Practical marker-based stratification of early gastric neoplasms in older adults.

[OBJECTIVE] With the population aging, gastric cancer is increasing in older adults. Our study aimed to investigate the clinicopathologic features of early gastric neoplasms in older adults and to identify immunohistochemical markers that distinguish indolent from aggressive lesions.

[METHODS] We examined 72 early-stage (ie, mucosal and submucosal) gastric neoplasms resected from patients aged 85 to 94 years. There were 8 markers used in the immunohistochemistry assay, including enteroblastic markers (SALL4 and glypican 3).

[RESULTS] Of 72 cases, 94% were tubular neoplasms: 40 gastric intraepithelial neoplasia/dysplasias (20 low grade, 20 high grade) and 28 adenocarcinomas. A combination of MUC5AC and/or p53 correctly identified 93% of adenocarcinomas and achieved the highest accuracy (0.90) and specificity (1.00) in distinguishing high-risk lesions (high-grade intraepithelial neoplasia/dysplasias and adenocarcinomas), with an area under the curve of 0.934. Enteroblastic differentiation, confirmed by SALL4 and/or glypican 3, was found in 25% of adenocarcinomas. This differentiation was significantly associated with lymphatic (P = .021) and venous (P = .043) invasion.

[CONCLUSIONS] MUC5AC/p53 immunohistochemistry is highly effective in identifying high-risk lesions. Enteroblastic differentiation is relatively common and is associated with lymphovascular invasion. These findings support the use of targeted immunohistochemistry for accurately diagnosing and managing this vulnerable and understudied age group.