Analysis and Exploration of the Relationship Between the Status of Serum Tumor Markers and Clinicopathological Features and Curative Effects in Gastric Cancer and Gastroesophageal Junction Tumor.

Background: The detection of tumor markers for predicting the therapeutic efficacy is relatively rare at present. The combined elevation of carcinoembryonic antigen (CEA), CA19-9, CA72-4, and CA125 and others may predict the efficacy of immunotherapy combined with chemotherapy, which is helpful for the precise screening of patients. This study aimed to investigate the correlation between serum tumor marker expression and clinical features, including stage, differentiation, primary site, and metastatic diameter. It also examined the relationship between tumor marker levels and the therapeutic efficacy in advanced gastric cancer patients. Methods: We analyzed 327 patients with gastric or esophagogastric junction adenocarcinoma at Henan Provincial People's Hospital. CEA, CA19-9, CA125, and CA72-4 levels were categorized as negative, single-marker elevated, or multiple-marker (≥2) elevated. Clinical features and survival outcomes were evaluated. Results: Elevated marker numbers correlated significantly with advanced clinical stage, lower differentiation, Lauren classification type, and larger metastatic diameter. Patients with stage IV disease exhibited higher marker elevations than those with earlier stages. No significant association was observed between the number of tumor elevated markers and T/N stage, primary/metastatic site, or PD-L1 combined positive score >5. After first-line chemotherapy, the objective response rate was positively correlated with elevated tumor marker numbers, single- rather than multiple-marker elevation showed better progression-free survival. In immunotherapy combined with chemotherapy, any increase in a tumor marker ≥5 times with a total metastasis diameter <6 cm, indicating better short-term efficacy. Conclusion: Elevated serum tumor markers are associated with higher tumor burden, advanced stage, and poorer differentiation in gastric cancer, potentially serving as disease severity and treatment response predictors.