Comparison of surgical results in patients with advanced and limited disease with multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome

Evaluation and Surgical Management of Multiple Endocrine Neoplasias

Multiple endocrine neoplasia (MEN) syndromes are rare autosomal dominant diseases that are associated with a mixture of both endocrine and non-endocrine tumors. Traditionally, there are 2 types of MEN that have unique clinical associations: MEN 1 (parathyroid hyperplasia, pancreatic neuroendocrine tumors, and pituitary tumors) and MEN 2 (medullary thyroid carcinoma and pheochromocytoma), which is further classified into MEN 2A (adds parathyroid adenomas) and 2B (adds ganglioneuromas and marfanoid habitus). Many of the endocrine tumors are resected surgically, and the pre, intra, and postoperative management strategies used must take into account the high recurrence rates asscioated with MEN tumors.

Hereditary Syndromes Associated with Pancreatic and Lung Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PanNETs) and lung NETs (LNETs) represent a rare but clinically significant subgroup of neoplasms. While the majority is sporadic, approximately 17% of PanNETs and a subset of LNETs develop in the context of monogenic familial tumor syndromes, especially multiple endocrine neoplasia type 1 (MEN1) syndrome. Other inherited syndromes associated with PanNETs include MEN4, von Hippel-Lindau (VHL) syndrome, neurofibromatosis type 1 (NF1), and tuberous sclerosis complex (TSC). These syndromes are highly penetrant and their clinical manifestations may vary even among members of the same family. They are attributed to genetic mutations involving key molecular pathways regulating cell growth, differentiation, and angiogenesis. Pancreatic NETs in hereditary syndromes are often multiple, develop at a younger age compared to sporadic tumors, and are associated with endocrine and nonendocrine tumors derived from multiple organs. Lung NETs are not as common as PanNETs and are mostly encountered in MEN1 syndrome and include typical and atypical lung carcinoids. Early detection of PanNETs and LNETs related to inherited syndromes is crucial, and specific follow-up protocols need to be employed to optimize diagnosis and management. Genetic screening is recommended in childhood, and diagnostic screening starts often in adolescence, even in asymptomatic mutation carriers. Optimal management and therapeutic decisions should be made in the context of a multidisciplinary team in specialized centers, whereas specific biomarkers aiming to identify patients denoted to follow a more aggressive course need to be developed.

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, insulinomas, 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.

[Indication and Surgical Procedures for MEN1-associated Duodenopancreatic Neuroendocrine Neoplasms]

The optimal therapy of duodenopancreatic neuroendocrine neoplasia (dpNEN), which occurs in the context of multiple endocrine neoplasia type 1, is still a major challenge and is controversial. Due to the rarity of the disease, there is a lack of prospective randomised studies, so that most recommendations regarding the surgical indication and procedure are based on retrospective case series. In summary, surgical therapy is indicated for non-functional dpNEN > 2 cm, suspected malignancy and functionally active dpNEN. Enucleation or formal pancreatic resections with or without lymphadenectomy may be considered. The aim of therapy should be to eliminate hormone-associated symptoms and prevent an aggressive metastatic disease. At the same time, pancreatic function and quality of life should be preserved in the mostly young patients by resections that save as much parenchyma as possible.

European Neuroendocrine Tumor Society 2023 guidance paper for functioning pancreatic neuroendocrine tumour syndromes

This ENETS guidance paper aims to provide practical advice to clinicians for the diagnosis, treatment and follow-up of functioning syndromes in pancreatic neuroendocrine tumours (NET). A NET-associated functioning syndrome is defined by the presence of a clinical syndrome combined with biochemical evidence of inappropriately elevated hormonal levels. Different hormonal syndromes can be encountered in pancreatic NET patients, including insulinoma, gastrinoma as well as the rare glucagonoma, VIPoma, ACTHoma, PTHrPoma, carcinoid syndrome, calcitoninoma, GHRHoma and somatostatinoma. The recommendations provided in this paper focus on the biochemical, genetic and imaging work-up as well as therapeutic management of the individual hormonal syndromes in well-differentiated, grade 1-3, functioning NET with the primary tumour originating in the pancreas, and for specific subtypes also in the duodenum.

Successful Lifetime/Long-Term Medical Treatment of Acid Hypersecretion in Zollinger-Ellison Syndrome (ZES): Myth or Fact? Insights from an Analysis of Results of NIH Long-Term Prospective Studies of ZES

Analysis of the efficacy/pharmacology of long-term/lifetime medical treatment of acid hypersecretion in a large cohort of ZES patients in a prospective study. This study includes the results from all 303 patients with established ZES who were prospectively followed and received acid antisecretory treatment with either H2Rs or PPIs, with antisecretory doses individually titrated by the results of regular gastric acid testing. The study includes patients treated for short-term periods (<5 yrs), patients treated long-term (>5 yrs), and patients with lifetime treatment (30%) followed for up to 48 years (mean 14 yrs). Long-term/lifelong acid antisecretory treatment with H2Rs/PPIs can be successfully carried out in all patients with both uncomplicated and complicated ZES (i.e., with MEN1/ZES, previous Billroth 2, severe GERD). This is only possible if drug doses are individually set by assessing acid secretory control to establish proven criteria, with regular reassessments and readjustments. Frequent dose changes both upward and downward are needed, as well as regulation of the dosing frequency, and there is a primary reliance on the use of PPIs. Prognostic factors predicting patients with PPI dose changes are identified, which need to be studied prospectively to develop a useful predictive algorithm that could be clinically useful for tailored long-term/lifetime therapy in these patients.

Long-Term Outcomes for Patients with Multiple Endocrine Neoplasia Type 1 and Duodenopancreatic Neuroendocrine Neoplasms

BACKGROUND

Liver metastasis from duodenopancreatic neuroendocrine neoplasms (DP-NENs) is a major cause of mortality in multiple endocrine neoplasia type 1 (MEN1) patients, yet much of their natural history is unknown.

METHODS

This longitudinal, retrospective cohort study analyzed all MEN1 patients with imageable functional (F) and nonfunctional (NF) DP-NENs (1990-2021) for liver metastasis-free survival (LMFS) and overall survival (OS).

RESULTS

Of 138 patients, 85 (61.6%) had imageable DP-NENs (28 F, 57 NF), and the mean largest tumor size was 1.8 ± 1.4 cm. Multifocality was present in 32 patients (37.7%). Surgery was performed for 49 patients (57.7%). During an 11-year median follow-up period (IQR, 6-17 years), 23 (27.1%) of the patients had liver metastasis, and 19 (22.4%) patients died. Death was attributed to liver metastasis in 60% of cases. The patients with F-DP-NENs versus NF-DP-NENs more often had liver metastasis (46.4% vs. 15.8%; p = 0.002) but had similar 10-year LMFS (80.9 vs. 87.0%; p = 0.44) and OS (82.7 vs. 94.3%; p = 0.69). The patients with NF-DP-NENs had surgery when their tumors were larger (p < 0.001). Tumor size was not associated with liver metastasis (p = 0.89). The average growth rate was 0.04 cm/year (SE, 0.02 cm/year; p = 0.01) during active surveillance for NF-DP-NENs (n = 38). Liver metastasis developed in four patients with tumors smaller than 2 cm. The risk of liver metastasis was independent of surgery (hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.21-2.93; p = 0.72) and death (HR, 0.51; 95% CI, 0.08-3.06; p = 0.46).

