What is the standard treatment in essential thrombocythemia.
The treatment of patients with essential thrombocythemia (ET) should be based primarily on the expected risk of major thrombotic complications. Although the specific values chosen for separating different risk categories are in part arbitrary, the following recomendations can be made. Young asymptomatic subjects with platelet counts below 1,500x10(9)/L are at lower risk and can be followed untreated. However, it should be emphasized that thrombotic events can also occur in a small percentage of these lower-risk cases. Low-dose aspirin (100-300 mg/day) should be given to patients with symptoms of microvascular occlusion, such as erythromelalgia or transient neurological attacks, and avoided in those with bleeding manifestations. The risk/benefit of low-dose aspirin in the primary prevention of thrombosis in asymptomatic patients remains uncertain. For high-risk patients (age >60 years, or platelet count >1,500x10(9)/L, or previous thrombosis), hydroxyurea, plus aspirin in the case of thrombosis, is the treatment of choice because its efficacy in preventing thrombotic complications has been proven in a randomized clinical trial. However, the possible long-term leukemogenicity of this drug, as well as that of other effective cytoreductive agents such as busulphan and pipobroman, remains a major concern. Anagrelide and interferon could overcome this worry but their efficacy has been hitherto demonstrated only in lowering the platelet count. Controlled clinical studies showing a benefit in preventing thrombotic and hemorrhagic complications are urgently needed.