Abstract
BACKGROUND: In clinical practice, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 are the most common markers measured before and after surgery for gastric cancer (GC). However, which pre- or post-operative combined tumour markers (CEA and CA19-9) have more prognostic value remains unclear. METHODS: Consecutive patients undergoing a resection for GC at the Fujian Medical University Union Hospital were included as a discovery database between January 2011 and December 2014. The prognostic impact of pre- and post-operative tumour markers was evaluated using Kaplan-Meier log-rank survival analysis and multivariable Cox regression analysis. The results were then externally validated. RESULTS: A total of 735 and 400 patients were identified in the discovery cohort and in the validation cohort, respectively. Overall survival rates decreased in a stepwise manner in association with the number of pre- and post-operative positive tumour markers (both P < 0.001). Multivariable analysis revealed that the number of pre-operative positive tumour markers was an independent prognostic factor (P < 0.05). For patients with abnormal pre-operative tumour markers, normalisation of tumour markers after surgery is an independent prognostic protective factor (hazard ratio (HR) = 0.618; 95% confidence interval (CI) = 0.414-0.921), and patients with both positive post-operative tumour markers had double the risk of overall death (HR = 2.338; 95% CI = 1.071-5.101). Similar results were observed in the internal validation and external validation cohorts. CONCLUSION: Pre-operative tumour markers have a better discriminatory ability for post-operative survival in GC patients than post-operative tumour markers, and the normalisation of tumour markers after surgery was associated with better survival.