Sexual Dimorphism in Children and Adolescents With Acute Lymphoblastic Leukemia: Influence on Incidence and Survival.

Acute lymphoblastic leukemia (ALL) incidence and poor prognosis are higher in male individuals. There is a lack of studies assessing the influence of sex in ALL. We documented this influence in a homogenous cohort. Three hundred three ALL Hispanic patients 1 to 20 years of age diagnosed over 10 years at a university hospital were evaluated. Patients were divided by sex and stratified by age. Survival rates were assessed by the Kaplan-Meier method, and the Cox model was used for univariate and multivariate analysis. The median age for female individuals was 6 years versus 9 years for male individuals (P=0.002). In the whole cohort, there was a male preponderance (P=0.025), with a 1.3 male-to-female ratio. For male individuals, the 5-year relapse-free survival was 46%; for female individuals, it reached 58.7%, (P=0.009). Male individuals 1-9 years of age had a lower 5-year relapse-free survival than female individuals, 51.5% versus 66.7% (95% confidence interval, 65.35-68.01; P=0.020); this was not the case for overall survival (P=0.660). The male-to-female ratio in the 10 to 15 years' group was 1.59, and 2.35 in the 16 to 20 years' group. Incidence and relapse of ALL were higher in male individuals. A skewed distribution in the 10 to 20 years' age group disproportionately affected male individuals, suggesting a hormonal influence.