Functional and non-functional pancreatic neuroendocrine tumours: ENETS or AJCC TNM staging system?

A review of functional pancreatic neuroendocrine tumors: Exploring the molecular pathogenesis, diagnosis and treatment

Pancreatic neuroendocrine tumors (PanNETs) are a rare subtype of pancreatic cancer and can be divided into functional (30-40%) and nonfunctional subtypes. The different subtypes of functional PanNETs (F-PanNETs) have a variety of classical presentations that raise suspicion for an underlying PanNET. It is estimated that 90% of PanNETs are sporadic, and the PI3K-Akt-mTOR and ATRX/DAXX signaling pathways have been recognized as key genetic pathways implicated in the pathogenesis. The other 10% of PanNETs may occur in the context of familial cancer syndromes such as MEN1. Chromogranin A is the most useful biomarker currently; however, several studies have shown limitations with its use, especially its prognostic value. Synaptophysin is a novel biomarker which has shown promising preliminary results however its use clinically has yet to be established. Blood tests assessing hormone levels, cross-sectional imaging, and endoscopic ultrasound remain at the core of establishing a diagnosis of F-PanNET. The treatment options for F-PanNETs include surgical methods such as enucleation, systemic therapies like chemotherapy and novel targeted therapies such as everolimus. The prognosis for F-PanNETs is more favorable than for nonfunctional PanNETs, however metastatic disease is associated with poor survival outcomes. Researchers should also focus their efforts on identifying novel pathways implicated in the pathogenesis of F-PanNETs in order to develop new targeted therapies that may reduce the need for surgical intervention and on the establishment of novel biomarkers that may reduce the need for invasive testing and allow for earlier detection of F-PanNETs.

Management of neuroendocrine tumor liver metastases

BACKGROUND

Neuroendocrine Tumors (NETs) are a group of tumors that arise from neuroendocrine cells, and are increasing in incidence worldwide. These tumors often metastasize to the liver, and management of these neuroendocrine tumor liver metastases (NELMs) requires a multi-disciplinary approach. We aim to provide a comprehensive update for treatment of NELMs.

METHODS

We completed a comprehensive systemic review of papers involving the diagnosis, treatment, and outcomes of NELMs. We identified 1612 records via Scopus database literature search. Two independent authors reviewed these records, with 318 meeting criteria for inclusion in the final systemic review.

RESULTS

Primary tumor resection with resection of liver metastases is the treatment of choice for patients with NELMs. Liver-directed therapies and liver transplantation can be considered for patients with unresectable liver metastases. Systemic medical therapy is used for managing tumor burden and symptoms caused by NELMs.

CONCLUSIONS

Advancement in liver-directed and targeted systemic therapies provide improved options for patients with unresectable tumors. Given the complexity of NELMs, management of NELMs necessitates multidisciplinary teams at comprehensive health centers.

A Comprehensive Review on Neuroendocrine Neoplasms: Presentation, Pathophysiology and Management

Neuroendocrine neoplasms (NENs) are a group of heterogeneous tumors with neuroendocrine differentiation that can arise from any organ. They account for 2% of all malignancies in the United States. A significant proportion of NEN patients experience endocrine imbalances consequent to increased amine or peptide hormone secretion, impacting their quality of life and prognosis. Over the last decade, pathologic categorization, diagnostic techniques and therapeutic choices for NENs-both well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs)-have appreciably evolved. Diagnosis of NEN mostly follows a suspicion from clinical features or incidental imaging findings. Hormonal or non-hormonal biomarkers (like serum serotonin, urine 5-HIAA, gastrin and VIP) and histology of a suspected NEN is, therefore, critical for both confirmation of the diagnosis and classification as an NET or NEC. Therapy for NENs has progressed recently based on a better molecular understanding, including the involvement of mTOR, VEGF and peptide receptor radionuclide therapy (PRRT), which add to the growing evidence supporting the possibility of treatment beyond complete resection. As the incidence of NENs is on the rise in the United States and several other countries, physicians are more likely to see these cases, and their better understanding may support earlier diagnosis and tailoring treatment to the patient. We have compiled clinically significant evidence for NENs, including relevant changes to clinical practice that have greatly updated our diagnostic and therapeutic approach for NEN patients.

Epidemiological trends for functional pancreatic neuroendocrine tumors: A study combining multiple imputation with age adjustment

Purpose

The purpose of this study was to examine trends in the incidence and incidence-based (IB) mortality of functional pancreatic neuroendocrine tumors(F-PNETs), and to identify factors associated with survival times.

Methods

Data were obtained from the Surveillance, Epidemiology, and End Results database from 2000 to 2017. Trends in the age-adjusted incidence of F-PNETs and IB mortality were examined using the Joinpoint Regression Program. Statistical analyses were run using chi-square tests, Kaplan-Meier curves, and the Cox proportional hazards model. Multiple imputation was used to deal with missing data.

