ELCC 2017: EGFR Mutation and Circulating Tumor DNA
Circulating tumor (ct) DNA may be used for diagnosis of epidermal growth factor receptor (EGFR) mutation in patients with advanced non–small cell lung cancer (NSCLC) and, in turn, may guide clinical decision-making about whether or not to offer EGFR inhibitor treatment to such patients. These are the findings presented by Rajiv Kumar, MD, of the Lung Cancer Department, The Institute of Cancer Research, and the Royal Marsden NHS Foundation Trust, and colleagues at the recent European Lung Cancer Conference (ELCC; Abstract 95PD).
The researchers used data from patients diagnosed with advanced NSCLC at the Royal Marsden Hospital between November 2015 and November 2016. They collected peripheral blood samples and examined ct DNA using the cobas® platform. Although this platform is currently used in clinical practice on tumor tissue, the diagnostic performance of the test in examining plasma samples for ct DNA EGFR testing had not been established before this prospective study.
The mean time to EGFR result was 8.4 days with the ct DNA plasma samples, compared with 11.2 days for tumor tissue. The concordance rate between ct DNA and the tumor was 87%, with a sensitivity of 65% and a specificity of 98%. The authors recommended that the cobas test for ct DNA be incorporated into routine clinical practice.