Change in karyotype between diagnosis and first relapse in acute myelogenous leukemia

We compared karyotype at first relapse with presenting karyotype in 212 patients with AML seen at MD Anderson Cancer Center (Houston, TX, USA) between 1975 and 1994. In 38% the karyotypes at diagnosis and relapse were identical. A stable karyotype was most frequent (70%) among patients who presented without cytogenetic abnormalities, suggesting that the finding of a normal karyotype is usually not due to sampling error. In contrast, a finding of insufficient metaphases at diagnosis was repeated at relapse in only 6% of cases. A change in karyotype occurred in 67% of 101 patients who presented with an abnormal karyotype and had sufficient metaphases for evaluation at relapse. The great majority of changes involved clonal evolution, clonal devolution (regression), or both; a purely normal karyotype and unrelated clones were seen in 11 and three of the 101, respectively. Change in karyotype between diagnosis and relapse and type of change were unrelated to remission duration. The only group in which karyotype at relapse vs that at diagnosis had a possible bearing on achievement of second CR were patients who presented with abnormalities other than inv(16), t(8;21) or t(15;17) and who at relapse had only normal metaphases; such patients had higher CR rates than comparable patients who retained their presenting abnormalities.