Growing Evidence for an Underestimation of Poor-Risk Cytogenetics in the International Prognostic Scoring System in Myelodysplastic Syndromes

The International Prognostic Scoring System (IPSS) for myelodysplastic syndromes (MDS) identifies bone marrow (BM) blasts, cytogenetics, and the number of cytopenias as major variables with impact on disease outcome. Weighting of these variables defines distinct subgroups using multivariate analysis approaches. Recent studies, including the work of our group, indicate an underestimation of unfavorable cytogenetics in the IPSS. To delineate the prognostic impact of poor-risk karyotypes in relation to blast counts, we studied clinical outcome of cytogenetic and blast count subgroups in a large cohort of 1440 patients with MDS. Using univariate analytic tools, median survival times of 158 patients with poor-risk cytogenetics and 66 patients with blast counts of > 20% were 11.1 months and 9 months, respectively. Median survival times of patients with poor-risk cytogenetics and normal blast counts (n = 60; median survival, 17 months) were not significantly different from those of good-risk karyotypes and highly elevated BM blasts (11%–20%: n = 89; median survival, 22 months; P = .098; > 20%: n = 32; median survival, 13 months; P = .892). Our data indicate an equal prognostic significance of poor-risk cytogenetics compared with highly elevated BM blasts and suggest a higher score for unfavorable karyotypes in future integrative prognostic systems in MDS.