PROGNOSTIC-SIGNIFICANCE OF SEX IN CHILDHOOD B-PRECURSOR ACUTE LYMPHOBLASTIC-LEUKEMIA - A PEDIATRIC-ONCOLOGY-GROUP STUDY

Purpose: In childhood B-precursor acute lymphoblastic leukemia (ALL), possible interactions among sex, time, and widely used prognostic fact ors (age, WBC count, and DNA index) were investigated for the first 5 years after diagnosis. Patients and Methods: All eligible patients age d 1 to less than 22 years, registered between February 1986 and Septem ber 1994 in two B-precursor ALL studies from the Pediatric Oncology Gr oup (POG), were included in the analysis. Cutpoints for age (3.0, 5.0, and 10.0 years), WBC count (10, 50, and 100 x 10(9)/L), and DNA index (DI; 1.16) were defined. Four time periods after diagnosis (years 1, 2, 3, and 4 and 5 combined) were selected for the study of prognostic significance over time. The cut-off date for analysis was April 1996. Results: A total of 3,717 children (2,010 boys and 1,707 girls) were i ncluded in the outcome analysis. No major differences between the sexe s were observed in age, duration of symptoms before registration, WBC count, hemoglobin level, platelet count, ploidy, presence of CNS disea se at diagnosis, or induction failure rate. Event-free survival (EFS) differences between sexes became significantly different from 2 years following diagnosis. At 5 years, in all subsets analyzed, boys fared w orse than girls, although not all differences were statistically signi ficant. Major sex differences in EFS were observed in older children ( 10 to 22 years), in patients with intermediate WBC counts (10 to 50 x 10(9)/ L), and in children who fit both of these subgroups, in whom th e 2-year EFS was almost 20% higher in girls than in boys, reaching a 3 8% difference at 5 years. Conclusion: This study shows an outcome inte raction among sex, time, and commonly used prognostic variables. The i mportant sex difference observed at 2 and 5 years suggests that more i ntensive consolidation and/or maintenance therapy in some boys with B- precursor ALL should be investigated. J Clin Oncol 16:2854-2863. (C) 1 998 by American Society of Clinical Oncology.