Epidermal growth factor receptor‐tyrosine kinase inhibitor therapy is especially beneficial to patients with exon 19 deletion compared with exon 21 L858R mutation in non‐small‐cell lung cancer: Systematic review and meta analysis

BACKGROUND The correlation between epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and EGFR sensitive mutation subtypes in advanced or metastatic non-small cell lung cancer (NSCLC) remains uncertain. We performed this meta-analysis to determine different clinical outcomes between patients with exon 19 deletion accepting EGFR-TKI therapy compared with those with exon 21 L858R mutation. METHODS PubMed and Web of Science were analyzed for eligible trials. Raw data were extracted to give pooled estimates of the effect of EGFR-TKI therapy on objective response rate (ORR), one-year progression-free survival (PFS), and two-year overall survival (OS). RESULTS We identified 13 eligible trials involving 912 patients. Prospective meta-analysis demonstrated that the ORR of the 19 deletion group was significantly higher than the 21 L858R mutation group (odds ratio [OR] 1.98, 95% confidence interval [CI] 1.18-3.33; P = 0.01), but no statistical significance between the one-year PFS rate of the 19 deletion and 21 L858R groups (OR 1.44, 95% CI 0.96-2.18; P = 0.08) was found. However, retrospective meta-analysis demonstrated that a significantly higher one-year PFS rate was associated with the 19 deletion group (OR 1.73, 95% CI 1.17-2.56; P = 0.006). The two-year survival rate of the 19 deletion group was significantly higher than the 21 L858R group (OR 5.27, 95 % CI 1.76-15.71; P = 0.003). CONCLUSIONS In advanced NSCLC patients, an exon 19 deleton may provide superior ORR, PFS, and OS after EGFR-TKI treatment compared with an exon 21 L858R mutation.