatments during follow-up of pNETs.Surgical resection is still the only curative therapeutic option for localized pNETs.However,a debulking operation has also been proven to be effective for controlling the disease.As for drug therapy,steroids and somatostatin analogues are the first-line therapy for those with positive expression of somatostatin receptor,while everolimus and sunitinib represent important progress for the treatment of patients with advanced pNETs.Great progress has been achieved in the combination of systematic therapy with local control treatments.The optimal timing of local control intervention,planning of sequential therapies,and implementation of multidisciplinary care remain pending.

Pathological differential diagnosis of solid-pseudopapillary neoplasm and endocrine tumors of the pancreas

AIM:To investigate differential points of solid-pseudo-papillary neoplasm (SPN) of the pancreas and pancre-atic endocrine tumor (PET).METHODS:Ten cases of SPN and fourteen cases of PET were studied in this retrospective study. Clinical and pathologic features,immunostaining reactions and β-catenin gene mutations were analyzed.RESULTS:The mean age of SPN patients was 25.6 years and these patients had no specific symptoms. The mean diameter of the tumors was 11.0 cm,9/10 cases were cystic or a mixture of solid and cystic structures,and there was hemorrhage and necrosis on the cut surface in 8/10 (80%) cases. Characteristic pseudo-papillary structure and discohesive appearance of the neoplastic cells were observed in all 10 (100%) cases. The results of immunostaining showed that nuclear expression of β-catenin and loss of E-cadherin in all the cases,was only seen in SPN. Molecular studies discov-ered that 9/10 (90%) cases harbored a point mutation of exon 3 in β-catenin gene. On the other hand,the mean age of PET patients was 43.1 years. Eight of 14 cases presented with symptoms caused by hypoglyce-mia,and the other 6 cases presented with symptoms similar to those of SPN. The mean size of the tumors was 2.9 cm,most of the tumors were solid,only 3/14 (21%) were a mixture of solid and cystic structures,and macroscopic hemorrhage and necrosis were much less common (3/14,21%). Histologically,tumor cells were arranged in trabecular,acinar or solid patterns and demonstrated no pseudopapillary structure and discohesive appearance in all 14 (100%) cases. The results of immunostaining and mutation detection were completely different with SPN that membrane and cytoplastic expression of β-catenin without loss of E-cadherin,as well as no mutation in β-catenin gene in all the cases. CONCLUSION:Both macroscopic and microscopic features of SPN are quite characteristic. It is not difficult to distinguish it from PET. If necessary,immunos-taining of β-catenin and E-cadherin is quite helpful to make the differential diagnosis.

CT manifestations and features of solid cystic tumors of the pancreas

Objective: To study retrospectively the manifestations and characteristics of solid cystic tumor of the pan- creas(SCTP) on CT. Methods: Nine patients with solid cystic tumor of the pancreas underwent resection with pathological and immunohistochemical confirmation. All the patients were female, aged 27.7 years on average at onset of the disease. CT scan was performed in patients with or without intravenous injection of contrast medium; it was also performed in the arterial phase in 4 pa- tients. Results: Solid and cystic structures were observed in tumors of the pancreas. Solid structure demonstrated low or iso-density on unenhanced CT, poor enhance- ment in the arterial phase and marked enhancement in the portal venous phase on contrast material-en- hanced CT. Cystic structure showed low density on both pre- and pro-contrast views. The CT findings of tumors with predominantly cystic or equal propor- tion of solid and cystic structure: mural nodules for solid structure, 'floating cloud' signs, or solid and cystic crossing distributions. Cystic structure of tumors predominately solid presenting as a beading appearance under capsule. In round, oval and com- pletely encapsulated tumors in the pancreas, the greater vessel enhanced with well-defined margins on pro-contrast images. No dilatation was observed of the common bile and pancreatic ducts. Conclusion: The characteristics of solid cystic tumor of the pancreas revealed by CT could confirm the di- agnosis of the disease in combination with onset age and sex of patients.

