Clinical value of carcinoembryonic antigen for predicting the incidence of brain metastases and survival in small cell lung cancer patients treated with prophylactic cranial irradiation

BACKGROUND: Although the role of prophylactic cranial irradiation (PCI) in the treatment of small cell lung cancer (SCLC) has been confirmed, the occurrence of brain metastases (BM) in patients remains a major problem. We designed this study to evaluate the clinical value of carcinoembryonic antigen (CEA) for predicting the incidence of BM and survival in SCLC patients who received PCI. MATERIALS AND METHODS: The records of 128 consecutive SCLC patients, who underwent PCI in our institute between 2005 and 2015, were analyzed. The collected data included clinicopathological features and the levels of CEA, neuron-specific enolase (NSE), cytokeratin 19 fragments (CYFRA21-1), and albumin. Kaplan–Meier and Cox regression analyses were used to determine the factors that affect BM and survival in SCLC patients after PCI. RESULTS: In total, 128 patients were identified, with a median (range) age of 62 (30–83) years. Thirty-two patients developed BM at some time during follow-up. The median levels of CEA, NSE, CYFRA21-1, and albumin were 7.6 ng/mL, 44 ng/mL, 4.6 ng/mL, and 42.1 g/L, respectively. In the multivariate analysis, CEA level (HR: 2.479, 95% CI: 1.101–5.581; P=0.028), advanced clinical stage (HR: 2.929, 95% CI: 1.338–6.413; P=0.007), and NSE level (HR: 3.021, 95% CI: 1.226–7.442; P=0.016) were significantly correlated with BM. CEA (HR: 1.903, 95% CI: 1.133–3.195; P=0.015) and advanced clinical stage (HR: 2.002, 95% CI: 1.227–3.267; P=0.005) were independently associated with worse overall survival in SCLC patients. CONCLUSION: CEA is an independent predictive factor for the incidence of BM after PCI in SCLC and can be used as a predictor of BM in SCLC. In addition, a high level of CEA indicates a poor prognosis in SCLC patients after PCI. Prospective randomized clinical studies are required to confirm these findings.