Prognostic factors and models in polycythemia vera, essential thrombocythemia, and primary myelofibrosis

Myeloproliferative neoplasms include essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF). These 3 diseases have common clinical features, such as a high risk of vascular complications, progression to secondary myelofibrosis, and clonal evolution into the blast phase. Current risk factors of ET and PV, used to predict events, are patient based: age >60 years and a history of thrombosis. Very recently, other parameters, such as leukocyte count and the presence of JAK2 (V617F) mutation, have been reported as potential risk factors. Prognosis in PMF is predicted at diagnosis by a combination of different risk factors, such as advanced age (age >60 years), anemia, leukocytosis (white blood cell count > 25 × 10(9)/L), the presence of blast cells (≥ 1%), and the presence of constitutional symptoms. This model may also predict survival when applied during follow-up.