Predictive factors for lymph node metastasis in additional gastrectomy after endoscopic resection of cT1aN0 gastric cancer.

PURPOSE: Endoscopic therapy for clinical T1aN0 (cT1aN0) gastric cancer is an excellent therapeutic strategy; however, pathological lymph node metastasis (LNM) occasionally occurs. Patients who have a potential for LNM are subject to additional gastrectomy. Our aim was to identify predictors of LNM in additional gastrectomy.
METHODS: One hundred and twelve cT1aN0 gastric cancer patients undergoing additional gastrectomy after endoscopic resection were identified between 1997 and 2013. Predictors for LNM were initially selected by a univariate analysis and applied to a multivariate analysis.
RESULTS: (1) Twelve patients (10.7 %) had LNM following additional gastrectomy. (2) Clinicopathological factors significantly associated with LNM were the depth of invasion (SM2 or deeper, designated as SM2) (p = 0.0018) and rigorous lymphatic invasion (ly2,3) (p < 0.001). (3) The univariate predictors for LNM were applied to the multivariate logistic regression model, and SM2 (p = 0.0027) and ly2,3 (p = 0.0028) remained significant predictors. (4) When classified into 2 × 2 subgroups, the predictability for LNM was as follows: SM2 plus ly2,3 (46.7 %), SM2 plus ly0,1 (10.0 %), M,SM1 plus ly2,3 (0 %), and M,SM1 plus ly0,1 (0 %).
CONCLUSIONS: In cT1aN0 gastric cancer patients, both SM2 and ly2,3 are significant predictors for LNM that may be important as references for additional gastrectomy after endoscopic resection.