Lymph node micrometastasis in node negative early gastric cancer

Aims: The clinical significance of lymph node micrometastasis for histologically node negative gastric cancer is not well documented. This study was to assess the incidence and to clarify the risk factors of lymph node micrometastasis in patients with node negative early gastric cancer (EGC). Methods: We investigated the lymph node micrometastasis with using an anticytokeratin immunohistochemical stain in 90 patients with node negative EGC who underwent curative resection between 1991 and 2000. Results: Among 3526 nodes from 90 patients, there were 17 cytokeratin immunohistochemical stain positive nodes from nine patients. The incidence of micrometastasis was higher in patients with lymphatic invasion (p = 0.012), venous invasion (p = 0.026) and larger tumor (p = 0.003). The independent risk factors for lymph node micrometastasis were lymphatic invasion (p = 0.004, RR = 22.915, 95% CI = 2.709 ∼ 193.828) and tumor size (p = 0.029, RR = 1.493, 95% CI = 1.042 ∼ 2.138). Although there were 10 deaths during the follow-up period of mean 67.6 months (1 month ∼ 147 months), there was no death from a cancer recurrence. Conclusions: The incidence of lymph node micrometastasis in patients with node negative early gastric cancer was 10%, and the independent risk factors for micrometastasis were lymphatic invasion and tumor size.