Features affecting outcome during remission induction of acute myeloid leukaemia in 619 adult patients.

Six hundred and nineteen patients with de novo acute myeloid leukaemia, entered into the Medical Research Council's eighth trial of therapy have been studied. All patients were treated with the same remission induction regimen. Pretreatment variables comprising age, clinical status, haematological status and a detailed marrow cytology and cytochemistry score have been analysed. Poorer remission rates have been found in older patients, in those with lower Karnofsky scores and in patients with a platelet count of less than 25 X 10(9)/l. Leukaemias showing evidence of cytoplasmic maturation along the granulocyte and monocyte lines, as evidenced by granules, Auer rods, a high percentage of Sudan black positive blast cells and morphological and cytochemical abnormalities of neutrophils were associated with a higher remission rate. Marrow eosinophilia was a good prognostic feature. Nuclear features of immaturity, i.e. increasing numbers and prominence of nucleoli were associated with a low remission rate. Abnormalities of the erythroid series, notably Periodic acid-Schiff positivity which was present in 133 cases (22% of the total), was associated with a low remission rate. Patient age and pretreatment Karnofsky score were the most useful predictors of treatment outcome.