Citations

Abstract Symptomatic burden in myeloproliferative neoplasms is present in most patients and compromises quality of life. We sought to validate a broadly applicable 18-item instrument (Myeloproliferative Neoplasm Symptom Assessment Form [MPN-SAF], coadministered with the Brief Fatigue Inventory) to assess symptoms of myelofibrosis, essential thrombocythemia, and polycythemia vera among prospective cohorts in the United States, Sweden, and Italy. A total of 402 MPN-SAF surveys were administered (English [25%], Italian [46%], and Swedish [28%]) in 161 patients with essential thrombocythemia, 145 patients with polycythemia vera, and 96 patients with myelofibrosis. Responses among the 3 administered languages showed great consistency after controlling for MPN subtype. Strong correlations existed between individual items and key symptomatic elements represented on both the MPN-SAF and the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30. Enrolling physicians' blinded opinion of patient symptoms (6 symptoms assessed) were highly correlated with corresponding patients' responses. Serial administration of the English MPN-SAF among 53 patients showed that most MPN-SAF items are well correlated (r > 0.5, P < .001) and highly reproducible (intraclass correlation coefficient > 0.7). The MPN-SAF is a comprehensive and reliable instrument that is available in multiple languages to evaluate symptoms associated with all types of MPNs in clinical trials globally.

Abstract In an international collaborative study, a central histologic review identified 891 patients with essential thrombocythemia, strictly defined by World Health Organization criteria. After a median follow-up of 6.2 years, 109 (12%) patients experienced arterial (n = 79) or venous (n = 37) thrombosis. In multivariable analysis, predictors of arterial thrombosis included age more than 60 years (P = .03; hazard ratio [HR] = 1.7), thrombosis history (P = .003; HR = 2.1), cardiovascular risk factors including tobacco use, hypertension, or diabetes mellitus (P = .007; HR = 1.9), leukocytosis (> 11 × 109/L; P = .04; HR = 1.7), and presence of JAK2V617F (P = .009; HR = 2.6). In contrast, only male gender predicted venous thrombosis. Platelet count more than 1000 × 109/L was associated with a lower risk of arterial thrombosis (P = .007; HR = 0.4). These associations, except the one with leukocytosis, remained significant (or near significant) when analysis was restricted to JAK2V617F-positive cases. The current study clarifies the contribution of specific disease and host characteristics to the risk of arterial versus venous thrombosis in essential thrombocythemia.

Abstract The Janus kinase 2 mutation, JAK2617V>F, is myeloid neoplasm-specific; its presence excludes secondary polycythemia, thrombocytosis, or bone marrow fibrosis from other causes. Furthermore, JAK2617V>F or a JAK2 exon 12 mutation is present in virtually all patients with polycythemia vera (PV), whereas JAK2617V>F also occurs in approximately half of patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF). Therefore, JAK2 mutation screening holds the promise of a decisive diagnostic test in PV while being complementary to histology for the diagnosis of ET and PMF; the combination of molecular testing and histologic review should also facilitate diagnosis of ET associated with borderline thrombocytosis. Accordingly, revision of the current World Health Organization (WHO) diagnostic criteria for PV, ET, and PMF is warranted; JAK2 mutation analysis should be listed as a major criterion for PV diagnosis, and the platelet count threshold for ET diagnosis can be lowered from 600 to 450 × 109/L. The current document was prepared by an international expert panel of pathologists and clinical investigators in myeloproliferative disorders; it was subsequently presented to members of the Clinical Advisory Committee for the revision of the WHO Classification of Myeloid Neoplasms, who endorsed the document and recommended its adoption by the WHO.