Unanswered questions in polycythaemia vera.

Abstract

Polycythaemia vera (PV) is a myeloproliferative disorder (MPD) characterised by clonal proliferation of haematopoietic factors resulting in an increased production of erythrocytes, leucocytes and platelets. The major complications of PV include an increased risk of thrombosis and haemorrhage. Long-term complications also include the development of myelofibrosis and leukaemia. The goals of PV treatment are to prevent thrombosis and bleeding without increasing the likelihood of long-term complications (1). Treatment strategies are based on risk stratification according to the presence of either of two high-risk factors (high risk: age >60 yr or a history of thrombosis) or the absence of these factors (low risk). An intermediate risk applies to patients who have cardiovascular risk factors without any high-risk factors. Current treatment recommendations include the use of phlebotomy (targeting haematocrit <45%) and low-dose aspirin for all patients (1). Cytoreductive therapy (e.g. hydroxyurea) is used only in high-risk patients due to the risk of drug-related side effects and potential leukaemic transformation (1). Although much has been achieved in the diagnosis and treatment of PV, several questions remain unanswered. These include uncertainty regarding: (i) the potential impact of the recently discovered janus kinase 2 (JAK2) mutation on PV diagnosis, (ii) the potential need to revise treatment algorithms in light of novel risk factors for thrombosis and (iii) the optimal targets of therapy for PV. This article will discuss these questions and possible directions for future research.