Background: Limited information exists on epidermal growth factor receptor (EGFR) molecular epidemiology in Greece. Next-generation sequencing (NGS) is the recommended method for EGFR genotyping in NSCLC. The Idylla Biocartis platform is a fully automated system for actionable EGFR mutation detection.
Research design and methods: We describe the prevalence of EGFR mutations in NSCLC patients in two high-volume clinical centers in Greece and compare key methods used for their determination. Eight hundred and fifty-seven FFPE samples from NSCLC patients were tested for EGFR mutations at University of Crete (UoC; n = 324) and at Evangelismos Hospital, Athens (Evangelismos; n = 503).
Results: The prevalence of EGFR mutations was 11.1% in the whole cohort (11.5% in non-squamous). The detection rate was 11.0% by NGS, 9.8% by Sanger and 11.3% by Idylla for the whole cohort (12.0% in non-squamous). The agreement between Idylla and Sanger was 93.2%. A targetable EGFR mutation was detected in 10.0% using tissue NGS alone, and in 16.0% using concurrent Idylla ctEGFR testing.
Conclusion: The frequency of EGFR mutations was as expected for a Caucasian population. The Idylla EGFR test performance is comparable to reference methods and with a shorter TAT. Adding a concurrent plasma Idylla test to tissue NGS testing increases the detection rate of EGFR mutations in NSCLC.
Keywords: Cartridge-based PCR system; NSCLC; Sanger sequencing; circulating cell-free DNA; epidermal growth factor receptor mutations; liquid biopsy.