BackgroundThe association of atherosclerotic cardiovascular disease (ASCVD) with cancer occurrence is not well examined, and the impact of common risk factors on the risk of cancer in ASCVD patients is not known. This study aimed to explore the effect and possible causes of ASCVD on cancer risk through a cohort study. MethodsA total of 14,665 age- and sex-matched pairs of participants were recruited from the Kailuan cohort (ASCVD vs non-ASCVD). A competing risk model was used to calculate the risk of cancer after ASCVD. ResultsA total of 1124 cancers occurred after 5.80 (3.05-9.44) years of follow-up. The ASCVD group had a reduced risk of cancer (hazard ratio 0.74; 95% confidence interval, 0.65-0.85). Also, the risk of cancer in the digestive system, respiratory system, urinary system, and reproductive system was reduced by 17%, 16%, 14%, and 52%, respectively. According to the status of systolic and diastolic blood pressure, fasting blood glucose, high-sensitivity C-reactive protein and body mass index after ASCVD, the risk of overall cancer and digestive system cancer decreased with the increase in the number of ideal indicators (P for trend < .01). With the increase of follow-up time, the risk of cancer and the 5 site-specific cancers gradually decreased. ConclusionsCancer risk can be reduced by controlling for common risk factors after ASCVD event. This risk reduction is site-specific-, time-, and the number of ideal indicator-dependent.