Specific organ metastases and survival of advanced non-small cell lung cancer (NSCLC) patients with EGFR mutation.

e21527 Background: The retrospective study was performed to evaluate the clinicopathological characteristics and survival associated with distant metastasis from advanced NSCLC with EGFR mutation. Methods: The records of metastasis NSCLC patients with EGFR mutation at the time of diagnosis between 2012 and 2018 were reviewed. The Kaplan-Meier method was used to assess survival curves and the log-rank test was used in the univariate analysis. The multivariate survival analysis were performed using the Cox proportional hazards model to investigate the effects of clinicopathological factors on survival. All the statistical analyses were performed using SPSS 23.0 statistical software and a statistically significant difference was determined as P < 0.05. Results: A total of 258 NSCLC patients with EGFR mutation were enrolled in this study, including 146 cases of female (56.6%), 241 cases of adenocarcinoma (93.4%) and 212 cases of non-smokers (82.2%). Among these patients, 65(25.2%), 111(43.0%), 22(8.5%), 107 (41.5%), 11(4.3%), 87 (33.7%), 65 (25.2%) had brain, bone, liver, lung, adrenal gland, pleural metastasis and extrathoracic lymph node metastases, respectively. The median OS of total patients was 32.9 months (95% CI: 29.8-36.0). In the univariate analysis, patients with metastases to the bone (p = 0.001), liver (p = 0.012), extrathoracic lymph node(p = 0.006), and pleural(p = 0.008) exhibited a poorer survival compared to those without metastases to these regions. Abdominal metastases (p = 0.005) and extremity metastases (p = 0.002) were statistically independent prognostic factors. Association between metastatic region and the response to TKI treatment, liver metastases (p = 0.033), extrathoracic lymph node metastases (p = 0.000) and bone metastases (p = 0.009) were correlated with the poor response of TKI treatment, and the abdominal metastasis ( p= 0.029) and extremity metastases ( p= 0.016) were correlated with the poor response of TKI treatment. Conclusions: Bone metastases, liver metastases, extrathoracic lymph node metastases and pleural metastases were independent prognostic factors of NSCLC patients with EGFR mutation. Liver metastases, extrathoracic lymph node metastases, and bone metastases were correlated with the poor response of TKI treatment.