LONG-TERM SURVIVAL OF PATIENTS WITH ACUTE MYELOID-LEUKEMIA - UPDATED RESULTS FROM 2 TRIALS EVALUATING POSTINDUCTION CHEMOTHERAPY

BACKGROUND. Although the prospect of long-term disease free survival ( LFS) after chemotherapy for acute myeloid leukemia (AML) is widely acc epted, few studies have reported long-term survival data. The authors therefore updated results from a 1981 report on a study conducted by t he University of Minnesota Masonic Cancer Center (UMMCC) and a 1989 re port on a study conducted by the North American Marrow Transplant Grou p (NAMTG). METHODS. Minimum follow-up of 21.6 years for living patient s was obtained for 26 patients who received weekly cytarabine and 6-th ioguanine maintenance therapy after achieving complete remission (CR) in the UMMCC study. Minimum follow-up of 7.7 years was obtained on 87 patients treated with high dose cytarabine intensification in first re mission in the NAMTG study. RESULTS. In the UMMCC study, the LFS rate was 28% and the overall survival rate was 15%. Nineteen percent of pat ients died in first CR at 1.3-12 years. Three patients remain alive in initial CR at >20 years. In the NAMTG study, the LFS rate was 49% and the overall survival rate was 45%. A total of 38 patients (44%) remai n alive in initial CR at a median of 11.4 years after diagnosis. An ad ditional patient is alive in second CR at 8.6 years after diagnosis. I n both studies, relapses after 3 years were relatively uncommon (11-12 %). CONCLUSIONS. Chemotherapy alone is curative in more than 40% AML p atients who achieve CR. Short-term, high dose cytarabine intensificati on appeared more efficacious, without increased toxicity, compared wit h low dose, prolonged cytarabine-based maintenance. However, for patie nts who cannot receive intensification, prolonged, low dose maintenanc e therapy is an acceptable alternative for achieving cure. A minimum f ollow-up of 3 years is a reasonable predictor of long-term survival an d should be obtained in studies evaluating therapeutic outcome in case s of AML. (C) 1997 American Cancer Society.