ARB cancer risk refuted
MedWire News: Research appears to allay concerns of a potential increase in cancer risk from use of angiotensin receptor blockers (ARBs).
A study of patients included in the UK General Practice Research Database found use of ARBs was not associated any increase in the overall risk of cancer - and may actually have protected patients against lung cancer.
Although there were small absolute increases in the risks of breast and prostate cancer associated with ARB use, the authors note that longer treatment was not associated with greater cancer risk, suggesting any risk increases might be down to confounding factors.
Dr Krishnan Bhaskaran (London School of Hygiene and Tropical Medicine) and colleagues analysed the data for 377,649 new users of ARBs or ACE inhibitors who had been taking the drugs for at least a year.
Over the median 4.6-year follow-up, there was no evidence of any increase in cancer among those ever exposed to ARBs, while the relative risk of lung cancer was reduced in this group by 16%.
However, ARB users had significant 11% and 10% increased relative risks of breast and prostate cancer, respectively. In absolute terms, these risks corresponded to 0.5 and 1.1 extra cases per 1000 person years among those at highest baseline risk. But, as there was no evidence of increasing risk for any or specific cancers with longer duration of treatment, the authors say "we cannot exclude non-causal explanations for these observed associations".
Nevertheless, the authors write in the BMJ, if further research suggests a causal relationship for these two cancer types, it may be necessary consider whether patients at high risk "would benefit from alternative, equally effective antihypertensive drugs".
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Caroline Price