EGFR mutations in patients with non-small cell lung cancer from mainland China and their relationships with clinicopathological features: a meta-analysis.

Many studies have reported the EGFR mutations in Chinese non small cell lung cancer (NSCLC) patients and their relationship with clinicopathological characteristics. But the frequency and type of EGFR mutations are varied. The relationship between EGFR mutations and clinicopathological characteristics remains unclear. We systematically reviewed studies of EGFR mutations in mainland Chinese NSCLC patients. Standard statistical methods for meta-analysis were applied. A total of 5,442 patients from 21 studies were included in the meta-analysis. The overall EGFR mutation rate was 37.5% (2,039/5,442). Among those 1,935 patients with detailed data about EGFR mutation types, the most prevalent mutation type was L858R, which accounted for 38.3% of all EGFR mutations. EGFR-TKIs sensitive mutations occupied 88.5% of all EGFR mutations. While the acquired EGFR-TKIs resistant mutations (T790 M) could occur naturally at the frequency of 1.5% without exposure of EGFR-TKIs. Male patients had a lower mutation rate than female patients (32.6% versus 53.0%, OR=0.40, 95% CI: 0.34-0.48, P < 0.001). The EGFR mutation rate for smokers was 19.2%, lower than that for non-smokers (47.9%) (OR = 0.40, 95% CI: 0.34-0.48, P < 0.001). Patients with adenocarcinoma had a higher mutation rate than those with non-adenocarcinoma (50.2% versus 17.0%, OR = 4.84, 95% CI: 4.07-5.75, P < 0.001). EGFR mutation rate did not differ significantly between stage I and stage II/III/IV patients (35.8% versus 32.2%, OR = 1.08, 95% CI: 0.84-1.43, P = 0.580). Our results show that EGFR mutation rate is high in mainland Chinese NSCLC patients. EGFR-TKIs sensitive mutations are main types of mutations. EGFR mutations are significantly associated with gender, smoking history, histology type, but not stage.