Clinical significance of preoperative carcinoembryonic antigen level for clinical stage I non-small cell lung cancer: can preoperative carcinoembryonic antigen level predict pathological stage?

The purpose of the present study was to retrospectively analyze the clinicopathological characteristics and clarify whether or not the preoperative carcinoembryonic antigen (CEA) level could be used as a decision-making factor as an adjunct to the TNM staging system in patients with clinical stage I non-small cell lung cancer (NSCLC). Between 1993 and 2006, 815 patients who had clinical stage I NSCLC were analyzed retrospectively. The CEA level was defined as being either normal (CEA<or=5 ng/ml), high (5<CEA<or=30 ng/ml) and very high (CEA>30 ng/ml) sub-groups. The rate of patients with an elevated CEA level was 33.6%. The five-year disease-free survival rates for patients with normal, high and very high CEA levels were 76.7, 60.0 and 31.3%, respectively. The survival curve for patients with a normal CEA level almost overlapped that for p-stage I, that for a high CEA level nearly overlapped that for p-stage II, and that for a very high CEA level nearly overlapped that for p-stage III. The present study demonstrated that the preoperative CEA level was a very good predictor of the pathological stage. These findings suggest that the preoperative CEA level may be useful as an adjunct to the TNM staging system.