Optimal Safety Margins and Scoring System for Endoscopic Submucosal Dissection of Crawling-Type Early Gastric Cancer

Background/Aims: Crawling-type adenocarcinoma (CTAC) is a subtype of gastric cancer characterized by lateral spreading, which makes margin assessment challenging. We aimed to evaluate the risk factors and characteristics of CTAC and provide guidance for achieving optimal resection margins during endoscopic submucosal dissection (ESD). Methods: This retrospective study analyzed prospectively collected data from 4,788 patients who underwent ESD for early gastric cancer between January 2012 and December 2023. The endoscopic and histopathological features of CTAC and the factors associated with lateral margin positivity (LMP) were identified. Results: Overall, 199 patients (4.2%) were classified as having CTAC. The CTAC group had a significantly higher LMP rate than the non-CTAC group (20.6% vs 4.2%; p<0.001). Risk factors for LMP in patients with CTAC were identified using logistic regression, and a scoring system was developed: 3 points, non-greater curvature side; 1 point, lesion long axis ≥20 mm; 2 points, expected minimum safety margin <5 mm; and 1 point, expected minimum safety margin 5-10 mm. Patients were categorized into low-risk (0-1 point, 2.6% LMP rate), moderate-risk (2-4 points, 18.8% LMP rate), and high-risk (5-6 points, 48.5% LMP rate) groups. Compared to the low-risk group, the moderate-risk group had an odds ratio of 8.538 (95% confidence interval, 1.116 to 65.355; p=0.039), and the high-risk group had an odds ratio of 34.824 (95% confidence interval, 4.263 to 284.466; p=0.001) for exhibiting LMP. Conclusions: Lesion size, location, and safety margins influenced the risk of LMP, emphasizing the importance of optimizing safety margins during ESD for CTAC.