Circulating free DNA as a marker of response to chemoradiation in locally advanced head and neck squamous cell carcinoma.

Abstract

Liquid biopsy has moved from bench to bedside as a non-invasive biomarker for early diagnosis and monitoring treatment response. This study investigated the role of circulating free DNA (cfDNA) as a diagnostic marker in locally advanced head and neck squamous cell carcinoma (HNSCC) and in monitoring response to chemoradiation therapy. Serum was collected from treatment naïve, histopathologically diagnosed tumors in 24 HNSCC cases and 16 normal controls. CfDNA levels were quantified using β globin gene amplification. The cfDNA level was significantly elevated in HNSCC (992.67 ± 657.43 ng/mL) as compared to healthy controls (60.65 ± 30.42 ng/mL, P = <0.001). The levels of cfDNA did not significantly correlate with TNM stage, lymph node involvement and grade. In responders, percentage decrease in cfDNA levels was 9.57% and 29.66%, whereas in nonresponders percentage increase was 13.28% and 24.52% at the end of three months of follow-up. Our study adds to the evidence that cfDNA levels are significantly higher in HNSCC cases and provides some evidence that levels increase with tumor progression. CfDNA may be a promising prospective non-invasive marker to predict response in patients undergoing chemo-radiotherapy.