Essential Thrombocythemia in Armenia: A Nationwide Study

Context: Essential thrombocythemia (ET) is a myeloproliferative neoplasm, with an incidence of 1.2 to 3.0 per 100,000 population per year in the United States, with a median age of 58 years. In developing countries, there are certain diagnostic and therapeutic limitations, which affect the outcomes. There were no studies to evaluate the epidemiology, diagnostic and therapeutic patterns of essential thrombocythemia in Armenia. Objective: The purpose of this study is to explore the incidence, diagnostic and therapeutic limitations, and outcomes for patients with ET in Armenia. Design: This nationwide study included all patients with a diagnosis of ET in the Republic of Armenia from 2003 to 2019, which were registered through the registry of the Hematology Center after Prof. Yeolyan. Medical records were reviewed retrospectively and analyzed. Results: A total of 76 patients were registered over a period of 17 years. Incidence was 2 per million, the prevalence was 23 per million in 2019. The median age was 52 years, the mean age was 50 y. 68% were female. Splenomegaly was observed in 40% of patients. The mean platelet count at diagnosis was 1257 × 109/ L; range [429 × 109/L-2747 × 109/ L]. Bone marrow biopsy report on ET confirmation was available for 59 patients (77.6%). The genetic testing was available since 2014, and was done in 13 cases (17.1%). JAK2 V617F mutation was positive in 8 (61.5%) of them. Thrombotic and hemorrhagic complications were reported in 5 and 3 patients, respectively. Hydroxyurea was the most common first-line therapy (92%), second first-line therapies were low-dose aspirin (6.4%) and alpha-interferon (1.6%). The 5-year survival for the group was 87%, the 10-year survival was 70.0%. Conclusions: This is the first study to explore the situation of ET epidemiology, diagnosis, and treatment in Armenia. The incidence was similar to the reported rates from other countries, but the median age was younger in our cohort. Hydroxyurea was the most commonly used cytoreductive therapy, and the study showed certain diagnostic limitations. Further prospective studies to explore these findings are needed.