New research that suggests high cholesterol is inversely related to colorectal cancer risk has implications for statin use.
Statins have been shown to reduce high blood pressure and prevent cardiovascular disease, and some research suggests the medications may also have a protective effect against colorectal cancer. For example, according to research published in 2014 in the journal Cancer Causes and Control, “statin use is associated with a modest reduced risk of [colorectal cancer].” But previous studies linking statins to lower cancer risk did not account for the effect of high cholesterol itself on that risk.
Researchers from the Perelman School of Medicine at the University of Pennsylvania performed an observational analysis to attempt to unravel the relationship among cholesterol, statin use and colorectal cancer risk.
Examining the Connection
Published in the journal PLOS Medicine, the research examined more than 22,000 patients with colorectal cancer and a control group of nearly 90,000 people without colorectal cancer, drawing from a database of primary care practice patients in the United Kingdom. Researchers examined associations of colorectal cancer with statin use, serum total cholesterol and change in total cholesterol level.
The study found that for every 1 mmol/L increase in total blood cholesterol, there was an approximate 10 percent reduction in the risk of colorectal cancer. This link was observed regardless of statin use.
“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 use, there was no difference in risk,” lead author Ronac Mamtani, MD, MSCE, Assistant Professor of Hematology/Oncology with the Perelman School of Medicine and the Abramson Cancer Center, stated in a news release. “Together, these data demonstrate a complex association between statins, cholesterol and colorectal cancer.”
The study also examined cholesterol levels of those diagnosed with colorectal cancer. A decrease in serum total cholesterol levels of greater than 1 mmol/L a minimum of one year before the diagnosis was associated with a 1.25-fold and a 2.36-fold higher risk for cancer among statin users and nonusers, respectively.
The data suggest statins should not be used as a preventive measure for colorectal cancer. However, the research may indicate total cholesterol levels could aid early diagnosis of colorectal cancer.
“[A]n otherwise unexplained reduction in serum total cholesterol by more than 1 mmol/L may not be a favorable indicator, but rather a signal of occult colorectal cancer,” the article in PLOS Medicine states.
Further study is needed to determine the efficacy of total cholesterol as a biomarker for colorectal cancer risk or early detection, the researchers add.