CEA is an independent prognostic indicator that is associated with reduced survival and liver metastases in SCLC.

Small-cell lung cancer (SCLC) is classified into two stages, limited-stage small-cell lung cancer (LS-SCLC) and extensive-stage small-cell lung cancer (ES-SCLC), with ES-SCLC being associated with reduced survival. However, disease stage alone is not a very precise predictor of survival time. The aim of this study is to search for a prognostic indicator that can be used in conjunction with the staging system in SCLC. We performed a prospective analysis of 116 patients with SCLC undergoing standard chemotherapy with or without radiotherapy. Expression levels of 12 tumor markers were measured at the time of diagnosis by a commercial protein chip system, and patients were followed up for a maximum of 54 weeks. CEA was the most frequently detected tumor marker in SCLC, with 32.8% of samples scoring positive, and was also the only marker that correlated with overall survival. The average survival time was 16.78 months for patients with CEA below 5 ng/ml and 11.4 months for patients with CEA above 5 ng/ml (P < 0.001). In contrast, no association was found between tumor stage and overall survival. CEA expression was independent of tumor stage (P = 0.930). CEA is an independent prognostic factor that can be used in conjunction with disease stage in SCLC.