Consolidation chemotherapy in AML: Are we playing with a full deck of cards?

Abstract

The safe diminution of leukemic cell numbers to a level such that the patient will not succumb to their disease has been an achievable, yet often elusive goal in AML. Disease heterogeneity based both on biological features as well as on patient characteristics such as age, exposure to prior to anti-cancer chemotherapy and co-morbidities play a role in an allowing the physician to predict which patient has a greater or lesser chance to be cured after a diagnosis of acute myeloid leukemia. Cure rates range from 95% in younger patients with non-high-risk acute promyelocytic leukemia to essentially zero in older adults with intrinsically resistant biologies such as complex karyotype and/or TP53 mutations. One unifying feature of all AMLs, however, is the notion that whatever initial therapy is used, while possible to eradicate all morphological evidence of disease in a sizeable fraction of patients, an initial cycle (or two) is not sufficient to yield a low enough disease burden to prevent eventual relapse. Thus, the application of additional chemotherapy after the initial complete remission is received (post-remission therapy generally or consolidation therapy if a myelointense approach is used) is absolutely required for the patient to have a reasonable chance at cure. The widely accepted principle of the need to provide post-remission therapy leads to multiple controversies pertaining to the appropriate intensity, drug choice, and duration of exposure to consolidation chemotherapy, which can range from repetitive cycles of non-intensive therapy, up to and including a myeloblative allogeneic stem cell transplant. In this review, both the principles and the individual strategies that can be used once remission is achieved, will be examined.