These drugs, known as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), lower blood pressure by relaxing veins and arteries and allowing the heart to pump blood more easily.
Studies in animals have shown that these medications might slow the growth of pancreatic cancer. Several small studies in people suggest the same thing, but the numbers of patients included were too small to draw firm conclusions.
In the new study, researchers examined data on 3.7 million adults from Italy, and identified 8,158 people diagnosed with pancreatic cancer between 2003 and 2011.
The study, published last month in the journal BMC Cancer, found that the vast majority of these patients (86%) died within about 6 months of their diagnosis.
But patients who took ARBs after their pancreatic cancer diagnosis had a 20% lower risk of dying, compared to similar patients who did not take ARBs.
In a smaller group of patients who had surgery for their cancer, ARB users had a 28% lower risk of dying.
Also, patients with pancreatic cancer who took ACE inhibitors had a 13% lower risk of dying in the first 3 years after diagnosis, but this benefit shrank later.
But "ARBs and ACE inhibitors still need to be considered experimental treatments for pancreatic cancer," cautions study investigator Scott Keith, PhD, of Thomas Jefferson University in Philadelphia.
Timothy Pawlik, MD, PhD, also cautions not to jump to firm conclusions based on this study.
"While provocative, the data cannot be considered conclusive," says Pawlik, with the Ohio State University Comprehensive Cancer Center.
"The study is retrospective, which makes it susceptible to selection and treatment bias. In addition, the data were derived from an administrative health care database, which can be notorious for lacking granular clinical data," he points out.
Pawlik also notes that studies evaluating the benefits of blood pressure medications on cancer risk and outcomes is mixed. Several previous studies, for instance, suggest ACE inhibitors and ARBs may protect against malignancies such as colorectal cancer, while other data suggests a possible link between ACE inhibitors and a higher risk for certain cancers, such as lung cancer.