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Dive into the research topics where Merav Fraenkel is active.

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Featured researches published by Merav Fraenkel.


Best Practice & Research in Clinical Gastroenterology | 2012

Epidemiology of gastroenteropancreatic neuroendocrine tumours

Merav Fraenkel; M.K. Kim; Antongiulio Faggiano; G.D. Valk

Gastroenteropancreatic neuroendocrine tumours are a heterogeneous group of tumours arising from diffuse endocrine cells, causing unique clinical syndromes. These tumours, formerly named carcinoid, can involve any part of the gastrointestinal tract and the endocrine pancreas and have a wide range of malignant potential: from benign to poorly differentiated tumours. In this review we will summarize the data available on the epidemiology of gastroenteropancreatic tumours as it is reported from around the world. This includes annual incidence rates at the various anatomic sites, and trends in incidence rates with time. In addition age and stage at presentation, gender and racial differences and finally prognosis and survival were collected when reported.


Endocrine-related Cancer | 2014

Incidence of gastroenteropancreatic neuroendocrine tumours: a systematic review of the literature

Merav Fraenkel; Michelle K. Kim; Antongiulio Faggiano; W. W. de Herder; Gerlof D. Valk

Based on the current medical literature, the worldwide incidence of neuroendocrine tumours (NETs) seems to have increased; however, a systematic literature overview is lacking. This study aimed to collect all available data on the incidence of gastroenteropancreatic (GEP)-NETs and characteristics of population to establish their epidemiology. A sensitive MEDLINE search was carried out. The papers were selected via a cascade process that restricted the initial pool of 7991 articles to 33, using predefined inclusion and exclusion criteria. Original articles evaluating the incidence of sporadic GEP-NETs in regional, institutional and national registries were considered. The majority of data originated from the US National Cancer Institute Surveillance, Epidemiology and End Results database and from national cancer registries in Western Europe. Generally, because of the retrospective nature of existing databases the outcomes of studies might be biased, which hinders the drawing of firm conclusions. The age-adjusted incidence of GEP-NETs has increased steadily over the past four decades (1973-2007), increasing 3.65-fold in the USA and 3.8- to 4.8-fold in the UK. Incidence has changed variably from one anatomical site to another. The greatest increase in incidence occurred for gastric and rectal NETs, while the smallest increase occurred for small intestine NETs. There were gender and racial differences, which differed site by site and, in some cases, changed over time. The incidence rates (IRs) of GEP-NETs have increased significantly in the last 40 years. Data are only available from North America, Western Europe and Japan. A site-by-site analysis revealed that the IRs of some NETs increased more than those of others.


PLOS ONE | 2013

Association between Bone Mineral Density and Incidence of Breast Cancer

Merav Fraenkel; Victor Novack; Yair Liel; Michael Koretz; Ethel Siris; Larry Norton; Tali Shafat; Shraga Shany; David B. Geffen

Introduction Previous studies have suggested an inverse relationship between bone mineral density (BMD) and breast cancer incidence. The primary objective of this study was to assess whether BMD is associated with risk of subsequent breast cancer occurrence in the female population of southern Israel. Methods The electronic medical charts of women who underwent BMD at the Soroka Medical Center (SMC) between February 2003 and March 2011 were screened for subsequent breast cancer diagnoses. Women were divided by tertiles of BMD at 3 skeletal sites: lumbar spine (LS, L1–4), total hip (TH) and femoral neck (FN). The incidence of breast cancer was calculated. Results Of 15268 women who underwent BMD testing, 86 were subsequently diagnosed with breast cancer. Most women in the study were older than 50 years (94.2% and 92.7%, respectively; p = 0.597). Women who subsequently developed breast cancer had a higher mean body-mass index (BMI) (30.9±5.5 vs. 29.1±5.7 p = 0.004) and the mean BMD Z-score was significantly higher than in those without breast cancer for all 3 skeletal sites (LS: 0.36±1.58 vs. −0.12±1.42, p = 0.002; TH: 0.37±1.08 vs. 0.03±1.02, p = 0.002; FN: 0.04±0.99 vs. −0.18±0.94; p = 0.026). Women in the highest Z-score tertiles at the FN and TH had a higher chance of developing breast cancer compared to the lowest tertile; odds ratio of 2.15, 2.02, respectively (P = 0.004 and 0.01 respectively). No association was found between the BMD Z-score and the stage, histology, grade or survival from breast cancer. Conclusions This study provides additional support for an inverse association between BMD and the risk of breast cancer.


