Circulating tumor DNA (ctDNA)-based minimal residual disease in non-small cell lung cancer

Lung cancer is the second most common cancer worldwide and the leading cause of cancer-related fatalities, with non-small cell lung cancer (NSCLC) accounting for 85% of all lung cancers. Over the past forty years, patients with NSCLC have had a 5-year survival rate of only 16%, despite improvements in chemotherapy, targeted therapy, and immunotherapy. Circulating tumor DNA (ctDNA) in blood can be used to identify minimal residual disease (MRD), and ctDNA-based MRD has been shown to be of significance in prognostic assessment, recurrence monitoring, risk of recurrence assessment, efficacy monitoring, and therapeutic intervention decisions in NSCLC. The level of MRD can be obtained by monitoring ctDNA to provide guidance for more precise and personalized treatment, the scientific feasibility of which could dramatically modify lung cancer treatment paradigm. In this review, we present a comprehensive review of MRD studies in NSCLC and focus on the application of ctDNA-based MRD in different stages of NSCLC in current clinical practice.