Surgical treatment of sporadic pancreatic neuroendocrine tumors: a state of the art review

An integrative view on glucagon function and putative role in the progression of pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC)

Cancer metabolism research area evolved greatly, however, is still unknown the impact of systemic metabolism control and diet on cancer. It makes sense that systemic regulators of metabolism can act directly on cancer cells and activate signalling, prompting metabolic remodelling needed to sustain cancer cell survival, tumour growth and disease progression. In the present review, we describe the main glucagon functions in the control of glycaemia and of metabolic pathways overall. Furthermore, an integrative view on how glucagon and related signalling pathways can contribute for pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC) progression, since pancreas and liver are the major organs exposed to higher levels of glucagon, pancreas as a producer and liver as a scavenger. The main objective is to bring to discussion some glucagon-dependent mechanisms by presenting an integrative view on microenvironmental and systemic aspects in pNETs and HCC biology.

Novel scoring system for recurrence risk classification of surgically resected G1/2 pancreatic neuroendocrine tumors - Retrospective cohort study

BACKGROUND

Existing staging systems for pancreatic neuroendocrine neoplasms only provide accuracy in stratifying disease severity without enough sensitivity in prognosis predicting. Previously presented models mainly set overall survival as endpoint but ignore the importance of recurrence.

METHODS

Univariate and multivariate analyses were retrospectively conducted on the potential prognostic factors of 245 patients who underwent curable surgery of G1/2 pancreatic neuroendocrine tumors from December 2002 to May 2018 in our institute. Proposed model based on statistically significant factors were tested for recurrence risk classification estimation validity as measured by discrimination (receiver operator characteristic [ROC] curve and Harrell's c-index [HCI]) and calibration.

RESULTS

Multivariate analyses found lymph node metastasis, larger tumor size and grade 2 independent risk factors of disease-free survival (DFS). The novel scoring system for recurrence risk classification sorted patients into three groups: score<15.4 for low risk (79.0%, 3- and 5-year recurrence risk 0.8% and 4.3%, median DFS not reached), score>15.4, <24.5 for intermediate risk (20.8%, 3- and 5-year recurrence risk 11.6% and 21.4%, median DFS 70 months) and score >24.5 for high risk (10.2%, 3- and 5-year recurrence risk 37.3% and 68.7%, median DFS 49 months).The area under curve (AUC) and HCI of our system were 0.871 and 0.929, superior to those of European Neuroendocrine Tumor Society (AUC 0.833, HCI 0.806).

CONCLUSION

The presented system can be utilized to identify G1/2 pancreatic neuroendocrine tumors patients with high recurrence risk, which might be appropriate for peri-operative adjuvant therapy.

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 WHO 2010 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.

The clinical value of secretin-enhanced MRCP in the functional and morphological assessment of pancreatic diseases

Secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) provides a non-invasive way, with which, to evaluate pancreatic duct (PD) anatomy and exocrine pancreatic function. S-MRCP can be added to the routine pancreas MR examination in equivocal cases. Moreover, it can detect subtle PD involvement, allowing diagnosis of early, rather than end-stage, pancreatic diseases. Although S-MRCP is a valuable non-invasive diagnostic method, it is only performed in a few centres due to relative high cost. Furthermore, less familiarity with its indications, the examination technique, and image interpretation also contribute to its limited use. Thus, the purpose of this article is to explain secretin's mechanism of action, the examination technique, the clinically relevant indications, the advantages, and limitations. Finally, we will focus on image analysis and its role in achieving an early and accurate diagnosis of specific pancreatic and PD diseases.

Surgical resection of pancreatic neuroendocrine neoplasm by minimally invasive surgery-the robotic approach?

Over the past decade, there has been increasing adoption of minimally invasive pancreatic surgery world-wide and this has naturally expanded to the management of pancreatic neuroendocrine neoplasms (PNENs). More recently, robotic pancreatic surgery (RPS) was introduced to overcome the limitations during laparoscopic pancreatic surgery (LPS). Due to the relative rarity of PNEN and the novelty of minimally invasive pancreatic surgery in particular RPS today, the evidence for robotic surgery in PNENs remains extremely limited. Presently, the available evidence is limited to a few low level retrospective case-control studies. These studies suggest that RPS may be associated with a higher splenic preservation rates and lower open conversion rates compared to conventional laparoscopic surgery. Ideally a prospective randomized trial should be performed but this would be extremely challenging due to the rarity of PNEN, making it almost impossible to conduct a sufficiently powered trial.

