Large registry study finds no excess cancer risk with ARB use
MedWire News: An analysis of more than 100,000 patients taking angiotensin receptor blockers (ARBs) has found no signal that these drugs are associated with an increased risk for cancer, with the exception of a small increase in male genital cancers.
Indeed, the data suggest that ARB use may actually be associated with a reduced overall risk for cancer death, write Björn Pasternak (Statens Serum Institut, Copenhagen, Denmark) and team in the journal Circulation.
The study was conducted after a recent meta-analysis of nine trials found that ARB users had a modestly increased risk for incident cancer, with a rate ratio (RR) of 1.08 versus placebo or comparator drugs. That analysis also identified a significantly increased risk for lung cancer associated with ARB use (RR=1.25).
To investigate further, Pasternak and team obtained data on new users of ARBs and ACE inhibitors from a nationwide registry-based cohort. All participants were aged 35 years or above and were started on treatment between 1998 and 2006.
Among 107,466 ARB users, 3954 cases of cancer were detected during 312,753 person-years of follow-up; meanwhile, among 209,692 ACE inhibitor users, 6214 cases of cancer were detected during 435,207 person-years of follow-up. The adjusted RR for the comparison was 0.99, indicating no significant difference.
Further analyses found no evidence that cancer risk increased with increasing duration of ARB exposure (RR increase per year=0.99) or that the risk differed among individual ARB agents.
The only significant findings were an increased risk for cancer of male genital organs (RR=1.15), observed in a subgroup analysis, and a reduced risk for overall cancer mortality (RR=0.77).
"Confidence intervals were narrow, allowing exclusion of a 4% increase in the risk of cancer," the authors remark.
They conclude: "Although the angiotensin receptor system is involved in the process of carcinogenesis, experimental data point, if anything, toward beneficial effects of angiotensin signaling inhibition.
"Clinicians can continue to prescribe ARBs without concern about an excess risk of cancer."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Joanna Lyford