[Correlation between Changes in Serum Level of CEA and CYFRA 21-1 and Objective Response of Chemotherapy.].

Background: Serum levels of tumor markers are associated with tumor metabolism or apoptosis, changes of which after chemotherapy may reflect tumor response to treatment. The aim of this study was to assess the predictive role of changes in serum levels of carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA 21-1) during chemotherapy in patients with advanced non-small cell lung cancer.
Methods: Changes in serum levels of CEA and CYFRA 21-1 were investigated retrospectively after one cycle of chemotherapy in 42 patients with advanced NSCLC. Correlations between the changes and radiological objective response were analyzed.
Results: After two cycles of chemotherapy, radiological objective response rate was 28.6%. At baseline, gender, age, clinical stage, serum levels of CEA and CYFRA 21-1 were not different between patients with objective response (OR) and no response (NR). After one cycle of chemotherapy, compared to baseline level, declines in serum levels of CEA and CYFRA 21-1 were observed in patients with OR, but have no statistical significance. In contrast, reduction of CEA and CYFRA 21-1 over baseline after one cycle of chemotherapy showed statistically significant difference between OR and NR. When reduction percentages of CEA and CYFRA 21-1 were used to predict objective response of chemotherapy, the area under the ROC curve (AUC) was 0.875 for CEA and 0.919 for CYFRA 21-1. According to the ROC curve, a 22% reduction of CEA yielded a sensitivity of 58.3% and a specificity of 97%, 51% reduction of CYFRA 21-1 with a sensitivity of 83.3% and a specificity of 93.3%. When above reduction percentages were used as cutoffs for prediction of radiological objective response, combination of the CEA and CYFRA 21-1 yielded a sensitivity of 91.7% and a specificity of 86.7%.
Conclusions: Reduction percentages of CEA and CYFRA 21-1 during chemotherapy could be used to evaluate chemotherapy efficacy in patients with advanced NSCLC. The cutoffs of reduction percentage need further research.