Abstract
Acute promyelocytic leukemia (APL) is highly curable with the combination of ATRA and anthracycline based chemotherapy (CT), but very long term results of this treatment, when CT should be added to ATRA and the role of maintenance treatment remain uncertain. In our APL 93 trial that included 576 newly diagnosed APL, with a median follow up of 10 years, 10 year survival was 77%. Maintenance treatment significantly reduced 10 year cumulative incidence of relapses, from 43.2% to 33%, 23.4% and 13.4% with no maintenance, maintenance using intermittent ATRA, continuous 6 mercaptopurine+methotrexate and both treatments, respectively (p<0.0001). Maintenance particularly benefited patients with WBC >5000/ul. Early addition of CT to ATRA significantly improved 10 year EFS, but without significant effect on OS. The 10-year cumulative incidence of deaths in CR, mainly resulting from myelosuppression, was 5.7%, 15.4% and 21.7% in patients aged < 55, 55- 65 years and > 65 years, respectively, supporting the need for less myelosuppressive treatments, particularly for consolidation therapy. This study is registered at http://clinicaltrials.gov as NCT00599937.