Evaluation of the relationship between serum carcinoembryonic antigen level and treatment outcome in surgically resected clinical-stage I patients with non-small-cell lung cancer

The relationship between preoperative serum carcinoembryonic antigen (CEA) level and treatment outcome for 39 clinical-stage I patients with surgicall y resected nonsmall-cell lung cancer (NSCLC) was retrospectively studied. S erum CEA levels were measured with an enzyme-linked immunosorbent assay kit , with the upper limit of normal defined as 6.7 ng/mL based on the 95% spec ificity level for benign lung disease in our hospital. Patients with serum CEA greater than or equal to 6.7 ng/mL (n=9) were more likely to have advan ced disease at surgery than those with serum CEA < 6.7 ng/mL (n = 30) (77.8 % vs 16.7%, p = 0.0049). This increase in disease stage at surgery was main ly due to mediastinal lymph node metastasis. The sensitivity and specificit y of serum CEA in the detection of pathological N2 disease were 62.5% and 8 71%, respectively Survival for the high CEA group was significantly worse t han that for the low CEA group (median survival time, 40.2 vs 75.8 months, p = 0.0125). Relapse-free survival for the high CEA group was also poorer t han that of the low CEA group (p= 0.0032). In a multivariate analysis, seru m CEA level was the most dominant factor affecting relapse-fuee survival (h azard ratio = 6.68, p = 00053). These findings suggest that preoperative se rum CEA level is useful not only in detection of mediastinal lymph node met astasis, but also in prediction of survival for clinical-stage I patients w ith NSCLC.