CONCLUSIONS

Although the observed outcomes in this study were better than historical data, small NF-DP-NENs still developed liver metastasis and liver metastasis remains a major cause of death. These results suggest that size as a sole criterion for surgery may be insufficient to predict tumor behavior.

Secretin Stimulation Test and Early Diagnosis of Gastrinoma in MEN1 Syndrome: Survey on the MEN1 Florentine Database

CONTEXT

Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited endocrine cancer syndrome. Multiple gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs) affect 30% to 80% of MEN1 patients, with the most common functioning GEP-NET being gastrinoma. Biochemical identification of hypergastrinemia may help to recognize the presence of gastrinomas before they are detectable by instrumental screening, enabling early diagnosis and start of therapy, preferably before tumor progression and metastases occurrence.

OBJECTIVE

Evaluate the effectiveness of secretin stimulation test to precociously diagnose the presence of gastrin-secreting tumors.

DESIGN

Results of secretin stimulation tests, performed between 1991 and February 2020, were retrospectively analyzed, as aggregate, in a cohort of MEN1 patients with GEP-NETs.

SETTING

Data were extracted from the MEN1 Florentine database.

PATIENTS

The study included 72 MEN1 patients with GEP-NETs who underwent a secretin stimulation test for the evaluation of gastrin secretion.

OUTCOMES

A positive secretin stimulation test was assumed with a difference between basal fasting serum gastrin (FSG) and the maximum stimulated value of gastrin over 120 pg/mL.

RESULTS

The secretin stimulation test showed a secretin-induced hypergastrinemia in 27.8% (20/72) of patients with GEP-NETs, and a positive test in 18 cases. The test allowed the identification of a positively stimulated hypergastrinemia in 75.0% (3/4) of patients who presented a basal FSG within the normal range.

CONCLUSIONS

Diagnosis of gastrinoma is complex, difficult, and controversial. Results of this study confirm that a positive secretin stimulation test allows early diagnosis of gastrinomas, even in the presence of borderline or normal levels of nonstimulated FSG.

Pancreaticoduodenectomy Is the Best Surgical Procedure for Zollinger-Ellison Syndrome Associated with Multiple Endocrine Neoplasia Type 1

Simple Summary

Approximately 30% of patients with multiple endocrine neoplasia type 1 (MEN1) develop the Zollinger–Ellison syndrome (ZES), caused by solitary or multiple duodenal gastrinomas. Its management, especially regarding indication, timing, and type of surgery, is highly controversial. Therefore, the present study evaluated the long-term outcomes of pancreaticoduodenectomy (PD) versus non-PD resections in MEN1-ZES with regard to biochemical cure and quality of life. We found in a series of 35 patients that initial PD is the superior surgical procedure for MEN1-ZES, leading to long-term cure in about 80% of patients, fewer duodenopancreatic reoperations and an acceptable quality of life. Based on the results of this study, MEN1-ZES should be considered a surgically curable disease.

Abstract

Aim: The aim of this research was to evaluate the long-term outcome of pancreaticoduodenectomy (PD) versus other duodenopancreatic resections (non-PD) for the surgical treatment of the Zollinger–Ellison syndrome (ZES) in patients with multiple endocrine neoplasia type 1 (MEN1). Methods: Prospectively recorded patients with biochemically confirmed MEN1-ZES who underwent duodenopancreatic surgery were retrospectively analyzed in terms of clinical characteristics, complications, cure rate, and long-term morbidity, including quality of life assessment (EORTC QLQ-C30). Results: 35 patients (16 female, 19 male) with MEN1-ZES due to duodenopancreatic gastrinomas with a median age of 42 (range 30–74) years were included. At the time of diagnosis, 28 (80%) gastrinomas were malignant, but distant metastases were only present in one (3%) patient. Eleven patients (31.4%) underwent pancreatoduodenectomy (PD) as the initial procedure, whereas 24 patients underwent non-PD resections involving duodenotomy with gastrinoma excision, enucleation of the pNEN from the head of the pancreas, and peripancreatic lymphadenectomy, either with or without distal pancreatectomy (i.e., either Thompson procedure, n = 12, or DUODX, n = 12). There was no significant difference in perioperative morbidity and mortality between the two groups (p ≥ 0.05). One (9%) patient of the PD group required reoperation for recurrent or metastatic ZES compared to eight (22.8%) patients of the non-PD resection groups. After a median follow-up time of 134 months (range 6–480) nine of 11 (82%) patients in the PD group, two of 12 (16%) patients in the Thompson procedure group, and three of 12 (25%) patients in the DUODX group had normal serum gastrin levels. In addition, the global health QoLScore was better in the PD group (76.9) compared to the Thompson procedure (57.4) and DUODX (59.5) groups. Conclusions: Initial PD seems to be the superior surgical procedure for MEN1-ZES, resulting in a long-term cure rate of about 80%, fewer duodenopancreatic reoperations, and an acceptable quality of life.

Metastatic Patterns of Duodenopancreatic Neuroendocrine Tumors in Patients With Multiple Endocrine Neoplasia Type 1

Patients with multiple endocrine neoplasia 1 syndrome (MEN1) often develop multifocal duodenopancreatic neuroendocrine tumors (dpNETs). Nonfunctional pancreatic neuroendocrine tumors (PanNETs) and duodenal gastrinomas are the most frequent origins of metastasis. Current guidelines recommend surgery based on tumor functionality, size ≥2 cm, grade or presence of lymph node metastases. However, in case of multiple primary tumors it is often unknown which specific tumor metastasized. This study aims to unravel the relationship between primary dpNETs and metastases in patients with MEN1 by studying endocrine differentiation. First, it was shown that expression of the endocrine differentiation markers ARX and PDX1 was concordant in 18 unifocal sporadic neuroendocrine tumors (NETs) and matched metastases. Thereafter, ARX, PDX1, Ki67 and gastrin expression, and the presence of alternative lengthening of telomeres were determined in 137 microscopic and macroscopic dpNETs and 36 matched metastases in 10 patients with MEN1. ARX and PDX1 H-score clustering was performed to infer relatedness. For patients with multiple metastases, similar intrametastases transcription factor expression suggests that most metastases (29/32) originated from a single NET of origin, while few patients may have multiple metastatic primary NETs. In 6 patients with MEN1 and hypergastrinemia, periduodenopancreatic lymph node metastases expressed gastrin, and clustered with minute duodenal gastrinomas, not with larger PanNETs. PanNET metastases often clustered with high grade or alternative lengthening of telomeres-positive primary tumors. In conclusion, for patients with MEN1-related hypergastrinemia and PanNETs, a duodenal origin of periduodenopancreatic lymph node metastases should be considered, even when current conventional and functional imaging studies do not reveal duodenal tumors preoperatively.

