Takeuchi M, et al. - The present study sought to investigate risk factors for lymph node (LN) metastasis in non-sentinel node (SN) basins in early gastric cancer. Using classification and regression tree (CART) analysis, the researchers determined risk factors for metastasis in non-SN basins and identified a prediction model for non-SN basin metastasis. For this investigation, five hundred fifty patients who were diagnosed with cT1N0M0 or cT2N0M0 gastric cancer with a single lesion and underwent SN mapping were enrolled. Risk factors for LN metastasis in non-SN basins among gastric cancer patients were macrometastasis in SN basins, lymphatic invasion, and number of identified SNs ≥ 5. A prediction model with CART analysis was identified. It was observed in the findings that patients with macrometastasis in SN basins and lymphatic invasion were considered to be at the highest risk for LN metastasis.