Changing patterns of Serum CEA and CA199 for Evaluating the Response to First-line Chemotherapy in Patients with Advanced Gastric Adenocarcinoma

Background: This study was designed to investigate the value of CEA and CA199 in predicting the treatmentresponse to palliative chemotherapy for advanced gastric cancer. Materials and
Methods: We studied 189 patientswith advanced gastric cancer who received first-line chemotherapy, measured the serum CEA and CA199 levels,used RECIST1.1 as the gold standard and analyzed the value of CEA and CA199 levels changes in predictingthe treatment efficacy of chemotherapy.
Results: Among the 189 patients, 80 and 94 cases had increases ofbaseline CEA (≥5 ng/ml) and CA199 levels (≥ 27U/ml), respectively. After two cycles of chemotherapy, 42.9%patients showed partial remission, 33.3% stable disease, and 23.8% progressive disease. The area under theROC curve (AUC) for CEA and CA199 reduction in predicting effective chemotherapy were 0.828 (95%CI0.740-0.916) and 0.897 (95%CI 0.832-0.961). The AUCs for CEA and CA199 increase in predicting progressionafter chemotherapy were 0.923 (95%CI 0.865-0.980) and 0.896 (95%CI 0.834-0.959), respectively. Patients whoexhibited a CEA decline ≥24% and a CA199 decline ≥29% had significantly longer PFS (log rank p=0.001,p<0.001). With the exception of patients who presented with abnormal levels after chemotherapy, changes of CEAand CA199 levels had limited value for evaluating the chemotherapy efficacy in patients with normal baselinetumor markers.
Conclusions: Changes in serum CEA and CA199 levels can accurately predict the efficacy offirst-line chemotherapy in advanced gastric cancer. Patients with levels decreasing beyond the optimal criticalvalues after chemotherapy have longer PFS.