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1759 Myeloproliferative Neoplasms in Patients below 25 Years Old at Diagnosis: A Retrospective International Cooperative Work

Program: Oral and Poster Abstracts
Session: 634. Myeloproliferative Syndromes: Clinical: Poster I
Hematology Disease Topics & Pathways:
anticoagulant drugs, Diseases, Non-Biological, Therapies, Pediatric, chemotherapy, MPN, Young Adult, Polycythemia vera, Study Population, thrombocythemia, Myeloid Malignancies
Saturday, December 1, 2018, 6:15 PM-8:15 PM
Hall GH (San Diego Convention Center)

Ianotto Jean-Christophe, MD, PhD1,2*, Jean-Jacques Kiladjian, MD, PhD2,3, Marta Sobas, MD4,5*, Parvis Sadjadian, MD6*, Lee-Yung Shih, MD7, Maria Bieniaszewska, MD5,8*, Ilona Seferynska, MD PhD5,9*, Mary Frances McMullin, MD10, Joanna Waclaw, MD5,11*, Laurence Legros, MD, PhD12,13*, Krzysztof Lewandowski, MD5,14*, Mihnea Zdrenghea, MD, PhD15*, Aitor Abuin Blanco, MD16*, Anna Armatys, MD5,17*, Jan Samuelsson, MD, PhD18, Adrianna Spalek, MD5,17*, Anna Angola Figueras, MD19*, Marie Lauermannova, MD20*, Maria Noya21*, Jarosław Czyż, MD5,22*, Anna Szmigielska-Kaplon5,23*, Rajko Kusec, MD, PhD24*, Joanna Gora Tybor, MD5,9*, Anna Masternak, MD5,25*, Jan J. Michiels, PhD26, Malgorzata Skowronek, MD5,27*, Jean-Loup Demory, MD, PhD2,28*, Katell Le Du, MD2,29*, Sonja Zweegman, MD, PhD30*, Carlos Besses Raebel, MD, PhD31, Stephane Giraudier, MD, PhD32,33*, Martin Griesshammer, MD, PhD34* and Claire N. Harrison, MD, DM, FRCP, PRCPath35

1Institute of Oncology and Hematology, Hopital Morvan, CHRU de Brest, Brest, France
2France Intergroupe des Néoplasies Myéloprolifératives, FIM collaborative group, Paris, France
3Hôpital Saint-Louis, Paris, France
4Department of Hematology, Wroclaw Medical University, Wroclaw, Poland
5Polish Adult Leukemia Group, PALG collaborative group, Warsaw, Poland
6University Clinic for Hematology, Oncology and Palliative Cares, University of Bochum, Minden, Germany
7Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
8Department of Hematology and Transplantation, Gdansk Medical University and Clinical Center, Gdansk, Poland
9Department of Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
10Queen's University Belfast, Belfast, United Kingdom
11Department of Hematology, Jagiellonian University Hospital, Krakow, Poland
12Department of Hematology, Centre Hospitalier Universitaire de Nice, Nice, France
13France Intergroupe des Néoplasies Myéloprolifratives, FIM collaborative group, Paris, France
14Department of Hematology and Bone Marrow Transplantation, Poznan University of Medical Sciences, Poznan, Poland
15Institute of Oncology, University Hospital of Cluj, Cluj-Napoca, Romania
16Department of Hematology, Clinical Hospital, Santiago de Compostela, Spain
17Department of Hematology and Bone Marrow Transplantation, Medical University of Silesia, Katowice, Poland
18Department of Hematology, Stockholm South Hospital, Linkoping, Sweden
19Department of Hematology, Hospital del Mar, Barcelona, Spain
20Institute of Hematology and Blood Transfusion, Prague, Czech Republic
21Department of Hematology, Complexo Hospitalario Juan Canalejo, A Coruna, Spain
22Department of Hematology, Collegium Medicum, Bydgoszcz, Poland
23Department of Hematology, Medical University, Lodz, Poland
24Department of Hematology, Dubrava University Hospital, Zagreb, Croatia
25Department of Hematology, State Hospital, Opole, POL
26Goodheart Institute & Foundation Center Europe, Rotterdam, Netherlands
27Department of Hematology, Holy Cross Oncology Center, Kielce, Poland
28Department of Hematology, Hopital St. Vincent De Paul, Lille, France
29Department of Hematology, Centre Jean Bernard - Clinique Victor Hugo, Le Mans, France
30Department of Hematology, University Medical Center, Amsterdam, Netherlands
31Department of Hematology, Hospital del Mar-IMIM, Barcelona, Spain
32Service de Biologie Cellulaire, INSERM UMRS 1131, Hospital of Saint-Louis, Paris, France
33INSERM UMR-S1131, Institut Universitaire d'Hématologie, Université Paris-Diderot, Assistance Publique-Hôpitaux de Paris Hôpital Saint-Louis, Paris, France
34Department of Hematology, Oncology, Hemostaseology and Palliative Care, Johannes Wesling Clinic, Minden, Germany
35Department of Haematology, Guy's Hospital, London, United Kingdom

