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

Management of primary hyperparathyroidism in MEN1: From initial subtotal surgery to complex treatment of the remaining gland

Multiple endocrine neoplasia type 1 (MEN1) is a rare genetic disease with autosomal dominant transmission, which can cause various tumors, particularly endocrine, in a given patient. Primary hyperparathyroidism (PHPT) is the most common and earliest manifestation, leading to surgery before the age of 50 in most patients. Biological severity and renal and/or bone complications dictate the timing of parathyroid surgery. The objective is to correct hypercalcemia to prevent impact, while minimizing the risk of hypoparathyroidism. The most widely recommended procedure is subtotal parathyroidectomy (3 or 3.5 glands removed), with thymic horn resection via a cervical route. The development of imaging techniques, however, makes it possible to discuss partial surgery (resection of 1 or 2 glands) on a case-by-case basis depending on preoperative imaging and other elements such as patient age. Finally, hypercalcemia recurrence after initial surgery is a common feature of MEN1, and management of the remaining gland is challenging with various options: reoperation, calcimimetics and US-guided ablation or therapeutic abstention.

Multiple Endocrine Neoplasia Type 1

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN1) is a rare genetic disease of autosomal dominant inheritance, with an estimated prevalence of 3-20/100 000. Its main feature is neuroendocrine neoplasia in the parathyroid glands, the endocrine pancreas, the duodenum, and the pituitary gland. In this article, we review the diagnostic and therapeutic options for MEN1-associated tumors.

METHODS

We present an analysis and evaluation of retrospective case studies retrieved from PubMed, guidelines from Germany and abroad, and our own experience.

RESULTS

The disease is caused by mutations in the MEN1 gene. Mutation carriers should participate in a regular, specialized screening program from their twenties onward. The early diagnosis and individualized treatment of MEN1-associated tumors can prevent the development of life-threatening hormonal syndromes and prolong the expected life span of MEN1 patients from 55 to 70 years, as well as improving their quality of life. Surgical treatment is based on the location, size, growth dynamics, and functional activity of the tumors. The evidence for treatment strategies is derived from retrospective studies only (level III evidence) and the optimal treatment is often a matter of debate. This is a further reason for treatment in specialized centers.

CONCLUSION

MEN1 is a rare disease, and, consequently, the evidence base for its treatment is limited. Carriers of disease-causing mutations in the MEN1 gene should be cared for in specialized interdisciplinary centers, so that any appreciable tumor growth or hormonal activity can be detected early and organ-sparing treatment can be provided.

The lesion detection rate of Ga-68 DOTATATE PET/MR in multiple endocrine neoplasia type 1

INTRODUCTION

The purpose of the study was to determine the usefulness of Ga-68 DOTATATE PET/MR in the identification of tumours in individuals with multiple endocrine neoplasia type 1 (MEN1).

METHODS

In this retrospective investigation, five individuals who had tested positive for a hereditary MEN1 variant underwent Ga-68 DOTATATE PET/MR between May 2020 and January 2023. Several types of tumours associated with MEN1 were studied. MEN1-related tumours included pituitary, parathyroid, gastroenteropancreatic, and adrenal. The rates of lesion identification between MRI, Ga-68 DOTATATE PET, and Ga-68 DOTATATE PET/MRI were examined. The maximum and mean standard uptake values (SUVmax and SUVmean) were evaluated in carefully delineated volumes of interest (VOI) for the relevant tumours.

RESULTS

Of the 24 primary lesions, 14 were identified by Ga-68 DOTATATE PET, 18 by MRI, and 20 by Ga-68 DOTATATE PET/MRI. Two pituitary tumours were detected by all three techniques. All parathyroid tumours that were not detected by Ga-68 DOTATATE PET and MRI were found by Tc-99m MIBI SPECT/CT or/and EUS. Ga-68 DOTATATE PET/MR detected more gastroenteropancreatic lesions. All adrenal tumours not identified by Ga-68 DOTATATE PET were found by MRI or CT. The median SUVmax for lesions identified on Ga-68 DOTATATE PET/MRI was 18.4 (range, 3.8-85.2), and the median SUVmean was 12.0 (range, 2.3-49.8).