Current surgical management of pancreatic endocrine tumor liver metastases

BACKGROUND: The management of metastatic disease in pancreatic endocrine tumors (PETs) demands a multidisciplinary approach and the cooperation of several medical specialties. The role of surgery is critical, even when a radical excision cannot always be achieved. DATA SOURCES: A PubMed search of relevant articles published up to February 2011 was performed to identify current information about PET liver metastases regarding diagnosis and management, with an emphasis on surgery. RESULTS: The early diagnosis of metastases and their accurate localization, most commonly in the liver, is very important. Surgical options include radical excision, and palliative excision to relieve symptoms in case of failure of medical treatment. The goal of the radical excision is to remove the primary tumor bulk and all liver metastases at the same time, but unfortunately it is not feasible in most cases. Palliative excisions include aggressive tumor debulking surgeries in well-differentiated carcinomas, trying to remove at least 90% of the tumor mass, combined with other additional destructive techniques such as hepatic artery embolization or chemoembolization to treat metastases or chemoembolization to relieve symptoms in cases of rapidly growing tumors. The combination of chemoembolization and systemic chemotherapy results in better response and survival rates. Other local destructive techniques include ethanol injection, cryotherapy and radiofrequency ablation. CONCLUSION: It seems that the current management of PETs can achieve important improvements, even in advanced cases.

Pancreatic neuroendocrine tumors: Therapeutic challenges and research limitations

Pancreatic neuroendocrine tumors(PNETs)are known to be the second most common epithelial malignancy of the pancreas.PNETs can be listed among the slowest growing as well as the fastest growing human cancers.The prevalence of PNETs is deceptively low;however,its incidence has significantly increased over the past decades.According to the American Cancer Society’s estimate,about 4032(>7%of all pancreatic malignancies)individuals will be diagnosed with PNETs in 2020.PNETs often cause severe morbidity due to excessive secretion of hormones(such as serotonin)and/or overall tumor mass.Patients can live for many years(except for those patients with poorly differentiated G3 neuroendocrine tumors);thus,the prevalence of the tumors that is the number of patients actually dealing with the disease at any given time is fairly high because the survival is much longer than pancreatic ductal adenocarcinoma.Due to significant heterogeneity,the management of PNETs is very complex and remains an unmet clinical challenge.In terms of research studies,modest improvements have been made over the past decades in the identification of potential oncogenic drivers in order to enhance the quality of life and increase survival for this growing population of patients.Unfortunately,the majority of systematic therapies approved for the management of advanced stage PNETs lack objective response or at most result in modest benefits in survival.In this review,we aim to discuss the broad challenges associated with the management and the study of PNETs.

Comprehensive treatment of a functional pancreatic neuroendocrine tumor with multifocal liver metastases

A 64-year-old man was admitted to the Sun Yat-Sen University Cancer Center with chief complaints of recurrent abdominal pain and diarrhea for about 3 years and with a history of surgical repair for intestinal perforation owing to stress ulcer. Positron emission tomography （PET）/computed tomography （CT） demonstrated a primary tumor on the pancreatic tail with multifocal liver metastases. Pathological and immunohistochemistry staining revealed the lesion to be a pancreatic neuroendocrine tumor （pNET）. According to the latest World Health Organization （WHO, 2013） classification, the tumor was classified as stage IV fimctional G1 pNET. After referral to the multidisciplinary treatment board （MDT）, the patient was started on periodic dose of omeprazole, somatostatin analogues and Interferon α （IFNα） and had scanning follow-ups. Based upon the imaging results, CT-guided radioactive iodine-125 （1251） seeds implantation therapy, radiofrequency ablation therapy （RFA） or microwave ablation technique were chosen for the treatment of the primary tumor. Transarterial chemoembolization （TACE）, RFA and microwave ablation techniques were decided upon for liver metastases. The patient showed beneficial response to the treatment with clinically manageable low-grade side effects and attained partial remission （RECIST criteria） with a good quality of life.

SIGNIFICANCE OF EXPRESS OF SOME NONHORMONAL ANTIGENS IN PANCREATIC ENDOCRINE TUMORS

Objective: To study the express of some nonhormonal antigens in pancreatic endocrine tumors. Methods: The nonhormonal antigens including Alpha subunit of human chorionic gonadotropin (α HCG), progesterone receptors (PR), 7B2, HISL 19, in normal pancreatic islets and in 52 cases of pancreatic endocrine tumors (PET) were investigated by immunohistochemistry. Results: It was found that HCG can be detected in PET but not in normal islet cells. HCG immunoreactivity was expressed by 3 of 28 (10.7%) benign PET and by 14 of 24 (58.3%) malignant PET.PR was found by 20 of 28(71.4%) benign PET and by 7 of 24 (29%) malignant PET. 7B2 was detected by 23 of 28 (82.1%) benign PET and by 13 of 24 (54.2%) malignant PET. HISL 19 was appeared by 23 of 28 benign PET and by 11 of 24 (46%) malignant PET. Golgitype persisted in 87.5% malignant tumors. Conclusion: The assay of nonhormonal antigens may be well defined the clinico pathological characteristics of PET.

