Postgastrectomy gastric cancer patients are at high risk for colorectal neoplasia: a case control study

BACKGROUND/AIMS: Several studies have shown that colorectal neoplasms (CRN) including colorectal cancer (CRC) may be prevalent in patients with gastric cancer. However, in most of these studies, colonoscopy to investigate the prevalence of CRN was performed prior to surgery. We aimed to investigate whether CRN was more prevalent in postgastrectomy gastric cancer patients than in healthy individuals. METHODS: We reviewed the medical records of those patients within a cohort of gastric cancer patients with gastrectomy who underwent colonoscopy between 2016 and 2017. Controls age- and sex-matched with gastric cancer patients at a 2:1 ratio were identified among those who underwent colonoscopy at a health-promotion center. The frequencies of CRN, advanced CRN (ACRN), and CRC among patients with gastrectomy were compared with those in the control subjects. A total of 744 individuals (gastric cancer, 248; control, 496) were included. RESULTS: The rates of CRN and ACRN in the gastric cancer group were higher than those in the healthy individuals (CRN, 47.6% vs. 34.7%, P<0.001; ACRN, 16.9% vs. 10.9%, P=0.020). The rate of CRC was comparable between the 2 groups (2.0% vs. 0.6%, P=0.125). Multivariate analysis identified previous gastrectomy for gastric cancer and male sex as significant risk factors for (A)CRN. CONCLUSIONS: CRN and ACRN were more prevalent in patients who underwent surgery for gastric cancer than in the control group. Regular surveillance colonoscopy at appropriate intervals is indicated after gastrectomy.