RESUMEN
BACKGROUND: circulating tumor DNA (ctDNA) is a source of tumor genetic material for EGFR testing in NSCLC. Real-word data about liquid biopsy (LB) clinical practice are lacking. The aim of the study was to describe the LB practice for EGFR detection in North Eastern Italy. METHODS: we conducted a multi-regional survey on ctDNA testing practices in lung cancer patients. RESULTS: Median time from blood collection to plasma separation was 50 min (20-120 min), median time from plasma extraction to ctDNA analysis was 24 h (30 min-5 days) and median turnaround time was 24 h (6 h-5 days). Four hundred and seventy five patients and 654 samples were tested. One hundred and ninety-two patients were tested at diagnosis, with 16% EGFR mutation rate. Among the 283 patients tested at disease progression, 35% were T790M+. Main differences in LB results between 2017 and 2018 were the number of LBs performed for each patient at disease progression (2.88 vs. 1.2, respectively) and the percentage of T790M+ patients (61% vs. 26%).