Results

A total of 142 patients with F-PNETs met the study inclusion criteria. It was found that the incidence of F-PNETs decreased over the study period, with an annual percent change (APC) of -2. 5% (95% CI [-4. 3, -0. 5], P<0. 05). This decrease was found to be significant for women, and also when limited to cases with distant disease or rare F-PNETs, with APCs of -4. 2% (95% CI [-7. 4, -0. 9], P<0. 05), -6. 7% (95% CI [-10. 4, -2. 8], P<0. 05), and -9. 1% (95% CI [-13. 5, -4. 4], P<0. 05), respectively. The Cox regression analysis revealed that the tumor size, tumor stage, tumor type, and surgical resection were associated with F-PNETs mortality.

Conclusions

This was the first population-based epidemiological study of F-PNETs and we found a continual decrease in the incidence of F-PNETs from 2000 to 2017. The prognosis and survival times were closely related to the calendar year at diagnosis, tumor stage, and tumor size.

Predicting Progression, Recurrence, and Survival in Pancreatic Neuroendocrine Tumors: A Single Center Analysis of 174 Patients

INTRODUCTION

The European Neuroendocrine Tumor Society, ENETS, reports variables of prognostic significance in pancreatic neuroendocrine tumors (PNET). However, studies have short follow-ups, and the optimal treatment remains controversial. We aimed to determine overall survival (OS), progression-free survival (PFS) after conservative treatment, and recurrence-free survival (RFS) after surgery and further to find predictors of aggressive PNET behavior to support treatment decisions.

METHODS

174 patients with PNET treated at Aarhus University Hospital from 2011 to 2021 were included in a retrospective cohort study. Patients were divided into surgically resected (SUR, n=91) and medically or conservatively treated (MED, n=83). Variables were tested in univariate and multivariate survival analysis. Median follow-up time was 3.4 years in the MED group and 4.5 years in the SUR group.

RESULTS

The 5-year OS was 95% and 65% for the SUR and MED groups, respectively. The 5-year RFS in the SUR group was 80% whereas the 5-year PFS in the MED group was 41%. Larger tumor size, Ki67 index, tumor grade, and stage were predictive of shorter OS, RFS, and PFS. Further, chromogranin A was a predictor of OS. Larger tumor size was associated with higher stage and grade. Only 1 of 28 patients with stage 1 disease and size ≤2 cm developed progression on a watch-and-wait strategy during a median follow-up of 36 months.

CONCLUSION

This study supported the ENETS staging and grading system to be useful to predict OS, PFS, and RFS in PNET. Further, our data support that small, localized, low-grade PNETS can be followed with active surveillance.

A comprehensive validation of the novel 8th edition of American Joint Committee on Cancer staging manual for the long-term survivals of patients with non-functional pancreatic neuroendocrine neoplasms

Histologically, the World Health Organization has classified pancreatic neuroendocrine neoplasms (p-NENs) into well-differentiated pancreatic neuroendocrine tumors (G1/G2 p-NETs) and poorly-differentiated pancreatic neuroendocrine carcinoma (G3 p-NECs) based on tumor mitotic counts and Ki-67 index. Recently, the 8th edition of American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) staging manual has incorporated some major changes in 2017 that the TNM staging system for p-NENs should only be applied to well-differentiated G1/G2 p-NETs, while poorly-differentiated G3 p-NECs be classified according to the new system for pancreatic exocrine adenocarcinomas. However, this new manual for p-NENs has seldom been evaluated.Data of patients with both G1/G2 and G3 non-functional p-NENs (NF-p-NENs) from our institution was retrospectively collected and analyzed using 2 new AJCC 8th staging systems. We also made survival comparisons between the 8th and 7th edition system separately for different subgroups.For G1/G2 NF-p-NETs, there were 52 patients classified in AJCC 8th edition stage I, 40 in stage II, 41 in stage III and 19 in stage IV. As for G3 NF-p-NECs, 17, 19, 24, and 18 patients were respectively defined from AJCC 8th edition stage I to stage IV. In terms of the AJCC 7th staging system, the 230 patients with NF-p-NENs were totally distributed from stage I to stage IV (94, 63, 36, 37, respectively). For the survival analysis of both G1/G2 NF-p-NETs and G3 NF-p-NECs, the AJCC 7th edition system failed to discriminate the survival differences when compared stage III with stage II or stage IV (P > .05), while the 8th edition ones could perfectly allocate patients into 4 statistically different groups (P < .05). The HCIs of AJCC 8th stage for G1/G2 NF-p-NETs [HCI=0.658, 95% confidence interval (CI)=0.602-0.741] and stage for G3 NF-p-NECs (HCI=0.704, 95% CI=0.595-0.813) was both statistically larger than those of AJCC 7th stage for different grading NF-p-NENs [(HCI=0.578, 95% CI=0.557-0.649; P=.031), (HCI=0.546, 95% CI=0.531-0.636; P = .019); respectively], indicating a more accurate predictive ability for the survivals of NF-p-NENs.Our data suggested the 2 new AJCC 8th staging systems were superior to its 7th edition for patients with both G1/G2 NF-p-NETs and G3 NF-p-NECs.

