Causes and Consequences: ET is caused by abnormal blood forming cells in the bone marrow and spleen that overproduce a kind of blood cell called platelets (aka thrombocytes).
Goals: The goals of treatment for ET are aimed at reducing the risk of the most common serious medical problems faced by patients with ET: abnormal blood clots; and abnormal bleeding. There are no universally accepted standard guidelines for therapy but there are several recommendations that are commonly used.
1) Routine use of low dose aspirin (100 mg/day). *
2) Platelet lowering drugs (so called “cytoreductive therapy”), for patients felt to be at higher risk for clot (age > 60 years, or history of prior clot) or bleeding (platelet count > 1,500,000, or current abnormal bleeding).
a. A target platelet count of ≤ 600,000/mcL is often used for patients treated with cytoreductive therapy. (J Clin Oncol 8:556-62, 1990: NEJM 332:1132-1135, 1995)
* Exception for patients with history of gastric ulcers or other reasons to avoid aspirin.