Analysis of the development of gastric cancer after resecting colorectal lesions using large-scale health insurance claims data

Background Colorectal endoscopic resection (C-ER) is spreading due to the increase of colorectal cancer (CRC) in Japan. Gastric cancer (GC) sometimes occurs after C-ER. We aimed to analyze the status of GC after C-ER using large-scale data. Methods We retrospectively used commercially anonymized health insurance claims data of 5.71 million patients from 2005 to 2018, and extracted 62,392 patients >= 50 years old who received C-ER. The incidence and risk factors of GC were analyzed. Additionally, subjects were divided into >= 2 cm group and < 2 cm group and risks of GC were analyzed. Results The median age (range) was 58 (50-75) years and the overall rate of GC was 0.68% (423/62,392). Multivariate analysis showed that significant risk factors for GC [ odds rates (OR), 95% confidence interval (CI)] were colorectal lesion size = 2 cm (1.75, 1.24- 2.47, p = 0.002), age = 65 y.o. ( 1.65, 1.31-2.07, p < 0.001), male (2.35, 1. 76-3.13, p < 0.001), diabetes mellitus (1.40, 1.02-1.92, p = 0.035), liver disease (1.54, 1.06-2.24, p = 0.025), Helicobacter pylori infection (2.10, 1.65- 2.67, p < 0.001), chronic atrophic gastritis ( 1.58, 1.14- 2.18, p = 0.006), and CRC ( 1.72, 1.10-2.68, p = 0.017). The rate of GC in the = 2 cm was significantly higher than that in < 2 cm groups (1.17% and 0.65%, p < 0.001). According to the number of significant risk factors, the rates of GC and the hazard ratios of GC (95%CI) were 0.64% and 3.64 (2.20-6.02) and 1.95% and 11.17 (6.57-19.00) for patient with 1-2 and = 3 risk factors, compared with patients without risk factors. Conclusions Using large-scale data, risk factors for GC, including colorecal lesions = 2 cm after C-ER could be investigated.