Utility of end consolidation bone marrow aspirates in childhood acute lymphoblastic leukemia [ALL]: A Pediatric Oncology Group study [POG].

8564 Background: There is little information on the value of bone marrow aspirates (BMA) as a guide to treatment in pediatric ALL. Although BMA morphology provides useful information at diagnosis, end of induction, and end of therapy, its value when performed at the end of consolidation is not known. During the conduct of several POG protocols, a decision was made to discontinue end of consolidation BMA. This provided an opportunity to study the value of BMA at that time point. METHODS: We reviewed end of consolidation BMA morphology from four POG protocols, (POG 9201 Pilot for good-risk ALL; POG 9201, phase III study for good-risk ALL; and POG 9405/9605, phase III study for standard-risk ALL). Patients were stratified into low-, standard-, and high-risk groups according to NIH criteria (age, white count, CNS involvement), DNA index, and cytogenetics. POG 9201 Pilot, 9201, and 9605 defined the end of consolidation as week 25, and POG 9405 as week 28. 2086 study coordinator charts were reviewed: 697 [POG 9201 Pilot/9201], 301 [POG 9405], and 1088 [POG 9605]. Remission was defined as: M1: 0-5% blasts; M2: > 5-25%; M3: > 25%, with at least 200 cells counted. High-risk patients were not reviewed. RESULTS: 776 patients (330/697, 66/301 and 380/1088) had complete information, including differential count, on the end of consolidation marrow (reflects study amendment to discontinue BMA). 773 of 776 (99.6%) of patients with end of consolidation BMA had M1 marrow. Two of 3 who had M2 marrow relapsed (28 and 45 months after achieving remission), and the third is continuously disease free (60 months). CONCLUSIONS: Routine BMA at the end of consolidation is not of prognostic or therapeutic value and should be restricted to protocols in which randomization to different treatments is after that time point. Traditional morphologic review will likely be supplanted by more sensitive measures of minimal residual disease, such as cytogenetics, flow cytometry, or molecular markers. No significant financial relationships to disclose.

Duke Scholars

Author Joanne Kurtzberg Pediatrics, Transplant and Cellular Therapy