Treatment of de novo acute myeloid leukaemia in Hong Kong: a twenty-year experience (1975 to 1996)

Background : Small patient numbers and short follow-up are common in some acute myeloid leukaemia (AML) studies and data on secondary malignancies after treatment of AML are rare.
Aims : To determine the prognostic factors and long-term treatment results.
Methods : A retrospective study of patients with de novo AML under the age of 60 over a 20-year period in which two induction therapy regimens: 7:3 (1975–1983) and 7:3:7 (1984–1996) and three consolidation chemotherapy regimens: 5:2 (1975–1983), 5:2:5 (1984–1990) and Ara-C/mitoxantrone (1991–1996) were used. Disease-free (DFS), overall survivals (OS) and prognostic factors were analysed.
Results : Two-hundred and two of 276 (73%) patients attained complete remission (CR). The CR rates of 7:3 and 7:3:7 regimens were 70.5% and 74.5% respectively ( p =0.92). The median DFS was 12 months and the projected DFS at 10- and 20-years were 23% and 21% respectively. For patients consolidated with 5:2, 5:2:5 and Ara-C/ mitoxantrone, the median DFS was 15 m, 12 m and 11 m respectively and the projected ten-year DFS were 27%, 21% and 18% respectively ( p =0.2). Ninety per cent of relapses occurred within two years from remission but there were two late relapses at 109 m and 120 m respectively. Young age and FAB M3 subtype were favourable prognostic factors to OS ( p =0.04) and DFS ( p =0.006) respectively. There was no secondary solid tumour in the long-term survivors.
Conclusion : Our experience confirmed the efficacy of standard-dose Ara-C/daunorubicin and the prognostic value of age and FAB subtype. Median and projected DFS were similar to western studies.