Prognostic value of day 14 blast percentage and the absolute blast index in bone marrow of children with acute lymphoblastic leukemia.

The product of the percentage blasts on the bone marrow aspirate (BMA) and the biopsy cellularity has been termed the "absolute blast index aspirate" (ABI-aspirate) and is used to measure disease response on day 7 of induction therapy. The authors compared the event-free survival (EFS) in high-risk and standard-risk patients as identified by the ABI-aspirate and the BMA percentage blasts on day 14 of induction therapy. Both indices identified high-risk cases. EFS of patients categorized as high-risk by these 2 methods and the high-risk criteria used by the authors' service (WCC of > 20 x 10(9)/L, age < 2 and > 8 years and a peripheral blood blast count of > 1.0 x 10(9)/L on day 8 of induction) did not differ. There was concordance between patients identified as high risk by all 3 methods. The results confirmed the prognostic value of the ABI-aspirate and the BMA percentage blasts on day 14 of induction therapy, but these methods were not superior to the high-risk criteria currently in use.