ACE inhibitors/ARBs lower colorectal cancer risk

Last Updated: 2020-07-07

By Will Boggs MD

NEW YORK (Reuters Health) - The use of angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) is associated with a lower risk of colorectal cancer following a normal colonoscopy, according to a study in Hong Kong.

"ACE inhibitors/ARBs may have potential chemopreventive effects on colorectal cancer (CRC) development, particularly within the first 3-year after normal colonoscopy," Dr. Wai K. Leung from The University of Hong Kong, Queen Mary Hospital, Hong Kong told Reuters Health by email. "However, this finding will require further validation in other cohort or randomized controlled studies."

The impact of ACE inhibitors/ARBs on cancer risk remains controversial, with some studies showing an increased risk of certain cancers.

Dr. Leung and colleagues used data from Hong Kong's territory-wide electronic healthcare database to determine whether baseline ACE inhibitor/ARB use was associated with CRC development in patients with prior colonoscopy negative for CRC.

Among 187,897 patients 2005 and 2013, the incidence of CRC in the 3 years after colonoscopy was 15.2 cases per 10,000 person-years. The crude risk of post-colonoscopy CRC was 26% higher among ACE inhibitor/ARB users than among nonusers.

In a propensity score-adjusted analysis, however, the risk of CRC in the 3 years after colonoscopy was 22% lower among patients who used ACE inhibitors/ARBs, an absolute reduction of 3.2 cases per 10,000 person-years, according to the online report in Hypertension.

In subgroup analyses, ACE inhibitor/ARB use was associated with a 23% lower risk of distal CRC but a nonsignificant 17% risk reduction for proximal CRC.

Longer duration of ACE inhibitor/ARB use was associated with a greater reduction in the risk of post-colonoscopy CRC (25% reduction with at least 2 years' use versus a nonsignificant reduction with shorter use).

The protective effect of ACE inhibitors/ARBs was limited to the first 3 years after the normal colonoscopy; the adjusted risk beyond 3 years did not differ significantly between users and nonusers.

Moreover, the protective effect of ACE inhibitors/ARBs was confined to patients aged 55 years and older and patients with a history of colon polyps.

After propensity score adjustment, there was no association between ACE inhibitors/ARBs and the risk of lung, prostate, or breast cancer.

"While we are not suggesting people to start ACE inhibitors/ARBs to prevent cancer, there may be additional benefits in choosing ACE inhibitors/ARBs over other antihypertensive medications in some patients who are at higher risk of CRC (e.g., those with history of colorectal polyps)," Dr. Leung said.

SOURCE: https://bit.ly/2VQOgn4 Hypertension, online July 6, 2020.