Real world EGFR testing practices for non-small cell lung cancer by thoracic pathology laboratories across Europe.

e21064 Background: Testing for EGFR mutations is an essential recommendation in both the ESMO and ASCO guidelines for metastatic non-squamous NSCLC, and is considered mandatory in European countries. However, in practice, considerable challenges are often faced when performing routine biomarker testing, including access to testing, inadequate tissue samples, and long turnaround times (TATs). Methods: In order to evaluate the real-world EGFR testing practices of thoracic pathology laboratories across Europe, an online survey was set up and validated by The Pulmonary Pathology Working Group of the European Society of Pathology and distributed to 64 expert testing laboratories across Europe. The retrospective survey focused on the laboratory organisation and daily practice of pathologists and molecular biologists between 2018 and 2021, and covered the clinical circumstances in which EGFR testing was performed, sample types used, molecular biology techniques performed, average TATs for determining EGFR status, annual EGFR testing rates, laboratory accreditation, and external quality assessment. Results: TATs varied greatly depending on different parameters (notably relating to testing practices and methods used) both between and within countries. TATs were slightly (but non-significantly) faster for liquid biopsy samples (Mean: 7 days, IQR 4.5-12.5) when compared to tissue samples (mean 7 days, IQR 5-15) but were reported to take as long as 20 or 30 days, respectively. Discrepancies in TATs may be due in part to reflex testing practices, as 20% (11/54) of laboratories performed EGFR testing only at the request of the clinician. Many laboratories across Europe still favour targeted sequencing as a primary method of EGFR mutation identification; 32.7% indicated that they only used targeted techniques, and 45.1% indicated they used targeted sequencing followed by NGS, depending on the case. Reported testing volumes were consistent over time with no significant decrease in the number of EGFR tests performed observed in 2020, despite the increased pressure and difficulties faced by testing facilities during the COVID-19 pandemic. ISO 15189 accreditation was reported by 42% of molecular biology laboratories for targeted sequencing, and by 42.3% for NGS. 92% (49/53) of laboratories indicated they regularly participate in an EQA scheme. Conclusions: The results of the survey highlight the strong heterogeneity of EGFR testing that still occurs within thoracic pathology and molecular biology laboratories across Europe. Even among expert testing facilities there remains large variability in testing capabilities, reflex testing practice and laboratory accreditation, which stresses the urgent need to harmonize budgets and reimbursement in Europe, in addition to harmonization of the technologies and decision-making algorithms.