Katsuro Ichimasa, Masashi Misawa, Jimmy Bok Yan So, Fumiaki Ishibashi, Taishi Okumura, Yasuharu Maeda, Sho Suzuki, Tetsuo Nemoto, Khay Guan Yeoh, Kazuo Ohtsuka
Early gastric cancer (EGC) is increasingly managed by endoscopic resection (ER); however, lymph node metastasis (LNM), which occurs in approximately 5%-10% of cases, remains the key determinant for recommending additional gastrectomy. Current guideline-based strategies, including the eCura system, provide structured risk stratification but rely on categorical decision-making and may lead to overtreatment, as nearly 90% of patients undergoing additional surgery do not have LNM. Artificial intelligence (AI) has emerged as a promising tool for improving LNM predictions. Machine learning models using clinicopathological variables have demonstrated promising discriminatory performance (area under the curve, 0.69-0.94), often outperforming conventional scoring systems such as eCura. However, these approaches rely on predefined variables and are susceptible to interobserver variability in pathological assessments. Whole-slide image-based AI directly analyzes histopathological images, offering an objective and reproducible approach. Although evidence for EGC is limited, recent multicenter data have demonstrated promising results using routine hematoxylin and eosin-stained slides. Beyond the LNM risk, treatment decisions should also consider patient factors such as age, comorbidities, and competing mortality risks. AI is expected to support treatment decision-making by integrating these multidimensional factors, enabling more personalized and risk-adapted management after ER.