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.