No Increased Cancer Risk with ARBs vs ACEIs

Angiotensin-receptor blockers (ARBs) are not associated with an increased overall cancer risk, according to a study in the British Medical Journal.

The researchers analyzed British general practice data on nearly 378,000 patients with at least 1 year of initial treatment with ARBs or angiotensin-converting enzyme inhibitors (ACEIs). Overall and specific cancer risks were compared for the two types of antihypertensive drugs, considering the effects of cumulative treatment time. About 20,000 cancers were diagnosed during a median follow-up time of 4.6 years.

The overall cancer risk was not significantly different for patients taking ARBs versus ACEIs, after adjustment for a wide range of demographic and clinical factors. The rates of breast and prostate cancer were higher in ARB users: adjusted hazard ratios 1.11 and 1.10, respectively. However, the absolute excess risks were small: no more than 0.5 per 1000 person-years for breast cancer and 1.1 per 1000 person-years for prostate cancer.

Treatment with ARBs had a possible protective effect against lung cancer: hazard ratio 0.84. The risk of colon cancer was not affected.

One recent trial reported increased cancer mortality among patients taking candesartan. Such an association is plausible because of the role of angiotensin II receptors in angiogenesis, cell proliferation, and tumor progression.

However, this large database study found no increase in the overall risk of cancer among patients starting treatment with ARBs compared with ACEIs. The risk of lung cancer may even be reduced in ARB users. Small increases in the risk of breast and prostate cancer were unrelated to the duration of ARB treatment, raising the possibility of a noncausal explanation. [Bhaskaran K, et al. Angiotensin receptor blockers and risk of cancer: cohort study among people receiving antihypertensive drugs in UK General Practice Research Database. BMJ 2012; 344:e2697.]

June 2012 (Vol. 4, Number 6)