Abstract
BACKGROUND: Gastric cancer (GC) is an aggressive malignancy of the gastrointestinal tract characterized by high recurrence rates following radical gastrectomy. To enhance treatment efficacy, reduce recurrence, and improve patient survival, adjuvant chemotherapy is commonly administered based on established postoperative guidelines. Despite advancements in chemotherapy delivery, the overall response rate remains below 50%, primarily due to the lack of targeted therapies tailored to specific patient populations. AIM: To explore sensitive biomarkers to assess the efficacy of postoperative adjuvant chemotherapy in appropriate patient subgroups. METHODS: This study retrospectively analyzed 1628 patients who underwent radical gastrectomy for GC at our hospital in 2017 and 2018, with a subsequent five-year follow-up. Patients were divided based on whether they received postoperative adjuvant chemotherapy. The study aimed to determine optimal cutoff values for various biomarkers-neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 199, CA724, and CA242-using receiver operating characteristic (ROC) curves. Based on the optimal ROC cut-off, a novel combined metric, NLR-CEA, was developed to assess the efficacy of adjuvant chemotherapy following GC surgery. RESULTS: Cox subgroup analysis demonstrated that postoperative adjuvant chemotherapy significantly improved overall survival in the NLR-CEA_Low group with a rate of 0.41 (0.26-0.63). In the NLR-CEA_Middle group, the protective effect was observed at 0.69 (0.54-0.87), while in the NLR-CEA_High group, it was 0.73 (0.53-0.99). Notably, a 32% difference in the efficacy of chemotherapy was observed between the NLR-CEA_Low and NLR-CEA_High groups. CONCLUSION: NLR-CEA is an effective biomarker for evaluating the efficacy of postoperative adjuvant chemotherapy in GC. Patients with NLR-CEA_Low exhibit significantly better responses to chemotherapy compared to those with NLR-CEA_High.