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

Abstract

7029 Background: The IPSS is applicable only to newly diagnosed patients (pts) with MDS at the time of initial diagnosis. These constitute a small fraction of pts referred to tertiary centers or accrued on research studies. Aims: To develop a prognostic model that addresses problems of the IPSS (e.g. cytogenetic categories, cut offs for cytopenias, prior therapy), that is applicable to any pt with MDS and CMML. Methods: We analyzed 1915 pts with MDS referred to MDACC from 1993 to 2005 (including CMML, secondary MDS, MDS with prior therapy). Only 507 pts (26%) had primary MDS without prior therapy (i.e. patients categorizable by IPSS). Pts were randomly divided into a study (n=958) and a test (n=957) group. Results: The IPSS tested in the total population was prognostic but demonstrated significantly different and worse survivals in the subsets of pts with non-newly diagnosed MDS. Multivariate analysis in the study group identified the following adverse prognostic characteristics: poor performance status (ECOG ≥ 2), older age (cut offs 60 and 65 years), thrombocytopenia (cut offs 30 and 50x109/L), anemia (cut off 12g/dl), increased marrow blasts percent (cut offs 5% and 10%), leukocytosis (cut off 20x109/L), chromosome 7 or complex (more or equal 3 abnormalities), and prior transfusions. Although several factors were part of IPSS, cutoffs for anemia, thrombocytopenia and blasts, and cytogenic subsets, were different. Based on this, an MDS prognostic model was developed that divided pts into four prognostic groups (Table). The model was validated in the test group. Applying the prognostic model within the four IPSS risk groups was highly prognostic in each, regardless of whether pts had primary MDS without prior therapy. Applying IPSS within each of the 4 risk groups of the new MDS model was not prognostic. Conclusion: The new proposed MDS model is more precise than IPSS, and applies to all pts with MDS or CMML regardless or prior therapy or duration of MDS MDS risk group Percent Median Survival (mos) / % 3-year survival Study group Test group Low 16 54/65 45/58 Intermediate 1 24 25/35 23/35 Intermediate 2 24 14/18 13/18 High 36 6/5 6/5 No significant financial relationships to disclose.