Epidermal growth factor receptor (EGFR) mutations are the most common oncogenic drivers in non-small-cell lung cancer (NSCLC). Significant developments have taken place which highlight the differences in tumor biology that exist between the mutant and wild-type subtypes of NSCLC. Patients with advanced EGFR-mutant NSCLC have a variety of EGFR-targeting agents available proven to treat their disease. This has led to superior patient outcomes when used as a monotherapy over traditional cytotoxic systemic therapy. Attempts at combining EGFR agents with other anticancer systemic treatment options, such as chemotherapy, antiangiogenic agents, and immunotherapy, have shown varied outcomes. Currently, no specific combination stands out to cause a shift away from the use of single-agent EGFR inhibitors in the first-line setting. Similarly, adjuvant EGFR inhibitors, are yet to significantly add to patient overall survival if used at earlier timepoints in the disease course. Liquid biopsy is an evolving technology with potential promise of being incorporated into the management paradigm of this disease. Data are emerging to suggest that this technique may be capable of identifying early resistance mechanisms and consequential disease progression on the basis of the analysis of blood-based circulating tumor cells.
Keywords: EGFR; circulating tumor cells; epidermal growth factor receptor; non-small-cell lung cancer; tyrosine kinase inhibitors.