What Are the Place and Modalities of Surgical Management for Pancreatic Neuroendocrine Neoplasms? A Narrative Review

Pancreatic neuroendocrine neoplasms (panNENs) are a heterogeneous group of tumors derived from cells with neuroendocrine differentiation. They are considered malignant by default. However, their outcomes are variable depending on their presentation in the onset of hereditary syndromes, hormonal secretion, grading, and extension. Therefore, although surgical treatment has long been suggested as the only treatment of pancreatic neuroendocrine neoplasms, its modalities are an evolving landscape. For selected patients (small, localized, non-functional panNENs), a "wait and see" strategy is suggested, as it is in the setting of multiple neuroendocrine neoplasia type 1, but the accurate size cut-off remains to be established. Parenchyma-sparring pancreatectomy, aiming to limit pancreatic insufficiency, are also emerging procedures, which place beyond the treatment of insulinomas and small non-functional panNENs (in association with lymph node picking) remains to be clarified. Furthermore, giving the fact that the liver is generally the only metastatic site, surgery keeps a place of choice alongside medical therapies in the treatment of metastatic disease, but its modalities and extensions are still a matter of debate. This narrative review aims to describe the current recommended surgical management for pancreatic NENs and controversies in light of the actual recommendations and recent literature.

Incidence of Lymph Node Metastases and Impact of Radical Surgery for Duodenal Neuroendocrine Tumors

BACKGROUND

Despite the high frequency of regional lymph node (LN) metastases associated with duodenal neuroendocrine tumors (D-NETs), the impact of these metastases on survival and the ideal extent of LN dissection are unknown. We used the National Cancer Database (NCDB) to investigate factors associated with survival, including LN metastases and types of surgery, in patients with D-NETs.

METHODS

All patients with D-NETs recorded in the NCDB between 2004 and 2016 were included in the study. We applied a multivariate Cox regression model to assess the relationship between the clinicopathological characteristics and overall survival (OS).

RESULTS

We identified 7613 patients, among whom 4886 local excisions and 233 radical surgeries had been performed. Among patients with at least 1 LN pathologically examined, the overall incidence of LN metastasis was 41.2%. For all patients, the median OS was 10.6 years. Univariate analyses showed equivalent OS in N0 and N1 groups (HR,0.83; 95% CI,0.64-1.09) and diminished OS in those who had undergone radical surgery compared with those who had undergone local resection (HR,1.35; 95% CI,1.02-1.8). In multivariable analyses, tumor size >50 mm and having more than 9 positive LNs were associated with diminished OS (HR,1.64 and 5.2; 95% CI,1.25-2.16 and 1.91-14.18), whereas the type of surgery did not remain in the model.

CONCLUSION

Our study revealed that the presence of regional LN metastases and extent of surgery did not affect OS among patients with D-NETs. Radical resection to clear occult LN metastases for nonfunctioning, sporadic D-NETs was not supported by the current study.

New therapies for patients with multiple endocrine neoplasia type 1

In 1953, for the first time, Paul Wermer described a family presenting endocrine gland neoplasms over several generations. The transmission was autosomal dominant and the penetrance was high. Forty years later in 1997, the multiple endocrine neoplasia type 1 (MEN1) gene was sequenced, thus enabling diagnosis and early optimal treatment. Patients carrying the MEN1 gene present endocrine but also non-endocrine tumors. Parathyroid, pancreatic and pituitary impairment are the three main types of endocrine involvement. The present article details therapeutic management of hyperparathyroidism, neuroendocrine pancreatic tumors and pituitary adenomas in patients carrying the MEN1 gene. Significant therapeutic progress has in fact been made in the last few years. As concerns the parathyroid glands, screening of family members and regular monitoring of affected subjects now raise the question of early management of parathyroid lesions and optimal timing of parathyroid surgery. As concerns the duodenum-pancreas, proton-pump inhibitors are able to control gastrin-secreting syndrome, reducing mortality in MEN1 patients. Mortality in MEN1 patients is no longer mainly secondary to uncontrolled hormonal secretion but to metastatic (mainly pancreatic) disease progression. Tumor risk requires regular monitoring of morphological assessment, leading to iterative pancreatic surgery in a large number of patients. Finally, pituitary adenomas in MEN1 patients are traditionally described as aggressive, invasive and resistant to medical treatment. However, regular pituitary screening showed them to be in fact infra-centimetric and non-secreting in the majority of patients. Consequently, it is necessary to regularly monitor MEN1 patients, with regular clinical, biological and morphological work-up. Several studies showed that this regular monitoring impairs quality of life. Building a relationship of trust between patients and care provider is therefore essential. It enables the patient to be referred for psychological or psychiatric care in difficult times, providing long-term support and preventing any breakdown in continuity of care.

Clinical aspects of multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome characterized by the co-occurrence of primary hyperparathyroidism, duodenopancreatic neuroendocrine tumours (NETs) and/or pituitary adenomas. MEN1 can predispose patients to other endocrine and non-endocrine tumours, such as cutaneous tumours, central nervous system tumours and breast cancer. Endocrine tumours in patients with MEN1 differ from sporadic tumours in that they have a younger age at onset, present as multiple tumours in the same organ and have a different clinical course. Therefore, patients with overt MEN1 and those who carry a MEN1 mutation should be offered tailored biochemical and imaging screening to detect tumours and evaluate their progression over time. Fortunately, over the past 10 years, knowledge about the clinical phenotype of these tumours has markedly progressed, thanks to the implementation of national registries, particularly in France and the Netherlands. This Review provides an update on the clinical management of MEN1-related tumours. Epidemiology, the clinical picture, diagnostic work-up and the main lines of treatment for MEN1-related tumours are summarized. Controversial therapeutic aspects and issues that still need to be addressed are also discussed. Moreover, special attention is given to MEN1 manifestations in children and adolescents.

