OBJECTIVETo compare the results of cytogenetic and IPSS grouping of primary myelodysplastic syndromes (pMDS) patients classified by FAB- or WHO classification.

METHODSTwo hundred and thirty seven cases of pMDS who were previously classified according to FAB criteria were reclassified with WHO classification. A comparison was made between the results of the two classifications.

RESULTSFor the detection rates of cytogenetic abnormality and its risks group, there was no difference among the FAB subgroups but the detection rate was different between the WHO refractory cytopenia with multilineage dysplasia (RCMD) and RA subgroups (74.4% and 42.5%, respectively) (P < 0.001). The percentage of good karyotype abnormalities in RA (65.0%) was higher than that in RCMD (24.4%) (P < 0.001), and the percentages of intermediate and poor karyotype abnormalities in RCMD (48.9% and 26.7%, respectively) were higher than that in RA (27.5% and 7.5%, respectively) (P < 0.05). There was a good correlation between the subgroups and IPSS risk groups for both the WHO classification and the FAB classification, but the WHO classification further reflected the differences between RCMD and RA and RAEB-I and RAEB-II subgroups. The percentage of low-risk group in RCMD (1.1%) was lower than that in RA (10.0%) (P < 0.05), and the percentage of high-risk group in RAEB-II (30.5%) was higher than that in RAEB-I(0) (P < 0.001).

CONCLUSIONFor the correlation between subgroups and cytogenetic abnormalities and IPSS risk groups, the WHO-classification is better than the FAB-classification.