Treatment and Survival in Acute Leukemia: A New South Wales Study Comparing Adolescents and Young Adults with Children and Adults

Objective. To investigate age differences in treatment and survival from acute lymphoblastic (ALL) and acute myeloid leukemia (AML). Methods. 1053 ALL/566 AML patients diagnosed in 2003-2015 on the New South Wales Cancer Registry were included. Treatment within 12 months from diagnosis was assessed using linked registry, hospital, and health-insurance data. Differences by age at diagnosis in treatment and survival were investigated using socio-demographically adjusted regression analyses, with adolescents and young adults (AYA, 15-24 years) as the reference category. Results. Children were less likely than AYA to start ALL treatment > 3 days from diagnosis (adjusted odds ratio (aOR 0.39, 95% CI 0.27-0.57)) and to have multiple treatment types (aOR 0.22, 95% CI 0.14-0.34). For AML, aOR of treatment start > 3 days was 0.16 (95% CI 0.09-0.29) for children compared with AYA, with no age differences in treatment types. Five-year disease-specific survival for ALL was 84%. Children were less likely than AYA to die from ALL (adjusted subhazard ratio (aSHR 0.32, 95% CI 0.22-0.50)). For AML, the corresponding survival was 73% without an age difference. Children having multiple treatment types for ALL had an increased risk of mortality at aSHR 2.67 (95% CI 1.53-4.67), but not adults at 1.26 (95% CI 0.67-2.47) (interaction p = 0.017). Time from diagnosis to initial treatment start and initial treatment type were not associated with mortality outcomes after adjusting for socio-demographic variables. Conclusion. Children with ALL had better survival. ALL Mortality were negatively associated with multiple treatment types.