High hyperdiploid acute lymphoblastic leukemia (ALL)—A 25-year population-based survey of the Austrian ALL-BFM (Berlin-Frankfurt-Münster) Study Group

Background: Approximately 30% of childhood acute lymphoblastic leukemia (ALL) cases are high hyperdiploid (HD). Despite their low relative recurrence risk, this group accounts for the overall largest relapse proportion. Procedure: To evaluate potential risk factors in our population-based cohort of patients with HD ALL enrolled in four Austrian ALL-BFM (Berlin-Frankfurt-Munster) studies from 1986 to 2010 (n= 210), we reviewed the clinical, laboratory, and cytogenetic data of the respective cases in relation to their outcome. Results: The 5-year event-free (EFS) and overall survival (OS) of the entire group was 83.1 +/- 2.7% and 92.0 +/- 1.9%, respectively. Univariate analysis revealed that trisomy 17 was significantly associated with a better EFS and OS, whereas trisomy 10 and a modal chromosome number (MCN) > 53 chromosomes were significantly associated with a better OS. Except for the latter, findings remained valid in multivariate analysis. Conclusions: In line with previous studies, our retrospective analysis shows that MCN and specific trisomies are relevant prognostic indicators in an ALL-BFM cohort of patients with HD ALL. However, considering the current dominant role of minimal residual disease monitoring for prognostic stratification in ALL, including this particular subgroup, it is unlikely that this information is compelling enough to be utilized for refined risk classification in future ALL-BFM treatment protocols.