The characteristics and outcome of patients with late relapse acute myelogenous leukemia

The characteristics and outcome of 58 patients with acute myelogenous leukemia (AML) who experienced relapse after a first remission duration longer than 18 months (late-relapse AML) were analyzed and compared with those of 278 patients with earlier relapses. Late-relapse AML was associated with a lower incidence of antecedent hematologic disorder, leukocytosis, and elevated creatinine and lactic acid dehydrogenase (LDH) levels. A favorable karyotype (inversion of chromosome 16; translocations between chromosomes 8 and 21, or 15 and 17) was more frequent in patients whose first remission was 12 months or longer compared with < 12 months (30% v 10%; P < .0001). An unfavorable karyotype (chromosome 5 and 7 abnormalities, trisomy 8, other changes) was more frequent in the latter category (16% v 42%; P < .0001). Thirty-seven of the 58 patients (64%) with late-relapse AML achieved complete remission (CR). The incidence of CR increased significantly with an increased first remission duration from < 12, 12 to 18, and > 18 months (17% v 41% v 64%; P < .0001), while the incidence of resistant disease was significantly lower (59% v 36% v 19%; P < .0001). When effective antileukemic regimens were considered, remission rates were also significantly increased by the duration of first remission (24% v 48% v 72%; P < .001). Compared with patients with earlier relapse, those with late-relapse AML had a longer median survival from salvage therapy (3.5 v 12 months; P < .01), and longer median second remission durations (3.5 v 11 months; P < .01). We conclude that late-relapse AML has unique clinical, cytogenetic, and prognostic characteristics, and remains extremely sensitive to chemotherapy with a potential cure fraction. The duration of first remission is an important prognostic parameter in AML relapse and may be useful in the design and analysis of future salvage programs.