Adult Acute Myeloid Leukemia in Remission
An analysis of the SWOG/ECOG (E-3489) randomized trial of postremission therapy according to cytogenetic subgroups suggested that in patients with unfavorable cytogenetics, allogeneic BMT was associated with an improved relative risk of death, whereas in the favorable cytogenetics group, autologous transplantation was superior. These data were based on analysis of small subsets of patients and were not statistically significant. While secondary myelodysplastic syndromes have been reported following autologous BMT, the development of new clonal cytogenetic abnormalities following autologous BMT does not necessarily portend the development of secondary myelodysplastic syndromes or AML.[Level of evidence: 3iiiDiv] Whenever possible, patients should be entered on clinical trials of postremission management.
Because BMT can cure about 30% of patients who experience relapse following chemotherapy, some investigators suggested that allogeneic BMT can be reserved for early first relapse or second complete remission without compromising the number of patients who are ultimately cured; however, clinical and cytogenetic information can define certain subsets of patients with predictable better or worse prognoses using postremission chemotherapy. Good-risk factors include t(8; 21), inv(16) associated with M4 AML with eosinophilia, and t(15; 17) associated with M3 AML. Poor-risk factors include deletion of 5q and 7q, trisomy 8, t(6; 9), t(9; 22), and a history of myelodysplasia or antecedent hematologic disorder. Patients in the good-risk group have a reasonable chance of cure with intensive postremission therapy, and it may be reasonable to defer transplantation in that group until early first relapse. The poor-risk group is unlikely to be cured with postremission chemotherapy, and allogeneic BMT in CR1 is a reasonable option for patients with an HLA-identical sibling donor. However, even with allogeneic stem cell transplantation, the outcome for patients with high-risk AML is poor (5-year DFS of 8% to 30% for patients with treatment-related leukemia or myelodysplasia). The efficacy of autologous stem cell transplantation in the poor-risk group has not been reported to date but is the subject of active clinical trials. Patients with normal cytogenetics are in an intermediate-risk group, and postremission management should be individualized or, ideally, managed according to a clinical trial.