AB84. Prognostic value of examined lymph node count on patients with node-negative gastric cancer

Objective: Count of positive lymph node could assess the prognosis of node-positive gastric cancer patients according to the 7^th Union for International Cancer Control (UICC) TNM classification system. However, the same staging system defines lymph node-negative gastric cancer regardless of the number of examined lymph nodes (eLNs). We aimed to determine the minimum number of eLNs required for curative gastrectomy and explore an appropriate category based on the count of eLNs for precise predication the prognosis of patients with negative lymph node metastasis gastric cancer after curative surgery.

Methods: We retrospectively analyzed the clinicopathologic characteristics and overall survival (OS) of 497 patients with node-negative gastric cancer after curative gastrectomy to evaluate the association between survival and the number of eLNs.

Results: Patients had a better survival outcome with eLNs >15 compared with those with eLNs ≤15 for the entire cohort. With the multivariate survival analysis, we demonstrated the depth of invasion, and the number of eLNs was the independent predictors of OS of patients with node-negative gastric cancer. According to the cut-point analysis, T2-T4 patients with 11-15 eLNs had a significantly longer mean OS than those with 4-10 eLNs or 1-3 eLNs.

Conclusions: Number of eLNs could predict the prognosis of node-negative gastric cancer. In order to improve the long-term survival more than 15 eLNs is recommended during lymphadenectomy.

Keywords: Lymph node count; gastric cancer; prognosis; TNM classification