Can Remission Duration Be Prolonged in Acute Myeloid Leukaemia?

Abstract

It would be possible to prolong the state of remission indefinitely in acute myeloid leukaemia (AML) arising de novo by reducing the size of the blast-cell population to zero, because it seems probable, though not certain, that the leukaemic blast cells constitute a clone, genetically isolated from the normal stem-cell population from which they arose, and that their selective destruction would leave a normal stem-cell population with a relatively low risk of generating a second clone of leukaemia cells. However, the number of patients who survive for long periods following the type of treatment now widely used is far too small to permit speculation on the incidence of late relapses or on the question of their nature, i.e., to know whether they arise from persistent leukaemia cells belonging to the original clone or from the emergence of an unrelated new clone. Perhaps the clonal concept of leukaemia-cell populations is false, just as it would be false to describe the megaloblasts of pernicious anaemia as constituting a clone, but present-day cell-destructive treatments for leukaemia are based on the assumption that leukaemia-cell populations are clones that originate from a single cell transformed as a consequence of a rare event in an essentially normal stem-cell population, unlikely to recur if the patient survives following treatment that succeeds in destroying all the leukaemia cells.