Multiple Endocrine Neoplasia Type 1: Latest Insights

Multiple endocrine neoplasia type 1 (MEN1), a rare tumor syndrome that is inherited in an autosomal dominant pattern, is continuing to raise great interest for endocrinology, gastroenterology, surgery, radiology, genetics, and molecular biology specialists. There have been 2 major clinical practice guidance papers published in the past 2 decades, with the most recent published 8 years ago. Since then, several new insights on the basic biology and clinical features of MEN1 have appeared in the literature, and those data are discussed in this review. The genetic and molecular interactions of the MEN1-encoded protein menin with transcription factors and chromatin-modifying proteins in cell signaling pathways mediated by transforming growth factor β/bone morphogenetic protein, a few nuclear receptors, Wnt/β-catenin, and Hedgehog, and preclinical studies in mouse models have facilitated the understanding of the pathogenesis of MEN1-associated tumors and potential pharmacological interventions. The advancements in genetic diagnosis have offered a chance to recognize MEN1-related conditions in germline MEN1 mutation-negative patients. There is rapidly accumulating knowledge about clinical presentation in children, adolescents, and pregnancy that is translatable into the management of these very fragile patients. The discoveries about the genetic and molecular signatures of sporadic neuroendocrine tumors support the development of clinical trials with novel targeted therapies, along with advancements in diagnostic tools and surgical approaches. Finally, quality of life studies in patients affected by MEN1 and related conditions represent an effort necessary to develop a pharmacoeconomic interpretation of the problem. Because advances are being made both broadly and in focused areas, this timely review presents and discusses those studies collectively.

Complications After Major Surgery for Duodenopancreatic Neuroendocrine Tumors in Patients with MEN1: Results from a Nationwide Cohort

Background

Little is known about complications after major duodenopancreatic surgery for duodenopancreatic neuroendocrine tumors (dpNETs) in multiple endocrine neoplasia type 1 (MEN1). Therefore, the incidence and severity of complications after major surgery for MEN1-related dpNETs were assessed.

Methods

Patients were selected from the population-based Dutch MEN1 database if they had undergone a Whipple procedure or total pancreatectomy from 2003 to 2017. Complications were graded according to the Clavien–Dindo classification (grade III or higher complications were considered a severe complication) and definitions from the International Study Group of Pancreatic Surgery. The Cumulative Complication Index (CCI^®) was calculated as the sum of all complications weighted for their severity. Univariable logistic regression was performed to assess potential associations between predictor candidates and a severe complication.

Results

Twenty-seven patients (median age 43 years) underwent a major duodenopancreatic resection, including 14 Whipple procedures and 13 total pancreatectomies. Morbidity and mortality were 100% (27/27) and 4% (1/27), respectively. A severe complication occurred in 17/27 (63%) patients. The median CCI^® was 47.8 [range 8.7–100]. Grade B/C pancreatic fistulas, delayed gastric emptying, bile leakage, hemorrhage, and chyle leakage occurred in 7/14 (50%), 10/27 (37%), 1/27 (4%), 7/27 (26%), 3/27 (11%) patients, respectively. Patients with a severe complication had longer operative time and higher blood loss. After Whipple, new-onset endocrine and exocrine insufficiency occurred in 1/13 and 9/14 patients, respectively.

Conclusions

Major duodenopancreatic surgery in MEN1 is associated with a very high risk of severe complications and cumulative burden of complications and should therefore be reserved for a select subgroup of patients with MEN1-related dpNETs.

Supplementary Information

The online version of this article (10.1245/s10434-020-09496-1) contains supplementary material, which is available to authorized users.

Multiple Endocrine Neoplasia Type 1 and the Pancreas: Diagnosis and Treatment of Functioning and Non-Functioning Pancreatic and Duodenal Neuroendocrine Neoplasia within the MEN1 Syndrome - An International Consensus Statement

The better understanding of the biological behavior of multiple endocrine neoplasia type 1 (MEN1) organ manifestations and the increase in clinical experience warrant a revision of previously published guidelines. Duodenopancreatic neuroendocrine neoplasias (DP-NENs) are still the second most common manifestation in MEN1 and, besides NENs of the thymus, remain a leading cause of death. DP-NENs are thus of main interest in the effort to reevaluate recommendations for their diagnosis and treatment. Especially over the last 2 years, more clinical experience has documented the follow-up of treated and untreated (natural-course) DP-NENs. It was the aim of the international consortium of experts in endocrinology, genetics, radiology, surgery, gastroenterology, and oncology to systematically review the literature and to present a consensus statement based on the highest levels of evidence. Reviewing the literature published over the past decade, the focus was on the diagnosis of F- and NF-DP-NENs within the MEN1 syndrome in an effort to further standardize and improve treatment and follow-up, as well as to establish a "logbook" for the diagnosis and treatment of DP-NENs. This shall help further reduce complications and improve long-term treatment results in these rare tumors. The following international consensus statement builds upon the previously published guidelines of 2001 and 2012 and attempts to supplement the recommendations issued by various national and international societies.

Metastatic Potential and Survival of Duodenal and Pancreatic Tumors in Multiple Endocrine Neoplasia Type 1: A GTE and AFCE Cohort Study (Groupe d'étude des Tumeurs Endocrines and Association Francophone de Chirurgie Endocrinienne)

OBJECTIVE

To assess the distant metastatic potential of duodeno-pancreatic neuroendocrine tumors (DP-NETs) in patients with MEN1, according to functional status and size.

SUMMARY BACKGROUND DATA

DP-NETs, with their numerous lesions and endocrine secretion-related symptoms, continue to be a medical challenge; unfortunately they can become aggressive tumors associated with distant metastasis, shortening survival. The survival of patients with large nonfunctional DP-NETs is known to be poor, but the overall contribution of DP-NETs to metastatic spread is poorly known.

METHODS

The study population included patients with DP-NETs diagnosed after 1990 and followed in the MEN1 cohort of the Groupe d'étude des Tumeurs Endocrines (GTE). A multistate Markov piecewise constant intensities model was applied to separate the effects of prognostic factors on 1) metastasis, and 2) metastasis-free death or 3) death after appearance of metastases.

RESULTS

Among the 603 patients included, 39 had metastasis at diagnosis of DP-NET, 50 developed metastases during follow-up, and 69 died. The Markov model showed that Zollinger-Ellison-related tumors (regardless of tumor size and thymic tumor pejorative impact), large tumors over 2 cm, and age over 40 years were independently associated with an increased risk of metastases. Men, patients over 40 years old and patients with tumors larger than 2 cm, also had an increased risk of death once metastasis appeared.

CONCLUSIONS

DP-NETs of 2 cm in size or more, regardless of the associated secretion, should be removed to prevent metastasis and increase survival. Surgery for gastrinoma remains debatable.

The Landmark Series: Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) comprise a heterogeneous group of neoplasms arising from pancreatic islet cells that remain relatively rare but are increasing in incidence worldwide. While significant advances have been made in recent years with regard to systemic therapies for patients with advanced disease, surgical resection remains the standard of care for most patients with localized tumors. Although formal pancreatectomy with regional lymphadenectomy is the standard approach for most PNETs, pancreas-preserving approaches without formal lymphadenectomy are acceptable for smaller tumors at low risk for lymph node metastases. Furthermore, observation of small, asymptomatic, low-grade PNETs is a safe, initial strategy and is generally recommended for tumors < 1 cm in size. In this Landmark Series review, we highlight the critical studies that have defined the surgical management of PNETs.

