Pretreatment flow cytometry of DNA content in adult acute leukemia

Flow cytometric analyses of bone marrow cellular DNA content were performed in 115 adult patients with acute leukemia to assess whether and how proliferative activity relates to other disease and host parameters, to antileukemic effect of induction chemotherapy, and to patient prognosis. Eighty previously untreated patients had a smaller S-phase compartment than patients with morphologically normal bone marrow and than 35 patients studied in leukemic relapse. Among previously untreated patients, those with AML had a smaller S-phase compartment than patients with ALL. Hypodiploid leukemias had a higher G₂M proportion than other cytogenetic categories, while lowest S and G₂M phases were seen in patients with inevaluable metaphases. Pretreatment S-phase compartment size correlated positively with degree of bone marrow blast cytoreduction during the first 8 days of induction treatment, but not with complete remission or with response duration. Magnitude of cytoreduction, however, correlated with complete remission, response duration, and survival. The pretreatment S-phase compartment size was a prognostic determinant only in patients with low cytoreduction. There was an inverse correlation between S-phase compartment size and number of courses to complete remission. The authors' study suggests that the percentage of pretreatment bone marrow cells in S phase is predictive for rate of cell kill and number of courses necessary for remission, but not for attainment of complete remission.