In this study, therefore, we examined the efficacy of a labeled dose (40 mg/day), as well as a lower starting dose of 30 mg/day or downward dose adjustment from 40 mg/day during the treatment period (collectively described as <40 mg/day), of afatinib as a first-line therapy for NSCLC patients bearing favorable EGFR-TK mutations. Here, EGFR is linked to non-small cell lung carcinoma.