Surgical Management of Neuroendocrine Tumours of the Pancreas

Neuroendocrine tumours of the pancreas (pNET) are rare, accounting for 1-2% of all pancreatic neoplasms. They develop from pancreatic islet cells and cover a wide range of heterogeneous neoplasms. While most pNETs are sporadic, some are associated with genetic syndromes. Furthermore, some pNETs are 'functioning' when there is clinical hypersecretion of metabolically active peptides, whereas others are 'non-functioning'. pNET can be diagnosed at a localised stage or a more advanced stage, including regional or distant metastasis (in 50% of cases) mainly located in the liver. While surgical resection is the cornerstone of the curative treatment of those patients, pNET management requires a multidisciplinary discussion between the oncologist, radiologist, pathologist, and surgeon. However, the scarcity of pNET patients constrains centralised management in high-volume centres to provide the best patient-tailored approach. Nonetheless, no treatment should be initiated without precise diagnosis and staging. In this review, the steps from the essential comprehensive preoperative evaluation of the best surgical approach (open versus laparoscopic, standard versus sparing parenchymal pancreatectomy, lymphadenectomy) according to pNET staging are analysed. Strategies to enhance the short- and long-term benefit/risk ratio in these particular patients are discussed.

Insights into Effects/Risks of Chronic Hypergastrinemia and Lifelong PPI Treatment in Man Based on Studies of Patients with Zollinger-Ellison Syndrome

The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25–70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are <5 years of duration and little data exist for >10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10–20 years). Zollinger–Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in <30% of patients with ZES, a long-term cure is not possible, these patients have life-long hypergastrinemia and require life-long treatment with PPIs. Therefore, ZES patients have been proposed as a good model of the long-term effects of hypergastrinemia in man as well as the effects/side-effects of very long-term PPI treatment. In this article, the insights from studies on ZES into these controversial issues with pertinence to chronic PPI use in non-ZES patients is reviewed, primarily concentrating on data from the prospective long-term studies of ZES patients at NIH.

Contemporary surgical management of the Zollinger-Ellison syndrome in multiple endocrine neoplasia type 1

About 30% of patients with MEN1 develop a Zollinger-Ellison syndrome. Meanwhile it is well established that the causative gastrinomas are almost exclusively localized in the duodenum and not in the pancreas, MEN1 gastrinomas occur multicentric and are associated with hyperplastic gastrin cell lesions and tiny gastrin-producing micro tumors in contrast to sporadic duodenal gastrinomas. Regardless of the high prevalence of early lymphatic metastases, the survival is generally good with an aggressive course of disease in only about 20% of patients. Symptoms can be controlled medically. The indication, timing, type, and extent of surgery are highly controversial and are discussed in detail in this article by a thorough and critical review of literature. More radical procedures, like partial pancreaticoduodenectomy, are weighed against less aggressive local excision of gastrinomas and the pros and cons of both approaches are discussed in terms of long-term morbidity, biochemical cure, and survival.

Surgical management of Zollinger-Ellison syndrome: Classical considerations and current controversies

Zollinger-Ellison syndrome (ZES) is characterized by gastric acid hypersecretion causing severe recurrent acid-related peptic disease. Excessive secretion of gastrin can now be effectively controlled with powerful proton pump inhibitors, but surgical management to control gastrinoma itself remains controversial. Based on a thorough literature review, we design a surgical algorithm for ZES and list some significant consensus findings and recommendations: (1) For sporadic ZES, surgery should be routinely undertaken as early as possible not only for patients with a precisely localized diagnosis but also for those with negative imaging findings. The surgical approach for sporadic ZES depends on the lesion location (including the duodenum, pancreas, lymph nodes, hepatobiliary tract, stomach, and some extremely rare sites such as the ovaries, heart, omentum, and jejunum). Intraoperative liver exploration and lymphadenectomy should be routinely performed; (2) For multiple endocrine neoplasia type 1-related ZES (MEN1/ZES), surgery should not be performed routinely except for lesions > 2 cm. An attempt to perform radical resection (pancreaticoduodenectomy followed by lymphadenectomy) can be made. The ameliorating effect of parathyroid surgery should be considered, and parathyroidectomy should be performed first before any abdominal surgery for ZES; and (3) For hepatic metastatic disease, hepatic resection should be routinely performed. Currently, liver transplantation is still considered an investigational therapeutic approach for ZES. Well-designed prospective studies are desperately needed to further verify and modify the current considerations.

Prognostic factors and survival in MEN1 patients with gastrinomas: Results from the DutchMEN study group (DMSG)

Background and objectives

Gastrinomas are the most prevalent functioning neuroendocrine tumors (NET) in multiple endocrine neoplasia type 1 (MEN1). Guidelines suggest medical therapy in most patients, but surgery may be considered in a subgroup. Currently, factors to guide management are necessary. This population‐based cohort study assessed prognostic factors of survival in patients with MEN1‐related gastrinomas.

Methods

Patients with MEN1 having gastrinomas were identified in the Dutch MEN1 database from 1990 to 2014 based on fasting serum gastrin (FSG) levels and/or pathology. Predictors of overall survival were assessed using Cox regression.

Results

Sixty‐three patients with gastrinoma (16% of the MEN1 population) were identified. Five‐ and 10‐year overall survival rates were 83% and 65%, respectively. Prognostic factors associated with overall survival were initial FSG levels ≥20x upper limit of normal (ULN) (hazard ratio [HR], 6.2 [95% confidence interval, 1.7‐23.0]), pancreatic NET ≥2 cm (HR 4.5; [1.5‐13.1]), synchronous liver metastases (HR 8.9; [2.1‐36.7]), gastroduodenoscopy suspicious for gastric NETs (HR 12.7; [1.4‐115.6]), and multiple concurrent NETs (HR 5.9; [1.2‐27.7]).

Conclusion

Life expectancy of patients with MEN1 gastrinoma is reduced. FSG levels and pancreatic NETs ≥2 cm are prognostic factors. FSG levels might guide surveillance intensity, step‐up to additional diagnostics, or provide arguments in selecting patients who might benefit from surgery.

Recent advances in the diagnosis and management of pancreatic neuroendocrine tumours

The incidence of pancreatic neuroendocrine tumours (PNET) is rising mainly due to the increased use of cross-sectional imaging. Although many PNETs are asymptomatic and non-functioning, the overall 5-year survival is still less than 50%. In this article, we review the advances in diagnosis, classification and staging of PNET that have evolved with the development of new cross-sectional imaging methods and biopsy techniques. With accurate classification, evidence-based, individualised prognostic outcomes and treatments are able to be given which are also discussed.

Insights into the biology and treatment strategies of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are the second most common primary pancreatic neoplasms after pancreatic ductal adenocarcinoma. PNETs present with widely various clinical manifestation and unfavorable survival rate. The recent advances in next generation sequencing have significantly increased our understanding of the molecular landscape of PNETs and help guide the development of targeted therapies. This review intends to outline a holistic picture of the tumors by discussing current understanding of clinical presentations, up-to-date treatment strategies, novel mouse models, and molecular biology of PNETs. Furthermore, we will provide insight into the future development of more effective targeted therapies that are necessary to manage PNETs.

