Diagnostic strategy based on preoperative serum CEA levels in clinical stage IA NSCLC

Abstract

17011 Background: Following surgery, clinical stage IA NSCLC diagnosed using non-interventional examinations is occasionally pathological stage III or IV. The level of carcinoembryonic antigen (CEA) in serum has been reported to be a predictor of up-staging to advanced stages, however, there are few multi-center studies of serum CEA that utilized a short accrual period. Methods: A multi-center retrospective study was performed to assess serum CEA level as a predictor of advanced stage in 862 consecutive patients with clinical stage IA NSCLC from 2002 to 2004. The subjects were 493 males with a mean age of 65.2 years old, 460 of whom were smokers, who had a total of 689 adenocarcinomas with a mean tumor size of 19.5 cm. They were divided into 4 groups by smoking status and adenocarcinoma histology, after which AUC was calculated using an ROC curve, which provided an estimate of the probability efficiency of pathological diagnosis of stage III or stage IV. When AUC was greater than 0.7, sensitivity, specificity, and positive predictive values were calculated, and multivariate Cox regression analysis was performed to confirm independence. Results: There were 72 cases (8.1%) in an advanced stage. AUC was greater than 0.7 in the group of non-smokers with an adenocarcinoma (n = 413), in which the sensitivity, specificity, and positive predictive values were 0.14, 0.97, and 0.64, respectively, with a CEA cut-off level of 20 ng/ml. Thus, serum CEA level was shown to be an independent predictive factor. Conclusions: In smokers with an adenocarcinoma, a high level of CEA in serum was frequently found in those with pathologically advanced disease, thus intervention should be mandated in such cases. [Table: see text] No significant financial relationships to disclose.