CONCLUSION

The combination of Ga-68 DOTATATE PET and MRI demonstrated a higher detection rate and may be more useful in the work-up of MEN1 providing a panoramic view of MEN1-related lesions. To increase the identification of MEN1-associated neuroendocrine lesions in the parathyroid gland, approaches other than Ga-68 DOTATATE PET/MRI should be used.

Major Genetic Motifs in Pituitary Adenomas: A Practical Literature Update

BACKGROUND

The literature includes many studies examining the genetic abnormalities that influence pituitary adenomas (PAs). We aimed to state the collective knowledge on the genetic underpinnings of PAs by organizing, summarizing, and consolidating the literature to serve as a comprehensive review for scientists and clinicians of the most up-to-date information underlying the genetic landscape of PAs.

METHODS

The PubMed and Google Scholar databases were searched using multiple key words and combined Medical Subject Headings terms; only articles published in English between January 2000 and January 2022 were included. Articles in which the focus did not relate to genetics, that included mainly anecdotal evidence, or that were single case studies were eliminated.

RESULTS

PAs are one of the most common intracranial neoplasms. However, the genetic underpinnings for these tumors are not yet fully elucidated. There are several categories of PAs: clinically significant versus not clinically significant, functional versus nonfunctional, and germline-derived versus sporadic origin. Each of these disease subcategories is characterized by unique genetic aberrations. Recently, more genes and other types of genetic aberrations have been identified as possible causes of PAs, such as copy number variations and altered levels of microRNAs.

CONCLUSIONS

This review serves to consolidate and summarize the literature discussing the genetic motifs of PAs to help physicians and scientists deliver patient-centered therapies.

Thymic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1

OBJECTIVE

MEN1 is associated with an increased risk of developing tumors in different endocrine organs. Neuroendocrine tumors of the thymus (TNETs) are very rare but often have an aggressive nature. We evaluated patients with MEN1 and TNET in three university hospitals in Finland.

DESIGN/METHODS

We evaluated patient records of 183 MEN1-patients from three university hospitals between the years 1985-2019 with TNETs. Thymus tumor specimens were classified according to the new WHO 2021 classification of TNET. We collected data on treatments and outcomes of these patients.

RESULTS

There were six patients (3.3%) with MEN1 and TNET. Five of them had the same common gene mutation occurring in Finland. They originated from common ancestors encompassing two pairs of brothers from sequential generations. The mean age at presentation of TNET was 44.7 ± 11.9 years. TNET was classified as atypical carcinoid (AC) in five out of six patients. One patient had a largely necrotic main tumor with very few mitoses and another nodule with 25 mitoses per 2 mm², qualifying for the 2021 WHO diagnosis of large cell neuroendocrine carcinoma (LCNEC). In our patients, the 5-year survival of the TNET patients was 62.5% and 10-year survival 31.3%.

CONCLUSION

In this study, TNETs were observed in one large MEN1 founder pedigree, where an anticipation-like earlier disease onset was observed in the most recent generation. TNET in MEN1 patients is an aggressive disease. The prognosis can be better by systematic screening. We also show that LCNEC can be associated with TNET in MEN1 patients.

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.

Exploring the MEN1 dependent modulation of caspase 8 and caspase 3 in human pancreatic and murine embryo fibroblast cells

MEN1 mutation causes pancreatic neuroendocrine neoplasia and benign malignancies of the parathyroid, the adrenal cortex and pituitary gland. The transcriptional activity of its product menin promotes the expression of genes deputed to several cellular mechanism including cell death. Here, we focused on its implication in the activation of the initiator and executioner caspases after staurosporine mediated cell death in 2D and 3D human and murine cell models. The administration of staurosporine, a well-known inducer of apoptotic cell death, caused a significant reduction of BON1, QGP1 and HPSC2.2 cell viability. The transient knockdown of MEN1, performed by using a specific siRNA, caused a significant down-regulation of CDKN1A and TP53 transcripts. The treatment with 1 µM of staurosporine caused also a significant down-regulation of MEN1 and was able to restore the basal expression of TP53 only in QGP1 cells. Transient or permanent MEN1 inactivation caused a decrease of caspase 8 activity in BON1, HPSC2.2 cells and MEN1-/- MEFs treated with staurosporine. Caspase 3/7 activity was suppressed after administration of staurosporine in MEN1 knocked down HPSC2.2 and MEN1-/- MEFs as well. The cleaved caspase 8 and caspase 3 decreased in human cells after MEN1 knockdown and in MEN1-/- MEFs. The treatment with staurosporine caused a reduction of the size of MEN1+/+ MEFs spheroids. Instead, MEN1-/- MEFs spheroids did not show any significant reduction of their size. In conclusion, MEN1 controls the activity of the initiator caspase 8 and the executioner caspase 3 in human and murine cells. Restoring of a functional MEN1 and interfering with the apoptotic mechanism could represent a future strategy for the treatment of MEN1-related malignancies.