Frontiers of Hormone Research | 2015

Epidemiology of Neuroendocrine Tumors.

Merav Fraenkel; Antongiulio Faggiano; Gerlof D. Valk

Formerly named carcinoids, neuroendocrine tumors originate from diffuse endocrine cells, can involve any part of the gastrointestinal tract, endocrine pancreas and bronchopulmonary (BP) tree, and have a wide range of malignant potential. This chapter summarizes the data available on the epidemiology of neuroendocrine neoplasia (NEN) from around the world, including the relative frequency according to organ of origin, annual incidence rates (IR) and trends in IR at the various anatomic sites, age and stage at presentation, racial and gender differences in IR and 5-year survival rates. Over time, changes have been made in the classification and registration of NEN, both in the same registry and across the globe, thus confounding the possibility to draw conclusions as to the true rise in IR of NEN that is observed all over the world. BP NEN has become the most common site in many western countries, while NEN of the rectum is more common in the Far East. In some countries, appendiceal NEN is the most common site in females. When compared to adenocarcinoma of the same location, the prognosis of NEN patients is better. Five-year survival rates are highest for NEN originating in the rectum and appendix, but lower in small intestinal and pancreatic NEN. Future research is needed to understand the contribution of genetic and environmental factors to NEN epidemiology.


Hormone and Metabolic Research | 2014

Androgen Receptor CAG Repeat Length in Relation to Phenotype Among Females with Nonclassical 21-Hydroxylase Deficiency

S. Ben-Shachar; I. Ayalon; H. Reznik-Wolf; Y. Tenenbaum-Rakover; N. Zuckerman-Levin; O. Cohen; A. Lifshitz; Merav Fraenkel; Y. Toledano; V. Roash; I. Koren; D. Modan-Moses; D. Hirsch; A. Schachter-Davidov; S. Israel; O. Eyal; N. Weintrob

Nonclassical 21-hydroxylase deficiency (NC21OHD) manifests with various degrees of post natal virilization. The length of CAG repeats of the androgen receptor gene (AR) is inversely correlated to activity of the human androgen receptor (AR) and affects phenotype of several androgen-dependent disorders. The aim of the study was to investigate the associations between CAG repeat length and the phenotype of females with NC21OHD. CAG repeat length and AR inactivation were assessed in females with NC21OHD, and related to their clinical presentation. CAG repeat length and AR inactivation were assessed in 119 females with NC21OHD. Biallelic mean (BAM) of the CAG repeat length and the weighted BAM (WBAM) were related to various clinical parameters. Age at diagnosis and age of menarche positively correlated with BAM (r=0.22, p=0.02, and r=0.23, p=0.01, respectively). A shorter (<25) BAM was associated with younger age at diagnosis (14.8 vs. 21.4 years, p<0.01), at adrenarche (8.1 vs. 10.2 years, p<0.01) and gonadarche (9.9 vs. 11.2 years, p<0.01), and higher corrected height standard deviation score at diagnosis (0.77 vs. 0.15, p=0.01). Precocious pubarche and precocious puberty were more frequent in these with the shorter BAM. Results of WBAM were similar. The CAG repeat length of the AR gene contributes to the clinical diversity of the phenotype in females with NC21OHD.


Endocrine-related Cancer | 2018

Preventive medicine for von Hippel-Lindau disease-associated pancreatic neuroendocrine tumors.

Tobias Krauss; Alfonso Massimiliano Ferrara; Thera P. Links; Ulrich F. Wellner; Irina Bancos; Andrey Kvachenyuk; Karina Villar Gómez de las Heras; Marina Yukina; Roman Petrov; Garrett Bullivant; Laura von Duecker; Swati S Jadhav; Ursula Ploeckinger; Staffan Welin; Camilla Schalin-Jäntti; Oliver Gimm; Marija Pfeifer; Joanne Ngeow; Kornelia Hasse-Lazar; Gabriela Sanso; Xiao-Ping Qi; Umit Ugurlu; Rene Eduardo Diaz; Nelson Wohllk; Mariola Pęczkowska; Jens Aberle; Delmar Munir Lourenço; Maria Adelaide Albergaria Pereira; Maria Candida Barisson Villares Fragoso; Ana O. Hoff

