Chris Abbosh, MD, PhD, The Francis Crick Institute & Cancer Research UK & University College London Cancer Institute, London, UK, discusses the use of circulating tumor DNA (ctDNA) as a minimal residual disease (MRD) biomarker in non-small cell lung cancer (NSCLC). This technique can be used to identify patients with residual disease after surgery, which could make it easier for clinicians to decide on adjuvant treatment. It could also help in clinical trials, because being able to predict which patients are likely to relapse means that escalation of adjuvant treatment need only occur for a smaller group of patients. Dr Abbosh also discusses the IMvigor010 trial (NCT02450331) and the lung TRACERx trial (NCT01888601). This interview took place at the International Society of Liquid Biopsy (ISLB) 2021 Virtual Meeting.