Measurement of circulating tumor DNA to guide management of patients with lymphoma.

In recent years, advances have been made in methods to assess response to therapy in lymphoma. Ideally, response assessment tools should be highly sensitive and specific for identifying a disease, should carry a minimal risk of harm to the patient, and should provide reproducible results. Traditional surveillance methods have included clinical assessment and, in many cases, routine surveillance imaging. Minimal residual disease (MRD) refers to the detection of disease level below that of these traditional surveillance methods. Either circulating tumor cells or their nucleic acid fragments released from necrotic/apoptotic cells can be measured in circulating peripheral blood, referred to as circulating tumor DNA (ctDNA). ctDNA can be detected with allele-specific polymerase chain reaction (ASO-PCR) or with next-generation sequencing (NGS) techniques. The use of ctDNA as a monitoring strategy in lymphoma can aid in assessment of disease burden, as well as prognostication, customization of therapy ("risk-adapted" strategies), monitoring for relapse, and consideration of early intervention ("preemptive" strategies), while reducing radiation exposure from surveillance imaging modalities that are presently used. In this review, we discuss the current state of the art in ctDNA measurement, as well as the clinical data supporting its potential utility in the management of lymphoma patients.