NEW YORK (Reuters Health) – Treatment with the angiotensin receptor blocker (ARB) candesartan is not associated with either carcinogenesis or cancer death compared with non-ARB standard antihypertensive treatment, suggests a study from Japan.
“The results of the present study have really robust support for the recent FDA Drug Safety Communication: No increase in risk of cancer with certain blood pressure drugs: Angiotensin Receptor Blockers (ARBs),” Dr. Hiroshi Ogawa, of The Heart Institute of Japan in Tokyo, told Reuters Health.
The FDA communication is available here: http://www.fda.gov/Drugs/DrugSafety/ucm257516.htm.
Studies on ARBs and cancer risk have yielded mixed results. A recent meta-analysis suggested that ARBs modestly increase the risk for cancer compared to placebo or comparator drugs.
However, another meta-analysis failed to demonstrate increased cancer risk with common antihypertensive drugs including ARBs. Furthermore, two large-scale cohort studies also failed to show a link between ARB therapy and increased cancer risk.
In an attempt to clarify the issue, Dr. Ogawa and colleagues conducted a substudy of a randomized controlled trial in which hypertensive patients with coronary artery disease were randomly assigned to receive either candesartan-based treatment (n = 1,024) or non-ARB-based drug therapy, including angiotensin-converting enzyme inhibitors (n = 1,025).
During a median follow-up of 4.2 years, new cancer (the primary end point of the substudy) occurred in 5.37% of subjects in the candesartan group and 5.66% of those in the non-ARB-based treatment group, yielding a hazard ratio of 0.95.
“Advanced age and male gender were independently and significantly correlated with subsequent incidence of cancer in our study population,” Dr. Ogawa said.
Death due to cancer occurred in 1.66% in the candesartan group and 2.44% in the standard therapy group (hazard ratio 0.74).
Kaplan-Meier estimates of survival without new cancer and cancer deaths demonstrated that candesartan-based therapy does not accelerate the occurrence of new cancer (log-rank, P = 0.84) or cancer death (P = 0.39) compared to non-ARB-based drug treatment.
“In developed nations, the lifetime risk of cancer is about 40%, with rates increasing over time,” Dr. Ogawa commented. “As a result, cancer is one of the major causes of death in modern societies. Studies show that due to the recent improvement of therapeutic modalities for patients with cardiovascular disease, about a half of all deaths among these patients are non-cardiovascular in nature.”
“Our study suggests that ARB candesartan-based therapy is not associated with either carcinogenesis or cancer death compared with non-ARB standard antihypertensive treatment,” Dr. Ogawa said.
While these findings are reassuring, the researchers caution that their study is not without limitations. It was a retrospective analysis of a prospective randomized study that was not designed to investigate cancer incidence as an outcome. Also, periodic cancer screening was not required; therefore, cases of cancer might have been missed.
The median follow-up period of 4.2 years also might have been too short to detect any cancer incidence. In addition, the study population might be relatively young and at a lower risk of incident cancer.
The researchers also note that a larger scale, prospective, randomized trial is required to elucidate the presence of a “class effect” of ARBs, as well as any different effects among these agents.
Reference:
Am J Cardiol. 2012.
