ABSTRACT
PURPOSE: Monitoring mutation status in circulating free DNA (cfDNA) during target therapy could hold significant clinical importance in non-small cell lung cancer (NSCLC). Our aim is to establish if EGFR mutational status change on cfDNA has predictive value that can impact clinical management of NSCLC patients care. METHODS: This study included 30 patients with EGFR-mutated NSCLC. Blood samples were collected at diagnosis (T0) and in 19 patients during therapy (T1). RESULTS: Concordance between T0 and T1 EGFR mutation status for patients evaluable for both samples (n = 19) was 79%, with a sensitivity of 100% (95% CI: 55.5-100.0) and specificity of 60.0% (95% CI: 26.2-86.8). For the patients in oncological therapy with targeted drug and with T1 sample available (n = 18), survival outcomes were evaluated. For both mutation-negative T0 and T1 patients, 12-month progression-free survival (PFS) was 66.7% (95% CI: 27.2-100.0) and 12-month overall survival (OS) was 100% (95% CI: 1.00-1.00); for patients mutated both at T0 and T1, PFS was 22.2% (95% CI: 6.5-75.4%) and OS was 55.6% (95% CI: 20.4-96.1%). CONCLUSION: EGFR mutation status can be assessed using cfDNA for routine purposes and longitudinal assessment of plasma mutation is an easy approach to monitor the therapeutic response or resistance onset.