Association between primary tumor location and lymph node metastatic patterns in gastric cancer: A single-center retrospective study.

Gastric cancer is a common malignancy of the digestive system worldwide, and lymph node metastasis is a key determinant for prognosis assessment and therapeutic decision-making. Patterns of lymphatic drainage and nodal spread may differ according to the primary tumor location. This study aimed to investigate the relationship between primary tumor site and lymph node metastatic characteristics. A total of 160 patients who underwent curative gastrectomy between February 2022 and June 2024 were retrospectively reviewed. According to the primary tumor location, patients were categorized into the cardia, body, and antrum groups. Lymph node metastasis rate, involved stations, metastatic extent, and lymph node ratio (LNR) were compared among groups. Multivariate logistic regression was performed to identify independent risk factors. The metastasis rates in the cardia, body, and antrum groups were 74.5%, 63.5%, and 58.5%, respectively, showing a decreasing trend. Cardia tumors predominantly involved stations No. 1 and No. 2, whereas antral tumors mainly involved stations No. 5 and No. 6 (P < .05). Patients with poorly differentiated or special-type histology had significantly higher LNRs. Multivariate analysis indicated that primary tumor located in the cardia, T3-T4 stage, and poor differentiation were independent risk factors (P < .05). Patients with diffuse-type lymphatic spread had markedly lower 3-year disease-free and overall survival compared with those with localized spread. Primary tumor location is closely associated with lymph node metastatic patterns in gastric cancer. Cardia tumors are more prone to longitudinal and cross-regional metastasis, while high T-stage and poor differentiation are linked with extensive nodal involvement and worse prognosis. Combined assessment of primary site and LNR may provide a useful reference for preoperative evaluation and lymphadenectomy planning.