Quantifying measurable residual disease correctly

Determining the measurable residual disease (MRD) level in a patient with leukemia is used to decide on treatment. The MRD result is an estimate of the true level of MRD in the patient and indicates whether the latter is likely to fall above or below a consensus “cut-off” MRD level, which is used to decide between two treatments of different intensity. The cut-off level is based on evidence from clinical trials concerning the probabilities, consequences, and weightings of outcomes, including relapse, morbidity, mortality, and subsequent treatments. The principle underlying general agreement on the value of the cut-off is that decisions based on it will maximise the positive outcomes and minimise the negative outcomes for the patient population as a whole.