Myeloproliferative neoplasms (MPN) are most common in old people (>60 years) and are rarely identified in children and young adults where information about complication rates and long-term data are lacking. To improve our knowledge, we retrospectively collected cases of young patients diagnosed with MPN before 25 years of age and analysed data of their disease to date, including vascular events and disease evolution.

Data were collected in 29 hospital centres from 12 countries. Between 1971 and 2018, 335 young patients were diagnosed for an MPN before the age of 25. They were mostly females (n=246; 73.4%) with a median age of 20.3 years at diagnosis (2.5 months-25 years). Essential thrombocythemia was diagnosed in 234 patients (69.8%), polycythemia vera in 60 (17.9%) and myelofibrosis or unclassified MPN in 41 (12.3%).

Most of the diagnoses were made following a coincidental blood count analysis (n=75; 51%) some based on symptoms (n=57; 38.8%) or thrombotic events (n=15; 10.2%). In terms of complications before or at diagnosis, 31 (9.3%) patients experienced thrombosis, mostly venous (75%) and 13 (3.9%) had hemorrhage. At diagnosis, the median leukocyte count was 9x109/l (range: 3-22.8), median hemoglobin count 140 g/l (65-220) and median platelet count 900x109/l (99-3290). To assess the diagnosis, 158 patients (47.2%) had had bone marrow aspirates and 214 (63.9%) a bone marrow biopsy. Mutational status was available in 319 (90%) cases: 194 (60.8%) were JAK2V617F positive, 48 (15%) had a calreticulin mutation, 76 (23.8%) were triple-negative and 1 patient had MPL mutation.

The median follow-up of the cohort was 7.7 years (0-46.8) with 134 patients (40%) having follow-up for more than 10 years. 81 female patients (32.9%) experienced pregnancies. During this period, 295 patients (88%) received at least one drug for their MPN: 254 patients (77.2%) received antithrombotic drug and 222 patients (66.5%) a cytoreductive drug. As first line of treatment, hydroxycarbamide was given to 111 patients (50%) whereas anagrelide was given to 56 patients (25.2%) and interferon to 50 (22.5%).

During the follow-up, 97 patients (29%) experienced at least one complication. In terms of cardiovascular events, 38 (11.3%) patients experienced thromboses with 50 events in total (recurrences in 12 cases), including 33 venous events (66%) of which 15 were localized in the splanchnic territory (45.5%). Hemorrhagic events were recorded in 34 cases (10.1%). During the follow-up, 39 patients (11.6%) have evolved: 11 from ET to PV (28.2%), 26 into MF (66.7%) and 2 into AML (5.1%). All evolutions were exclusive: one event per patient. At the time of the analysis, 66 patients (19.7%) were declared as lost of follow up and 4 were dead (1.2%).

This is the largest cohort of patients aged below 25 years at the time of diagnosis demonstrates that despite their youth most of them (88%) received drug(s) for the management of their MPN. There was a high incidence of complications (29%), with vascular events and disease evolution occurring at equal frequency although death was uncommon (1.2%). Rates of events were disease evolution: 1.51/100pts/y; thromboses: 1.47 and hemorrhages: 1.32. No specific national or international guidance exists for MPN patients of this age; but our data suggest that these are not benign conditions and patients need to be carefully followed and treated.

Disclosures: Kiladjian: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffmann-La Roche AG: Other: Provided Pegylated Interferon Alpha 2a; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Provided Ruxolitinib . Giraudier: Novartis: Research Funding. Griesshammer: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Harrison: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria; Gilead: Honoraria, Speakers Bureau; CTI BioPharma: Consultancy, Honoraria.

*signifies non-member of ASH