INTERNATIONAL SCORING SYSTEM FOR EVALUATING PROGNOSIS IN MYELODYSPLASTIC SYNDROMES

Despite multiple disparate prognostic risk analysis systems for evalua ting clinical outcome for patients with myelodysplastic syndrome (MDS) , imprecision persists with such analyses. To attempt to improve on th ese systems, an International MDS Risk Analysis Workshop combined cyto genetic, morphological, and clinical data from seven large previously reported risk-based studies that had generated prognostic systems. A g lobal analysis was performed on these patients, and critical prognosti c variables were re-evaluated to generate a consensus prognostic syste m, particularly using a more refined bone marrow (BM) cytogenetic clas sification. Univariate analysis indicated that the major variables hav ing an impact on disease outcome for evolution to acute myeloid leukem ia were cytogenetic abnormalities, percentage of BM myeloblasts, and n umber of cytopenias; for survival, in addition to the above, variables also included age and gender. Cytogenetic subgroups of outcome were a s follows: ''good'' outcomes were normal, -Y alone, del(5q) alone, del (20q) alone; ''poor'' outcomes were complex (ie, greater than or equal to 3 abnormalities) or chromosome 7 anomalies; and ''intermediate'' o utcomes were other abnormalities. Multivariate analysis combined these cytogenetic subgroups with percentage of BM blasts and number of cyto penias to generate a prognostic model. Weighting these variables by th eir statistical power separated patients into distinctive subgroups of risk for 25% of patients to undergo evolution to acute myeloid leukem ia, with: low (31% of patients), 9.4 years; intermediate-1 (INT-1; 39% ), 3.3 years; INT-2 (22%), 1.1 years; and high (8%), 0.2 year. These f eatures also separated patients into similar distinctive risk groups f or median survival: low, 5.7 years; INT-1, 3.5 years; INT-2, 1.2 years ; and high, 0.4 year. Stratification for age further improved analysis of survival. Compared with prior risk-based classifications, this Int ernational Prognostic Scoring System provides an improved method for e valuating prognosis in MDS. This classification system should prove us eful for more precise design and analysis of therapeutic trials in thi s disease. (C) 1997 by The American Society of Hematology.