[Clinical observation of EGFR-TKI as a first-line therapy on advanced non-small cell lung cancer].

Background and Objective: It has been proven that epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) significantly benefits advanced non-small cell lung cancer (NSCLC) patients harboring EGFR mutations in progression-free survival time with better tolerance. This study is undertaken to analyze efficacy and tolerance of advanced NSCLC patients harboring EGFR mutations taking EGFR-TKI as a first-line therapy.
Methods: Tumor samples from 54 patients with advanced NSCLC were examined for EGFR activating mutations (deletion mutation in exon 19 and the L858R point mutation in exon 21) by direct sequencing. The patients were first-line treated with oral administration of EGFR-TKI until disease progression. The efficacy and adverse events were observed, and survival was followed up.
Results: Among the patients, 61% (33 of 54) had EGFR exon 19 deletion, and 39% (21 of 54) had EGFR L858R point mutation. All patients received first-line TKI therapy. The total response rate was 96%, median progression free survival (PFS) was 8.3 months and median survival was 19.5 months. The patients with EGFR exon 19 deletion had significantly longer median PFS (9 versus 7 months, P=0.002) and longer median overall survival (OS)(25 versus 16 months, P=0.001) than patients with EGFR L858R point mutation. There is no significance in efficacy between gefitinib and erlotinib, and gefitinib is safer than erlotinib. The most common adverse events were rash and diarrhea. Two (4%) grade 4 skin toxity effects, two (4%) grade 3 aminotransferase level elevations, and one (1) grade 3 stomatitis were observed.
Conclusion: The first-line EGFR-TKI treatment in advanced NSCLC patients harboring EGFR mutations is efficient and safe, which is more efficient in patients with EGFR exon 19 deletion than those with EGFR L858R mutation.