Survival Differences Between Males and Females Diagnosed With Childhood Cancer

Abstract

Background: Males have worse survival for childhood cancer, but whether this disparity exists among all childhood cancer types is undescribed.

Methods: We estimated sex differences in survival for 18 cancers among children (0-19 years) in Surveillance, Epidemiology, and End Results 18 (2000-2014). We used Kaplan-Meier survival curves (log-rank P values) to characterize sex differences in survival and Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between sex and death for each cancer type. We used an inverse odds weighting method to determine whether the association between sex and death was mediated by stage of disease for solid tumors.

Results: Males had worse overall survival and a higher risk of death for acute lymphoblastic leukemia (HR = 1.24, 95% CI = 1.12 to 1.37), ependymoma (HR = 1.36, 95% CI = 1.05 to 1.77), neuroblastoma (HR = 1.28, 95% CI = 1.09 to 1.51), osteosarcoma (HR = 1.29, 95% CI = 1.08 to 1.53), thyroid carcinoma (HR = 3.25, 95% CI = 1.45 to 7.33), and malignant melanoma (HR = 1.97, 95% CI = 1.33 to 2.92) (all log-rank P values < .02). The association between sex and death was mediated by stage of disease for neuroblastoma (indirect HR = 1.12, 95% CI = 1.05 to 1.19), thyroid carcinoma (indirect HR = 1.24, 95% CI = 1.03 to 1.48), and malignant melanoma (indirect HR = 1.28, 95% CI = 1.10 to 1.49). For these six tumors, if male survival had been as good as female survival, 21% of male deaths and 13% of total deaths after these cancer diagnoses could have been avoided.

Conclusions: Consideration of molecular tumor and clinical data may help identify mechanisms underlying the male excess in death after childhood cancer for the aforementioned cancers.

Figure 1.

Kaplan-Meier survival curves for cancers with sex differences in overall survival. A) Acute lymphoblastic leukemia. B) Ependymoma. C) Neuroblastoma. D) Osteosarcoma. E) Thyroid carcinoma. F) Malignant melanoma. Surveillance, Epidemiology, and End Results 18 (2000–2014). Two-sided P values were calculated using a log-rank test.