Clinical classification and evaluation of treatment response in acute myeloid leukaemia on the basis of differences of leukaemic cell differentiation.

Abstract

A simple rating system is proposed in which 3 levels of increasing differentiation ‐ ‘A’, ‘B’, and ‘C’ ‐ are defined for the leukaemic cells in acute myeloid leukaemia. Using this rating system a series of 31 patients with acute myeloid leukaemia could be divided into an ‘A’‐group of 12 cases, a ‘B’‐group of 10 cases, and a ‘C’‐group of 9 cases.A statistically significant association was found between high leucocyte counts and low degree of leukaemic cell differentiation, and vice versa. The occurrence of the ‘C’‐cases exclusively in patients over 48 years of age differed significantly from that seen for the ‘A’‐cases, the latter being evenly distributed throughout all age groups. Observation of leukaemic cell maturation during treatment suggests that the appearance of more highly differentiated leukaemic cells as well as a reduction of the leukaemic cell mass represents a positive response to treatment. Thus, the proposed rating system may be more sensitive to marginal therapeutic benefits than conventional rating systems.