High‐risk childhood acute lymphoblastic leukemia in China: Factors influencing the treatment and outcome

Abstract

Acute lymphoblastic leukemia (ALL) with high-risk features has an inferior outcome. Factors influencing the treatment and outcome of pediatric ALL with high-risk features in developing countries have not been well studied. High-risk features were defined as: age <1 year or >10 years, white blood cell (WBC) > 50 x 10(9)/L, CNS or testicular involvement at diagnosis, T-ALL, BCR-ABL/MLL-AF4, poor prednisone response, slow early response to induction chemotherapy which was defined as M3 status (>25% blasts) on day 15 bone marrow with age >6 years or presenting WBC > 20 x 10(9)/L at diagnosis and/or non-remission (NR) after 33 days of induction therapy. Ninety-one children were analyzed. The total rate of treatment abandonment was 24.2% and treatment-related mortality was 3.3% (3/91). The event-free survival (EFS) was 52.3% (95% CI, 41.5-63.1%) at 4 years and 49.9% (95% CI, 38.9-60.9%) at 8 years, respectively. When the cases who abandoned treatment were excluded, the EFS of the remainder was 68.3% (95% CI, 56.5-80.1%) at 4 years and 65.2% (95% CI, 52.5-77.9%) at 8 years, respectively. NR on day 33 or BCR-ABL remained as an independent unfavorable prognostic factor in the Cox model even if more intense chemotherapy was administrated. A decreased treatment-related death frequency was associated with an improved outcome of leukemia. This emphasizes the importance of improving supportive care in developing countries for children with high-risk ALL who receive very intensive chemotherapy. Treatment abandonment remains a prominent reason for treatment failure in China.