Clinical and molecular characteristics of the patients in the liquid biopsy study in mEGFR-NSCLC in a Spanish population (OPH-1).

e21515 Background: The liquid biopsy (LB) is an important tool in the diagnostic and follow up of the patients with non-small cell lung cancer (NSCLC) and can provide big information about the mutational variability of the disease during of the treatment. Methods: We conducted a multicenter study with 200 patients with EGFR-mutated NSCLC, treated with first-line TKI therapy. We analyse the ctDNA by dPCR pre-treatment, at 8 weeks, at 7 months and at the progression of the disease (PD). Results: A total of 200 patients (60% women / 40% men) were included. The median of age was 68-year. The never smokers were 56% and 34% ex-smokers. 92% of the cases were adenocarcinomas. According to the stag…