Younger adults with acute myeloid leukemia in remission for ≥3 years have a high likelihood of cure: The ECOG experience in over 1200 patients

• Late relapse of AML is rare after 3 years of first remission, and the majority of these patients can be considered cured.
• Most cases of late relapse appear to represent re-emergence of the original clone, not a new therapy-related leukemia.
• Most of the 14 late relapse patients tested had a normal karyotype at diagnosis.
• If late relapse does occur, outcomes are relatively favorable (median OS after late relapse 3.2 years).

We examined 1229 younger patients with acute myeloid leukemia who achieved CR1 on Eastern Cooperative Oncology Group trials. We defined late relapse as occurring after ≥3 years of CR1. With median follow-up of 11.3 years, there were 14 late relapses (1.1% of CR1 patients; 3.3% of 3-year CR1 patients). Eight achieved second CR and median overall survival after late relapse was 3.2 years. Most patients tested (9/11) had a normal karyotype at diagnosis; none had new cytogenetic abnormalities at relapse. Late relapse is rare and nearly all 3-year CR1 patients are cured. If late relapse occurs, outcomes are relatively favorable.