Cell-free DNA as a prognostic marker in stage I non-small-cell lung cancer patients undergoing stereotactic body radiotherapy.

Objective: To evaluate whether plasma cell-free DNA (cfDNA) was related to clinical outcome in inoperable stage I non-small cell lung cancer (NSCLC) patients undergoing stereotactic body radiotherapy (SBRT).Materials and methods: Plasma cfDNA was assessed at baseline, before the last day and 45 days after the end of SBRT, in 22 NSCLC patients. Twenty-two healthy controls were also evaluated.Results: Plasma cfDNA was higher in patients than in controls. An association with unfavourable disease-free survival was found for continuous baseline cfDNA increments (HR=5.9, 95%CI: 1.7-19.8, p=0.04).Conclusion: Plasma cfDNA may be a promising prognostic biomarker in high-risk NSCLC patients.