Serum Carcinoembryonic Antigen Levels and the Risk of Whole-body Metastatic Potential in Advanced Non-small Cell Lung Cancer

Background: This study aimed to clarify the clinical associations between serum carcinoembryonic antigen (CEA) levels and whole-body metastatic distribution in stage IV NSCLC patients. Methods: This study analyzed 377 eligible patients between June 2007 and December 2012. All patients enrolled in the study were newly diagnosed with stage IV NSCLC and had records of pre-treatment serum CEA levels. The serum CEA levels were categorized as normal (< 5 ng/ml) or abnormal (≥ 5 ng/ml) to reveal clinically correlated factors with abnormal serum CEA levels. Results: The median age of the study cohort was 65 years old (range, 30-94), and 236 (62.6%) patients were male. Two hundred seventy-seven (73.5%) patients had tumors with a histology that is consistent with adenocarcinoma. The median serum CEA value was 8.2 ng/ml (range, 0.1-2872.7), and 218 (57.8%) patients had abnormal serum CEA levels. In multivariate analysis, abnormal serum CEA levels had statistically strong associations with non-squamous cell histology (P=0.002), bone (P=0.001), and brain metastases (P=0.005); and were also closely correlated with positive metastatic LN status (P=0.083) and pulmonary metastasis (P=0.065). Very high serum CEA levels (≥ 100 ng/ml) were additionally correlated with abdominal/pelvic metastasis (P < 0.001). Conclusions: Our findings suggested that abnormal serum CEA levels were strongly correlated with increased whole-body metastatic potential in advanced NSCLC. The results provided evidence for future exploratory anti-CEA targeting and intensive systemic assessment in advanced NSCLC patients with abnormal serum CEA levels.