Survival From Childhood Hematological Malignancies in Denmark: Is Survival Related to Family Characteristics?

BACKGROUND: Due to diverse findings as to the role of family factors for childhood cancer survival even within Europe, we explored a nationwide, register-based cohort of Danish children with hematological malignancies.

METHODS: All children born between 1973 and 2006 and diagnosed with a hematological malignancy before the age of 20 years (N = 1,819) were followed until 10 years from diagnosis. Kaplan-Meier curves and Cox proportional hazards models estimating hazard ratios (HR) and 95% confidence intervals (CI) were used to assess the impact of family characteristics on overall survival in children with hematological malignancies.

RESULTS: Having siblings and increasing birth order were associated with reduced survival from acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Associations with AML were strongest and statistically significant. HRs of 1.62 (CI 0.85; 3.09) and 5.76 (CI 2.01; 16.51) were observed for the fourth or later born children with ALL (N = 41) and AML (N = 9), respectively. Children with older parents showed a tendency toward inferior ALL survival, while for AML young maternal age was related to poorer survival. Based on small numbers, a trend toward poorer survival from non-Hodgkin lymphoma was observed for children having siblings and for children of younger parents.

CONCLUSIONS: Further research is warranted to gain further knowledge on the impact of family factors on childhood cancer survival in other populations and to elaborate potential underlying mechanisms and pathways of those survival inequalities.