Abstract • 22

Recent development of the International Prognostic Scoring System (IPSS) has provided an improved risk-based classification for adult MDS patients in comparison with prior methods (Blood 89:2079, 1997). Major features of this system are: (1) Consistent clinical characterization, including central morphologic classification based on the FAB system; marrow dysplasia in ≥2 hemopoietic cell lines with blast % enumerated; clinical stability for ≥4 weeks; exclusion of 'proliferative' CMML patients (WBC ≥12,000/µl). (2) Refined marrow cytogenetic classification: Poor (i.e., complex or chromosome 7 anomalies), Good (Normal, -Y, 5q- or 20q- alone) or Intermediate (other) categories. (3) Statistically combining features demonstrated by multivariate analysis to be independently significant (% marrow blasts, cytogenetics category, number of cytopenias) separated patients into 4 distinctive risk groups. In this context, a number of the current pediatric MDS classifications will be discussed. As difficulties persist in evaluating clinical outcome in pediatric MDS, it is suggested that an International Risk Analysis Workshop be convened combining data from well characterized pediatric MDS patients, utilizing the above or similar methods (e.g., also stratifying for congenital vs acquired MDS & age, exclusion of 'proliferative' JMML patients, analysis of Hb F levels) to determine which critical variables impact significantly on clinical outcome. Following this analysis, a consensus system attempting to improve prognostic classification for pediatric MDS should be generated. Such a system may prove useful for more precise analysis and design of treatment options for these patients.