Comparative Analysis of Two Methods for the Detection of EGFR Mutations in Plasma Circulating Tumor DNA from Lung Adenocarcinoma Patients

Mutations in the epidermal growth factor receptor ( ) are associated with various solid tumors. This study aimed to compare two methods for the detection of mutations in circulating tumor DNA (ctDNA) from lung adenocarcinoma (LUAD) patients and to evaluate the clinical significance of mutations in ctDNA. In this prospective cohort study, the mutation status of 77 patients with stage IIIB or IV LUAD was first determined using lung cancer tissue. The amplification refractory mutation system (ARMS) and single allele base extension reaction combined with mass spectroscopy (SABER/MassARRAY) methods were also used to detect mutations in plasma ctDNA from these patients and then compared using the mutation status in lung cancer tissue as a standard. Furthermore, the relationship between the presence of mutations in ctDNA after receiving first-line EGFR-tyrosine kinase inhibitor (EGFR-TKI) therapy and survival was evaluated. The overall sensitivity and specificity for the detection of mutations in plasma ctDNA by ARMS and SABER/MassARRAY were 49.1% vs. 56% and 90% vs. 95%, respectively. The agreement level between these methods was very high, with a kappa-value of 0.88 (95% CI 0.77-0.99). Moreover, 43 of the patients who carried mutations also received first-line EGFR-TKI therapy. Notably, patients with mutations in plasma ctDNA had significantly shorter progression-free survival (9.0 months, 95% CI 7.0-11.8, vs. 15.0 months, 95% CI 11.7-28.2; = 0.02) and overall survival (30.6 months, 95% CI 12.4-37.2, vs. 55.6 months, 95% CI 25.8-61.8; = 0.03) compared to those without detectable mutations. The detection of mutations in plasma ctDNA is a promising, minimally invasive, and reliable alternative to tumor biopsy, and the presence of mutations in plasma ctDNA after first-line EGFR-TKI therapy is associated with poor prognosis.