Results of acute lymphoblastic leukemia treatment in children in the Slovak Republic

Treatment of childhood acute lymphoblastic leukemia (ALL) according to the 1st Slovak protocol started in the Slovak Republic in 1971 in eight pediatric departments. Gradually, two other protocols were written, and 496 children were treated with these three protocols from 1971 to 1992. Since 1992, all children have been treated in three pediatric oncological departments. From 1992 to 1996, protocols for standard and high-risk ALL were developed that were used for 111 children in Bratislava, while the centres in Banska Bystrica and Kosice had started to use BFM protocols. Since 1997, all patients with ALL have been treated according to ALL BFM 95, and since 2002, they have been included in the ALL IC BFM 2002 study. We evaluated treatment results in the standard arm of ALL BFM 95 and compared it with previous Slovak protocols. Rates of complete remission increased from 90.6% in the first Slovak protocol to 97.1% in BFM 95; EFS and OS increased from 0.46 and 0.50 to 0.67 and 0.72, respectively. Relapse rates decreased from 42% to 20.5%. EFS was significantly worse in children with leukocyte counts >100×109/l and in the HR group in comparison to standard- and medium-risk groups. OS was also significantly worse in T-cell ALL than in B-cell ALL. Death rates in the 1st complete remission decreased gradually in the Slovak protocols from 10.4% to 1.8%, but were high in BFM 95 (10.8%) due to more intensive therapy and initial unsatisfactory experiences with BFM protocols. All parameters improved in the ALL IC BFM 2002 study.