Neither long-term statin use nor atherosclerotic disease is associated with risk of colorectal cancer

Background & aims: Statin use has been reported to reduce risk for colorectal cancer (CRC) whereas atherosclerotic disease has been reported to increase risk, but findings have been inconsistent. We aimed to establish the association of statin use and coronary atherosclerosis with CRC.

Methods: We performed a population-based case control study of patients with a first diagnosis of CRC cancer between January 1, 1991, and December 31, 2008 (n = 9979), using the Danish National Registry of Patients. As many as 10 population controls were matched to each patient using risk set sampling (n = 99,790). Statin use before cancer diagnosis (or control index date) was determined via county prescription databases and evidence of coronary atherosclerosis using International Classification of Diseases codes. We calculated incidence rate ratios using conditional logistic regression, adjusted for multiple covariates.

Results: Among patients with CRC, statin use was modest (7.7%), but 23.5% of use was long term (≥5 years). Ever use of statins (≥2 prescriptions) slightly reduced CRC risk, compared with relative to never/rare use (incidence rate ratio [IRR] = 0.87, 95% confidence interval = 0.80-0.96). However, long-term use did not affect risk compared with never/rare use (IRR = 0.95, 95% 0.80-1.12). No associations were observed between atherosclerosis, myocardial infarction, or stroke, and CRC incidence.

Conclusions: Although there is a weak inverse association between ever use of statins and CRC incidence, there was no trend with increasing duration of use, so statins do not appear to reduce CRC risk. We did not confirm the reported association between atherosclerosis and CRC risk.