Gastric enterochromaffin-like cell changes in multiple endocrine neoplasia type 1

BACKGROUND

Gastric enterochromaffin-like cell (ECL) tumours can occur in patients with multiple endocrine neoplasia type 1 (MEN1), especially in those affected by Zollinger Ellison syndrome (ZES). Since the prevalence of ECL lesions is not well defined yet, the present study evaluated the presence and extent of ECL lesions in MEN1 patients with and without ZES.

METHODS

Multiple endocrine neoplasia type 1 patients being part of a regular screening program (2014-2018) underwent gastroduodenoscopies with biopsies of the stomach and determination of serum gastrin and chromogranin A levels. Haematoxylin- and immunostaining with chromogranin A, gastrin and VMAT I and II (vesicular monoamine transporter I and II) of the biopsies were performed.

RESULTS

Thirty-eight MEN1 patients, of whom 16 (42%) were diagnosed and treated earlier for ZES, were analysed. In ten of 16 (62.5%) ZES patients, a locally scattered, mixed image of diffuse, linear and micronodular mild hyperplasia was present. In addition, two of these patients (13%) showed small (max 1.5 mm in size) intramucosal ECL tumours. Neither ECL changes, nor tumours were found in MEN1 patients without ZES (n = 22). In MEN1/ZES patients, the median serum gastrin level was significantly elevated compared to MEN1 patients without ZES (206 pg/ml vs. 30.5 pg/ml, p < .001). A subgroup analysis of the serum gastrin and chromogranin A levels of MEN1/ZES patients with or without ECL hyperplasia did not show significant differences (gastrin level: p = .302, chromogranin A: p = .464).

CONCLUSION

Enterochromaffin-like cell hyperplasia and gastric carcinoids occur only in MEN1 patients with ZES, but less frequently than reported.

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.

Gender Differences in Multiple Endocrine Neoplasia Type 1: Implications for Screening?

BACKGROUND

Some gender-related differences have been reported in multiple endocrine neoplasia type 1 (MEN1), although not all reports are conclusive. This systematic review with analysis of the own MEN1 cohort evaluates gender differences and potential consequences for screening.

METHODS

A systematic review of the literature between 1990 and 2019 with the search terms "MEN1" or "multiple endocrine neoplasia type 1" and "gender" or "sex" was performed. In addition, the prospectively collected data of a genetically confirmed MEN1 cohort of the Philipps University Marburg were retrospectively analyzed.

RESULTS

Review of the literature identified five retrospective case series with original data of 1,057 MEN1 patients. One series suggested a higher frequency of pancreatic neuroendocrine neoplasms (NEN), especially gastrinomas, in men (61 vs. 54%) and a higher frequency of pituitary tumors in women (47 vs. 30%), but others did not. Only thymic NEN occurred predominantly in men throughout all studies. Women with MEN1 were found to have an increased risk of breast cancer. In the own series consisting of 116 MEN1 patients (male = 58, female = 58), thymic lesions were also more frequently detected in male patients (male = 5, female = 1). No gender difference was found with regard to the other manifestations.

CONCLUSION

Regarding the typical MEN1 tumor manifestations, gender-adapted diagnostic and therapeutic approaches cannot be recommended. Female MEN1 patients should be encouraged to participate in breast cancer screening programs.

