Outcomes and prognostic factors of Chinese children with acute lymphoblastic leukemia in Hong Kong: Preliminary results

Background. The Chinese population is the biggest ethnic group in the world. However, there are few reports on the treatment outcome of childhood acute lymphoblastic leukaemia(ALL) among the Chinese population. Procedure. Sixty-five children with ALL were treated with a modified protocol of the Medical Research Council United Kingdom Acute Lymphoblastic Leukaemia protocol X(MRC UKALL X) at the Prince of Wales Hospital, Hong Kong. Most patients were ethnic Chinese. They were divided into groups A and B, depending on whether their presenting leucocyte count being was less or greater than 50 x 10 9 /1, respectively. Group A patients of received induction, early intensification (week 5), cranial irradiation, and maintenance for 3 years. Group B patients received an additional late intensification (week 20). Results. The median follow-up duration was 6.8 years(range: 3.4-10.1 years). The event-free and overall survival rates of all patients at 7 years were 66% (confidence interval ICI( 53-76) and 75% (Cl 63-84), respectively. The event-free survival rates of groups A and B at 7 years were 67% (Cl 52-79) and 60% (Cl 32-80), respectively (P= 0.39). The overall survival rates of groups A and B at 7 years were 80% (Cl 66-89) and 60%(Cl 32-80), respectively (P = 0.07). With this treatment protocol, the factors which adversely affected the outcome were age ( 10 years) and T-cell subtype. Sex, white blood count at diagnosis, and FAB subtypes were not statistically significant prognostic factors. Conclusions. The treatment outcomes were comparable with those reported from the MRC UKALL X trials.