Pediatric Myelodysplastic Syndrome in Korea: Clinical Characteristics and Comparison of Prognostic Scoring Systems

Kook, Hoon; Kim, Moon Kyu; Ghim, Thad T; Moon, Hyung Nam; Park, Kyung Duk; Park, Hyun Jin; Seo, Jong Jin; Shin, Hee Young; Ahn, Hyo Seop; Lee, Kun Soo; Lee, Kwang Chul; Lee, Soon Yong; Lee, Young Ho; Hwang, Pyoung Han; Hwang, Tai Ju

Abstract

PURPOSE
Myelodysplastic syndromes (MDS) are heterogeneous clonal stem cell disorders characterized by morphological and functional abnormal hematopoiesis, resulting in cytopenias in the peripheral blood. MDS in children are very rare and their clinical characteristics, natural history, the most effective treatment and prognostic factors need to be elucidated. In addition, consensus for the classification of pediatric MDS has not been reached yet. This multicenter, retrospective study aimed to describe the characteristics and the disease courses of 75 MDS patients from 11 University Hospitals in Korea, seen between 1991 and 2001. METHODS: Kaplan-Meier probability of leukemic transformation and overall survival were plotted. And the usefulness of prognostic scoring systems, including French-American-British (FAB) classification, Bournemouth scoring system (BSS), and International Prognostic Scoring System (IPSS) in the prediction of transformation to acute myelogenous leukemia (AML) and overall survival was evaluated. RESULTS: The median age was 65 months (2~175 months) and the sex ratio was 2.6: 1 (M: F). Fourteen patients (18.7%) were unable to be allocated into any subtype of FAB. The frequency of FAB subtypes in Korea was similar to that of Western countries except for higher proportion of refractory anemia (RA, 47.5%). Median survival was 54 months with Kaplan-Meier 5-yr survival probability of 31.9% and 2-yr probability of transformation to AML was 23.7%. None of the FAB, BSS, and IPSS was capable of discriminating subgroup of patients for the prediction of survival. However, all of the FAB (P=0.004), BSS (P=0.001), and IPSS (P=0.02) were able to subdivide subgroups for the prediction of transformation to AML. CONCLUSION: The characteristics of pediatric MDS in Korea were different from those of other countries, in light of the higher proportion of RA, the low percentage of inherited diseases, and the low percentage of cytogenetic abnormalities. However, the reasons of the differences were not clear. Moreover, none of the prognostic scoring systems, including IPSS, was reliably predictive of survival, reflecting differences from adult cases. With this multicenter study, we suggest the necessity of a prospective study for the classification and treatment. A newer, effective method should be developed for the prediction of disease progression and survival in pediatric MDS.