Clinicopathologic Features of Early Gastric Cancer after Heli-cobacter pylori Eradication in Japanese Patients: Comparative Study between Early (<10 Years) and Late (>10 Years) Onset

Background/Objectives: Eradication therapy for Helicobacter pylori gastritis was approved for insurance coverage by the Japanese government in 2013. Since then, the incidence of gastric cancer discovered after eradication (GCAE) has increased. However, there are only a few reports of GCAE diagnosed more than 10 years after eradication. We investigated the clinicopathological characteristics of early-stage GCAE, including histological types and the interval from eradication to diagnosis. Methods: Overall, 379 patients with a total of 448 GCAE lesions treated with endoscopic resection or surgery at our hospital between January 2015 and December 2021 were assessed, and 315 patients with a known interval from eradication to diagnosis of GCAE with a total of 354 lesions were included. We classified the cases into two groups: differentiated-type GCAE (D-GCAE; 279 patients, 318 lesions) and undifferentiated-type GCAE (UD-GCAE; 36 patients, 36 lesions). Results: Smoking and a mild-to-moderate degree of atrophy were risk factors associated with differentiated-type gastric cancer occurring more than 10 years after H. pylori eradication. Additionally, the rate of a mixture of histological types with relatively high malignant potential was significantly higher in UD-GCAE presenting more than 10 years after eradication group than those presenting within 10 years after eradication.