Analysis of risk factors for peritoneal metastasis in patients with advanced gastric cancer

Peritoneal metastasis is a common and adverse pattern of disease spread in patients with advanced gastric cancer, yet its clinicopathological determinants are not fully clarified. This retrospective observational study included 154 patients with histopathologically confirmed advanced gastric cancer treated at a single tertiary center between January 2020 and December 2024. Patients were categorized into a peritoneal metastasis group (n = 38) and a non-peritoneal metastasis group (n = 116) according to predefined diagnostic criteria based on contrast-enhanced computed tomography, staging laparoscopy, cytology, and intraoperative findings. Demographic, clinical, pathological, imaging, and intraoperative variables were extracted from electronic medical records, and comparisons between groups were performed using t tests and χ2 tests. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for peritoneal metastasis. Baseline characteristics, including age, sex, body mass index, and major comorbidities, were comparable between groups, whereas Eastern Cooperative Oncology Group performance status ≥ 2 was more frequent in the peritoneal metastasis group. In multivariate analysis, tumor size ≥ 5 cm (odds ratio [OR] = 3.49, 95% confidence interval [CI]: 1.63-7.50), diffuse Lauren type (OR = 3.32, 95% CI: 1.49-7.42), lymphovascular invasion (OR = 2.59, 95% CI: 1.23-5.45), and peritoneal thickening or nodules on computed tomography (OR = 4.95, 95% CI: 2.17-11.28) were independently associated with peritoneal metastasis. These findings indicate that combining routine histopathological features with standard imaging signs may improve preoperative risk stratification and help select candidates for staging laparoscopy and individualized treatment strategies in advanced gastric cancer.