Prognostic factors and survival after surgical resection of pancreatic neuroendocrine tumor with validation of established and modified staging systems

Background: Pancreatic neuroendocrine tumors(PNETs) display wide heterogeneity with highly variable prognosis. This study aimed to identify variables related to survival after surgical resection of PNET.Methods: A total of 143 patients were identified from a prospectively maintained database. Patient characteristics were analyzed and prognostic factors for overall survival and progression-free survival were evaluated. The WHO, ENETS and AJCC scoring systems were applied to the cohort, and their ability to predict patient outcomes were compared.Results: Multivariate analysis found that female gender, lymph node metastases and increasing WHO2010 grade to be independently associated with reduced overall survival(P < 0.05). Patients requiring multi-visceral resection or debulking surgery found to be associated with shortest survival. ROC analysis found the ENETS and AJCC scoring systems to be similarly predictive of 5-year overall survival. Modified Ki67 significantly improved its accuracy in predicting 5-year overall survival(AUROC: 0.699 vs 0.605;P < 0.01).Conclusions: Multi-visceral or debulking surgery is associated with poor outcomes. There seems to be no significant difference between enucleation and anatomical segmental resection. Available scoring systems have reasonable accuracy in stratifying disease severity, with no system identified as being superior.Prognostic stratification with modified grading systems needs further validation before applied in clinical practice.

Endoscopic ultrasound-guided fine-needle aspiration for diagnosing a rare extraluminal duodenal gastrointestinal tumor

Duodenal gastrointestinal stromal tumors(GISTs) are extremely rare disease entities, and the extraluminal type is difficult to diagnose. These tumors have been misdiagnosed as pancreatic tumors; hence, pancreaticoduodenectomy has been performed, although partial duodenectomy can be performed if accurately diagnosed. Developing a diagnostic methodology including endoscopic ultrasonography(EUS) and fine-needle aspiration(FNA) has allowed us to diagnose the tumor directly through the duodenum. Here, we present a case of a 50-year-old woman with a 27-mm diameter tumor in the pancreatic uncus on computed tomography scan. EUS showed a well-defined hypoechoic mass in the pancreatic uncus that connected to the duodenal proper muscular layer and was followed by endoscopic ultrasoundguided fine-needle aspiration(EUS-FNA). Histological examination showed spindle-shaped tumor cells positively stained for c-kit. Based on these findings, the tumor was finally diagnosed as a duodenal GIST of the extraluminal type, and the patient underwent successful mass resection with partial resection of the duodenum. This case suggests that EUS and EUS-FNA are effective for diagnosing the extraluminal type of duodenal GISTs, which is difficult to differentiate from pancreatic head tumor, and for performing the correct surgical procedure.

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.

Molecular alterations in pancreatic tumors

Genetic alterations in pancreatic tumors can usually be classified in:(1)Mutational activation of oncogenes;(2)Inactivation of tumor suppressor genes;and(3)Inactivation of genome maintenance genes controlling the repair of DNA damage.Endoscopic ultrasound-guided fine-needle aspiration has improved preoperative diagnosis,but the management of patients with a pancreatic lesion is still challenging.Molecular testing could help mainly in solving these“inconclusive”specimens.The introduction of multi-gene analysis approaches,such as next-generation sequencing,has provided a lot of useful information on the molecular characterization of pancreatic tumors.Different types of pancreatic tumors(e.g.,pancreatic ductal adenocarcinomas,intraductal papillary mucinous neoplasms,solid pseudopapillary tumors)are characterized by specific molecular alterations.The aim of this review is to summarize the main molecular alterations found in pancreatic tumors.

