Current treatment practice for essential thrombocythaemia in adults.

Essential thrombocythaemia (ET) is a relatively benign chronic myeloproliferative disorder that occurs primarily in middle-aged patients. Its clinical course is characterised by thomboembolic and, less frequently, by haemorrhagic complications. Life expectancy of ET is generally of normal length and progression to acute leukaemia is a rare event. About one third of all patients are asymptomatic at diagnosis and many of them remain without complications for years. Therefore, the main challenge for treating patients with ET is to select patients who will benefit from a cytoreductive or antiplatelet therapy, because it is doubtful whether the beneficial effects of therapy outweigh the potential hazards in all cases. For this reason a risk stratification in high and low risk ET patients is essential. The treatment of ET has evolved from alkylating agents to hydroxyurea (HU) or pipobroman and more recently to agents such as IFN-alpha and anagrelide. Aspirin as an antiplatelet therapy is also expected to play a part in the treatment of ET. HU is first-line therapy for elderly patients with high risk ET. In young ET patients without ET related complications and a platelet count << 1000 - 1500 x 10(9)/l abstention from cytoreductive therapy or therapy with low-dose aspirin alone seems to be appropriate. The aim of this review is to address the current treatment practice for ET in adults.