Pretreatment risk factors for endoscopic noncurative resection of gastric cancers with undifferentiated‐type components

Background and Aim Endoscopic submucosal dissection (ESD) is recommended for the treatment of early gastric cancers with an undifferentiated‐type component, clinically diagnosed as intramucosal lesions ≤ 2 cm, without ulceration. In the JCOG1009/1010 trial, ESD could be performed with stomach preservation in 70% of such patients whose pathological findings met the curative resection criteria. However, additional gastrectomy was required for the remaining 30%. We identified the pretreatment risk factors for noncurative resection. Methods Post‐hoc analysis indicated that 336 patients were identified in the JCOG1009/1010 trial; among them, 243 and 93 patients were categorized into the curative or noncurative resection groups, respectively, based on the pathological findings of the resected specimens. We explored the pretreatment risk factors for noncurative resection and investigated their associated pathological findings. Results Multivariable analysis revealed that a pretreatment tumor size > 1 cm was an independent risk factor for noncurative resection (odds ratio, 3.538; 95% confidence interval, 2.020–6.198, P 1 cm (n = 172) had a histological tumor size > 2 cm (22.1% vs 4.3%, odds ratio, 6.313; 95% confidence interval, 2.73–14.599, P