Lymphatic invasion as the solitary risk factor for extraperigastric lymph node metastasis in early gastric cancer.

Background: Lymph node metastasis, particularly to extraperigastric lymph nodes, is an important issue in determining the suitability of minimally invasive treatment for early gastric cancer. However, there is a paucity of research focused on identifying risk factors for extraperigastric lymph node metastasis, which is crucial for optimizing treatment selection.

Methods: Patients who underwent radical gastrectomy for early gastric cancer between 2007 and 2023 at Korea University Guro Hospital and Kyung Hee University Hospital at Gandong in Seoul, Korea, were reviewed retrospectively. We compared clinicopathologic characteristics to find out risk factors for lymph node metastasis between the no lymph node metastasis, perigastric lymph node metastasis, and extraperigastric lymph node metastasis groups.

Results: A total of 1,021 patients were included in the study, with 90.0% in the lymph node metastasis, 7.94% in perigastric lymph node metastasis, and 2.06% in extraperigastric lymph node metastasis groups. Clinicopathologic analysis revealed the lymph node metastasis group exhibited a greater prevalence of mucosal lesions (55.2%), whereas the perigastric lymph node metastasis and extraperigastric lymph node metastasis groups demonstrated a greater incidence of SM3 invasion (55.6% and 52.4%, respectively; P < .001). Lymphatic invasion were found to be significantly different among the groups (P < .001). Multinomial logistic regression identified lymphatic invasion as a sole significant risk factor for the perigastric lymph node metastasis and extraperigastric lymph node metastasis groups. The 5-year relapse-free survival rates were 99.0% (lymph node metastasis), 94.5% (perigastric lymph node metastasis), and 100% (extraperigastric lymph node metastasis) (P = .011).

Conclusion: This multicenter retrospective analysis indicates that lymphatic invasion is the primary independent predictor of extraperigastric lymph node metastasis in patients with early gastric cancer. Future prospective research is warranted to validate this result and establish guidelines for treatment decision-making for early gastric cancer.