Evaluation of the diagnostic value of combined gastrointestinal endoscopy and serum CEA and CA19-9 levels in gastrointestinal tumor

Gastroscopy is the gold standard for diagnosing gastrointestinal tumors but has limitations in early tumor detection. Serum biomarkers carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) are widely used in cancer screening and diagnosis; however, their sensitivity and specificity are often insufficient when used alone. Therefore, combining gastroscopy with serum biomarker testing may improve early diagnostic accuracy. This study aimed to evaluate the diagnostic value of combining gastroscopy with serum CEA and CA19-9 testing for gastrointestinal tumors. This retrospective cohort study included patients who visited our hospital from January 2023 to January 2025 for gastrointestinal diseases and underwent gastroscopy. We applied propensity score matching (PSM) to control for confounding factors, resulting in 60 patients in the experimental group (gastrointestinal malignant tumor group) and 80 patients in the control group (nonmalignant gastrointestinal tumor group). Serum levels of CEA and CA19-9 were measured using chemiluminescent immunoassay. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic performance of each method and analyze the effectiveness of the combined test. The study found that the combination of gastroscopy with serum CEA and CA19-9 testing significantly increased the diagnostic sensitivity and specificity for gastrointestinal malignant tumors. The sensitivity and specificity for gastroscopy alone were 92.5% and 85.5%, respectively. The sensitivity and specificity for serum CEA and CA19-9 combined testing were 95.0% and 90.0%, respectively. When gastroscopy was combined with serum biomarkers, the diagnostic sensitivity increased to 97.5%, with specificity of 92.5%. Additionally, serum CEA and CA19-9 levels were positively correlated with tumor staging, with levels significantly increasing as tumor stage progressed. This study demonstrates that combining gastroscopy with serum CEA and CA19-9 testing provides significant clinical advantages in diagnosing gastrointestinal tumors. The combined test significantly improves diagnostic sensitivity and specificity, particularly for early screening and tumor staging evaluations.