Prognostic impact of specific chromosomal aberrations in a large group of pediatric patients with acute myeloid leukemia treated uniformly according to trial AML-BFM 98

Abstract

Purpose: Because cytogenetic data are essential for risk stratification of childhood acute myeloid leukemia (AML), the impact of chromosomal aberrations is crucial.

Patients and methods: Data of a large group of patients younger than 18 years treated according to study AML-Berlin-Frankfurt-Münster (BFM) 98 (n = 454), including their cytogenetics, were analyzed.

Results: The favorable outcome in the subgroups of patients with t(8;21), inv(16), and t(15;17), with an overall survival of 91% (SE, 4%), 92% (SE, 6%), and 87% (SE, 5%), respectively, was confirmed. Within this group, the 5-year probability of event-free survival (pEFS) of all 17 children with t(8;21) and additional aberrations apart from del(9q) or -X/-Y was 100%. As expected, the cytogenetic finding of a complex karyotype (n = 35; pEFS, 33%; SE, 8%) or a monosomy 7 (n = 12; pEFS, 17%; SE, 11%) was associated with a poor outcome. Compared with remaining patients with cytogenetic data (pEFS, 48%; SE, 2%), prognosis in patients with an MLL rearrangement (n = 91) was inferior (pEFS, 34%; SE, 5%; P = .0005). Particularly, children with t(9;11) and additional aberrations (n = 13; pEFS, 31%; SE, 14%) and MLL rearrangements other than t(9;11) and t(11;19) (n = 41; pEFS, 24%; SE, 7%) had an unfavorable outcome. Nine patients with aberrations in 12p showed an adverse prognosis (pEFS, 11%; SE, 10%). The outcome of patients with aberrations of chromosome 5 (n = 13) was better than expected (pEFS, 50%; SE, 13%).

Conclusion: Because the prognostic value of rare recurrent chromosomal aberrations still has to be elucidated, these data will contribute to future risk stratification for the treatment of pediatric AML.