Quantitative analysis of preoperative, intraoperative and postoperative circulating cellfree DNA in patients with resectable non-small cell lung cancer

Introduction: Circulating cell-free DNA (cfDNA) in the peripheral blood has been shown to predict prognosis in advanced non-small cell lung cancer (NSCLC). However, little is known regarding the clinical significance of the above biomarker in patients with operable NSCLC. Aim: We herein aimed to further evaluate the clinical relevance of quantitative analysis of cfDNA in central and peripheral blood samples, obtained from patients with resectable NSCLC before, during and after surgical treatment. Patients-Methods: Patients (n=35) with operable NSCLC were prospectively enrolled. A group of sex and age-matched healthy controls (n=30) was also recruited. Peripheral blood samples were collected preoperatively and postoperatively (immediately after surgery and on the 14th post-operative day), while central venous blood was also collected intraoperatively. The results of quantitative cfDNA analysis were correlated with baseline clinicopathological features of patients. Results: Preoperative cfDNA concentrations in NSCLC patients were significantly higher as compared to controls (p=0.002). Furthermore, cfDNA concentrations were significantly higher immediately postoperatively compared to baseline (p<0.001), and significantly lower on the 14th postoperative day compared to immediately postoperatively (p<0.001). Intraoperative cfDNA concentrations were also significantly higher in stage III as compared to stage I patients (p=0.018). Conclusions: cfDNA concentrations may be higher in operable NSCLC patients as compared to healthy controls, and may be further increased with disease progression and, temporarily, with surgical manipulation.