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Background: The application of endoscopic and local resections for early gastric cancers is limited by the presence of regional lymph node (LN) metastases. We sought to determine the incidence and predictors of LN metastases in patients with early gastric cancer.
Methods: A total of 71 patients with pT1 gastric adenocarcinoma underwent radical surgery without neoadjuvant therapy at our institution between 1995 and 2011. Preoperative endoscopic ultrasound (EUS) staging was performed on 17 patients. Clinicopathologic factors predicting regional LN metastases were analyzed.
Results: LN metastases were present in 2 of 28 (7.1%) T1a tumors and 14 of 43 (32.6%) T1b tumors, for an overall rate of nodal positivity of 23%. The median number of examined LN for the entire cohort was 15, including 20 for LN-positive patients and 15 for LN-negative patients. On univariate analysis, the presence of submucosal tumor invasion (p=0.012), lymphovascular invasion (LVI) (p<0.001), and positive nodal status by EUS (p<0.001) were significant predictors of LN metastasis. Tumor size, site, degree of differentiation, and perineural invasion status did not predict LN metastasis. The presence of LVI was the only factor that significantly predicted LN metastasis on multivariate analysis, as well as a significantly worse 5-year disease-specific survival. T1a tumors without LVI had a 4.3% rate of positive LN, whereas T1b tumors with LVI had a 64.3% rate of positive LN.
Conclusions: T1 gastric cancers limited to the mucosa, without evidence of LVI, and N0 on EUS can be safely considered for limited resection. However, given an unacceptably high incidence of LN metastasis, any T1 gastric cancer with submucosal invasion, LVI, or N+ by EUS should undergo radical resection with lymphadenectomy.