Correlation between status of epidermal growth factor receptor mutation and distant metastases of lung adenocarcinoma upon initial diagnosis based on 1063 patients in China

The study aimed to explore the correlations between status of epidermal growth factor receptor (EGFR) mutations and distant metastases. A total of 1063 patients with lung adenocarcinoma indentified with status of EGFR mutations from August 2010 to May 2015 at Shanxi Cancer Hospital were enrolled. 456 patients were confirmed with EGFR mutations. The associations among EGFR mutations, clinical factors, and distant metastases at initial diagnosis were evaluated. Patients harboring EGFR mutation were more likely to be female (P < 0.001), with no smoking history (P < 0.001), brain metastases (P = 0.029), and higher ECOG performance scores (P = 0.025). The correlation between EGFR mutation status and distant metastases showed statistical significance both in univariate (P = 0.022) and in multivariate analysis (OR 1.573, 95 % CI 1.202–2.059, P = 0.001) especially in brain metastases (OR 1.675, 95 % CI 1.132–2.479, P = 0.010) and lung metastases (OR 1.571, 59 % CI 1.101–2.243 P = 0.013). Furthermore, the 19del mutations showed associations with brain metastases (OR 1.586, 95 % CI 1.028–2.447, P = 0.037), and lung metastases (OR 1.587, 95 % CI 1.065–2.346, P = 0.023). The exon 21 point mutations showed statistically significant differences in liver metastases (OR 1.987, 95 % CI 1.094–3.067, P = 0.024). In conclusion, the EGFR mutations in lung adenocarcinoma patients were independently correlated with distant metastases. Subgroup analyses showed that patients harboring 19del mutations presented different distant metastases compared with those harboring 21 point mutaions.