Optimization of EGFR mutation testing by the fully-automated qPCR-based Idylla on whole slide and biopsy tumor tissue of non-small cell lung cancer.

Abstract

e20632 Background: The use in routine clinical practice of the EGFR tyrosine kinase inhibitors is limited to patients with advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) who have known EGFR mutations. Currently, patient care has to respond to several imperatives to make it broadly available to all patients; fast and accurate detection of EGFR mutations by a sensitive and specific standardized cost-effective method, easy-to-implement in settings with limited expertise in molecular diagnostics. The possibility to obtain EGFR testing results in less than few hours in a large number of pathology laboratories is recently guaranteed by the Idylla system. Methods: We evaluated the Idylla system (Biocartis) for the detection of EGFR mutations in archived formalin-fixed paraffin-embedded (FFPE) tumor samples from a series of 18 patients with lung adenocarcinoma and compared these results with those obtained by the Therascreen EGFR Pyro assay (Qiagen)-ISO 15189 accredited laboratory method. The results obtained with the two methods were compared on both whole tumor sections from surgical specimens and on tissue sections from three artificially constructed small biopsies (~1 mm diameter) from the same FFPE blocks. Cost-effectiveness and turnaround time comparison between the two methods was performed. Results: In the first assessment on whole tissue sections, the Idylla and pyrosequencing results had an agreement of 94%. When assessed on biopsy cores, Idylla demonstrated agreement with pyrosequencing in 16 of 18 cases (89%). The Idylla EGFR mutation assay produced results faster (sample to result time was about 180 minutes with about 2 minutes of hands on time) than pyrosequencing (sample to result time about 12 hours). For each patient, the Idylla was more cost-effective than pyrosequencin. Conclusions: The Idylla system showed a good sensitivity and was cost-saving in our setting. Because of the easy workflow, the Idylla system has the potential to expand EGFR testing to more pathology laboratories in a reliable and fast manner.