Outcome of a Risk-Adapted Treatment for Childhood Acute Lymphoblastic Leukemia in Thailand.

Abstract

Acute lymphoblastic leukemia (ALL) is the most curable cancer in children. In developing country with limited resource and manpower like Thailand, where 3 pediatris hematologists take care of 100 new cancer children per year, it is a challenge to achieve satisfactory outcome. We treated ALL according to a risk-adapted modified CCG-105 protocols (standard or intensive induction of remission, consolidation, 1800 cGy CNS radiation, and maintenance therapy with or without delayed intensification, DI) since 1988. We reported here the outcome of childhood ALL treated with this protocol between 1997–2004. 181 children with newly-diagnosed ALL in this period were classified into B-precursor, or T-cell ALL by immunophenotyping with flow cytometry. B-precursor ALL were classified as low risk group (age 1–10 yr and initial white cell count (WBC) <20,000/μl), standard-risk (age 1–10 yr and WBC between 20,000–50,000/μl) and high-risk (age >10 yr or WBC >50,000/μl). The low-risk group were assigned to protocol B (CCG-105 standard induction without DI, n=69). The standard- and high-risk group were assigned to protocol C (CCG-105 intensive induction with DI, n=71). All T-cell ALL (n=21) were assigned to a T-cell protocol (DFCI 85-01 high-risk group) which includes high-dose methotrexate and asparaginase. Infantile ALL (n=9), mature B-cell ALL (n=3), a child with t(1;19), and 5 children who refused treatment or received other protocols of treatment were excluded from analysis. The remission rates were 98.5% for protocol B, 92.4% for protocol C, and 83.3% for T-cell disease. All remission failure were attributed to early deaths. The 5-yr event-free survival (EFS ±95% confidence interval) was 83.1 ± .7% for low-risk group treated with protocol B, 75.9 ± 6.0% for protocol C, and 68.6 ± 12.1% for T-cell ALL. These outcomes are significantly higher than our previous report. (Nuchprayoon I, Songnui T, Vanichsetakul P, Seksarn P. Treatment of childhood acute lymphoblastic leukemia in Thailand- outcome and cost analysis. Blood 96 (11 suppl 1): 435a) and can be attributed to a better risk classification, more intensified treatment for standard-risk group and T-cell ALL, and better supportive care. Satisfactory outcome of childhood ALL can be achieved in developing country with risk-adapted treatment strategy. [Display omitted]