The significance of trisomy 8 in de novo acute myeloid leukaemia: the accompanying chromosome aberrations determine the prognosis. German AML Cooperative Study Group.

Trisomy 8 is the most frequent numerical chromosome aberration in acute myeloid leukaemia (AML). It occurs either as the sole anomaly or together with other clonal chromosome aberrations. We investigated whether accompanying chromosome anomalies influence the clinical outcome in patients with trisomy 8 and de novo AML. Since 1986, in 713 AML cases treated according to the protocols of the German AMLCG trials, chromosome analyses have been successfully performed. The overall incidence of trisomy 8 was 7.6%. Complete clinical follow-up data were available for 51 patients who were divided into three different categories: group 1: trisomy 8 as the sole cytogenetic anomaly (n = 20); group 2: trisomy 8 in addition to favourable chromosome aberrations (t(8;21)(q22;q22), t(15;17)(q22;q21), inv(16)(p13q22)) (n = 10); and group 3: trisomy 8 accompanied by other anomalies, in most cases of complex type (n = 21). Complete remission (CR) rates were 70%, 90% and 67% for groups 1, 2 and 3, respectively. Event-free survival (EFS) at 3 years differed significantly between patients with trisomy 8 only (37.5%), patients with trisomy 8 in combination with favourable aberrations (55.0%) and patients with trisomy 8 and other accompanying anomalies, mostly complex chromosome aberrations (9.0%) (group 1 v group 2: P=0.12; group 1 v group 3: P=0.005; group 2 v group 3: P=0.05). In this study patients with +8 as the sole cytogenetic anomaly had an intermediate prognosis, patients with +8 in addition to favourable chromosome aberrations maintained a good clinical outcome, and patients with +8 in combination with other abnormalities showed the worst prognosis.