Bone marrow recurrence after initial intensive treatment for childhood acute lymphoblastic leukemia

The authors studied the clinical outcome of 106 children with acute lymphoblastic leukemia (ALL) who developed a bone marrow recurrence as the first adverse event after contemporary intensified therapy.

Endpoints were the rates and lengths of second remission, the cumulative incidence of second hematologic recurrence, second event-free survival (EFS), and survival.

Bone marrow recurrences were isolated in 79 patients, and combined with an extramedullary site in 27 patients. The median time to recurrence was 2.6 years (range, 0.3-11.6 years). Seventy-six patients (71.7%) attained a second remission (median length, 0.7 year; range, 0.03-13.3 years). The 5-year survival probability among all patients was 24.2% +/- 4.2% (standard error). On multivariate analysis, time to first disease recurrence and blast cell lineage were found to be independent predictors of a second EFS (P = 0.008 and P = 0.028, respectively). The 5-year EFS estimate in patients with an initial disease remission of >/= 36 months was 42.6% +/- 7.8% but was only 12.5% +/- 3.9% among children with a short duration of disease remission (< 36 months). These estimates were 28.7% +/- 4.9% and 5.0% +/- 3.4%, respectively, for B blast and T blast cell lineages.

Despite acceptable long-term second EFS rates for certain subgroups, overall bone marrow recurrence after intensified first-line therapy for childhood ALL signals a poor outcome.