Statin use is associated with a reduced incidence of colorectal cancer: a colonoscopy-controlled case-control study

Background: The aetiology of colorectal cancer (CRC) remains elusive in the majority of cases. There is experimental evidence to show that HMG-CoA reductase inhibitors (statins) may inhibit proliferation and induce cause apoptosis in CRC cells and although some clinical studies have suggested that statins may protect against the development of CRC, this has not been a consistent finding. Therefore we have examined any potential protective effects of statins by comparing statin use in patients with colorectal cancer against a control group. Methods: This was a case-control study examining statin use in symptomatic patients attending for diagnostic colonoscopy. Statin use was compared between patients with CRC and a control group, who had all had normal colonoscopy. Structured interviews and clinical records notes were used to determine drug exposure. Logistic regression was used to compare statin exposure and correct for confounding factors. Results: There was a significant inverse association between previous statin use and a diagnosis of CRC (OR = 0.43 (95% confidence interval 0.25 - 0.80), p < 0.01). This inverse association was stronger with higher statin doses (OR = 0.19 (0.07 - 0.47), p < 0.01) and greater duration of statin use (statin use >5 years: OR = 0.18 (0.06 - 0.55), p < 0.01). Conclusions: Statins use was associated with a protective effect against the development of CRC. This effect is associated with a significant dose and duration response. These findings need to be repeated in other observational studies before an interventional study can be considered.