Pancreatic neuroendocrine tumors (PanNETs) are rare in von Hippel-Lindau disease (VHL) but cause serious morbidity and mortality. Management guidelines for VHL-PanNETs continue to be based on limited evidence, and survival data to guide surgical management are lacking. We established the European-American-Asian-VHL-PanNET-Registry to assess data for risks for metastases, survival and long-term outcomes to provide best management recommendations. Of 2330 VHL patients, 273 had a total of 484 PanNETs. Median age at diagnosis of PanNET was 35 years (range 10-75). Fifty-five (20%) patients had metastatic PanNETs. Metastatic PanNETs were significantly larger (median size 5 vs 2 cm; P < 0.001) and tumor volume doubling time (TVDT) was faster (22 vs 126 months; P = 0.001). All metastatic tumors were ≥2.8 cm. Codons 161 and 167 were hotspots for VHL germline mutations with enhanced risk for metastatic PanNETs. Multivariate prediction modeling disclosed maximum tumor diameter and TVDT as significant predictors for metastatic disease (positive and negative predictive values of 51% and 100% for diameter cut-off ≥2.8 cm, 44% and 91% for TVDT cut-off of ≤24 months). In 117 of 273 patients, PanNETs >1.5 cm in diameter were operated. Ten-year survival was significantly longer in operated vs non-operated patients, in particular for PanNETs <2.8 cm vs ≥2.8 cm (94% vs 85% by 10 years; P = 0.020; 80% vs 50% at 10 years; P = 0.030). This study demonstrates that patients with PanNET approaching the cut-off diameter of 2.8 cm should be operated. Mutations in exon 3, especially of codons 161/167 are at enhanced risk for metastatic PanNETs. Survival is significantly longer in operated non-metastatic VHL-PanNETs.


Hormone and Metabolic Research | 2016

Maternal First Trimester TSH Concentrations: Do They Affect Perinatal and Endocrine Outcomes?

Merav Fraenkel; Tali Shafat; Offer Erez; Y. Lichtenstein; J. Awesat; Victor Novack; Anat Tsur

We aimed to examine the distribution of 1(st) trimester TSH and evaluate its association with perinatal outcomes and future development of maternal thyrotoxicosis. This retrospective cohort study included data of all women without prior thyroid disease who delivered a singleton at our medical center from 1/2001 to 12/2011 and had a 1(st) trimester TSH<4.0 mU/l. Women were divided according to 1(st) trimester TSH concentrations into quartiles and by predefined TSH values (mU/l): 1) TSH<0.1; 2) TSH 0.11-0.2; 3) TSH 0.21-0.4; and 4) TSH 0.4-4. Obstetrical outcomes, hCG concentrations, and future thyroid status were collected from electronic medical records. A total of 13 841 women fulfilled the inclusion criteria. Mean maternal TSH concentration at 5 weeks of gestation was 2.09±0.83 mU/l and decreased to 1.29±0.87 mU/l in weeks 8-9 with an increase towards the end of the 1(st) trimester. Odds ratio for future thyrotoxicosis was 3.64 in the lowest compared to the highest TSH quartile and 10.03 in those with TSH<0.1 compared to TSH 0.41-4 mU/l. Rates of female fetuses were higher in the low TSH quartiles and in the lower TSH groups, however baby gender was not associated with increased risk of future thyrotoxicosis. Low maternal 1(st) trimester TSH quartiles or concentrations were not associated with adverse pregnancy outcome. Only a minor fraction of pregnant women with a low first tirmester TSH subsequently developed future thyrotoxicosis.


