Background: From 1991 until 2004 children with acute lymphoblastic leukemia (ALL) in the Netherlands were treated according to protocols ALL-8 and ALL-9 which were based on different principles. An earlier study showed that the outcome of adolescents highly differed on these protocols.
Procedure: In this retrospective study, we analyzed whether the outcome of older children 10-15 years of age at diagnosis differed between the Berlin-Frankfurt-Münster (BFM)-based ALL-8 regimen and the ALL-9 regimen. Two hundred fifty-four older children who were treated according to protocol ALL-8 (n = 82) or ALL-9 (n = 172) were included in the analysis.
Results: A higher 5-year event-free survival (EFS) rate was found for patients treated according to ALL-8 compared to ALL-9 (79 ± 5% vs. 65 ± 4%, P = 0.02). Patient characteristics did not differ except for a slightly higher age in ALL-8. Therefore, additional analyses were done including only patients who were 12-15 years of age. In this age group there was also a difference in the 5-year EFS (82 ± 5% vs. 61 ± 5%, P = 0.00) as well as in the 5-year overall survival rate; 89 ± 4% compared to 68 ± 5%, respectively (P = 0.01). Major difference between protocols was the use of a consolidation and reinduction/intensification course and higher cumulative doses of asparaginase, methotrexate, and anthracyclines in ALL-8.
Conclusions: Children 10-15 years of age have been undertreated with the ALL-9 regimen and benefit by intensive treatment components as used in ALL-8. We recommend using BFM-based protocols for these older children with ALL.
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