Evaluation and Management of Neuroendocrine Tumors of the Pancreas

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.

Effect of the transcription factor YY1 on the development of pancreatic endocrine and exocrine tumors: a narrative review

Pancreatic tumors are classified into endocrine and exocrine types, and the clinical manifestations in patients are nonspecific. Most patients, especially those with pancreatic ductal adenocarcinoma (PDAC), have lost the opportunity to receive for the best treatment at the time of diagnosis. Although chemotherapy and radiotherapy have shown good therapeutic results in other tumors, their therapeutic effects on pancreatic tumors are minimal. A multifunctional transcription factor, Yin-Yang 1 (YY1) regulates the transcription of a variety of important genes and plays a significant role in diverse tumors. Studies have shown that targeting YY1 can improve the survival time of patients with tumors. In this review, we focused on the mechanism by which YY1 affects the occurrence and development of pancreatic tumors. We found that a YY1 mutation is specific for insulinomas and has a role in driving the degree of malignancy. In addition, changes in the circadian network are a key causative factor of PDAC. YY1 promotes pancreatic clock progression and induces malignant changes, but YY1 seems to act as a tumor suppressor in PDAC and affects many biological behaviors, such as proliferation, migration, apoptosis and metastasis. Our review summarizes the progress in understanding the role of YY1 in pancreatic endocrine and exocrine tumors and provides a reasonable assessment of the potential for therapeutic targeting of YY1 in pancreatic tumors.

MRI-based radiomics approach for differentiation of hypovascular non-functional pancreatic neuroendocrine tumors and solid pseudopapillary neoplasms of the pancreas

BACKGROUND

This study aims to investigate the value of radiomics parameters derived from contrast enhanced (CE) MRI in differentiation of hypovascular non-functional pancreatic neuroendocrine tumors (hypo-NF-pNETs) and solid pseudopapillary neoplasms of the pancreas (SPNs).

METHODS

Fifty-seven SPN patients and twenty-two hypo-NF-pNET patients were enrolled. Radiomics features were extracted from T1WI, arterial, portal and delayed phase of MR images. The enrolled patients were divided into training cohort and validation cohort with the 7:3 ratio. We built four radiomics signatures for the four phases respectively and ROC analysis were used to select the best phase to discriminate SPNs from hypo-NF-pNETs. The chosen radiomics signature and clinical independent risk factors were integrated to construct a clinic-radiomics nomogram.

RESULTS

SPNs occurred in younger age groups than hypo-NF-pNETs (P < 0.0001) and showed a clear preponderance in females (P = 0.0185). Age was a significant independent factor for the differentiation of SPNs and hypo-NF-pNETs revealed by logistic regression analysis. With AUC values above 0.900 in both training and validation cohort (0.978 [95% CI, 0.942-1.000] in the training set, 0.907 [95% CI, 0.765-1.000] in the validation set), the radiomics signature of the arterial phase was picked to build a clinic-radiomics nomogram. The nomogram, composed by age and radiomics signature of the arterial phase, showed sufficient performance for discriminating SPNs and hypo-NF-pNETs with AUC values of 0.965 (95% CI, 0.923-1.000) and 0.920 (95% CI, 0.796-1.000) in the training and validation cohorts, respectively. Delong Test did not demonstrate statistical significance between the AUC of the clinic-radiomics nomogram and radiomics signature of arterial phase.

CONCLUSION

CE-MRI-based radiomics approach demonstrated great potential in the differentiation of hypo-NF-pNETs and SPNs.

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.

Prognosis analysis of patients with pancreatic neuroendocrine tumors after surgical resection and the application of enucleation

Objective

To investigate the prognostic factors of patients with pancreatic neuroendocrine tumor (pNETs) after surgical resection, and to analyze the value of enucleation for pNETs without distant metastasis that are well-differentiated (G1) and have a diameter ≤ 4 cm.

Methods

Data from pNET patients undergoing surgical resection between 2004 and 2017 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan–Meier analysis and log-rank testing were used for the survival comparisons. Adjusted HRs with 95% CIs were calculated using univariate and multivariate Cox regression models to estimate the prognostic factors. P < 0.05 was regarded as statistically significant.

Results

This study found that female, cases diagnosed after 2010, and pancreatic body/tail tumors were protective factors for good survival, while histological grade G3, a larger tumor size, distant metastasis, AJCC 8th stage III-IV and age over 60 were independent prognostic factors for a worse OS/CSS. For the pNETs that were well-differentiated (G1) and had a tumor diameter ≤ 4 cm, the type of surgery was an independent factor for the long-term prognosis of this group. Compared with pancreaticoduodenectomy and total pancreatectomy, patients who were accepted enucleation had better OS/CSS.

Conclusion

For pNETs patients undergoing surgical resection, sex, year of diagnosis, tumor location, pathological grade, tumor size, distant metastasis, race, and age were independent prognostic factors associated with the OS/CSS of patients. For pNETs patients with G1 and a tumor diameter less than 4 cm, if the tumor was located over 3 mm from the pancreatic duct, enucleation may be a wise choice.

