Down's syndrome and acute lymphoblastic leukaemia: clinical features and response to treatment

Aims-To examine the clinical and biological features of acute lymphoblastic leukaemia in children with Down's syndrome (DS), to compare their survival with other children, and to determine if entry to trials and survival has improved. Methods-Examination of presenting features and response to treatment in pat ients treated in two consecutive national trials, MRC UKALL X and XI. Results-The proportion of children with DS was significantly higher in UKAL L XI (1.9%) than UKALL X (0.9%). Children with DS tended to be under 10 yea rs and to have the common ALL subtype. Cytogenetic analysis showed that fav ourable features, such as high hyperdiploidy and t(12;21) were less frequen t but also that there was a lack of translocations associated with a poor p rognosis. Children with DS showed no increase in risk of relapse at any sit e but their survival and event free survival were inferior to other childre n. These results were caused by an increased number of infective deaths dur ing remission (11% compared to 2%). At five years overall survival was 73% in DS children compared with 82% in other children; event free survival was 53% compared to 63% in non-DS children. Conclusions-Entry of children with DS to national trials has increased and survival has improved. However they remain at risk of relapse and also of t reatment related mortality. These findings emphasise the need for both inte nsive chemotherapy and optimal supportive care.