Objectives: The study aimed to evaluate the prognostic significance of carcinoembryonic antigen levels in pleural lavage fluid (p-CEA) in patients with completely resected non-small-cell lung cancer (NSCLC).
Methods: We examined 72 patients who underwent curative surgical resections. Pleural lavage fluid was collected at thoracotomy before lung resection. Pleural lavage cytology and p-CEA were determined. The relationships between p-CEA and clinicopathological factors were analysed.
Results: Four patients (5.6%) had positive pleural lavage cytologies. The median p-CEA was 65.2 ng/g protein (range, 0-7331.7). p-CEA was significantly correlated with pleural invasion and CEA levels in serum (s-CEA). Receiver operating characteristic curve analysis identified an optimal cut-off of 38 ng/g protein for p-CEA for predicting recurrence [area under the curve (AUC) = 0.669; sensitivity = 91.7%; specificity = 43.7%; 95% confidence interval (CI) = 0.541-0.796; P = 0.020], whereas this could not be identified for s-CEA (AUC = 0.535; 95% CI = 0.392-0.678; P = 0.629). With a mean follow-up period of 57.5 months, 5-year disease-free survival (DFS) rates were 86.5% for p-CEA ≤ 38 ng/g protein and 47.7% for p-CEA >38 ng/g protein (P = 0.0013). Even for patients with Stage I lung cancer, 5-year DFS rates were 88.2 and 53.8%, respectively (P = 0.017). Multivariate Cox analysis revealed that p-CEA was a significant independent factor for DFS and overall survival.
Conclusions: Intraoperative p-CEA may be a more powerful prognostic determinant than s-CEA for patients with NSCLC.