Surgical Management of Neuroendocrine Tumor Liver Metastases

Patients with neuroendocrine tumor liver metastases (NETLMs) may develop carcinoid syndrome, carcinoid heart disease, or other symptoms from overproduction of hormones. Hepatic resection and cytoreduction is the most direct treatment of NETLMs in eligible patients, and cytoreduction improves symptoms, may reduce the sequelae of carcinoid syndrome, and extends survival. Parenchymal-sparing procedures, such as ablation and enucleation, should be considered during cytoreduction to maximize treatment of multifocal tumors while preserving healthy liver tissue. For patients with large hepatic tumor burdens, high-grade disease, or comorbidities precluding surgery, liver-directed and systemic therapies can be used to palliate symptoms and improve progression-free survival.

A Survival Analysis of Patients with Localized, Asymptomatic Pancreatic Neuroendocrine Tumors: No Surgical Survival Benefit when Examining Appropriately Selected Outcomes

BACKGROUND

Surgical resection for asymptomatic, localized, well-differentiated pancreatic neuroendocrine tumors (PNETs) is common yet controversial. Studies using overall survival as an endpoint have shown a benefit for resection; however, these results may be due to treatment selection bias. We assessed the impact of surgery on both overall (OS) and cancer-specific survival (CSS) for asymptomatic patients with stage I PNETs (AJCC 8th edition).

METHODS

Using SEER data, we identified 709 patients from 2007 to 2015 with well- and moderately differentiated stage I PNETs. We performed Kaplan-Meier survival estimates and adjusted Cox regression for OS and CSS.

RESULTS

Among 709 patients, 628 (88.6%) underwent surgery. There were 37 overall deaths and 11 cancer-specific deaths. All cancer-specific deaths occurred within 3 years of diagnosis. Five-year OS and CSS rates were 89% and 98%, respectively, for the population. Five-year OS rates were 56% in the non-surgical cohort versus 92% in the surgical cohort (log rank, p < 0.001). However, the 5-year CSS rates were similar; 94% in the non-surgical group and 98% in the surgical group (log rank, p  = 0.207). On multivariable analysis, surgery predicted improved OS but not CSS.

CONCLUSION

Although OS is superior in surgically treated stage I PNETs, CSS is not improved, implying treatment selection bias towards surgery being performed in healthier patients. These data suggest that overall survival is a problematic endpoint for the study of asymptomatic, stage I PNETs. Surgery should be individualized for this cohort of patients as the primary cause of death is non-cancer related.

A case report combining Dunbar syndrome and pancreatic neuroendocrine tumor

Background

Dunbar syndrome or median arcuate ligament syndrome is a rare disorder. In this disorder, a malposition of the arcuate ligament compresses the celiac trunk and causes nonspecific symptoms including postprandial pain, abdominal bruit and weight loss. Surgical management is the primary treatment.

Pancreatic neuroendocrine tumors (PNETS) are also rare. It comprises about 1–3% of pancreatic neoplasm. The patient could be symptomatic or asymptomatic depends on the tumor being functional or nonfunctional. In addition, surgical therapy is the choice.

Case presentation

In this paper, we report a case of 28 old female patient complaining from a long term of recurrent abdominal pain that doesn't releive on any kind of treatment, the multislices computerised tomography scan showed compress of the median arcuate ligament with an incidental mass in the tail of pancreas turned out to be a pancreatic neuroendocrine tumor.

Conclusions

The Dunbar syndrome and the Pancreatic neuroendocrine tumors must be kept in mind of phyciciens while the differential diagnosis of any recurrent abdominal pain.

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Dunbar syndrome or median arcuate ligament syndrome is a rare disorder which presented with abdominal pain.

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Celiac artery compression can be diagnosed with Multi slices computer tomography and selective catheter angiography, surgery is the treatment of choice.

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The Dunbar syndrome and the Pancreatic neuroendocrine tumors must be kept in mind during differential diagnosis of recurrent abdominal pain.

Metastatic pancreatic neuroendocrine tumors have decreased somatostatin expression and increased Akt signaling

BACKGROUND

Patients with pancreatic neuroendocrine tumors often present with metastases, which reduce survival. Molecular features associated with pancreatic neuroendocrine tumor tumorigenesis have been reported, but mechanisms of metastasis remain incompletely understood.

METHODS

RNA sequencing was performed on primary and metastatic pancreatic neuroendocrine tumors from 43 patients. Differentially expressed genes were identified, and quantitative polymerase chain reaction used to confirm expression differences. BON cells were transfected with short interfering RNAs and short hairpin RNAs to create knockdowns. Expression changes were confirmed by quantitative polymerase chain reaction, cell viability assessed, and protein levels evaluated by Western blot and immunofluorescence.

RESULTS

Nodal and hepatic metastases had decreased expression of somatostatin compared with primary tumors (P = .003). Quantitative polymerase chain reaction in a validation cohort confirmed 5.3-fold lower somatostatin expression in hepatic metastases (P = .043) with no difference in somatostatin receptor, synaptophysin, or chromogranin A expression. Somatostatin knockdown in BON cells increased cell metabolic activity, viability, and growth. Somatostatin-knockdown cells had significantly higher levels of phosphorylated Akt protein and higher mTOR compared with controls.

CONCLUSION

Pancreatic neuroendocrine tumor metastases have lower expression of somatostatin than primary tumors, and somatostatin knockdown increased growth in pancreatic neuroendocrine tumor cell lines. This was associated with increased activation of Akt, identifying this pathway as a potential mechanism by which loss of somatostatin expression promotes the metastatic phenotype.