Unsuccessful diagnostic cytogenetic analysis is a poor prognostic feature in acute myeloid leukaemia

Chromosome banding analysis is the gold standard method for the identification of recurrent cytogenetic abnormalities in acute myeloid leukaemia (AML). It allows stratification of AML patients into subgroups with distinct responses to therapy and survival. Unfortunately, a variety of issues hamper cytogenetic evaluation in c. 10% of cases [unsuccessful cytogenetics (UC)] and the outcome of these patients is poorly understood. To better define the significance of UC in patients with AML, we compared the baseline characteristics and the prognostic impact of 94 (6%) patients, whose standard metaphase analysis yielded unacceptable results, to the remaining 1403 AML patients with successful cytogenetic analysis treated on successive Southwestern Oncology Group protocols. The incidence of UC increased with age, with peak incidence in patients older than 60 years. These patients had a lower response rate to induction chemotherapy (complete remission rate of 43%) and dismal 5-year survival rates (16%), which was especially poor in patients older than 60 years (<5%). The complete remission and survival rates were similar to those seen in patients with unfavourable karyotype. The early death rate was not increased. These results suggest that UC increases with age and predict for poor outcomes, similar to the outcomes of patients with unfavourable karyotype.