An exhaustive analysis of over a 100,000 individuals has confirmed the absence of unbiased association between statin use and a person’s risk of colorectal cancer; however, an inverse relation of risk and cholesterol levels was identified.
An exhaustive analysis of over a 100,000 individuals, by researchers at the University of Pennsylvania School of Medicine, has confirmed the absence of unbiased association between statin use and a person’s risk of colorectal cancer (CRC). However, the authors identified an inverse association between total serum cholesterol and the risk of CRC.
While cholesterol levels are monitored in adults over 40 years of age in the United States, statins, which are most commonly prescribed to regulate blood cholesterol, are thought to reduce the risk of CRC. For their study published in PLOS Medicine, researchers from Penn medicine hypothesized that this association may be due to systematic bias, and they evaluated the independent association of CRC with statin use, cholesterol levels, and changes in cholesterol concentration.
Using health data of 22,163 CRC cases and 86,538 matched controls from The Health Improvement Network database, the authors discovered a reduction in the risk of CRC with statin use (long-term: odds ratio [OR], 0.95; 95% confidence interval [CI], 0.91-0.99; short-term: OR, 0.92; 95% CI, 0.85-0.99). A subsequent subgroup analysis, which included over 23,000 individuals who continued or discontinued statin therapy, found that the risk of developing CRC was no greater in those who discontinued their medication (OR, 0.98; 95% CI, 0.79-1.22). However, an increase in serum cholesterol was independently associated with a reduction in CRC risk (OR, 0.89 per mmol/L increase; 95% CI, 0.87-0.91), if cholesterol levels were measured close to the cancer diagnosis (less than 6 months: OR, 0.76; 95% CI, 0.47-0.61; greater than 24 months: OR, 0.98; 95% CI, 0.93-1.03).
Ronac Mamtani, MD, MSCE, an assistant professor of Hematology/Oncology, Perelman School of Medicine at the University of Pennsylvania and the Abramson Cancer Center, and lead author of the study, said in a statement, “There appears to be an artificially protective effect of statins. Although the risk of colorectal cancer was lower in statin users versus non-users, when we compared those who continued statin therapy versus those who discontinued the therapy, such that each group shared the same indication for statin therapy, there was no difference in risk.”
“While unexplained decreases in blood total cholesterol should alert physicians to consider colon cancer as one potential explanation, future studies are needed to determine the utility of blood cholesterol as a marker for early detection of colon cancer,” Mamtani added.
Mamtani R, Lewis JD, Scott FI, et al. Disentangling the association between statins, cholesterol, and colorectal cancer: a nested case-control study. PLoS Medicine. 2016;13(4):e1002007. doi:10.1371/journal.pmed.1002007.