IMPORTANCE OF THE DAY-7 BONE-MARROW BIOPSY AS A PROGNOSTIC MEASURE OFTHE OUTCOME IN CHILDREN WITH ACUTE LYMPHOBLASTIC-LEUKEMIA

The presence of greater than or equal to 25% blasts in a marrow aspira te obtained on day 7 of induction followed by a remission at day 28 ha s been associated with a poor prognosis in children with acute lymphob lastic leukemia (ALL). We evaluated whether a day 7 marrow biopsy may be used to more accurately assess therapeutic reduction of leukemia tu mor burden. Studied were 76 children with ALL enrolled on CCG protocol s at B.C.'s Children's Hospital who received both a day 7 aspirate and biopsy and were in remission by day 28. Evaluation for the correlatio n of the percentage aspirate blasts on day 7 with the biopsy demonstra ted a moderate correlation with the percentage biopsy blasts (R = 61), but not correlation with tile biopsy cellularity. We saw a similar pr ediction of outcome by the percentage blasts on day 7 marrow aspirate in this study as reported previously al day 7 absolute blast index-asp irate (ABI-aspirate) calculated as the product of the biopsy cellulari ty with the percentage blasts on the aspirate. The ABI-aspirate signif icantly predicted patient outcome with 83% survival in those with an A BI-aspirate oi <.06 compared to 51% in those greater than or equal to. 06 (P=.01) and was highly significant when analyzed as a continuous pr edictor (P=.0041. This is the first study to demonstrate tl?at informa tion gained from the day 7 marrow biopsy can improve prediction oi out come in children with ALL. Based on this preliminary study, we recomme nd that large population ALL therapy trials evaluate the role of the d ay 7 marrow biopsy for outcome prediction in children with ALL. (C) 19 97 Wiley-Liss, Inc.