[Studies of children with acute lymphoblastic leukemia (ALL) who relapsed. Relationship of site of relapse, time and prognosis].

One hundred and forty patients out of 511 children with ALL who were entered in the study of the Children's Cancer & Leukemia Study Group from 1981 through March 1988 had relapsed by August 1988. The sites of relapse were BM (including concurrent CNS relapse) in 96 cases (70%), CNS in 36 cases (25%), and testicles in 8 cases (5%). A second complete remission was induced in 57 of the 75 patients (76%) with ALL in the first BM relapse. The projected disease-free survival (DFS) for those in the second BM remission was 26.0% at 2 years and the length of the first remission was correlated with the outcome. In the patients in early marrow relapse within 12 months after diagnosis, the probability of maintaining a second remission at 2 years was 6.7% compared to 29.8% in those in intermediate marrow relapse. All patients in late relapse after more than 48 months from diagnosis are surviving with no evidence of disease. The outcome of the patients with isolated extra-marrow relapse was so favorable that the probability of maintaining a second remission for those in CNS relapse was 41.4% at 3 years, and 57.1% in patients in testicular relapse. These data suggest that 20-30% of patients relapsing after more than 12 months from diagnosis may be salvaged, but those who relapsed during active therapy within the first 12 months after diagnosis, other types of treatment should by considered.