Phenotypes Associated With MEN1 Syndrome: A Focus on Genotype-Phenotype Correlations

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant inherited tumor syndrome, associated with parathyroid, pituitary, and gastro-entero-pancreatic (GEP) neuroendocrine tumors (NETs). MEN1 is usually consequent to different germline and somatic mutations of the MEN1 tumor suppressor gene, although phenocopies have also been reported. This review analyzed main biomedical databases searching for reports on MEN1 gene mutations and focused on aggressive and aberrant clinical manifestations to investigate the potential genotype-phenotype correlation. Despite efforts made by several groups, this link remains elusive to date and evidence that aggressive or aberrant clinical phenotypes may be related to specific mutations has been provided by case reports and small groups of MEN1 patients or families. In such context, a higher risk of aggressive tumor phenotypes has been described in relation to frameshift and non-sense mutations, and predominantly associated with aggressive GEP NETs, particularly pancreatic NETs. In our experience a novel heterozygous missense mutation at c.836C>A in exon 6 was noticed in a MEN1 patient operated for macro-prolactinoma, who progressively developed recurrent parathyroid adenomas, expanding gastrinomas and, long after the first MEN1 manifestation, a neuroendocrine uterine carcinoma. In conclusion, proof of genotype-phenotype correlation is limited but current evidence hints at the need for long-term interdisciplinary surveillance in patients with aggressive phenotypes and genetically confirmed MEN1.

Single gland excision for MEN1-associated primary hyperparathyroidism

IMPORTANCE

Guidelines advocate subtotal parathyroidectomy (SPTX) or total parathyroidectomy with autotransplantation (TPTX) with bilateral cervical thymectomy for primary hyperparathyroidism (pHPT) associated with multiple endocrine neoplasia type 1 (MEN1). However, both procedures are associated with a significant risk of permanent hypoparathyroidism.

OBJECTIVE

The aim of the current study was to compare long-term results of either single gland excision (SGE, 1-2 glands), SPTX and TPTX for the treatment of MEN1-associated pHPT.

DESIGN AND SETTING

Data of genetically confirmed MEN1 patients who underwent surgery for pHPT between 1987 and 2017 were retrieved from a prospective database and were retrospectively analysed.

RESULTS

Eighty-nine MEN1 patients underwent either TPTX (n = 38, 42.7%), SPTX (n = 23, 25.8%) or SGE (n = 28, 31.5%). The rate of disease persistence after initial surgery was 2.6%, 0% and 14.2% in the TPTX, SPTX and SGE groups, respectively. After median follow-up of 112 (range 7-411) months, the rate of recurrent pHPT was significantly higher in the SGE group (n = 19, 21.3%) compared with the TPTX (n = 4, 4.4%, P = .001) and the SPTX (n = 9, 10.1%, P = .03) groups. Analysis of the recurrence-free time among the surgical groups revealed a significant difference (P = .036). The median time to recurrence was significantly shorter after SGE (101, range 3-301 months) than after SPTX (139, range 28-278 months, P = .018) and TPTX (204, range 75-396 months, P = .049). Twelve (32%) patients who underwent TPTX developed permanent hypoparathyroidism compared with only 4 (17%, P = .06) in the SPTX and 0 in the SGE group (P = .001).

CONCLUSION

Given the high rate of postoperative permanent hypoparathyroidism after TPTX and SPTX, SGE is a valid option for the treatment of MEN1-associated pHPT.

Results of Duodenopancreatic Reoperations in Multiple Endocrine Neoplasia Type 1

BACKGROUND

To evaluate the outcome of duodenopancreatic reoperations in patients with multiple endocrine neoplasia type 1 (MEN1).

METHODS

MEN1 patients who underwent reoperations for duodenopancreatic neuroendocrine neoplasms (dpNENs) were retrieved from a prospective database and retrospectively analyzed.

