Increased standardised incidence ratio of cardiovascular diseases among colorectal cancer patients

Purpose Evidence regarding the relationship between colorectal cancer and the risk of cardiovascular disease (CVD) is limited. Thus, in this study, we aimed to determine the standardised incidence ratio (SIR) of CVDs in colorectal cancer patients in Taiwan. Methods A population-based cohort study enrolling the incident colorectal cancer population based on the Cancer Registry Database from 2007 to 2016 was conducted ( n = 94,233, mean age: 62.4 years, 43.0% women). New cases of CVD, including coronary heart disease and ischemic stroke, through 31 December 2018 were obtained from the National Health Insurance Research Database and National Death Registry. Compared with the general population ( n = 1,977,659, mean age: 44.3 years, 49.6% women), age- and sex-specific SIRs for CVDs were calculated by the time since diagnosis. Results A total of 6852 cardiovascular events occurred in colorectal cancer patients during a median follow-up of 4.4 years. The SIR of CVD was highest in the first year after diagnosis (SIR: 1.45, 95% confidence interval: 1.39–1.50); however, this decreased to the same value as that of the general population in later years. Similar patterns were observed for the SIR of coronary heart disease. However, the SIR of ischemic stroke among colorectal cancer patients was low from the second year following cancer diagnosis. Conclusions Colorectal cancer patients are at an increased risk of developing CVD, especially coronary heart disease, during the first 3 years following colorectal cancer diagnosis.