Involvement in the tumor-infiltrating CD8(+) T cell expression by the initial disease of remnant gastric cancer

BACKGROUND: Remnant gastric cancer (RGC) has been increasing for various reasons such as a longer life span, medical progress, and others. It generally has a poor prognosis, and its mechanism of occurrence is unknown. The purpose of this study was to evaluate the clinicopathological features of and clarify the oncological features of RGC. METHODS: Between January 2002 and January 2017, 39 patients with RGC following distal gastrectomy underwent curative surgical resection at the Okayama University Hospital; their medical records and immunohistochemically stained extracted specimens were used for retrospective analysis. RESULTS: On univariate analysis, initial gastric disease, pathological lymph node metastasis, and pathological stage were the significant factors associated with poor overall survival (p=0.014, 0.0061, and 0.016, respectively). Multivariate analysis of these 3 factors showed that only initial gastric disease caused by malignant disease was an independent factor associated with a poor prognosis (p=0.014, hazard ratio: 4.2, 95% confidence interval: 1.3–13.0). In addition, tumor-infiltrating CD8(+) T cells expression was higher in the benign disease group than in the malignant group (p=0.046). CONCLUSIONS: Initial gastrectomy caused by malignant disease was an independent poor prognostic factor of RGC, and as one of the causes, lower level of tumor-infiltrating CD8(+) T cells in RGC may involve in. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12957-022-02853-2.