Extracapsular lymph node spread: a new prognostic factor in gastric cancer.

BACKGROUND: Lymphatic spread is 1 of the most relevant prognostic factors for gastric carcinoma. The current International Union Against Cancer (UICC) pN staging system is based on the number of metastatic lymph nodes and does not take into consideration the characteristics of the metastatic lymph nodes itself. The aim of the current study was to examine the prognostic value of extracapsular lymph node involvement in gastric cancer and to find correlations with clinicopathological parameters.
METHODS: Tissue samples were obtained from 159 gastric cancer patients who underwent gastrectomy with D2-lymphadenectomy in 142 (89.3%) cases and subtotal gastrectomy with D2-lymphadenectomy in 17 (10.7%) cases. The number of resected lymph nodes, number of metastatic lymph nodes, and number of metastatic lymph nodes with extracapsular lymph node involvement were determined. Extracapsular spread was defined as infiltration of cancer cells beyond the capsule of the metastatic lymph node.
RESULTS: Ninety-six (60.4%) patients had lymph node metastasis. In 57 (35.8%) cases, extracapsular lymph node involvement was also detected. Extracapsular lymph node involvement was significantly associated with higher pN-category (P < .001), higher pM category (P = .048), and higher UICC stages (P = .001). According to the Kaplan-Meier log-rank statistical method, extracapsular lymph node involvement was significantly associated with poor survival (P = .001). In the multivariate analysis besides pT (P < .001) and R-category (P = .009), extracapsular lymph node involvement also remained as an independent prognostic factor (P = .003), whereas the UICC pN-category (P = .822) lost its prognostic value.
CONCLUSIONS: Extracapsular lymph node involvement is associated with higher tumor stages and is an independent negative prognostic factor in gastric cancer. In future staging systems for gastric cancer, extracapsular lymph node involvement should be considered.