Acute Lymphoblastic Leukemia in Japanese Adolescents; Biology and Toxicity Profile

Abstract 4290 BACKGROUND In the treatment for acute lymphoblastic leukemia (ALL), adolescents were reported to have worse prognosis than children because of their treatment compliance and response. In this study, we compared clinical features, treatment toxicity and outcome between children and adolescents treated with Japan Association of Childhood Leukemia Study (JACLS) ALL-02 protocol. METHODS The dataset of 1246 eligible patients enrolled in the study between April 2002 and May 2008 was analyzed. The patients were assigned into five categories; SR (PGR, age between 1 and 9 years, WBC RESULTS ETV6-RUNX1 and hyperdiploidy were significantly less frequent in adolescents. The rates of PGR and CR on day 33 in adolescents were significantly lower than those in younger patients (82.7% vs. 90.5%, p CONCLUSIONS The results indicated that poorer outcome in adolescents with ALL may not result from severe treatment toxicities, but link with some specific biology of the leukemic cells. Disclosures: No relevant conflicts of interest to declare.