Monitoring Treatment Response in EGFR-Mutant NSCLC

This segment explores the evolving role of circulating tumor DNA (ctDNA) in monitoring treatment response in EGFR-mutant non-small cell lung cancer (NSCLC). Drs. Mark Socinski and Susan Scott discuss how ctDNA complements conventional radiographic assessment, while emphasizing that its routine use outside of clinical trials remains limited. Dr. Scott explains that she primarily incorporates ctDNA testing when imaging findings or treatment response are equivocal, helping determine whether patients receiving osimertinib-based therapy may require closer evaluation or therapeutic adjustment. In contrast, when patients demonstrate the expected robust radiographic response to treatment, she finds limited additional value in serial ctDNA monitoring. The discussion highlights the strengths and current limitations of ctDNA as a biomarker and underscores the need for prospective evidence to better define its role in guiding response assessment and treatment decisions in routine clinical practice.