Journal of Clinical Oncology, Vol 15, 2231-2237, Copyright © 1997 by American Society of Clinical Oncology
Philadelphia chromosome in relapsed childhood acute lymphoblastic leukemia: a matched-pair analysis. Berlin-Frankfurt-Munster Study Group
B Beyermann, HP Adams and G Henze
Department of Pediatric Oncology/Hematology, Children's Hospital, Virchow Medical Center, Humboldt University, Berlin, Germany.
PURPOSE: The translocation t(9;22)(q34;q11), known as Philadelphia
chromosome (Ph1) or its molecular equivalent the expression of BCR-ABL-
mRNA, is one of the most striking and well-characterized cytogenetic
abnormalities in leukemia. Although investigated for more than 30 years, it
remains unclear whether the Ph1 is an independent risk factor for outcome
of leukemia or not. METHODS: A matched-pair analysis was performed within a
homogeneous group of patients, which consisted of children who presented
with a first relapse of acute lymphoblastic leukemia (ALL) who were treated
according to ALL relapse trials (ALL- REZ BFM) protocols. A total of 307
patients were eligible for this analysis: 30 positive and 277 negative for
Ph1. Positive patients were matched exactly for time point of relapse (on
[during] or off [after cessation of] front-line therapy), site, and
immunophenotype, and as close as possible for duration of first remission,
peripheral blast- cell count, WBC count, and year of relapse diagnosis.
RESULTS: The probability of event-free survival is 0.46 at 5 years for
negative and 0.11 for positive patients, respectively (P = .0006).
Multivariate analysis showed risk ratios of 4.229 for relapse on therapy,
3.561 for Ph1 and/or expression of BCR-ABL- mRNA, 1.691 for high peripheral
blast- cell count, and 0.232 for bone marrow transplantation. CONCLUSION:
It was shown that the Ph1 is indeed an independent risk factor in childhood
relapsed ALL. There are striking similarities between these patients and
children at initial diagnosis, as well as adult patients. Therefore, it is
highly suggestive that the Ph1 is also an independent risk factor under all
of these circumstances.