Adolescents with acute lymphoblastic leukaemia: Outcome on UK national paediatric (ALL97) and adult (UKALLXII/E2993) trials

Background. Adolescents with acute lymphoblastic leukaemia (ALL) have languished in the shadow of success of the outcome of therapy in childhood ALL. Their treatment has always been incorporated into either paecliatric or adult clinical trials depending on the mode of referral and hence there is a need to address an age and risk specific strategy for improving the outcome of this neglected group of patients. This article has summarised the recent and updated retrospective comparative analysis of adolescents treated on the Medical Research Council (MRC) trials. This analysis adds further emphasis to the treatment approach and the merits and limitations of treatment of adolescents on paediatric and adult trials. Methods. A retrospective comparative analysis of adolescents aged 15-17 years, treated on either MRC ALL97/revised 99 (n=61), a randomised paecliatric trial or UKALLXII/E2993 (n = 67), an adult trial, between 1997 and 2002 was undertaken. Result. Results suggest a trend towards a superior outcome on paediatric trials. The 5-year EFS on ALL97 was 65% (95% CI = 52-78%) and on UKALLXII/E2993 was 49% (95% CI = 37-61%; P = 0.01). Multivariate analysis allowing for age and Ph status, diminished the EFS difference, but confirmed a reduced rate of death in remission in patients managed on the paediatric protocol. Conclusions. Despite limitations in the methodology, comparative studies including our MRC study suggest a consistent advantage for adolescents managed intensively on paecliatric trials. Redefining age limits with risk-based strategy and multi-centre collaboration should be considered to improve the survival of young adults.