Abstract
BACKGROUND: Afatinib is indicated for patients with advanced-stage non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations, including uncommon mutations. However, the differences in survival benefits between patients with different types of EGFR mutations remain unclear. OBJECTIVES: This study aimed to compare the effectiveness of afatinib treatment in patients harboring the EGFR-G719X mutation with that in patients carrying other uncommon EGFR mutations. DESIGN: This was a retrospective study. METHODS: Ninety-two patients with locally advanced and metastatic NSCLC, of whom 49 patients with EGFR-G719X mutations that were both single and compound, and 43 patients harbored other uncommon EGFR mutations, who were treated with afatinib as first-line treatment. The patients were followed up and evaluated every 3 months or when there were symptoms of progressive disease. The endpoints were the objective response rate (ORR), time-to-treatment failure (TTF), and overall survival (OS). RESULTS: The average ages of patients with the EGFR-G719X and uncommon EGFR mutations were 62.7 years and 63.1 years, respectively. There were no significant differences in sex or smoking history between the two groups. In total, 28.6% of patients with the G719X mutation and 23.3% of patients with other mutations had brain metastases. The ORR of patients with the G719X mutation was 79.6%, which was 10% higher than that of patients with other EGFR mutations. Patients harboring the EGFR-G719X mutation had median TTF and median OS periods of 19.3 months and 31.4 months, respectively, which were significantly higher than those of patients carrying other mutations at 11.2 months. Subgroup analysis showed that TTF and OS benefits were observed in female patients, patients without brain metastasis, and patients with good performance status who harbored the G719X mutation. CONCLUSION: Patients with the EGFR-G719X mutation achieve significantly better TTF and OS benefits than those with other uncommon EGFR mutations.