Introduction: With the International Association for the Study of Lung Cancer (IASLC) recommendations promoting liquid biopsy as a primary detection tool, a new era of research has begun. The authors aimed to study the concordance of plasma genotyping platforms against the tissue gold standard. Methods: 184 patients with non-small cell lung cancer underwent EGFR genotyping using Cobas, droplet digital polymerase chain reaction (ddPCR) and Therascreen assays from 2019-2020. Results: Of 184 cases, 70 were positive by Cobas, 51 by ddPCR and 69 by Therascreen. The sensitivity of Cobas was 97.1% and the sensitivity of ddPCR was 71%. Receiver operating characteristic analysis showed an area under the curve of 0.977 for Cobas and 0.846 for ddPCR. Conclusion: In line with the FLAURA trial of osimertinib making its way to first-line and given the IASLC recommendations, it is important to understand the attributes of these tests to initiate appropriate treatment.
Lay abstract Lung cancer is one of the most common malignancies and has been known to have a dismal outcome. However, owing to evolution in the knowledge of disease biology and processes, many molecules have been discovered that can be used in targeted therapy. To institute this modality of treatment, detection of alterations in these specific molecules, namely: EGFR, ALK, ROS1, RET, MET, KRAS G12C, BRAF V600E, NTRK1, NTRK2, NTRK3 and ERBB2 is necessary. This has traditionally been done using single-gene assays, which require more tissue. This is a major limitation in cases of non-small cell lung carcinoma, as the biopsies are small. Hence, new technologies like next-generation sequencing have emerged that offer a one-stop solution for these cases. In cases where tissue is very scant, the use of peripheral blood has now been recommended by international guidelines for primary detection of these molecular alterations. This article describes the concordance of tissue-based detection and blood-based detection using three different assays, for the detection of EGFR alterations. Although promising results were obtained largely for blood-based assays, liquid and tissue biopsies are complementary.