A Practical Decision-Making Strategy Based on Clinical Triple Features for Egfr-Tkis to Treat Advanced Non-Small Cell Lung Cancer Patients with Unknown Egfr Mutation Status.

e19082 Background: EGFR mutated lung cancers are strongly associated with clinical characteristics of never- smoking history and adenocarcinoma histology type, and tended to develop multiple pulmonary metastases.Whether multiple pulmonary metastatic lung adenocarcinomas with never-smoking history would respond to EGFR-TKIs as those harboring EGFR active mutation remains unclear. Methods: 223 consecutive metastatic non-small cell lung cancer (NSCLC) patients with unknown EGFR status who received EGFR-TKIs as salvage therapy after failure of previous platinum-based chemotherapy in Shanghai Pulmonary hospital between 2009 and 2011 were included to the study. Available CT scans, routinely performed at baseline and one month after the start of EGFR-TKIs therapy, were reviewed independently by two investigators. For the purposes of this study, diffuse pulmonary metastatic nodules were defined as multiple nodules distributed diffusely throughout the whole lung with at least 20 nodules within the unilateral lung field. Paraffin embedded tissues were available for 45 of 223 patients for EGFR gene mutation test. Results: Of 134 never-smokers with lung adenocarcinoma,70 patients responded to EGFR-TKIs with an objective response rate (ORR) of 52.2% (70/134), and the ORR for the 62 patients with diffuse pulmonary metastatic nodules was 79% (49/62). Among the 20 patients with confirmed EGFR mutation (based on the available 45 archived specimen), the ORR was 75% (15/20). The multivariate analyses showed that the presence of diffused multiple pulmonary metastatic nodules, activating EGFR mutation and female are independent predictive factors of the response to EGFR-TKIs. Conclusions: Patient selection based on specific clinical features to recieve EGFR-TKI treatment yield high response rate comparable to that selected by EGFR mutation status. It is practical to consider EGFR-TKI as salvage therapy in non-smoking patients with lung adenocarcinoma characterized by diffuse pulmonary nodules when EGFR mutation testing is a challenge.