RESULTS

Twelve of 101 MEN1 patients underwent up to three reoperations, resulting in a total of 18 reoperations for dpNEN recurrence. Patients initially underwent either formal pancreatic resections (n = 7), enucleations (n = 3), or duodenotomy with lymphadenectomy for either NF-pNEN (seven patients), Zollinger-Ellison syndrome (ZES, three patients), organic hyperinsulinism (one patient) or VIPoma (one patient). Six patients had malignant dpNENs with lymph node (n = 5) and/or liver metastases (n = 2). The indication of reoperations was NF-pNEN (five patients), ZES (five patients), organic hyperinsulinism (one patient), and recurrent VIPoma (one patient). Median time to first reoperation was 67.5 (range 6-251) months. Five patients required a second duodenopancreatic reoperation for 60-384 months after initial surgery, and one patient underwent a third reoperation after 249 months. The rate of complications (Clavien-Dindo ≥3) was 28%. Four patients required completion pancreatectomy. Six patients developed pancreoprivic diabetes. After a median follow-up of 18 (6-34) years after initial surgery, ten of 12 patients are alive, one died of metastatic pancreatic VIPoma, and one died of metastatic thymic NEN.

CONCLUSION

Reoperations are frequently necessary for dpNEN in MEN1 patients, but are not associated with an increased perioperative morbidity in specialized centers. Organ-sparing resections should be preferred as initial duodenopancreatic procedures to maintain pancreatic function and avoid completion pancreatectomy.

Multiple Endocrine Neoplasia Type 1 (MEN1): An Update and the Significance of Early Genetic and Clinical Diagnosis

Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary tumor syndrome inherited in an autosomal dominant manner and characterized by a predisposition to a multitude of endocrine neoplasms primarily of parathyroid, enteropancreatic, and anterior pituitary origin, as well as nonendocrine neoplasms. Other endocrine tumors in MEN1 include foregut carcinoid tumors, adrenocortical tumors, and rarely pheochromocytoma. Nonendocrine manifestations include meningiomas and ependymomas, lipomas, angiofibromas, collagenomas, and leiomyomas. MEN1 is caused by inactivating mutations of the tumor suppressor gene MEN1 which encodes the protein menin. This syndrome can affect all age groups, with 17% of patients developing MEN1-associated tumors before 21 years of age. Despite advances in the diagnosis and treatment of MEN1-associated tumors, patients with MEN1 continue to have decreased life expectancy primarily due to malignant neuroendocrine tumors. The most recent clinical practice guidelines for MEN1, published in 2012, highlight the need for early genetic and clinical diagnosis of MEN1 and recommend an intensive surveillance approach for both patients with this syndrome and asymptomatic carriers starting at the age of 5 years with the goal of timely detection and management of MEN1-associated neoplasms and ultimately decreased disease-specific morbidity and mortality. Unfortunately, there is no clear genotype-phenotype correlation and individual mutation-dependent surveillance is not possible currently.

Diagnosing Nonfunctional Pancreatic NETs in MEN1: The Evidence Base

In multiple endocrine neoplasia type 1 (MEN1), nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) are the most frequently diagnosed NETs and a leading cause of MEN1-related death. The high prevalence and malignant potential of NF-pNETs outline the need for an evidence-based screening program, as early diagnosis and timely intervention could reduce morbidity and mortality. Controversies exist regarding the value of several diagnostic tests. This systematic review aims to evaluate current literature and amplify an up-to-date evidence-based approach to NF-pNET diagnosis in MEN1. Three databases were systematically searched on the diagnostic value of biomarkers and imaging modalities. Twenty-seven studies were included and critically appraised (modified Quality Assessment of Diagnostic Accuracy Studies). Another 12 studies, providing data on age-related penetrance and tumor growth, were included to assess the optimal frequency and timing of screening. Based on current literature, biomarkers should no longer play a role in the diagnostic process for NF-pNETs, as accuracies are too low. Studies evaluating the diagnostic value of imaging modalities are heterogeneous with varying risks of bias. For the detection of NF-pNETs, endoscopic ultrasound (EUS) has the highest sensitivity. A combined strategy of EUS and MRI seems to be the most useful. Gallium 68 octreotate-DOTA positron emission tomography-CT could be added if NF-pNETs are diagnosed to identify metastasis. Reported growth rates were generally low, and two distinct phenotypes were observed. Surveillance programs should focus on and be adapted to the presence of substantial growth in NF-pNETs. The optimal age to start screening must yet be determined, as insufficient evidence for an evidence-based recommendation was available.