Systematic Review and Metaanalysis of Lymph Node Metastases of Resected Pancreatic Neuroendocrine Tumors

BACKGROUND

The optimal surgical strategy for pancreatic neuroendocrine tumors (PNETs) is unknown. However, current guidelines recommend a watch-and-wait strategy for small nonfunctional PNETs (NF-PNETs). The aim of this study is to investigate the risk stratification and prognostic significance of lymph node metastasis (LNM) of PNETs to guide decision-making for lymphadenectomy.

PATIENTS AND METHODS

The MEDLINE and Web of Science databases were systematically searched for studies reporting either risk factors of LNM in resected PNETs or survival of patients with LNM. The weighted average incidence of LNM was calculated according to tumor characteristics. Random-effects metaanalyses were performed, and pooled hazard ratios (HR) and their 95% confidence intervals (CI) were calculated to determine the impact of LNM on overall survival (OS). In subgroup analyses, NF-PNETs were assessed.

RESULTS

From a total of 5883 articles, 98 retrospective studies with 13,374 patients undergoing resection for PNET were included. In all PNETs, the weighted median rates of LNM were 11.5% for small (≤ 2 cm) PNETs and 15.8% for G1 PNETs. In NF-PNETs, the rates were 11.2% for small PNETs and 10.3% for G1 PNETs. LNM of all PNETs (HR 3.87, 95% CI 3.00-4.99, P < 0.001) and NF-PNETs (HR 4.98, 95% CI 2.81-8.83, P < 0.001) was associated with worse OS.

CONCLUSIONS

LNM is potentially prevalent even in small and well-differentiated PNETs and is associated with worse prognosis. A watch-and-wait strategy for small NF-PNETs should be reappraised, and oncologic resection with lymphadenectomy can be considered. Prospective and controlled studies are needed in the future.

Theranostic approaches in nuclear medicine: current status and future prospects

Introduction: Theranostics is an emerging field in which diagnosis and specific targeted therapy are combined to achieve a personalized treatment approach to the patient. In nuclear medicine clinical practice, theranostics is often performed utilizing the same molecule labeled with two different radionuclides, one radionuclide for imaging and another for therapy.Areas covered: The authors review the clinical applications of different radiopharmaceuticals in the field of interest, including the well-established use of radioactive iodine in differentiated thyroid cancer, radiolabeled metaiodobenzylguanidine (MIBG) in neuroblastoma and the clinical impact of peptide radionuclide receptorial therapy (PRRT) in the management of neuroendocrine tumors. Furthermore, the more cutting-edge and recently introduced theranostic approaches will be reviewed, such as the radioligand therapy with ¹⁷⁷Lu-prostate specific membrane antigen (PSMA) and targeted alpha therapy in castration-resistant prostate cancer. Finally, the main applications of PET for the imaging of biomarkers suitable for the non-radionuclide targeted therapy will be covered.Expert opinion: Theranostics is envisaging a revolutionary clinical approach which is deeply connected with the concept of personalized medicine and ruled by a 'patient-centered' vision. In this perspective, the theranostic applications will need well-trained specialists, capable to manage not only the technological aspects of the discipline, but also to deal with the more innovative oncological therapies in a multidisciplinary setting.

Lymphovascular Invasion Predicts Lymph Node Involvement in Small Pancreatic Neuroendocrine Tumors

INTRODUCTION

Pancreatic neuroendocrine tumors (p-NETS) are increasing in incidence, and prognostic factors continue to evolve. The benefit of lymphadenectomy for p-NETS ≤2 cm remains unclear. We sought to determine the significance of lymphovascular invasion (LVI) for small p-NETS.

METHODS

The National Cancer Database was queried for patients with p-NETS ≤2 cm and with ≥1 evaluated lymph node (LN), years 2004-2015. Demographic, clinical, and treatment characteristics were analyzed. Multivariate logistic regression was performed to identify predictors of LN positivity.

