IPSET-thrombosis better identifies thrombosis-free survival: A Turkish cohort

© 2015 Elsevier Inc. All rights reserved.Introduction Essential thrombocythemia (ET) is the most common of the myeloproliferative neoplasms. For better predicting the occurrence of thrombotic events, an International Prognostic Score of Thrombosis for ET (IPSET-Thrombosis) was recently developed. We aimed to investigate the validity of IPSET-Thrombosis in a Turkish patient cohort and to compare the efficacy of IPSET-Thrombosis and conventional risk scoring systems in predicting thrombosis-free survival. Patients and Methods We retrospectively evaluated the clinical characteristics and risk factors for thrombosis in 112 Turkish patients. Median thrombosis-free survival and Harrell C concordance indexes were calculated for both conventional and IPSET-Thrombosis. Results Median age of 112 patients included in the study was 61 (range, 27-90) years at the time of diagnosis. When patients were stratified according to the conventional risk stratification system, 43.8% of patients were in the low-risk group and 56.2% in the high-risk group. A total of 22.4% of low-risk and 42.9% of high-risk patients had at least one thromboembolic event. When patients were stratified according to the IPSET-Thrombosis, 33% were in the low-risk group, 26.8% in the intermediate-risk group, and 40.2% in the high-risk group. Considering IPSET-Thrombosis risk groups, 5.4% of low-risk, 26.7% of intermediate-risk, and 66.2% of high-risk patients had at least one thromboembolic event. Regarding IPSET-Thrombosis risk groups, 10-year thrombosis-free survival was 86.8% for low-risk, 39.4% for intermediate-risk, and 32.9% for high-risk groups (P <.001). Harrell C concordance indexes of conventional and IPSET-Thrombosis were 0.60 and 0.77, respectively. Conclusion By validating the reproducibility of IPSET-Thrombosis in Turkish ET patients, we found that IPSET-Thrombosis identifies thrombosis-free survival better than the conventional risk stratification system

Impact of CALR and JAK2V617F Mutations on Clinical Course and Disease Outcomes in Essential Thrombocythemia: A Multicenter Retrospective Study in Turkish Patients

Objective: In this study, we investigated the effects of calreticulin (CALR) and JAK2V617F mutational status on clinical course and disease outcomes in Turkish patients with essential thrombocythemia (ET). Materials and Methods: Seventeen centers from Türkiye participated in the study and CALR- and JAK2V617F-mutated ET patients were evaluated retrospectively. Results: A total of 302 patients were included, of whom 203 (67.2%) and 99 (32.8%) were JAK2V617F- and CALR-positive, respectively. CALR-mutated patients were significantly younger (51 years vs. 57.5 years, p=0.03), with higher median platelet counts (987x109/L vs. 709x109/L, p<0.001) and lower median hemoglobin levels (13.1 g/dL vs. 14.1 g/dL, p<0.001) compared to JAK2V617F-mutated patients. Thromboembolic events (TEEs) occurred in 54 patients (17.9%), 77.8% of which were arterial. Compared to CALR mutation, JAK2V617F was associated with a higher risk of thrombosis (8.1% vs. 22.7%, p=0.002). Rates of transformation to myelofibrosis (MF) and leukemia were 4% and 0.7%, respectively, and these rates were comparable between JAK2V617F- and CALR-mutated cases. The estimated overall survival (OS) and MF-free survival of the entire cohort were 265.1 months and 235.7 months, respectively. OS and MF-free survival durations were similar between JAK2V617F- and CALR-mutated patients. Thrombosis-free survival (TFS) was superior in CALR-mutated patients compared to JAK2V617F-positive patients (5-year TFS: 90% vs. 71%, respectively; p=0.001). Age at diagnosis was an independent factor affecting the incidence of TEEs. Conclusion: In our ET cohort, CALR mutations resulted in higher platelet counts and lower hemoglobin levels than JAK2V617F and were associated with younger age at diagnosis. JAK2V617F was strongly associated with thrombosis and worse TFS. Hydroxyurea was the most preferred cytoreductive agent for patients with high thrombosis risk