Bone | 2016

Seasonal changes in serum calcium, PTH and vitamin D levels in patients with primary hyperparathyroidism

Anat Nevo-Shor; Slava Kogan; Ben-Zion Joshua; Anat Bahat-Dinur; Victor Novack; Merav Fraenkel

BACKGROUND Seasonal variations of 25-hydroxyvitamin D, PTH and calcium levels are not well characterized in primary hyperparathyroidism (PHPT). Our objectives were to characterize seasonal changes in these parameters in PHPT patients, and to assess whether these seasonal changes affect clinical decision making. METHODS This is a retrospective study based on the electronic medical records of Clalit Health service in the south of Israel between 2000 and 2012. Patients 18years and older with PHPT (PTH>upper limit of norm (ULN) and serum calcium>10.5mg%) were included. Patients with renal failure or on Thiazide diuretics were excluded. All serum levels of calcium, PTH and 25-hydroxyvitamin D were collected and then stratified according to season. RESULTS 792 patients were classified as PHPT (72.2% female) and had a total of 2659 PTH tests, 1395 25-hydroxyvitamin D tests and 7426 calcium test. Fifty six percent of 25-hydroxyvitamin D levels were <50nmol/L. Seasonality was demonstrated in all three parameters: mean 25-hydroxyvitamin D was 13% higher in the summer compared to the winter (P<0.001), median PTH values showed opposite trend with a fall of about 8.4% in summer compared to winter (P<0.001). Calcium levels were higher during the autumn with a rise of about 0.2mg/dL in the mean calcium levels compared to spring and summer (P<0.001). The odds ratio of calcium level above 11.5mg/dL is highest in the autumn (OR=1.275, P=0.018). CONCLUSION We show seasonal variation in serum 25-hydroxyvitamin D, PTH, and calcium levels in patients with PHPT. These seasonal variations cause transition to pathological values that may influence diagnosis and treatment of PHPT patients.


International Journal of Gynecology & Obstetrics | 2018

Low thyroid‐stimulating hormone and its persistence beyond the first trimester of pregnancy

Merav Fraenkel; Tali Shafat; Avivit Cahn; Offer Erez; Victor Novack; Anat Tsur

To investigate predictors of low thyroid‐stimulating hormone (TSH) persisting beyond the first trimester and associated pregnancy outcomes.


npj Breast Cancer | 2015

Breast cancer survivors are at an increased risk for osteoporotic fractures not explained by lower BMD: a retrospective analysis

Merav Fraenkel; David B. Geffen; Victor Novack; Tali Shafat; Yuval Mizrakli; Samuell Ariad; Michael Koretz; Larry Norton; Ethel Siris

Background:An association between higher bone mineral density (BMD) and the diagnosis of breast cancer (BC) has been reported. Data on the risk of osteoporotic fractures in women with BC are conflicting.Aims:The objective of this study was to assess fracture risk adjusted for BMD in women with and without BC, and to assess whether fracture risk in BC patients is attributed to BMD or BC characteristics.Methods:Using electronic medical records of patients who underwent dual energy X-ray absorptiometry BMD studies at Soroka University Medical Center between February 2003 and March 2011, we identified women with subsequent diagnosis of osteoporotic fractures. BC status, demographic, health characteristics, BMD, and other laboratory findings were assessed. In BC patients data on grade, stage, and treatment were collected. Primary outcome was osteoporotic fracture, analyzed by Cox proportional hazards regression models.Results:During a median follow-up of 4.9 years in 17,110 women with BMD testing (658 BC patients), 1,193 women experienced an osteoporotic fracture (62 in BC and 1,131 in no-BC groups). In multivariate analysis adjusted for age, body mass index (BMI) and BMD, hazard ratio (HR) for any osteoporotic fracture in women with BC was 1.34 (P=0.026). BMD was similar among women with and without BC who fractured. BC patients who experienced an osteoporotic fracture had a trend for less-advanced BC, lower rates of chemotherapy treatment, and higher rates of tamoxifen treatment.Conclusions:BC survivors are at increased risk of an osteoporotic fracture, which is not explained by worse BMD. Chemotherapy or aromatase inhibitors did not contribute substantially to fracture risk among our BC survivors.

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Victor Novack

Ben-Gurion University of the Negev

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Tali Shafat

Ben-Gurion University of the Negev

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David B. Geffen

Ben-Gurion University of the Negev

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Michael Koretz

Ben-Gurion University of the Negev

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Larry Norton

Memorial Sloan Kettering Cancer Center

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Shraga Shany

Ben-Gurion University of the Negev

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Yair Liel

Ben-Gurion University of the Negev

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Anat Tsur

Clalit Health Services

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Offer Erez

Ben-Gurion University of the Negev

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Antongiulio Faggiano

University of Naples Federico II

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