Clinicopathologic score predicting lymph node metastasis in T1 gastric cancer

Background: Although gastrectomy with adequate regional nodal examination is considered the standard of care for invasive gastric adenocarcinoma, endoscopic resection has been adopted increasingly in select patients with T1 gastric cancer. The objective of this study was to identify preoperative predictors of lymph node metastasis in patients in the United States with T1 gastric cancer. Methods: Patients who underwent operative resection for T1 gastric cancer between 2000 and 2012 were identified from a multi-institutional database. Clinicopathologic predictors of lymph node metastasis were determined using univariate and multivariate logistic regression. A preoperative score was created, assigning points based on each variable's regression coefficient. Results: Among 835 patients with gastric cancer undergoing curative-intent surgical resection, 176 patients (20.5%) had T1 disease confirmed on final pathology. Of those, 38 patients (22%) had lymph node metastasis. Independent predictors of lymph node involvement on multivariate analysis were poor differentiation, T1b stage, lymphovascular invasion, and tumor size >2 cm. A clinicopathologic risk score composed of these 4 variables was created. Receiver operating curve analysis showed excellent discrimination (area under the curve = 0.79) and 100% sensitivity in detecting lymph node metastasis when only one of the aforementioned factors was present. Conclusions: In this cohort of U.S. patients with T1 gastric adenocarcinoma, the lack of lymph node involvement could be predicted by the absence of several unfavorable factors, including T stage, poor differentiation, lymphovascular invasion, and size >2 cm.