Refined chromosome analysis as an independent prognostic indicator in de novo myelodysplastic syndromes.

In a study of 56 consecutive adult patients with de novo myelodysplastic syndromes (MDS), all cases were successfully analyzed with two refined chromosome banding techniques. Most patients (44 of 56, 79%) were found to have a chromosome defect. The majority of these patients had a recurrent loss of chromosomal material rather than a reciprocal translocation or inversion, as commonly found in acute leukemia. The three largest chromosomal categories found were associated with a wide range of survival. Twelve patients (21%) had normal chromosomes, a stable clinical course, and long survival (median follow-up time of 49 months, with all patients alive). Nine patients had in common a single chromosome defect resulting in either monosomy 7 or deletion 7q. They had a median survival of 12 months, and four died of acute nonlymphocytic leukemia (ANLL). Of 12 patients with complex defects, 11 had a complete or partial loss of a chromosome 5 and a complete or partial loss of the long arm of a chromosome 7 or 20. They had a poor median survival of four months, and six patients died of ANLL. Although the French-American-British (FAB) classification was also found to have some prognostic value, FAB subgroups were chromosomally heterogeneous and showed less dramatic differences in median survival than the larger chromosomal subgroups. We have shown, for the first time, that a refined chromosomal analysis is an independent prognostic indicator in de novo MDS and may be helpful in establishing therapeutic approaches in this difficult group of heterogeneous disorders.