EGFR mutation analysis on circulating free DNA in NSCLC: a single-center experience

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.

This study included 30 patients with EGFR-mutated NSCLC. Blood samples were collected at diagnosis (T0) and in 19 patients during therapy (T1).

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%).

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.