Acute myeloid leukaemia in childhood: clinical features and prognosis.

Clinical and laboratory features at presentation were correlated with morphological (FAB) subclass of AML in a group of 112 children diagnosed between 1972 and 1982. Patients with a monocytic component of AML (M4, M5) had higher initial leucocyte counts, a higher incidence of extramedullary infiltration and of CNS involvement. In M4 AML CNS relapse occurred in patients with a high initial leucocyte count whereas in M5 AML CNS involvement tended to occur at presentation in children with low initial counts. Two-thirds of patients treated achieved remission and most failures were due to inadequate chemotherapy, although haemorrhage, leucostasis or metabolic complications caused early death in patients with M4 and M5 AML. With a minimum follow up of 3 years only 12% of patients are alive; these figures have not improved in consecutive series despite increasing intensity of induction and more recent availability of bone marrow transplantation. No features predictive of long-term survival were identified, but patients with myeloid differentiation (M1, M2, M3) did better than those with a monocytic or erythroid component (M4, M5, M6). The proportion of patients with AML curable by chemotherapy seems unlikely to increase without marked intensification of post-remission chemotherapy. More aggressive CNS prophylaxis may be of benefit in cases with a monocytic component.