The Association between Cytogenetic Abnormalities and Clinical Outcomes Based on Prognostic Factors of the Children Cancer Group (CCG) in Pediatric Patients with Acute Leukemia: Two Institutional Retrospective Studies

ABSTRACT

BACKGROUND: We investigated the incidence of cytogenetic abnormalities as well as the correlation of the cytogenetic abnormalities and clinical outcomes based on the prognostic factors of the Children Cancer Group (CCG) in children with acute leukemia. METHODS: We retrospectively reviewed the cytogenetic studies and clinical data from 99 children that were diagnosed with acute leukemia and treated with CCG regimens in two institutions. A conventional cytogenetic analysis was performed. RESULTS: The incidence of cytogenetic abnormalities was 51 (51.5%) in 99 patients, and 27 (39.7%) in acute lymphoblastic leukemia (ALL) patients and 24 (77.4%) in acute myelogenous leukemia (AML) patients. The most frequent cytogenetic abnormality was hyperdiploidy and t(821) in the ALL and AML patients, respectively. The overall survival rate (OS)/disease free survival rate (DFS) of the ALL patients was 74.0%/73.9%. The OS/DFS of the standard risk group (88.8%/85.2%) was significantly higher than that of the high-risk group (49.4%/39.3%) in the ALL patients (P=0.0005/P<0.0001). There was no significant difference in the survival rates according to the type of cytogenetic abnormalities among the ALL patients for the standard/high risk groups, based on the CCG prognostic factors. The OS/DFS of the AML patients were 43.4% and 41.7%, respectively, without significant differences of the survival rates according to the type of chromosomal abnormalities. CONCLUSION: There were significant differences of OS/DFS based on the risk groups in ALL patients when evaluated with the CCG prognostic factors (standard/high) and chromosomal abnormalities (good/ poor), respectively. However, there was no significant correlation between type of cytogenetic abnormalities and clinical outcomes based on the CCG prognostic factors in children with ALL as well as with AML.