Survival outcome after the first central nervous system relapse in children with acute lymphoblastic leukemia: a retrospective analysis of 79 patients in a joint program involving the experience of three Japanese study groups.

In a retrospective review of the survival outcome of children with isolated central nervous system (CNS) relapse of acute lymphoblastic leukemia (ALL), we identified 79 patients with CNS relapse among the eligible patients enrolled in ALL trials of 3 Japanese pediatric oncology study groups (Japanese Children's Cancer and Leukemia Study Group [JCCLSG], Tokyo Children's Cancer Study Group [TCCSG], and Japan Association of Childhood Leukemia Study [JACLS]) between 1989 and 1999. CNS relapses were diagnosed as the first adverse event between 1991 and 1999. The median age at the time of CNS relapse was 5.0 years (range, 0.7-15.1 years). The duration of the first remission ranged from 1.4 to 54 months (median, 12.4 months), and the observation period after CNS relapse ranged from 1 to 131 months (median, 27 months). Overall, 75 of the 79 patients achieved a second complete remission, 44 of whom had second relapses in the following sites: CNS, 18 patients; bone marrow, 15 patients; combined sites, 8 patients; and testis, 2 patients. Rates of overall survival and event-free survival at 4 years were 43.7% +/- 5.8% (mean +/- SE) and 32.9% +/- 5.5%, respectively. The probability of remaining in second remission was significantly correlated with the leukocyte count (P= .005) and age (P= .02) at the initial diagnosis.