Essential Thrombocythemia (ET)

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. 

Richard T. Silver MD Myeloproliferative Neoplasms Center 525 East 70th St., Starr Pavillion, 3rd Floor New York, NY 10021