Late Relapses in Adult Acute Myelogenous Leukemia: A Retrospective Study of Characteristics and Outcome in 76 Cases

Abstract

Relapses in acute myelogenous leukemia (AML) are generally considered of poor prognosis. Late relapses are known to represent a special entity with better prognosis. Whether late relapses occur from the original leukemic clone or not is still questioned.In order to provide clues, the characteristics and outcome of 76 patients with AML who had experienced a first relapse after a first complete remission (CR) duration longer than 18 months (late-relapse AML) were analyzed. Major differences, reflecting exclusively the tumor burden, were noted between presentations at initial diagnosis and after first relapse. Sixteen patients were initially classified as Ml, 22 as M2, 12 as M3, 12 as M4, 12 as M5, and two as M6. At the time of first relapse, morphologic changes of blast cells caused assignment to another FAB subgroup in only three patients by comparison with diagnosis. Cytological dyshemopoiesis features, involving at least one lineage, were observed in 29% of patients at diagnosis and 33% at relapse. Metaphase chromosomes were analyzed both at the time of diagnosis and at the time of first relapse only in 15 cases. No differences were noted in karyotypic patterns except in three patients: one patient with normal karyotype at diagnosis presented at relapse with – Y, +8 and +15; one presented at relapse with t( 15; 17) not detected at diagnosis; one with del(21) at diagnosis and t(l; 17) at relapse.Overall, none of the features at time of relapse allow us to suggest a relationship between these late relapses and the development of new leukemias.