Enrolling children with acute lymphoblastic leukaemia on a clinical trial improves event-free survival: a population-based study

BACKGROUND: The objectives of this study were to describe the impact of trial enrollment at diagnosis on event-free and overall survival in paediatric acute lymphoblastic leukaemic (ALL) using a population-based approach. METHODS: We conducted a retrospective cohort study that included children newly diagnosed with ALL between 1 and 14 years of age. The data source was the Cancer in Young People in Canada (CYP-C) national paediatric cancer population-based database. We conducted univariate and multiple Cox proportional hazards models. RESULTS: There were 2569 children with ALL; 1408 (54.8%) were enrolled on a clinical trial at initial diagnosis. Event-free survival at 5 years was 89.8%±0.9 vs 84.1%±1.2. (P<0.0001) for those enrolled and not enrolled on a clinical trial, respectively. Overall survival at 5 years was higher for those enrolled (94.1%±0.7) vs not enrolled (90.5%±1.0; P=0.001). In a model that adjusted for demographic, leukaemic and socioeconomic factors, enrollment on trials was significantly associated with better event-free survival (hazard ratio (HR) 0.67, 95% confidence interval (CI) 0.47–0.95; P=0.023), but not overall survival (HR 0.69, 95% CI 0.44–1.08; P=0.102). CONCLUSIONS: Event-free survival was significantly better in children with ALL enrolled on a clinical trial. Future research should identify barriers to clinical trial enrollment for children with ALL.