Cell kinetics with in vivo bromodeoxyuridine and flow cytometry: Clinical significance in acute non-lymphoblastic leukaemia

From 1986 to 1988, 54 consecutive previously untreated patients with acute non-lymphoblastic leukaemia (ANLL), median age 54 years, were treated for remission (CR) induction with vincristine and intravenous medium-dose cytarabine sequentially followed by daunomycin and infusion cytarabine. CR patients received intensive consolidation. Bone marrow blast kinetics was studied before therapy with in vivo bromodeoxyuridine and bivariate flow cytometry. CR rate was 70.2%, median CR was 13.2 months, responsive patient survival was 16.9 months and overall survival was 9.2 months. Besides lower median age, the 33 responsive patients also had shorter potential doubling time (T_pot) and greater cell production rate (PR) than the 14 unresponsive patients (mean values = 10.9 vs. 25.4 days, P <0.05, and 14.7 vs. 8.9 cells/100 cells/day, P <0.02, respectively), due to a higher mean labelling index (7.0 vs. 5.1%, P <0.05) and/or to a shorter mean DNA synthesis time (13.6 vs. 18.6 hours, P <0.05). Besides lower white blood cell count and bone marrow blast percentage, patients who experienced CR longer than 13.2 months had shorter T_pot (P <0.05) and a greater PR (P <0.02) than those who relapsed before this time. These data indicate that kinetic parameters have prognostic relevance in ANLL patients treated with sequential vincristine, cytarabine and daunomycin for inducing CR and with intensive consolidation after CR, a high proliferative activity being a favourable factor for both CR achievement and its duration.