Disease features in acute myeloid leukemia with t(8;21)(q22;g22). Influence of age, secondary karyotype abnormalities, CD19 status, and extramedullary leukemia on survival

Over a period of 14 years, 50 patients (12 children and 38 adults) of whom 46 had acute myeloid leukemia (AML) and 4 had myelodysplastic syndrome char acterized by the t(8;21)(q22;q22) translocation were referred to the Royal Marsden Hospital. The clinicopathological features of these cases were anal yzed to determine the influence of age, secondary karyotype abnormalities, and expression of the lymphoid marker CD19 on event free survival, and pres ence of extramedullary leukemia on overall survival. They were treated with a variety of chemotherapy protocols and some had bone marrow transplantati on. There appeared to be no difference in survival between children (age <1 7 years) and adults (age >16 years). Out of the 50 cases, 16 (32%) had the (8;21) translocation alone, 17 (34%) had additional loss of a sex chromosom e and the remaining 17 (34%) had other karyotype abnormalities of which del etion or translocation of the long arms of a #9 was most common (observed i n 8 of the 17 patients). The karyotype groups had a significant impact on s urvival, the group with loss of a sex chromosome having a poorer outcome an d the group with abnormalities of chromosome 9 having a better outcome. CD1 9 positivity was seen in 21 of the 33 cases (63%) in whom it was measured c ompared to 11% observed in controls with AML without a t(8;21). CD19 status did not exert any influence on event free survival. Extramedullary leukemi a (EML) occurred in 5 of the 50 cases (10%). In one patient it was observed at diagnosis but in the others it presented concurrent with bone marrow re lapse. The overall survival of patients with EML was worse than that of the other patients but did nor achieve statistical significance and was probab ly adversely affected by other factors.