Outcome of Childhood Acute Lymphoblastic Leukemia Treated Using the Thai National Protocols

In recent decades, the prognosis for childhood leukemia has improved, especially for acute lymphoblastic leukemia (ALL). In Thailand, though, the survival rate for ALL is unimpressive. In 2006, standard national protocols for childhood leukemia treatment were implemented. We herein report the outcome of the ALL national protocols and explanations behind discrepancies in outcomes between institutions.

Between March 2006 and February 2008, 486 children with ALL from 12 institutions were enrolled in the Thai national protocols. There were 3 different protocols based on specific criteria: one each for standard risk, high risk and Burkitt's ALL. We classified participating centers into 4 groups of institutions, namely: medical schools in Bangkok, provincial medical schools, hospitals in Bangkok and provincial hospitals. We also evaluated supportive care, laboratory facilities in participating centers, socioeconomics, and patient compliance. Overall and event-free survival were determined for each group using the Kaplan Meier method. Statistical differences were determined using the log-rank test. Previous outcomes of Thai childhood ALL treatment between 2003 and 2005 served as the historic control.

Five-year overall survival of ALL treated using the Thai national protocol was 67.2%; an improvement from the 63.7% of the 12-institute historical control (p-value=0.06). There were discrepancies in event-free survival of ALL between centers in Bangkok and up-country provinces (69.9% vs 51.2%, p-value <0.01). Socioeconomics and patient compliance were key elements in determining the outcome (65.5% vs 47.5%, 59.4% vs 42.9%) (p-value < 0.02).

Implementation of standard national protocols for childhood leukemia in Thailand did not significantly improve the outcome of ALL. Factors leading to better outcomes included (a) improvement of treatment compliance (b) prevention of treatment abandonment and