Prognostic significance of the revised French-American-British classification for acute lymphocytic leukaemia.

The French-American-British (FAB) classification of acute lymphocytic leukaemia (ALL) has recently been modified to improve its reproducibility. We therefore thought it beneficial to test the utility of this modified classification in the prognosis of children with ALL. Eighty-eight patients of less than 18 years of age with ALL were subtyped according to the modified FAB classification by two independent observers. The initial concordance was 86%. Seventy per cent of the patients were subtyped as L1, 27% as L2 and 3% as L3. Patients with L3 subtype were not analysed further. No significant differences were observed between L1 and L2 subtypes when the distribution of other prognostic factors were examined. No differences were observed between L1 and L2 subtypes in the achievement of complete remission. Patients with L1 morphology demonstrated no significant increased duration of first remission or survival when compared to patients with L2 morphology. We conclude that the morphology of lymphoblasts may not be an independent prognostic variable in patients with ALL.