Sex‐based disparities in outcome in pediatric acute lymphoblastic leukemia: a Children’s Oncology Group report

Background Boys with acute lymphoblastic leukemia (ALL) have historically experienced inferior survival compared to girls. This study determined whether sex‐based disparities persist with contemporary therapy and whether patterns of treatment failure vary by sex. Methods Patients 1 to 30.99 years old were enrolled on frontline Children’s Oncology Group trials between 2004 and 2014. Boys received an additional year of maintenance therapy. Sex‐based differences in the distribution of various prognosticators, event‐free survival (EFS) and overall survival (OS), and subcategories of relapse by site were explored. Results A total of 8202 (54.4% male) B‐cell ALL (B‐ALL) and 1562 (74.3% male) T‐cell ALL (T‐ALL) patients were included. There was no sex‐based difference in central nervous system (CNS) status. Boys experienced inferior 5‐year EFS and OS (EFS, 84.6% ± 0.5% vs 86.0% ± 0.6%, P = .009; OS, 91.3% ± 0.4% vs 92.5% ± 0.4%, P = .02). This was attributable to boys with B‐ALL, who experienced inferior EFS (hazard ratio [HR], 1.2; 95% confidence interval [95% CI], 1.1‐1.3; P = .004) and OS (HR, 1.2; 95% CI, 1.0‐1.4; P = .046) after adjustment for prognosticators. Inferior B‐ALL outcomes in boys were attributable to more relapses (5‐year cumulative incidence 11.2% ± 0.5% vs 9.6% ± 0.5%; P = .001), particularly involving the CNS (4.2% ± 0.3% vs 2.5% ± 0.3%; P