Blast cell kinetics and prognosis in acute nonlymphocytic leukemia

Abstract

The prognostic value of marrow blast cell kinetics has been examined in 67 previously untreated ANLL patients. All were treated with a combination of daunorubicin, cytosine arabinoside and 6-thioguanine (DAT). Pretreatment mitotic index (MI) and in vitro 3H-thymidine labeling index (LI) were broadly distributed with median values of 0.2% and 1.5% respectively. The initial MI and LI were not correlated to other variables at diagnosis such as age or peripheral blast count; furthermore, the two kinetic parameters were not found to be related to treatment outcome after therapy with the DAT regimen. In 43 patients the prognostic significance of the drug-induced perturbations of the initial LI has been investigated. A significantly lower response rate was found to occur among those patients who manifested a significant increase of the LI (by 100% or more over the baseline) 72 h after the first course of DAT. In fact 21 of the 33 patients with a decreasing or stable LI in response to therapy achieved complete remission, while only 2 of 10 did so in whom the initial LI rose significantly after therapy ( P < 0.05). We conclude: 1) MI and LI of the marrow blasts at diagnosis are not of practical prognostic value in ANLL; 2) close follow-up of the kinetic perturbations induced in the blast cells by treatment, seems to allow the early identification of patients unlikely to respond to standard chemotherapy in whom different therapeutic approaches should be attempted.