Proposal for a new risk model in myelodysplastic syndrome that accounts for events not considered in the original International Prognostic Scoring System

BACKGROUND: Recent studies have highlighted issues with the International Prognostic Scoring System (IPSS) model in relation to the exclusion of many subgroups that now represent a large proportion of patients with myelodysplastic syndrome (MDS) (eg, secondary MDS, chronic myelomonocytic leukemia [CMML] with leukocytosis, prior therapy) and its lack of applicability to most patients on investigational programs, because many would have received prior therapies and would have had MDS for a significant length of time. METHODS: The authors analyzed 1915 patients with MDS who were referred from 1993 to 2005 (including those with CMML, secondary MDS, and MDS with prior therapy). Only 507 patients (26%) had primary MDS without prior therapy (ie, classifiable by the IPSS). Patients were divided randomly into a study group (n = 958) and a test group (n = 957). RESULTS.: A multivariate analysis of prognostic factors in the study group identified the following adverse, independent factors as continuous and categoric values (Por=3) abnormalities, and prior transfusions. Cutoffs for anemia, thrombocytopenia and blasts, and cytogenetic subsets were different according to the IPSS. The new MDS prognostic model divided patients into 4 prognostic groups with significantly different outcomes. The model was validated in the test group. Applying the prognostic score of the new model within the 4 IPSS risk groups, overall, and in patients who had primary MDS without prior therapy was found to be highly prognostic in each subset. Applying the IPSS within each of the 4 risk groups of the new MDS model was not found to be prognostic. CONCLUSIONS: The new model accounts for duration of MDS and prior therapy. It is applicable to any patient with MDS at any time during the course of MDS.