Patient characteristics and clinical outcomes following initial surgical intervention for MEN1 associated pancreatic neuroendocrine tumours: A systematic review and exploratory meta-analysis of the literature

BACKGROUND

This systematic review aimed to define the outcomes of different pancreatic resection procedures for multiple endocrine neoplasia type 1 (MEN1) associated pancreatic neuroendocrine neoplasms (pNENs).

METHODS

A search of PubMed, MEDLINE and SCOPUS databases were performed in accordance with PRISMA guidelines.

RESULTS

Twenty-seven studies including 533 patients undergoing initial pancreatic resection for MEN1 associated pNENs were included in this systematic review. Three hundred and sixty-six (68.7%) distal pancreatectomies (DP), 120 (22.5%) sole enucleations (SE) and 47 (8.8%) pancreaticoduodenectomies (PD) were identified. SE was associated with a higher rate of recurrence than DP (25/67, 37% vs 40/190, 21% respectively, P = 0.008) but a lower rate of endocrine insufficiency than PD (1/20, 5% vs 8/21, 38% respectively, P = 0.010). A meta-analysis of major pancreatic resections (PD or DP) vs SE in 15 studies showed that SE is associated with an increased rate of recurrence (Major resection 42/184, 23% vs SE 20/53, 38% RR 0.65 CI 0.43-0.96 P = 0.032) but reduced rate of postoperative endocrine insufficiency (Resection 37/93, 40% vs SE 0/24, 0% RR 7.37 CI 1.57-34.64 P = 0.008). Similarly, insulinomas and functional pNENs overall had lower rates of recurrence and reoperation with major resection. There was no difference in the reoperation rates or survival outcomes after SE compared with major pancreatic resections at follow-up (pooled overall mean duration: 85 months).

CONCLUSION

Major pancreatic resections for MEN1 associated pNENs have a lower risk of recurrence and a higher risk of postoperative endocrine insufficiency when compared to sole enucleation, but a similar rate of reoperation and survival.

Prospective Evaluation of Results of Reoperation in Zollinger-Ellison Syndrome

OBJECTIVE

To determine the role of reoperation in patients with persistent or recurrent Zollinger-Ellison Syndrome (ZES).

BACKGROUND

Approximately, 0% to 60% of ZES patients are disease-free (DF) after an initial operation, but the tumor may recur.

METHODS

A prospective database was queried.

RESULTS

A total of 223 patients had an initial operation for possible cure of ZES and then were subsequently evaluated serially with cross sectional imaging-computed tomography, magnetic resonance imaging, ultrasound, more recently octreoscan-and functional studies for ZES activity. The mean age at first surgery was 49 years and with an 11-year mean follow-up 52 patients (23%) underwent reoperation when ZES recurred with imageable disease. Results in this group are analyzed in the current report. Reoperation occurred on a mean of 6 years after the initial surgery with a mean number of reoperations of 1 (range 1-5). After reoperation 18/52 patients were initially DF (35%); and after a mean follow-up of 8 years, 13/52 remained DF (25%). During follow-up, 9/52 reoperated patients (17%) died, of whom 7 patients died a disease-related death (13%). The overall survival from first surgery was 84% at 20 years and 68% at 30 years. Multiple endocrine neoplasia type 1 status did not affect survival, but DF interval and liver metastases did.

CONCLUSIONS

These results demonstrate that a significant proportion of patients with ZES will develop resectable persistent or recurrent disease after an initial operation. These patients generally have prolonged survival after reoperation and 25% can be cured with repeat surgery, suggesting all ZES patients postresection should have systematic imaging, and if tumor recurs, advise repeat operation.

Unmet Needs in Functional and Nonfunctional Pancreatic Neuroendocrine Neoplasms

Recently, the European Neuroendocrine Tumor Society (ENETS) held working sessions composed of members of the advisory board and other neuroendocrine neoplasm (NEN) experts to attempt to identify unmet needs in NENs in different locations or with advanced/poorly differentiated NENs. This report briefly summarizes the main proposed areas of unmet needs in patients with functional and nonfunctional pancreatic NENs.

Gastrinomas: Medical or Surgical Treatment

This article reviews the role of surgical and medical management in patients with Zollinger-Ellison syndrome (ZES) due to a gastrin-secreting neuroendocrine tumor (gastrinoma). It concentrates on the status at present but also briefly reviews the changes over time in treatment approaches. Generally, surgical and medical therapy are complementary today; however, in some cases, such as patients with ZES and multiple endocrine neoplasia type 1, the treatment approach remains controversial.

Current and emerging therapies for PNETs in patients with or without MEN1

Pancreatic neuroendocrine tumours (PNETs) might occur as a non-familial isolated endocrinopathy or as part of a complex hereditary syndrome, such as multiple endocrine neoplasia type 1 (MEN1). MEN1 is an autosomal dominant disorder characterized by the combined occurrence of PNETs with tumours of the parathyroids and anterior pituitary. Treatments for primary PNETs include surgery. Treatments for non-resectable PNETs and metastases include biotherapy (for example, somatostatin analogues, inhibitors of receptors and monoclonal antibodies), chemotherapy and radiological therapy. All these treatments are effective for PNETs in patients without MEN1; however, there is a scarcity of clinical trials reporting the efficacy of the same treatments of PNETs in patients with MEN1. Treatment of PNETs in patients with MEN1 is challenging owing to the concomitant development of other tumours, which might have metastasized. In recent years, preclinical studies have identified potential new therapeutic targets for treating MEN1-associated neuroendocrine tumours (including PNETs), and these include epigenetic modification, the β-catenin-wingless (WNT) pathway, Hedgehog signalling, somatostatin receptors and MEN1 gene replacement therapy. This Review discusses these advances.

Diagnosis of Zollinger-Ellison syndrome in the era of PPIs, faulty gastrin assays, sensitive imaging and limited access to acid secretory testing

In recent years the diagnosis of Zollinger-Ellison syndrome (ZES) has become increasingly controversial with several new approaches and criteria proposed, differing from the classical biochemical criterion of inappropriate hypergastrinemia (i.e., hypergastrinemia in the presence of hyperchlorhydria) (Table 1). These changes have come about because of the difficulty and potential dangers of stopping proton pump inhibitors (PPIs) for gastric acid analysis; the recognition than many of the current assays used to assess gastrin concentrations are unreliable; the development of sensitive imaging modalities that detect neuroendocrine tumors (NETs) including an increasing number of the primary gastrinomas; the increased use of percutaneous or endoscopic ultrasound (EUS)-directed biopsies/cytology and the general lack of availability of acid secretory testing. In this article we will discuss the basis for these controversies, review the proposed changes in diagnostic approaches and make recommendations for supporting the diagnosis of ZES in the modern era.

