Emergence of Circulating Tumor DNA as a Precision Biomarker in Lung Cancer Radiation Oncology and Beyond.

Circulating tumor DNA (ctDNA) is emerging as a transformative biomarker in the management of non-small cell lung cancer (NSCLC). This review focuses on its role in detecting minimal residual disease (MRD), predicting treatment response, and guiding therapeutic decision-making in radiation oncology and immunotherapy. Key studies demonstrate ctDNA's prognostic value, particularly in identifying relapse risk and refining patient stratification for curative-intent and consolidative treatments. Future research is essential to standardize ctDNA assays, optimize integration into clinical workflows, and expand its clinical utility. This biomarker holds substantial promise by enabling non-invasive, real-time monitoring and improving outcomes for patients with NSCLC and beyond.