Fourth International Workshop on Chromosomes in Leukemia 1982: Clinical significance of chromosomal abnormalities in acute nonlymphoblastic leukemia.

Seven hundred sixteen newly diagnosed patients were studied, to determine the clinical significance of chromosome analysis in ANLL. Karyotypes were classified in two ways. Cases were grouped into three categories, based on the presence of normal and abnormal metaphases. Cases were grouped into 12 categories based on more specific chromosome abnormalities (modified Chicago Classification). Both methods of classifying karyotypes, but especially the Chicago Classification, resulted in groups of patients with de novo ANLL with significantly different presenting clinical and hematologic features, including FAB type, leukocyte count, percent peripheral myeloblasts, platelet count, and DIC. Among patients with de novo ANLL, karyotypes, when classified according to the Chicago Classification, significantly correlated with frequency of initial complete remission and survival; the presence of normal and abnormal metaphases correlated with duration of first remission and survival. Among 305 intensively treated patients, the Chicago Classification also correlated with duration of first remission. Although both ways of classifying karyotype correlated with survival, even when other major risk factors in ANLL were considered, only the Chicago Classification was an independent prognostic factor among the intensively treated patients.