Relapse of TEL-AML1-Positive acute lymphoblastic leukemia in childhood: A matched-pair analysis

Purpose: The aim of this study was to investigate whether, in relapsed chil dhood acute lymphoblastic leukemia (ALL), the frequent genetic feature of T EL-AML1 fusion resulting from the cryptic chromosomal translocation t(12;21 )(p13;q22) is an independent risk factor. Patients and Methods: A matched-pair analysis was performed within a homoge neous group of children with first relapse of BCR-ABL-negative B-cell precu rsor (BPC) ALL treated according to relapse trials ALL-Rezidiv (REZ) of the Berlin-Frankfurt-Munster Study Group. A total of 249 patients were eligibl e for this study: 53 (21%) were positive for TEL-AML1, and 196(79%) were ne gative. Positive patients were matched for established most-significant pro gnostic determinants at relapse,:time point, and site of relapse, as well a s age and peripheral blast cell count at relapse. Results: Fifty pairs matching the aforementioned criteria could be determin ed. The probabilities with SE of event-free survival and survival at 5 year s for matched TEL-AML1 positives and negatives are 0.63 +/- 0.10 versus 0.3 8 +/- 0.10 (P =.09) and 0.82 +/- 0.09 versus 0.42 +/- 0.19 (P =.10), respec tively. These results were confirmed by multivariate analysis, revealing an independent prognostic significance of time point and site of relapse (bat h P < .001) but not of TEL-AML1 expression (P =.09). Conclusion: TEL-AML1 expression does not constitute an independent risk fac tor in relapsed childhood BCP-ALL after matching for relevant prognostic pa rameters. It undoubtedly characterizes genetically an ALL entity associated with established favorable prognostic parameters. High-risk therapeutic pr ocedures such as allogeneic SCT should be considered restrictively. (C) 200 1 by American Society of Clinical Oncology.