Thrombotic Events and Overall Survival in BCR-ABL1 Negative Myeloproliferative Neoplasms: A Single-Center Analysis

Aim: BCR-ABL1–negative myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are clonal disorders characterized by increased myeloid proliferation. This study retrospectively evaluated the clinical, demographic, molecular, and survival characteristics of patients with classical MPNs treated at the Hematology Outpatient Clinic, Dokuz Eylül University.Material and Methods: In this single-center retrospective analysis, data from 363 patients diagnosed between January 2012 and May 2021 were reviewed according to the 2016 WHO criteria: ET (n=230), PV (n=104), and PMF (n=29).Results: JAK2 mutations were identified in 85.1% of PV, 65.4% of ET, and 60% of PMF cases. Thrombosis at diagnosis occurred in 18% of PV, 19.1% of ET, and 10.3% of PMF patients. Cytoreductive therapy was administered to 88.2% of patients, predominantly hydroxyurea (85.7%). Leukemic and fibrotic transformations developed in 1.6% and 14.5% of cases, respectively. Among 126 patients with thrombotic events, JAK2 positivity was significantly associated with increased thrombotic risk (p=0.0025). Thrombosis was more frequent in patients aged >65 years (p=0.0047). Ten-year overall survival (OS) rates were 81% in PV, 79% in ET, and 38% in PMF. In multivariable Cox regression, age >65 years independently predicted inferior OS (p<0.001), and leukocytosis was similarly associated with poorer outcomes (p=0.026).Conclusion: Advanced age and JAK2 V617F mutation are key risk factors for thrombosis in classical MPNs. Hydroxyurea remains the most widely used cytoreductive therapy in clinical practice.