The association of the BRAF V600E mutation with a protective factor for lung metastases in papillary thyroid cancer

1307 Objectives: To investigate the relationship between BRAF V600E mutation and lung metastasis in papillary thyroid carcinoma (PTC).Methods A retrospective analysis of 1800 patients with PTC treated our department from January 2014 to July 2017, we excluded patients with other distant metastases, lung nodules that diagnosis were unclear. A total of 1774 patients with PTC, of which 96 cases with lung metastases. Data were analyzed by chi-square test, non-parametric rank sum test and logistic regression analysis using SPSS 19.0 software. A P-value of 0.05).The ROC analysis suggested size of largest metastatic LN>0.9cm to predict future lung metastasis with corresponding specificity of 0.750, sensitivity of 0.716, and AUC of 0.789 (95% CI 0.743-0.835, P 1 year(OR:3.603,95% CI: 1.274-10.189, P=.016), special pathological subtypes(OR:3.312, 95% CI:1.369-8.012, P=.008),larger primary tumor size(OR:2.490,95% CI:1.494-4.149,P=.000), size of largest metastatic LN>0.9cm(OR:4.319, 95% CI: 1.364-13.672, P=.013) denoted risks of lung metastasis, however, BRAF V600E mutation was a protective factor(OR:0.200, 95% CI: 0.099-0.405, P=.000) (Table 1).Conclusions The BRAF (V600E) mutation was a protective factor for lung metastases in papillary thyroid cancer. However, patients in PTC with special pathological subtypes, larger primary tumor size, size of largest metastatic LN>0.9cm and the interval time>1 year(from the first surgery to the first 131I treatment) were higher risk for lung metastasis.