Prognoses of MDS subtypes RARS, RCMD and RCMD-RS are comparable but cytogenetics separates a subgroup with inferior clinical course

In 2008, the WHO combined the former categories RCMD (refractory cytopenia with multilineage dysplasia) and RCMD-RS (ring sideroblasts ≥15%). We studied the clinical impact and genetic background of RARS, RCMD, and RCMD-RS in 1082 patients. Good karyotypes (IPSS) were similarly frequent in RARS, RCMD, and RCMD-RS. 2-year overall survival (OS) rates were similar in RARS, RCMD, and RCMD-RS (85.9%/89.0%/91.7%; n.s.). The 2-year OS rate was better in good than intermediate or poor karyotypes (p < 0.001). These results support to combine RCMD and RCMD-RS as performed by WHO and emphasize the prognostic power of cytogenetic criteria for these MDS subtypes.