History of treatment and long-term outcome of childhood acute lymphoblastic leukemia in Slovenia
Treatment and long-term outcome in Slovenian children and adolescents, treated for acute lymphoblastic leukaemia (ALL) were evaluated, mainly considering differences between treatment regimens being evolved during time. From year 1967 through 2004, 394 patients (pts) were treated and six therapeutic schemes had been used. Retrospectively 5-year overall survival ± standard error (5yOS), relapse rate (RR) and second neoplasm (SN) were estimated according to treatment regimen, age, and where recorded, also according to BFM risk group, white blood cell count and disease subtype. For treatment regimens used after year 1992, 5-year event-free survival ± standard error (5yEFS) was added to our observations. Among 75 pts enrolled in pre-POG treatment regimen, the probability of 5yOS was 25.3 ± 5.0%, while no data for RR and SN analysis were available. For 91 pts treated according to POG derived treatment, the probability of 5yOS was 61.6 ± 5.1%, with 64% RR and 5.5% occurrence of SN. Probability of 5yOS of 74.3 ± 7.4%, RR of 37% and 8.5% occurrence of SN were reached for 35 pts enrolled in ALL-BFM 83 protocol. ALL-BFM 86 protocol included 62 pts with 69.4 ± 5.9% probability of 5yOS, 33% RR and 3.2% occurrence of SN. For ALL-BFM 90 protocol the 5yEFS and 5yOS for 71 pts was 77.3 ± 5.2% and 81.8 ± 4.8%, respectively, with 17% RR and 1.5% occurrence of SN. Fifty-six patients enrolled in ALL-BFM 95 protocol reached 83.0 ± 5.2% 5yEFS and 92.6 ± 3.6% 5yOS, with 16% RR and 1.7% occurrence of SN. Stepwise rise of OS, decline in RR, reducing occurrence of SN and, for ALL-BFM 90 and ALL-BFM 95 protocol, improvements in EFS, were observed through time according to different treatment regimens. General improvement regarding OS, RR and occurrence of SN was most obvious after the application of BFM regimen with evident continuous rise in OS and decline in RR and occurrence of SN thereafter.