[Results and experiences with a modified BFM protocol for treatment of recurrences in children with acute lymphoblastic leukemia in East German areas].

Between 1988 and 1990, 55 patients with first relapses of acute lymphoblastic leukemia (ALL) were treated with a modified BFM-protocol (ALL REZ I/88). The patients were divided according to time and site of relapse: relapses with bone marrow involvement up to 6 months after stopping front line therapy (group A), relapses with bone marrow involvement beyond 6 month after therapy (group B) and isolated extramedullary relapses at any time (group C). During therapy the patients received alternating courses of polychemotherapy including infusions of intermediate dose methotrexate (1 g/m2 in 36 hours). The maintenance treatment consisted of daily oral thioguanine and biweekly intravenous (IV) MTX. The overall second remission rate was 89% (group A: 90%, group B: 86%, group C: 93%) and the probability of event free survival (EFS) at 4 years is 0.28 +/- 0.13 (group A: 0.22 +/- 0.12, group B: 0.24 +/- 0.18, group C: 0.57 +/- 0.15). We conclude, that with the treatment regimen applied, long lasting second remission can be achieved in about one third of patients even after intensive front line therapy. The most unfavourable prognoses were seen in patients with early bone marrow relapses (group A).