Evaluation Of The Fully Automated Idylla Egfr Mutation Assay In Chinese Patients With Lung Adenocarcinoma.

e21716 Background: Epidermal growth factor receptor ( EGFR) mutation testing is nowadays an essential part of lung adenocarcinoma diagnosis. Its rapid detection is of utmost significance in order to ensure that patients receive timely and appropriate treatment. However, the current techniques for EGFR examination in China, ARMS-PCR and NGS, often take 3~7 days to deliver the final results. In contrast, the fully automated Idylla EGFR assay could detect 51 EGFR mutations directly from formalin-fixed, paraffin-embedded (FFPE) samples within 2.5 hours with < 2 minutes of hands-on time. The test has proven both accurate and robust among Caucasian lung adenocarcinoma patients but has never been clinically validated in Chinese patients. Methods: FFPE samples were retrospectively collected from 94 lung adenocarcinoma patients followed by EGFR testing using the Idylla system. Seventy-eight samples were also previously assessed with ARMS-PCR, 9 with NGS and 7 with both. In case of discordance, repeat testing was performed on the same tissue block with a third method. The sensitivity and specificity of the Idylla EGFR assay were evaluated against ARMS-PCR or NGS. Mutations beyond the scope of detection by the Idylla EGFR assay were not included in the analyses. Results: Of the 94 tumors enrolled, 77 were stage I-II. The Idylla system was consistent with ARMS-PCR or NGS for the EGFR mutational profiles of 92 tumors: 80 positive and 12 negative. Among the 2 cases of discrepancy, one was wild-type using Idylla but were found to harbor G719X/S768I using ARMS-PCR (and confirmed by NGS), while the other one carried L858R according to Idylla, as confirmed by ARMS-PCR, but was discovered to have an additional mutation L861Q using NGS. The Idylla EGFR test had a sensitivity of 97.6%, a specificity of 100% and an overall concordance of 97.9%. Conclusions: The Idylla system provides a rapid, accurate and user-friendly solution to EGFR characterization, especially in time-sensitive scenarios where special expertise and staff training could be a challenge.