Surgery for pancreatic tumors in the midst of COVID-19 pandemic

The spread of the new coronavirus(COVID-19)infection in 2020 has had a significant impact on the treatment of cancer worldwide.During the COVID-19 pandemic,the biggest challenge for pancreatic surgeons is the difficulty in providing oncological care.In this review article,from the standpoint of surgeons,we explain the concept of triaging of patients with pancreatic tumors under the COVID-19 pandemic,and the actual impact of COVID-19 on the treatment of patients with pancreatic tumors.The most vital points in selecting the best therapeutic approach for patients with pancreatic tumors during this pandemic are(1)Oncologists need to tailor the treatment plan based on the COVID-19 phase,tumor malignant potential,and patients’comorbidities;and(2)Optimal treatment for pancreatic cancer should be planned according to the condition of each patient and tumor resectability based on national comprehensive cancer network resectability criteria.To choose the best therapeutic approach for patients with pancreatic tumors during this pandemic,we need to tailor the treatment plan based on elective surgery acuity scale(ESAS).Newly established ESAS for pancreatic tumor and flowchart indicating the treatment strategy of pancreatic cancer,are feasible to overcome this situation.

Central pancreatectomy:a new technique for resection of selected pancreatic tumors

BACKGROUND:Pancreatic tumors located in the neck region usually require pancreaticoduodenectomy or splenopancreatectomy.For small benign tumors enucleation is not usually feasible due to their size and localization;then pancreatectomy is often needed.Central pancreatectomy consists of a limited resection of the midportion of the pancreas and can be offered in benign and low-grade malignant tumors of the neck of the pancreas.The study aimed to evaluate whether central pancreatectomy has a place in pancreatic surgery. METHODS:In this study,which covered a period of 14 months,we performed central pancreatectomy in four selected patients.Preoperative evaluation and operative frozen section biopsy in indicated cases allowed proper selection for the procedure.Operative details,complications and follow-up were recorded. RESULTS:Four patients,two with serous cystadenoma,and one with an islet cell tumor,and one with a hydatid cyst, were identified for the procedure.The mean tumor size was 3 cm,the mean operative time was 217.5 minutes,and the mean blood loss was 382.5 ml.There was no morbidity or mortality in this series.No endocrine or exocrine deficiency was observed in any patient during a mean follow-up of 22.7 months. CONCLUSIONS:Central pancreatectomy is a procedure that offers excellent results in benign and low-grade malignant tumors.It preserves functional elements(endocrine and exocrine)of the pancreas and also eliminates the infective and hematological effects of splenectomy.Thus,central pancreatectomy should be included in the armamentarium of pancreatic surgery,and in order to obtain good results,proper indications and adequate experience are recommended.

Active surveillance in metastatic pancreatic neuroendocrine tumors:A 20-year single-institutional experience

BACKGROUND Pancreatic neuroendocrine tumors(PanNETs)are heterogeneous and indolent;systemic therapy is not essential for every patient with metastatic PanNET.The National Comprehensive Cancer Network guidelines state that delaying treatment is an option for PanNET with distant metastasis,if the patient has stable disease.However,specific factors that influence surveillance were not mentioned.In addition,data regarding the period of active surveillance in patients with metastatic PanNET are lacking.AIM To specifically determine factors influencing active surveillance in patients with liver metastatic nonfunctioning PanNETs(NF-PanNETs).METHODS Seventy-six patients with liver metastatic NF-PanNETs who received active surveillance from a high-volume institution were enrolled.Time to disease progression(TTP)and time to initiation of systemic therapy were determined.RESULTS Thirty-one(40.8%)patients had recurrent liver disease after R0 resection;45(59.2%)were diagnosed with liver metastasis.The median follow-up period was 42 mo and 90.7%patients were observed to have disease progression.The median TTP(mTTP)was 10 mo.Multivariate analysis showed that the largest axis of the liver metastasis>5 mm(P=0.04),non-resection of the primary tumor(P=0.024),and T3-4 stage(P=0.028)were associated with a shorter TTP.The mTTP in patients with no risk factors was 24 mo,which was significantly longer than that in patients with one(10 mo)or more(6 mo)risk factors(P<0.001).A nomogram with three risk factors showed reasonable calibration,with a C-index of 0.603(95%confidence interval:0.47-0.74).CONCLUSION Active surveillance may only be safe for metastatic NF-PanNET patients with favorable risk factors,and other patients progressed rapidly without treatment.Further studies with a larger sample size and a control group are needed.