Outcome of children and adolescents with a second or third relapse of acute lymphoblastic leukemia (ALL): a population-based analysis of the Austrian ALL-BFM (Berlin-Frankfurt-Münster) study group.

We analyzed outcome of a population-based cohort of 74 children with second and third acute lymphoblastic leukemia (ALL) relapse and aimed to identify prognostic factors. Duration of previous remission and site of relapse appeared of prognostic relevance as patients with a second remission duration >1.5 years and isolated extramedullary relapse did better. Neither patient with a second bone marrow relapse who underwent previous allogeneic transplantation nor patients with T-cell ALL survived. Overall, 7 of 74 (9%) patients are in long-term remission. Stem cell transplantation seemed to be the only curative option for systemic relapse of B-cell precursor ALL as all 4 surviving patients with a second/third relapse involving the bone marrow received a transplant. Conclusively, patients with a second ALL relapse are ideal candidates for phase I/II trials exploring new innovative drugs.