RESUMEN
We reviewed the clinical features and treatment outcome of 110 children with leukemia. Treatment was performed between 1980 and 2009 at our hospital. The mean age at onest was 5 years 6 months, the ratio of males to females was 1:0.72, and mean leukocyte count was 4.91×10<sup>4</sup>/μl. Subtypes of leukemia were acute lymphoblastic leukemia (ALL) in 79.1% of the patients, acute myeloid leukemia (AML) in 17.2%, and chronic leukemia in 3.6%. In all patients, the overall 30-year survival rate estimated by the Kaplan-Meier method was 67.4%. In the three decades from the 1980s, the overall 10-year survival rate has been improved significantly from 46.4% in the 1980s, 69.2% in the 1990s to 87.2% in the 2000s (P<0.01). The overall 10-year survival rate was 70.7% in all children with ALL, and 70.6% in all children with AML. But in the last decade, the 10-year survival rate was improved to 87.0% in children with ALL and 87.3% in children with AML. Twenty-four patients received hematopoietic stem-cell transplantation, and the 10-year survival rate was 58.6% after transplant. Second malignancies were detected in three patients, and six patients have long-term sequelae. In conclusionn, the treatment result of childhood leukemia has improved considerably, so that more intensive treatment for patients with poor prognosis and less toxic treatment for patients with good prognosis will be necessary in future.