The future: diagnostic and imaging advances in MEN1 therapeutic approaches and management strategies

Prospective randomized data are lacking, but current clinical expert guidelines recommend annual screening examinations, including laboratory assessments and various imaging modalities (e.g. CT, MRI, scintigraphy and EUS) for patients with multiple endocrine neoplasia type 1 (MEN1). Routine screening is proposed to detect and localize neuroendocrine manifestations as early as possible. The goal is timely intervention to improve quality of life and to increase life expectancy by preventing the development of life-threatening hormonal syndromes and/or metastatic disease. In recent years, some studies compared different and new imaging methods regarding their sensitivity and utility in MEN1 patients. This present article reviews the proposed diagnostic tools for MEN1 screening as well as potential future perspectives.

The future: surgical advances in MEN1 therapeutic approaches and management strategies

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary autosomal dominant disorder associated with numerous neuroendocrine tumors (NETs). Recent advances in the management of MEN1 have led to a decrease in mortality due to excess hormones; however, they have also led to an increase in mortality from malignancy, particularly NETs. The main challenges are to localize these tumors, to select those that need therapy because of the risk of aggressive behavior and to select the appropriate therapy associated with minimal morbidity. This must be applied to a hereditary disease with a high risk of recurrence. The overall aim of management in MEN1 is to ensure that the patient remains disease- and symptom-free for as long as possible and maintains a good quality of life. Herein, we review the changes that occurred in the last 20 years in the surgical management of MEN1-associated functional and non-functional pancreatico-duodenal NETs and thymic and bronchial NETs.

The future: medical advances in MEN1 therapeutic approaches and management strategies

Multiple endocrine neoplasia type 1 is a rare autosomal inherited disorder associated with a high risk for patients to simultaneously develop tumors of the parathyroid glands, duodenopancreatic neuroendocrine tumors and tumors of the anterior pituitary gland. Early identification of MEN1 in patients enables presymptomatic screening of manifestations, which makes timely interventions possible with the intention to prevent morbidity and mortality. Causes of death nowadays have shifted toward local or metastatic progression of malignant neuroendocrine tumors. In early cohorts, complications like peptic ulcers in gastrinoma, renal failure in hyperparathyroidism, hypoglycemia and acute hypercalcemia were the primary causes of early mortality. Improved medical treatments of these complications led to a significantly improved life expectancy. The MEN1 landscape is still evolving, considering the finding of breast cancer as a new MEN1-related manifestation and ongoing publications on follow-up and medical care for patients with MEN1. This review aims at summarizing the most recent insights into the follow-up and medical care for patients with MEN1 and identifying the gaps for future research.

Complicated Case Presentation: Management of Pancreatic Neuroendocrine Tumors in Multiple Endocrine Neoplasia Type 1

Multiple endocrine neoplasia type 1 (MEN1) is an inherited predisposition to tumors of the parathyroid glands, anterior pituitary, and pancreatic islet cells. In this review, we discuss the clinical case of a 45-year-old woman with MEN1 that was presented at the 2015 North American Neuroendocrine Tumor Society Symposium. In our review of this patient's complicated clinical course and subsequent operative management, we highlight controversies in the diagnosis and management of pancreatic neuroendocrine tumors in MEN1. In particular, this case illustrates the lack of consensus regarding the optimal biochemical and radiologic screening for pancreatic neuroendocrine tumors and absence of guidelines about the appropriate surgical approach for treatment. We review these controversies and discuss possible approaches to management.

Pancreatic neuroendocrine tumors: Challenges in an underestimated disease

Pancreatic neuroendocrine tumours (PanNETs) are considered a relatively unusual oncologic entity. Due to its relative good prognosis, surgery remains the goal standard therapy not only in localized disease but also in the setting of locally or metastatic disease. Most of the patients are diagnosed in metastatic scenario, where multidisciplinary approach based on surgery, chemotherapies, liver-directed and/or molecular targeted therapies are commonly used. Owing to a deeper molecular knowledge of this disease, these targeted therapies are nowadays widely implemented, being the likely discovery of predictive biomarkers that would allow its use in other settings. This review is focused on describing the different classifications, etiology, prognostic biomarkers and multidisciplinary approaches that are typically used in PanNET.

Islet Cell Tumors of the Pancreas

Islet cell tumors of the pancreas, also known as pancreatic neuroendocrine tumors, constitute less than 5% of pancreatic tumors, and 7% of all neuroendocrine tumors. Most are non-functional, and patients often present with metastatic disease. Functional tumors present with distinct clinical syndromes. Accurate staging is critical as surgery is both the cornerstone of treatment, and the only hope for cure. Medical management involves treating the manifestations of hormonal excess, and using somatastatin analogues when appropriate. Systemic chemotherapy, targeted molecular therapy, and peptide receptor radiotherapy may be used for refractory disease in lieu of or as an adjunct to surgery.

Controversies in surgery for multiple endocrine neoplasia type 1-associated Zollinger–Ellison syndrome

Zollinger–Ellison syndrome (ZES) is a common manifestation of multiple endocrine neoplasia type 1 (MEN1). At least 90% of MEN1-ZES patients have multiple duodenal gastrinomas, making the duodenum the target organ of ZES. The indication and the timing of surgery in MEN1-ZES is controversial, since there is yet no parameter that indicates an aggressive course of disease and long-term survival is generally good. An imageable, most likely nonfunctioning pancreatic neuroendocrine neoplasm (pNEN) >1–2 cm seems to be a good surrogate parameter to indicate surgery in order to prevent distant metastatic pNEN disease, although some groups indicate surgery at the time of biochemical ZES evidence. The optimal surgical procedure is also controversial. Different strategies encomprise local excision via duodenotomy with or without distal pancreatic resection and regional lymphadenectomy to partial pancreaticoduodenectomy. At present, the timing and type of surgery for MEN1-ZES should be individualized according to patient’s characteristics and preference.

Multiple Endocrine Neoplasia: Genetics and Clinical Management

Early diagnosis of multiple endocrine neoplasia (MEN) syndromes is critical for optimal clinical outcomes; before the MEN syndromes can be diagnosed, they must be suspected. Genetic testing for germline alterations in both the MEN type 1 (MEN1) gene and RET proto-oncogene is crucial to identifying those at risk in affected kindreds and directing timely surveillance and surgical therapy to those at greatest risk of potentially life-threatening neoplasia. Pancreatic, thymic, and bronchial neuroendocrine tumors are the leading cause of death in patients with MEN1 and should be aggressively considered by at least biannual computed tomography imaging.

