Monitoring after successful therapy for chronic myeloid leukemia.

Monitoring response to therapy for patients with chronic myeloid leukemia using an effective strategy is fundamental for achieving optimal patient outcomes. It will allow the initiation of timely therapeutic intervention for patients with a suboptimal response or kinase inhibitor therapy failure. Evidence is mounting that reaching molecular targets early in therapy is as important as the initial hematologic and cytogenetic response for the identification of patients who may have a poorer outcome. When the molecular target of a major molecular response is achieved at 18 months, patients reach a safe haven where loss of response is rare. However, this benefit is dependent on continuous drug adherence in most patients. As some patients reach their second decade of successful imatinib therapy, how long will frequent response monitoring be necessary? Assuming that very late relapse will be extremely rare for responding patients remaining on kinase inhibitor therapy, there are reasons for maintaining a regular molecular monitoring frequency, including monitoring adherence assessment and confirming sustained undetectable BCR-ABL1 for those considering a discontinuation trial and for late molecular recurrence in patients who maintain response after treatment discontinuation.