Pathology and Surgical Treatment of High-Grade Pancreatic Neuroendocrine Carcinoma: an Evolving Landscape

Pancreatic neuroendocrine neoplasms (PNENs) are rare, accounting for less than 5% of all pancreatic tumors. High-grade pancreatic neuroendocrine carcinomas (hgPNECs) represent about 5% of all PNENs. They show highly aggressive behavior with dismal prognosis. Throughout the last two decades, there has been a notable progress in basic and clinical research of PNENs and a therapeutic trend towards both more aggressive and minimally invasive surgery. Despite these advances, hgPNECs as a distinct clinical entity remains largely unexplored among surgeons. This review of current development in pathology reporting and surgical treatment of hgPNECs aims at increasing the awareness of an evolving field in pancreatic surgery.

Transcriptomic Profiling of Tumor Aggressiveness in Sporadic Nonfunctioning Pancreatic Neuroendocrine Neoplasms

OBJECTIVES

The aim of the study was to compare RNA sequencing data of sporadic nonfunctioning pancreatic neuroendocrine neoplasms (PNENs) to identify gene expression patterns that may be important for molecular differentiation of tumor aggressiveness.

METHODS

RNA sequencing was performed on samples of sporadic nonfunctioning PNENs, grouped as tumors with mild behavior (nonmetastatic and Ki67 < 5%) or aggressive behavior (metastatic and Ki67 ≥ 5%), on an Illumina Genome Analyzer II platform. Bioinformatic analyses were performed on the resulting data.

RESULTS

Of 22,810 identified transcripts from protein-coding genes, a set of 309 genes were significantly differentially expressed between the 2 groups, of which 166 were upregulated and 143 downregulated in the aggressive disease group. Among the top protein-coding upregulated genes, we found genes encoding proteins involved in DNA packaging, ability to taste, chromosome structuring, cytoskeleton structuring, and cell-cell signaling. Among the top protein-coding downregulated genes, we found genes encoding proteins involved in neuronal differentiation, cytoskeleton structuring, cell-cell signaling, and immunological processes.

CONCLUSIONS

A higher degree of tumor aggressiveness in sporadic nonfunctioning PNENs seems to be associated with upregulation of genes involved in regulation of the cell cycle and cell division. Small sample size and lack of a replication set are limitations of this study.

Prediction of survival and tumor recurrence in patients undergoing surgery for pancreatic neuroendocrine neoplasms

BACKGROUND

This study strives to define prognostic models for outcome after surgery for malignant pancreatic neuroendocrine tumors.

METHODS

Forty-one patients were included. Prognostic models for mortality and disease recurrence were developed with multivariate binary logistic regression.

RESULTS

The proposed prognostic model for tumor recurrence risk after surgery in percentage (AUROC = 0.774, 95%CI = 0.611-0.937) is: Risk in % = Exp(Y)/(1 + Exp(Y)), with Y = -4.360 + (0.015 × tumor diameter in cm) + (0.010 × preoperative platelet count in thousand/μl) + (1.077 × distant metastases, if yes = 1; if no = 0) + (-0.026 × Ki-67-positive cells in %) + (-1.086 × upper abdominal pain, if yes = 1; if no = 0). The proposed prognostic model for observed 3-year survival probability after surgery in % (AUROC = 0.932, 95%CI = 0.857-0.999) is: Survival probability in % = Exp(Y)/(1 + Exp(Y)), with Y = -12.492 + (0.054 × preoperative platelet count in thousand/μl) + (0.112 × minimal distance of the resection margin from the tumor in mm) + (-1.574 × number of positive lymph nodes) + (2.292 × histological tumor infiltration, if yes = 1; if no = 0) CONCLUSIONS: The platelet count was identified as a relevant risk factor. Proposed prognostic models with good model-fit display properties that indicate potential clinical usefulness.

Laparoscopic resection of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are a rare heterogeneous group of endocrine neoplasms. Surgery remains the best curative option for this type of tumor. Over the past two decades, with the development of laparoscopic pancreatic surgery, an increasingly larger number of PNET resections are being performed by these minimally-invasive techniques. In this review article, the various laparoscopic surgical options for the excision of PNETs are discussed. In addition, a summary of the literature describing the outcome of these treatment modalities is presented.