what is mrd

Minimal residual disease (MRD) is a term used to describe the small number of cancer cells that remain in the body after cancer treatment. MRD is common in patients with blood cancers, such as leukemia, lymphoma, and multiple myeloma. MRD testing has several important roles in cancer treatment, including determining whether treatment has eradicated the cancer or whether traces remain, comparing the efficacy of different treatments, monitoring patient remission status, detecting recurrence of the cancer, and choosing the treatment that will best meet those needs. MRD testing is technically demanding and time-consuming, and the tests are expensive, so they are usually available only through specialist centers as part of clinical trials. MRD can be measured on peripheral blood or bone marrow samples typically via standardized flow cytometry or molecular diagnostic techniques such as PCR or next-generation sequencing (NGS). The presence of MRD may lead to disease progression and relapse in multiple myeloma, and it is a strong predictor of relapse in other blood cancers. Achieving MRD(-) status early in the course of treatment has been shown to give patients a reduced risk of relapse and a stronger chance for longer overall survival.