Chromosomal abnormalities in 478 children with acute myeloid leukemia: Clinical characteristics and treatment outcome in a cooperative pediatric oncology group Study - POG 8821

We determined the type and frequency of chromosomal aberrations in leukemic cells of 478 children diagnosed with acute myeloid leukemia and enrolled i n the Pediatric Oncology Group study 8821. Of the 478 cases, 109 (22.8%) ha d normal karyotypes. Chromosomal abnormalities of 280 patients (58.6%) were classified into subgroups: 11q23 abnormalities (n = 88, 18.4%), t(8;21) (n = 56, 11.7%), t(15;17) (n = 55, 11.5%), inv(16)/t(16;16) (n = 28, 5.9%), t risomy 8 alone (n = 10, 2.1%). monosomy 7 (n = 9, 1.9%), non-Down-associate d trisomy 21 alone (n = 7, 1.5%), and rare recurrent chromosomal translocat ions (n = 27, 5.6%). The remaining 89 patients (18.6%) had miscellaneous cl onal abnormalities. Overall, 84.9% of the children achieved a complete remi ssion; the 4-year event-free survival (EFS) estimate was 33.8% +/- 2.4%. Re mission rates were significantly higher (96.4%, P = .011) for patients with t(8;21) and inv(16)/t(16: 16) but significantly lower (74.5%, P = .022) fo r those with t(15;17). The 4-year survival rate for all patients was 43.5% +/- 2.4%; for those with an inv(16)/t(16;16), 75.0% +/- 8.6%; a normal kary otype, 53.8% +/- 4.9%; a t(8;21). 51.6% +/- 7.3%; a t(15;17), 39.8% +/- 6.9 %; and an 11q23 abnormality, 32.9% +/- 5.1%. Four-year EFS estimates for pa tients with inv(16)/t(16; 16) (58.2% +/- 10.9%. P = .007), t(8;21) (45.1% /- 7.7%, P = .014), or normal karyotypes (43.1% +/- 5.0%, P = .012) were hi gher than the 4-year EFS estimate for all patients, but EFS estimates for p atients with t(15;17) (19.6% +/- 8.0%, P = .033) or 11q23 abnormalities (23 .8% +/- 4.8%, P = .0013) were lower. EFS estimates did not differ significa ntly among 11q23 subgroups. Limited analysis suggested that patients with i nv(16) can be salvaged better following relapse than those with t(8;21). Th us, patients with an inv(16)/t(16;16) may have high survival rates when tre ated with chemotherapy alone. (C) 1999 by The American Society of Hematolog y.