While angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) have been thrust into the spotlight during the ongoing pandemic, new research suggests long-term use could decrease a person’s risk of developing colorectal cancer.
Results of a study, which reviewed health records from nearly 200k adult patients, found patients taking ACE inhibitors or ARBs had a 22% lower risk of developing colorectal cancer over the next 3 years.
"This is the first study to show the potential beneficial effects of ACE inhibitors and ARBs on colorectal cancer development, based on a large group of patients who were colorectal cancer-free at the beginning of the study,” said study investigator Wai Leung, MD, clinical professor of medicine at the University of Hong Kong, in a statement from the American Heart Association
Despite previous research examining associations between use of ACE inhibitors and ARBs and modification of cancer risk, most of these studies contained flaws such as insufficient ability to account for confounding factors or insufficient follow-up length. With his in mind, Leung and a team of colleagues from Hong Kong and London designed their study as a territory-wide retrospective study of patient data from subjects 40 years of age or older in Hong Kong with a negative baseline colonoscopy between 2005-2013.
To identify subjects for inclusion, investigators chose to pull data from the Hong Kong Hospital Authority’s electronic healthcare database. For the purpose of analysis, investigators excluded all patients with colorectal cancer detected within 6 months of index colonoscopy, prior colorectal cancer, inflammatory bowel disease, and prior colectomy. In total, 210,346 patients were identified and, after the application of criteria, 187,897 were included in the study.
The primary outcome of the analysis as a diagnosis of colorectal cancer diagnosed from 6-36 months following the index colonoscopy. Furthermore, the analysis also assessed potential associated between sites of colorectal cancer, defined as proximal or distal cancer.
From the 187,897 patients included in the study, investigators obtained a total of 560,306 person-years of follow-up data. The median age of participants at index colonoscopy was 60.6 years and 48.9% of participants were men. Of note, 30,854 (16.4%)of the 187,897 patients included in the study were using ACE inhibitors or ARBs.
Upon analysis, a total of 854 (0.45%) patients developed colorectal cancer 6-36 months after index colonoscopy. Of these 854 cases, 147 were considered proximal cancers and 707 were distal cancers. In a propensity-matched analysis, results indicated use of ACE inhibitors or ARBs was associated with a lower risk of developing colorectal cancer within 3 years of index colonoscopy (aHR, 0.78; 95% CI, 0.64-0.96), but this effect was not present after 3 years (aHR, 1.18; 95% CI, 0.88-1.57).
Additionally, results of the analysis indicated every year increase use was associated with a lower risk of developing colorectal cancer risk in a duration-response matter. Further analysis also indicated the observed benefit was most prominent in patients aged 55 and older and those with a history of colonic polyps.
"The roles of ACE inhibitors and ARBs on cancer development are controversial and, in some cases, study findings are conflicting. Results of previous studies have been limited by several factors including a small number of patients and data only on short-term follow-ups,” said Leung in the aforementioned statement
. “Our results provide new insights on a potential role of these medications for colorectal cancer prevention.”
This study, “ACE (Angiotensin-Converting Enzyme) Inhibitors/ Angiotensin Receptor Blockers Are Associated With Lower Colorectal Cancer Risk
,” was published in Hypertension.