Statin use was associated with a lower risk for colorectal cancer after colonoscopy in a recent study.
Researchers in Hong Kong performed a retrospective cohort study using an electronic health care database to determine whether risk for colorectal cancer after colonoscopy is lower in patients who take statins versus those who do not. Patients ages 40 years and older who had had a colonoscopy between 2005 and 2013 were included, while those who had previous colorectal cancer, inflammatory bowel disease, previous colectomy, or colorectal cancer detected within six months of the index colonoscopy were excluded. Statin use was defined as taking statins for at least 90 days before the index colonoscopy. The study's primary outcome was postcolonoscopy colorectal cancer within three years, defined as colorectal cancer diagnosed within six and 36 months after negative findings on the index colonoscopy. Results were published Feb. 26 by Gut.
Overall, 187,897 patients were eligible for the study, 25,447 who took statins and 162,450 who did not. The mean age at index colonoscopy was 62.1 years. A total of 854 patients (0.5%) were diagnosed with colorectal cancer within three years of the index colonoscopy, 707 (82.8%) with distal and 147 (17.2%) with proximal disease. Median age at diagnosis was 75.9 years; median time from index colonoscopy to diagnosis was 1.2 years.
Among the 25,447 patients who took statins, 144 (0.5%) developed colorectal cancer within three years of the index colonoscopy (incidence rate, 15.0 per 10,000 person-years). After propensity-score matching of 17,662 patients who took statins and 30,304 who did not, those in the former group had a lower risk for colorectal cancer within three years (subdistribution hazard ratio, 0.72; 95% CI, 0.55 to 0.95). In stratified analysis, statins were associated with lower risk in the proximal but not the distal colon (subdistribution hazard ratios, 0.50 [95% CI, 0.28 to 0.91] and 0.80 [95% CI, 0.59 to 1.09], respectively). In subgroup analysis, statin use was associated with lower risk in patients 60 years of age or older, women, patients without diabetes, and patients without a history of polyps or polypectomy.
The researchers noted that data on family history, dietary habits, and medication adherence were not available and that most patients taking statins (77%) were prescribed simvastatin, among other limitations. However, they concluded that colorectal cancer risk after colonoscopy appears to be significantly lower, especially for proximal cancer, in patients who take statins versus those who do not. They called for additional studies to confirm their findings in other populations.