Response to Second-Line Erlotinib in an EGFR Mutation-Negative Patient with Non-Small-Cell Lung Cancer: Make No Assumptions

Erlotinib—an oral tyrosine kinase inhibitor (tki) of the epidermal growth factor receptor (egfr)—has commonly been used as a therapeutic option in metastatic non-small-cell lung cancer (nsclc) patients in the second- or third-line treatment setting. A mutation in the EGFR gene (EGFR M+) confers an increased response to this class of drugs. In the first-line setting, use of tkis is restricted to patients having a mutation. The importance of this biomarker has been questioned in subsequent treatment lines. Here, we report a case showing a positive response to erlotinib treatment in the second-line setting. The patient, an elderly male smoker with stage iv nsclc, had a tumour that was EGFR mutation-negative (wild-type EGFR). Based on this clinical case, we discuss the controversy concerning the need for, and impact of, testing for EGFR mutation after first-line treatment.