[Clinical Features of EGFR Double Mutation in Non-small Cell Lung Cancer].

BACKGROUND: The clinical features of patients with common single-mutation of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) has been well characterized. There is a high adenocarcinoma incidence rate among female patients with none or shorter smoking history. Those patients have higher objective response rate (ORR) and progression free survival (PFS) treated with EGFR tyrosine kinase inhibitors (EGFR-TKIs). However, it is still unclear that the clinical features of patients with EGFR double mutation and the sensitivity towards EGFR-TKIs treatment.

METHODS: We performed a retrospective cohort study of 1,238 primary NSCLC patients who had EGFR gene testing in Affiliated Hospital of Qingdao University from January 1, 2015 to December 31, 2016 and identified 603 patients with single mutation and 59 patients with double mutation. All genes were uniformly detected by using ARMS-PCR technology. We analyze the gene of 32 double-mutant patients with specific genotyping, and randomly selected 60 patients with single mutation and compared the clinical features with 59 patients with double mutation. Furthermore, we examined the efficacy of EGFR-TKIs treatment in lung cancer patients with double mutation and single mutation in EGFR.

RESULTS: The rare single mutation gene is the most common in patients with double mutation of EGFR. There is no significant statistical difference in gender, smoking history, age, pathological type or tumor-node-metastasis (TNM) staging among patients with single and double EGFR mutantion. In the double mutation patients treated with EGFR-TKIs, the objective response rate was 36.80%, the disease control rate was 68.40%. The objective response rate was 60.00% and the disease control rate was 90.00% in the patients with single mutation. However, overall PFS was significantly higher in EGFR single mutation patients (P=0.003), with median PFS of 12.0 months compared with 6.0 months in EGFR double mutation patients.

CONCLUSIONS: There was no significant difference between the clinical features of patients with EGFR double mutation and single mutation. Patients with EGFR double mutation is associated with poor survival underwent the first generation of EGFR-TKIs treatment compared with patients with a single mutation.