Results of aggressive chemotherapy for acute nonlymphoblastic leukemia in adults

Sixty-five patients with acute nonlymphoblastic leukemia, ranging in age from 16 to 73 years (median, 54), were treated with thioguanine, cytarabine, daunorubicin, prednisone, and vincristine to induce complete remission. Remission was maintained with monthly 5-day courses of cytarabine and thioguanine for 4 years. Of the entire group, 57% achieved complete remission and 29% died in the first 30 days of treatment. The median remission duration was 15 months, with 20% of the complete responders predicted to remain in complete remission for 4 years. No primary central nervous system relapses have occurred. Of six variables examined by multivariate analysis, only age was predictive of remission success. Before analysis, the patients were divided into groups by age: group 1--ages 16-42 years (n = 17); group 2--ages 43-59 years (n = 25); and group 3--ages 60-73 years (n = 23). Complete remission rates were 76% in group 1, 64% in group 2, and 35% in group 3 (P = 0.002). Lower remission rates for older patients resulted from more early deaths rather than resistant disease. Age and LDH levels affected remission duration. The median complete remission duration was 48 months in group 1 and 10 months in groups 2 and 3 (P = 0.004). In group 1, 41% of patients achieving complete remission are predicted to remain in complete remission for 4 years. We concluded that this five-drug induction regimen is highly effective for induction therapy in younger adults with acute nonlymphoblastic leukemia. The results in patients greater than or equal to 60 years of age are less satisfactory due to a lower remission rate and greater chance of early death. Furthermore, these results demonstrate that the program as described results in a longer duration of complete remission for patients of younger age.