RESULTS

Among 2,499 patients identified, tumor location was delineated as the head (26%), body (18%), tail (38%), or unspecified (18%); 74% were well-differentiated versus 10% moderate, 2% poor, and 14% unknown. LVI occurred in 11%. A median of 9 LNs were evaluated; overall positivity was 18%. Mean survival was significantly longer in node-negative patients (115 vs. 95 months, log-rank p < 0.0001). LVI was the strongest predictor of node involvement (OR 10.4, p < 0.0001) when controlling for tumor size, grade, and location. Subset analysis of patients with known LVI status, grade, location, and mitoses found that LVI was more likely in the setting of moderate-to-high tumor grade, 1-2 cm size, pancreatic head location, and high mitotic rate. Among patients with ≥2 of these 4 factors, 25% were node-positive.

CONCLUSIONS

Presence of LVI was the strongest predictor of node positivity. LVI on endoscopic biopsy should prompt resection and regional LN dissection to fully stage patients with small p-NETS. Patients with other high-risk factors should also be considered for resection and regional lymphadenectomy.

Prognostic Validity of the American Joint Committee on Cancer Eighth Edition TNM Staging System for Surgically Treated and Well-Differentiated Pancreatic Neuroendocrine Tumors: A Comprehensive Analysis of 254 Consecutive Patients From a Large Chinese Institution

OBJECTIVES

We aimed to validate the novel American Joint Committee on Cancer (AJCC) eighth edition staging manual for well-differentiated (G1/G2) pancreatic neuroendocrine tumors (pNETs).

METHODS

Data of eligible patients were retrospectively collected, grouped, and analyzed by applying the new AJCC system.

RESULTS

According to the AJCC eighth staging manual for pNETs, 93, 66, 53, and 42 patients had stage I, II, III, and IV disease, respectively, with estimated 5-year overall survival (OS) rates of 96.9%, 92.8%, 48.4%, and 16.8% (P < 0.005), respectively. A total of 57, 28, 20, and 17 patients with G1 pNETs and 36, 38, 33, and 25 ones with G2 tumors were defined by the new AJCC system as having stage I, II, III, and IV disease, respectively. The estimated 5-year OS for stage I, II, III and IV disease was 100.0%, 97.1%, 52.5%, and 18.2%, respectively, for G1 pNETs (P < 0.005) and 94.2%, 90.3%, 38.7%, and 12.7%, respectively, for G2 tumors (P < 0.005). The novel AJCC classification, tumor grading, and radical resection were all prognostic predictors for OS in patients with pNETs.

CONCLUSIONS

The new AJCC eighth staging system for well-differentiated pNETs was prognostic and might be adopted in clinical practice.

Survivals of patients with surgically treated and High-grade pancreatic neuroendocrine carcinomas: A comparative study between two American Joint Committee on Cancer 8th tumor-node-metastasis staging systems

BACKGROUND AND OBJECTIVE

We aimed to compare the two new defined tumor-node-metastasis (TNM) systems in the American Joint Committee on Cancer (AJCC) 8th staging manual for overall survival (OS) analysis of G3 pancreatic neuroendocrine carcinomas (p-NECs) that are currently proposed for pancreatic exocrine adenocarcinomas (p-EACs) and G1/G2 pancreatic neuroendocrine tumors (p-NETs), respectively.

METHODS

The data of patients who were surgically treated and histopathologically diagnosed with G3 p-NECs at West China Hospital of Sichuan University from January 2002 to June 2017 were retrospectively analyzed and compared using the two new AJCC staging systems.

RESULTS

Applying the p-EAC AJCC 8th TNM staging system to G3 p-NECs, the estimated 3-year OSs for each stage were 86.7%, 76.0%, 44.5% and 20.7%, respectively (P < 0.001). According to the G1/G2 p-NETs staging system, the estimated OSs at 3 years for each new AJCC stage were 100.0%, 83.6%, 47.1% and 20.7%, respectively (P < 0.001). The system for p-EACs significantly discriminated the survival difference of G3 p-NECs between Stage I and Stage II (P = 0.019), while the other one for G1/G2 p-NETs could not (P = 0.108). The consistent results of Akaike information criteria with Harrell's concordance index indicated that the AJCC 8th staging system for p-EACs was superior when applied to G3 p-NECs for its better prognostic stratification and more accurate prediction ability for OS.

CONCLUSIONS

Our analysis demonstrated that both TNM systems in the AJCC 8th staging manual were prognostic for patients with G3 p-NECs; however, the classification originally applied to p-EACs was superior and supported its use in clinical practice.

Lymphadenectomy in pancreatic neuroendocrine neoplasms: Why are we still debating?

Pancreatic Neuroendocrine Neoplasms (PNEN) are rare tumours exhibiting very heterogeneous behaviour. For these reasons, studies with high level of evidence are lacking. Whether lymphadenectomy should be performed for PNEN is a matter of debate. In this review, we perform a critical analysis of the available literature regarding the clinical significance of lymphnode metastases, the importance of lymphadenectomy, and the implications on disease-specific survival.