Role of Serum Carcinoembryonic Antigen (CEA) as a Predictive and Prognostic Marker of Response to Treatment in Patients with Advanced Non Small Cell Lung Cancer (NSCLC)

BACKGROUND: The carcinoembryonic antigen (CEA) is an important tumor marker for malignant tumors including non small cell lung cancer (NSCLC). High serum CEA levels have been identified as a prognostic factor in both resected and metastatic NSCLC. The role of CEA as a predictive marker of response to chemotherapy have not been widely evaluated. So far only few prospective studies published in literature. The aim of the present study is to assess the role of CEA as predictive and prognostic marker of response to chemotherapy in advanced NSCLC. METHODS: Seventy nine (79) patients with advanced NSCLC (stage IIIB or Stage IV), who had an raised serum CEA level (greater than10 ng/ml) at baseline and who had no more than one previous chemotherapy regimen, were included. Serum CEA levels were measured after three treatment cycles of platinum based chemotherapy (72 %) or a tyrosine kinase inhibitor (28 %). We assessed the change in serum CEA levels and the association with response measured by RECIS criteria. RESULTS: A total of 168 patients with the diagnosis of advanced NSCLC were screened for CEA levels before the start of CT. Seventy nine patients finally evaluated according to criteria in the study After three cycles of chemotherapy, Patients with overall response (OR) had a CEA level reduction of 76.7 % (95 % CI 80.4-68.9) ; while patients with stable disease (SD) and progressive disease (PD) had an increase of 9.4 % (95 % CI 1.5 to 17.3) and 87.5 % (95 % CI 60.9 to 114), respectively. The ROC curve analysis for the changes in CEA levels in responsive patients had an area under the curve (AUC) of 0.803 (95 % CI 0.67 to 0.93). Sensitivity and specificity were 85.4 and 86 % (p less than 0.003) respectively for a CEA level reduction of 28 % or greater. Patients that achieved a decrease in CEA levels 28 % presented an overall response in 76 % of cases, stable disease in 13 % and progression in 11 %, while patients who did not attain a reduction 28 % had an overall response of 14 %, stable disease of 20 % and progression of 66 % (p less than 0.006). The AUC in progressive disease was 0.840 (95 % CI 0.72 to 0.95; fig 14), with a sensitivity and specificity of 86.7 and 87.2 %, respectively, for a CEA level increase of 28 % from baseline. The median follow up time was of 8.72 3.97 months. PFS was longer in patients with 28 % reduction in CEA (p 10 mg/dl) at baseline.