Assessment of minimal residual disease in myeloma and the need for a consensus approach.

Treatment options for myeloma continue to develop at a rapid pace, and it is becoming increasingly challenging to determine the optimal therapeutic approaches because demonstrating a clear survival benefit now requires many years of follow-up. The detection of minimal residual disease (MRD) is recognized as a sensitive and rapid approach to evaluate treatment efficacy that predicts progression-free and overall survival independent of categorical response assessment and patients' biology. The benefit of MRD analysis is reflected in the many different techniques (multiparameter flow cytometry, quantitative polymerase chain reaction, and high-throughput sequencing) and collaborative groups (including EMN, ESCCA, ICCS, EuroFlow, and EuroMRD) that have performed collaborative projects to harmonize quantitative MRD detection. The time has come to adopt a consensus approach, and this report reviews the benefits and disadvantages of different strategies for MRD detection in myeloma and highlights the requirements for a sensitive, reproducible, and clinically meaningful cellular analytical approach.