Determinants of surgical resection for pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) include functioning and non-functional tumors. Functioning tumors consist of tumors that produce a variety of hormones and their clinical effects. Therefore, determinants of resection of pNETs should be discussed for each group of tumors. Less than 10% of insulinomas are malignant, therefore more than 90% of the cases can be cured by surgical resection. Lymphadenectomy is generally not necessary in insulinoma operation. If preoperative localization of the insulinoma is completed, enucleation from the pancreatic body or tail, and distal pancreatectomy can be performed safely by laparoscopy. When preoperative localization of a sporadic insulinoma is not confirmed, surgical exploration is needed. Intraoperative localization of a tumor, intraoperative insulin sampling and frozen section are required. The crucial purpose of surgical resection is to control inappropriate insulin secretion by removing all insulinomas. Gastrinomas are usually located in the duodenum or pancreas, which secrete gastrin and cause Zollinger-Ellison syndrome (ZES). Duodenal gastrinomas are usually small, therefore they are not seen on preoperative imaging studies or endoscopic ultrasound, and can be found only at surgery if a duodenotomy is performed. In addition, lymph node metastasis is found in 40-60% of cases. Therefore, the experienced surgeons should direct operation for gastrinomas. Surgical exploration with duodenotomy should be performed at a laparotomy. Other functioning pNETs can occur in the pancreas or in other locations. Curative resection is always recommended whenever possible after optimal symptomatic control of the clinical syndrome by medical treatment. Indications for surgery depend on clinical symptom control, tumor size, location, extent, malignancy and presence of metastasis. A lot of non-functioning pNETs are found incidentally according to the quality improvement of imaging techniques. Localized, small, malignant non-functioning pNETs should be operated on aggressively, while in possibly benign tumors smaller than 2 cm the surgical risk-benefit ratio should be carefully weighted. Surgical liver resection is generally proposed in curative intent to all patients with operable metastases from G1 or G2 pNET. The benefits of surgical resection of liver metastases have been demonstrated in terms of overall survival and quality of life. Complete resection is associated with better long-term survival.

Update on pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) are relatively rare tumors comprising 1-2% of all pancreas neoplasms. In the last 10 years our understanding of this disease has increased dramatically allowing for advancements in the treatment of pNETs. Surgical excision remains the primary therapy for localized tumors and only potential for cure. New surgical techniques using laparoscopic approaches to complex pancreatic resections are a major advancement in surgical therapy and increasingly possible. With early detection being less common, most patients present with metastatic disease. Management of these patients requires multidisciplinary care combining the best of surgery, chemotherapy and other targeted therapies. In addition to surgical advances, recently, there have been significant advances in systemic therapy and targeted molecular therapy.

Surgical management of advanced pancreatic neuroendocrine tumors: short-term and long-term results from an international multi-institutional study

BACKGROUND

The role of extended resections in the management of advanced pancreatic neuroendocrine tumors (PNETs) is not well defined.

METHODS

Between 1995 and 2012, 134 patients with PNET underwent isolated (isoPNET group: 91 patients) or extended pancreatic resection (synchronous liver metastases and/or adjacent organs) (advPNET group: 43 patients).

RESULTS

The associated resections included 27 hepatectomies, 9 vascular resections, 12 colectomies, 10 gastrectomies, 4 nephrectomies, 4 adrenalectomies, and 3 duodenojejunal resections. R0 was achieved in 41 patients (95%) in the advPNET. The rates of T3-T4 (73 vs 16%; p < .0001) and N+ (35 vs 13%; p = .007) were higher in the advPNET group. Mortality (5 vs 2%) and major morbidity (21 vs 19%) rates were similar between the 2 groups. The 5-year overall survival (OS) of the series was 87% in the isoPNET group and 66% in the advPNET group (p = .006). Only patients with both locally advanced disease and liver metastases showed worse survival (p = .0003). The advPNET group developed recurrence earlier [disease-free survival (DFS) at 5 years: 26 vs 81%; p < .001]. In univariate analysis, negative prognostic factors of survival were: poor degree of differentiation (p < .001), liver metastasis (p = .011), NE carcinoma (p < .001), and resection of adjacent organs (p = .013). The multivariate analysis did not highlight any factor that influenced OS. In multivariate analysis independent DFS factors were a poor degree of differentiation (p = .03) and the European Neuroendocrine Tumor Society stage (p = .01).

CONCLUSIONS

An aggressive surgical approach for locally advanced or metastatic tumors is safe and offers long-term survival.

Thoracic and duodenopancreatic neuroendocrine tumors in multiple endocrine neoplasia type 1: natural history and function of menin in tumorigenesis

Mutations of the multiple endocrine neoplasia type 1 (MEN1) gene lead to loss of function of its protein product menin. In keeping with its tumor suppressor function in endocrine tissues, the majority of the MEN1-related neuroendocrine tumors (NETs) show loss of heterozygosity (LOH) on chromosome 11q13. In sporadic NETs, MEN1 mutations and LOH are also reported, indicating common pathways in tumor development. Prevalence of thymic NETs (thNETs) and pulmonary carcinoids in MEN1 patients is 2-8%. Pulmonary carcinoids may be underreported and research on natural history is limited, but disease-related mortality is low. thNETs have a high mortality rate. Duodenopancreatic NETs (dpNETs) are multiple, almost universally found at pathology, and associated with precursor lesions. Gastrinomas are usually located in the duodenal submucosa while other dpNETs are predominantly pancreatic. dpNETs are an important determinant of MEN1-related survival, with an estimated 10-year survival of 75%. Survival differs between subtypes and apart from tumor size there are no known prognostic factors. Natural history of nonfunctioning pancreatic NETs needs to be redefined because of increased detection of small tumors. MEN1-related gastrinomas seem to behave similar to their sporadic counterparts, while insulinomas seem to be more aggressive. Investigations into the molecular functions of menin have led to new insights into MEN1-related tumorigenesis. Menin is involved in gene transcription, both as an activator and repressor. It is part of chromatin-modifying protein complexes, indicating involvement of epigenetic pathways in MEN1-related NET development. Future basic and translational research aimed at NETs in large unbiased cohorts will clarify the role of menin in NET tumorigenesis and might lead to new therapeutic options.

Zollinger-Ellison syndrome: classical considerations and current controversies

Zollinger-Ellison syndrome (ZES) is an endocrinopathy characterized by gastrin-secreting tumors, responsible for causing the formation of multiple, refractory, and recurrent peptic ulcers in the distal duodenum and proximal jejunum. Two main variants have been described, sporadic and those found in association with parathyroid and pituitary tumors, a genetic disorder known as multiple endocrine neoplasia-1 (MEN-1). Biochemical serum evaluation for elevated gastrin, followed by radiological or nuclear localization of the primary lesion, is mandated for establishing diagnosis. The mainstays of treatment include management of hypersecretory state with medical suppression of gastric acid production and surgical resection of primary tumor for the prevention of malignant transformation and metastatic complications. Medical therapy with proton pump inhibitors has virtually eliminated the need for acid-reducing surgical procedures. Surgical approach to sporadic and MEN-1-associated ZES varies based on our understanding of the natural history of the condition and the probability of cure; however, resection to a negative microscopic margin is indicated in both cases. Postoperative surveillance involves measurement of gastrin level, followed by imaging if elevation is detected. Re-excision of recurrent or resection of metastatic disease is a subject of controversy; however, at the present time aggressive cytoreductive approach is favored.