Dosage of Platelet Transfusions Could Be Halved Without Risk

The dose of platelets given by transfusion to cancer patients who become thrombocytopenic can be halved without increasing the risk of bleeding, according to a new study.

Researchers from the Puget Sound Blood Center (Seattle, WA, USA) compared three different doses of platelets given by transfusion to 1,350 cancer patients with hypoproliferative thrombocytopenia. The dosages of platelets selected were a low dose (1.1 × 10¹¹ platelets/m²), a medium dose (2.2 × 10¹¹ platelets/m², which corresponds most closely to the standard dose currently used), and a high dose (4.4 × 10¹¹ platelets/m²). The patients enrolled in the trial were expected to be hospitalized with platelet counts of 10,000 mL or less for more than 5 days, and this was the trigger for a platelet transfusion, which was given prophylactically on days when platelet counts reached or fell to below this level.

The study results show that there was no significant difference in the risk of bleeding across any of these doses, either in World Health Organization (WHO) grade 2 bleeding, which was the primary end point, or in the more severe cases. In addition, there was no difference in the number of patients who needed red blood cell (RBC) transfusions. There was one bleeding-related death in the high-dose group. Patients in the low-dose group received more platelet transfusions than those in the other two groups--a median of 5 transfusions, compared with 3 in both the medium- and high-dose groups--but received significantly fewer platelets. The study reported was presented at the American Society of Hematology (ASH) annual meeting, held during December 2008 in San Francisco (CA, USA).

"We have shown that the lower dose is not adverse for the patient," said lead researcher and study presenter Professor Sherrill Slichter, M.D., of the division of hematology. "The size of this trial permits us to say that this is what we should be doing now. I will be recommending that clinicians reduce the dose of platelets in transfusions, as the risk is not there."

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Puget Sound Blood Center