Oncologic outcomes of patients with negative nodal involvement on preoperative imaging undergoing surgery for gastric cancer

Preoperative assessment of lymph node status is crucial in guiding treatment decisions for gastric cancer (GC) patients. However, it may not always accurately detect occult lymph node metastasis (OLNM). Identifying patients at high risk for OLNM despite negative preoperative imaging (cN0) is critical for optimizing treatment strategies, particularly the consideration of neoadjuvant therapy or the extent of lymphadenectomy. GC patients with cTanyN0M0 who underwent upfront surgery at the Sixth Affiliated Hospital of Sun Yat-sen University from January 2008 to May 2023 were analyzed. Patients were stratified by postoperative pathological nodal involvement, and clinicopathological characteristics were compared, and a nomogram was constructed. A total of 722 patients were reviewed, 261 (36.15%) patients had postoperative pathologic lymph node involvement (pN+). The 5-year overall survival in the pN0 group and pN + group was 97.8% and 84.85% (p < 0.01), respectively. Multivariate analysis identified several variables associated with pN+, including body mass index (BMI) < 18.5 kg/m2 (OR 2.15, 95% CI 1.02–3.93, p < 0.01), serum carbohydrate antigen (CA)-199 (OR 2.51, 95% CI 1.31–4.95, p < 0.01), T2 staging (OR 4.71, 95% CI 2.70–8.54, p < 0.01), T3 staging (OR 8.0, 95% CI 4.71–13.99, p < 0.01), T4 staging (OR 15.81, 95% CI 6.39–41.45, p < 0.01), and poorly differentiated tumor (OR 3.02, 95% CI 1.46–6.79, p < 0.01). A nomogram constructed using those variables showed good discriminatory performance (AUC = 0.729) in predicting OLNM in GC. BMI, CA-199, T stage, and differentiation are associated with OLNM in GC. A nomogram predicting OLNM could help physicians in selecting optimal treatment strategies for GC patients. However, the model has not undergone external validation, and its clinical use should await confirmation in multicenter, prospective cohorts.