| Summary: | 碩士 === 長榮大學 === 醫學研究所 === 97 === Background
Acute lymphoblastic leukemia, a malignant disorder of lymphoid progenitor cells, affects both children and adults, with peak prevalence between the ages of 2 and 5 years. Approximately 200 children are diagnosed with acute lymphoblastic leukemia each year in Taiwan. Steady progress in development of effective treatments has led to a cure rate of more than 80% in children. The focus of modern treatment protocols for childhood acute lymphoblastic leukemia has turned increasingly to improving the quality of life of long-term survivors. We evaluate the significance of prognostic factors on survival in children with acute lymphoblastic leukemia.
Patients and Methods
From June 2000 to October 2008, 84 children and adolescents, 18 years of age or younger, with newly diagnosed acute lymphoblastic leukemia were enrolled in TPOG (Taiwan Pediatric Oncology Group) protocols for childhood acute lymphoblastic leukemia at Chang-Hua Christian hospital. Sixty-eight of 84 patients were evaluable for the study. Patients were stratified into three risk groups---standard risk (SR), high risk (HR), and very high risk (VHR), based on the presenting clinical features, biologic features of leukemia cells, and initial response to treatments.
Results
There were 47 boys and 21 girls. Median age at diagnosis was 5.3 years with the range of 0.7 to 17.9 years. At a median follow-up of 42.4months (range from 1.2 months to 107.4months), the 5-year overall survival (OS) and event-free survival (EFS) of all patients were 87.2+4.3(SE)% and 86.2+4.3%, respectively. The 5-year EFS was 100% for SR patients (n=21), 90.9+6.1% for HR patients (n=22), and 70.4+9.4% for VHR patients (n=25)(log rank p=0.016).
Age over 10 years at diagnosis, very high risk group, hepatomegaly and splenomegaly, positive Philadelphia chromosome and white blood cell count at diagnosis over 100x109 /L, were significant adverse prognostic factors to EFS. By multivariate analysis applied to the entire cohort, only the age over 10 years at diagnosis was independently associated with an inferior treatment outcome.
Conclusions
In our study, a large number of relapses appear not to be predictable with use of currently available prognostic factors, especially in those with very high risk group. Better identification of biologic defined risk groups and their risk-adapted treatment by incorporating minimal residual leukemia measurement and host pharmacogenetic determination into existing risk classification system may improve the cure rate of patients at true high risk of relapse.
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