KARYOTYPE IN MYELODYSPLASTIC SYNDROMES - RELATIONS TO MORPHOLOGY, CLINICAL EVOLUTION, AND SURVIVAL

One hundred eighty-eight unselected consecutive patients with ''de nov o'' myelodysplastic syndrome (MDS) were studied cytogenetically. They were subclassified as 4 refractory anemia with ringed sideroblasts (RA RS), 67 refractory anemia (RA), 58 refractory anemia with excess of bl asts (RAEB), 40 RAEB in transformation (RAEB-t), and 19 chronic myelom onocytic leukemia (CMML). The overall incidence of chromosome abnormal ities was 69%. The RAEB and RAEB-t patients showed karyotypic changes, more often than RA and CMML (76% and 100% vs. 56% and 42%, respective ly). The most frequent single anomaly was del(5)(q13-q22q33) (22 cases ), followed by monosomy 7 or del 7q (11 cases), del(11) (q14q23) (8 ca ses), trisomy 8 (4 cases). Complex karyotypes (defined by the presence of three or more structural or numerical abnormalities) were detected in 33 patients. With regard to the FAB classification, del (5)(q13q33 ) was associated with RA, and complex rearrangements with RAEB and RAE B-t Leukemic transformation occurred in 66 patients (46%), none with a normal karyotype or del(11)(q14q23) as single abnormality. In patient s carrying 5q- alone, acute evolution correlated with proximal breakpo int localization, being found in no case with del(5)(q13q33) but in th ree out of four cases with del(5)(q22q33). Acute leukemia (AL) progres sion happened in all cases with complex rearrangements and monosomy 7 or del(7q). Two of the four trisomy eight patients evolved in AL. By u sing the Cox proportional hazard regression analysis it was demonstrat ed that the karyotype abnormality was a significant predictor of leuke mic transformation (P < 0.001). Patients with abnormal karyotypes with out complex abnormalities had a survival (median survival 12 months) s horter than that of cases with only normal metaphases (median 83 month s) (P < 0.001); patients with a mixture of normal/abnormal metaphases had a median survival of 31 months. The median survival for complex ka ryotypes was 7 months. Among cases with single defects, del(5)(q13q33) showed the best survival (64 months), monosomy 7 and del (7q) the wor st (7 months) (P < 0.001). (C) 1994 Wiley-Liss, Inc.