Endoscopic, clinicopathological, and growth characteristics of minute gastric cancer.

Objective: To clarify the endoscopic, clinicopathological, and growth characteristics of minute gastric cancer (MGC) and to improve its detection rate.

Methods: Patients with early gastric cancer who underwent endoscopic submucosal dissection from July 2012 to September 2021 were retrospectively reviewed. MGC was defined as gastric cancer of 5 mm or less in size. Preoperative and postoperative endoscopic and pathological data were collected and analyzed. Follow-up information was collected until 9 April 2022.

Results: Eighty patients were enrolled, with 82 lesions observed under endoscopy and 87 diagnosed histopathologically. All patients received en bloc and curative resection. Compared with the time point when the last endoscopic examiniation prior to lesion deteciton was performed (t0), 64.29% of patients with MGC had disease progression at lesion detection (t1). However, 21.43% showed normal or only atrophic changes under white-light endoscopy, and their lesions were diagnosed accidentally by random biopsy. The majority of MGC lesions presented as type IIc and reddish, and 95.00% of cases had well-differentiated tubular adenocarcinoma. The mean growth rate of MGC was 0.0071 mm/day, and it took an average of 3.42 years to grow to 5 mm. There was no significant difference in the depth of invasion between the low cellular atypia group and the high cellular atypia group.

Conclusions: Type IIc and reddish appearance are main endoscopic features of MGC. For cases with no obvious endoscopic changes, multipoint biopsy is helpful. MGC is mostly well differentiated and grows relatively slowly; therefore, MGC can still have a chance to be identified and resected curatively if it is missed diagnosed.