Role of circulating tumor cells in locally advanced gastric cancer patients treated with neoadjuvant chemotherapy combined with surgery

To investigate the clinical value of circulating tumor cells (CTC) in neoadjuvant chemotherapy combined with surgical treatment for locally advanced gastric cancer and its predictive significance for prognosis. A retrospective analysis was conducted on 158 patients with locally advanced gastric cancer who received neoadjuvant chemotherapy combined with radical surgery from January 2023 to June 2025. Patients were divided into CTC-negative group (79 cases) and CTC-positive group (79 cases) based on baseline CTC detection results. All patients received 2-4 cycles of neoadjuvant chemotherapy with capecitabine plus oxaliplatin (XELOX) regimen. CTC detection was performed using the CellSearch® system at baseline (T0), post-chemotherapy pre-surgery (T1), 1 month post-surgery (T2), 3 months post-surgery (T3), and 6 months post-surgery (T4). The efficacy of neoadjuvant chemotherapy, pathological response, survival prognosis, and patterns of recurrence and metastasis were compared between the two groups. Survival analysis was performed using the Kaplan-Meier method, and independent prognostic factors were identified using Cox regression models. Patients in the CTC-positive group had larger tumor diameter, later clinical stage, and poorer differentiation (all P<0.05). The objective response rate was significantly higher in the CTC-negative group compared to the CTC-positive group (73.4% vs 49.4%, P=0.003), and the pathological complete response rate was also significantly higher (20.3% vs 6.3%, P=0.011). With a median follow-up of 24 months, the 18-month overall survival rate, disease-free survival rate, and recurrence-free survival rate were all significantly higher in the CTC-negative group than in the CTC-positive group (92.4% vs 82.3%, P=0.042; 78.5% vs 58.2%, P=0.001; 81.0% vs 62.0%, P=0.007). The recurrence and metastasis rate was significantly higher in the CTC-positive group (38.0% vs 19.0%, P=0.009), as was the peritoneal metastasis rate (15.2% vs 3.8%, P=0.015). Multivariate Cox regression analysis showed that baseline CTC positivity was an independent risk factor affecting disease-free survival (HR=2.01, 95%CI: 1.24-3.26, P=0.005). CTC dynamic change patterns had the highest prognostic predictive value (AUC=0.838). Baseline CTC detection and dynamic monitoring have important clinical value in neoadjuvant treatment of locally advanced gastric cancer, effectively predicting treatment response and assessing prognostic risk, providing important biomarker evidence for individualized treatment decision-making and risk stratification.