Number and Anatomical Extent of Lymph Node Metastases in Gastric Cancer: Analysis Using Intra-lymph Node Injection of Activated Carbon Particles (CH40)

Background: The long-term survival of 200 patients with gastric cancer who underwent radical gastrectomy was analyzed with respect to the number and anatomical extent of lymph node metastasis. All of the patients received intra-lymph node injection of fine activated carbon particle solution (CH40) during surgery. Methods: The average number of resected lymph nodes increased in line with the anatomical level of lymph node dissection; 32.5 per patient in 01,42.3 in D2,3 and 66.3 in 04. The percentage of blackened lymph nodes without metastasis (42.4%) was slightly higher than that of lymph nodes containing metastasis (37.2%), but the difference was not statistically significant. Of the 200 patients, 61 (30.5%) had microscopic evidence of metastatic lymph node involvement. Twenty-two patients had between one and three metastatic lymph nodes, 19 had between four and nine and 20 patients had more than nine. The 5-year survival rate was 93.1% in patients without lymph node metastasis, 71.9% in patients with 1-8 metastatic nodes, 36.1% in patients with 4-9 nodes and 19.2% in patients with >9 nodes. Results: The 5-year survival rate according to the anatomical extent of metastatic lymph nodes was 93.1% in nO, 63.1% in n1, 37.9% in n2, 27.8% in n3 and 0% in n4. The number of metastatic lymph nodes and also their anatomical extent were identified as independent prognostic factors for survival by multivariate analysis. Conclusion: The number and anatomical extent of metastatic lymph nodes have similar impacts on prognosis in gastric cancer.