Recurrent Childhood AML

Approximately 50% to 60% of relapses occur within the first year after diagnosis, with most relapses occurring by 4 years after diagnosis.[1] In the Medical Research Council (MRC) AML10 trial, which enrolled 359 children with AML and had a median follow-up of 6.5 years (range, 3.3–10.1 years), the vast majority of relapses (113 of 125 children had relapses) occurred in the bone marrow (alone or combined with an extramedullary site). In contrast, central nervous system (CNS) and other extramedullary sites of relapse with or without bone marrow relapse were uncommon (22 of 125 children). The median time to relapse was 295 days. For patients who completed therapy, 27% experienced relapsed disease during the first year off therapy. In the second year off therapy, among patients who remained in remission, 11% had relapsed disease. The relapse rate declined to 3% in the third year and 1% in the fourth year, and no relapses occurred in later years.[2]