Prevalence of MDS in Shanghai, China Using the WHO Classification.

The prevalence of subgroups of myelodysplastic syndrome (MDS) was determined in an unselected series of 92 patients presenting at Shanghai hospitals over a 10 month period. Diagnosis was established in a single laboratory, analyzing morphologic, immunophenotypic, fluorescence in situ hybridization (FISH) and cytogenetic data, according to the World Health Organization (WHO) revised classification. The frequencies of the major MDS subgroups were: refractory anemia (RA) 9.7%, refractory anemia with ringed sideroblasts (RARS) 1%, refractory anemia with excess blasts (RAEB) 15.2%, refractory cytopenia with multilineage dysplasia (RCMD) 52.6%, and MDS-unclassifiable (MDS-u) 7.6%. The subgroup, myelodysplastic/myeloproliferative diseases, unclassifiable (MDS/MPD-u) (9.7%) was also included for comparison with other studies. The median age at diagnosis for all cases was 57 yr. Males slightly predominated (53%). The overall incidence of clonal cytogenetic abnormalities was 24.7%. The most frequently encountered lesions were trisomy 8, 20q-, 5q- and 7q-. The prevalence of clonal cytogenetic abnormalities in each subgroup differed significantly from none in RA to 31% in RCMD. Deletions involving 5q- and 7q- were found predominantly in RAEB and RCMD subgroups. The incidence of MDS in China has been reported to be less than that in the West. However, information on the frequency of different subgroups of MDS in Shanghai previously has not been available. These cases presented at 24 hospitals serving a population of approximately 18 million. These results suggest major differences in the presentation and frequency of different subgroups of MDS between China and the West.