Impact of treatment delay in acute myeloid leukemia revisited

Current protocols for intensive treatment include targeted drugs specific for certain genetic subtypes.1 Subtyping is then often required before the start of treatment (other than hydroxyurea), and we must wait for genetic results for all patients.This requirement is medically motivated if it is unclear whether the patient will benefit from intensive treatment as compared with nonintensive targeted therapy, or if data show that targeted therapy is more effective if given on day 1 of an intensive protocol as compared with somewhat later.However, the requirement for immediate genetic subtyping of patients suited for intensive treatment is often based on a need for registration to a specific protocol or simply an arbitrary standard stated in the protocol.As a consequence, rapid diagnostic tools have been developed for required analyses according to specific protocols; now, fluorescence in situ hybridization and molecular results on FLT3, core-binding factor, IDH mutations, and more may be available within 72 hours.This is feasible for large centers but adds cost and logistic measures, and could be hard to achieve in the overall real-world setting, especially in developing countries.(However, if acute promyelocytic leukemia is suspected, urgent diagnostics are always required, and all-trans retinoic acid should be given even before diagnosis is confirmed to prevent early death.)Results from a large German retrospective multicenter study, recently published in Blood by R öllig et al, 2 were interpreted to mean that waiting for diagnostic tests would not be harmful.We here report corresponding data from the large Swedish population-based Acute Myeloid Leukemia (AML) Registry, 3,4 which, however, is showing better overall results in patients with immediate treatment despite these patients having had more advanced disease, as compared with patients who had delayed treatment.A median time of 3 days between diagnostic sampling and start of intensive treatment (time from diagnosis to treatment [TDT]) indicates that, in clinical practice, regarding AML as a medical urgency is an established routine.