Medications commonly prescribed to treat high blood pressure also could reduce the risk of colorectal cancer, according to a new study.
Researchers reviewed health records of 187,897 adults in Hong Kong from 2005 to 2013. Those who took medicines that block angiotensin, a chemical that causes arteries to narrow, had a 22% lower risk of developing colorectal cancer in the subsequent three years.
The drugs angiotensin converting enzyme inhibitor and angiotensin II receptor blocker – ACE-i and ARB, for short – are prescribed for conditions such as heart failure and heart disease. Doctors also commonly prescribe them to people with high blood pressure to relax and open blood vessels, thereby lowering blood pressure.
The study was published Monday in the American Heart Association journal Hypertension. It is the first to show the medicines' potential protective effect on the development of colorectal cancer, study author Dr. Wai K. Leung said in a news release.
"The roles of ACE inhibitors and ARBs on cancer development are controversial and, in some cases, study findings are conflicting," said Leung, who is clinical professor of medicine at the University of Hong Kong in China. "Results of previous studies have been limited by several factors including a small number of patients and data only on short-term follow-ups. Our results provide new insights on a potential role of these medications for colorectal cancer prevention."
Colorectal cancer is the third most common cancer and the second-leading cause of cancer death worldwide.
The study also showed the benefits of ACE inhibitors and ARBs in people 55 or older and those with a history of colon polyps. The benefit was limited to the first three years.
"While ACE-i and ARBs are taken by patients with high blood pressure, heart failure and kidney diseases, the reduction in colorectal cancer risk may be an additional factor for physicians to consider when choosing anti-hypertensive medications," Leung said.
Researchers said the results should be verified in a randomized clinical trial that would actively follow patients to determine the potential benefits of these medications on colorectal cancer risk.
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