Survival of childhood acute lymphoid leukaemia in Yorkshire by clinical trial era, 1990-2011.

Gender-specific differences in survival by clinical trial era in Yorkshire were assessed for children with acute lymphoid leukaemia (ALL) enrolled onto UKALLXI, ALL97/99 or UKALL2003 (n = 630; 1990-2011). For males, there was a non-significant improvement in survival for ALL97/99 [hazard ratio (HR) = 0·77; 95% confidence interval (CI) 0·43-1·42) and a significant improvement for UKALL2003 (HR = 0·50; 95%CI 0·25-0·99) compared to UKALLXI. For females, survival was significantly improved for ALL97/99 (HR = 0·33; 95%CI 0·14-0·78), and non-significantly improved for UKALL2003 (HR = 0·51; 95%CI 0·25-1·08) compared to UKALLXI. Modest overall survival improvements masked clinically important gender-specific changes over time by trial era, requiring confirmation in larger population-based studies.