MONDAY, May 14, 2012 (HealthDay News) -- Widely used blood pressure medications called beta blockers do not cut a person's odds of developing colon cancer, a new study contends.
Beta blockers, which include drugs such as alprenolol, carvedilol, propranolol and atenolol, are commonly prescribed to older adults for high blood pressure and heart conditions.
Prior research has also linked use of the drugs to a decreased risk of cancer. This theory is based on animal and laboratory studies that found that the stress hormone norepinephrine can promote the growth and spread of cancer cells. Beta blockers inhibit this hormone's action.
"One of the holy grails in the war on cancer is preventing angiogenesis, which is the growth of new blood vessels to feed tumor cells," explained Dr. David Robbins, associate chief of the Center for Advanced Therapeutic Endoscopy at Lenox Hill Hospital in New York City.
"Some investigators have speculated that an indirect benefit of certain blood pressure medicines may be to help curb the growth of new blood vessels in breast and perhaps colon cancer," said Robbins, who was not involved in the new study.
In this study, published online May 14 in the journal Cancer, a team led by Michael Hoffmeister, of the German Cancer Research Center in Heidelberg, compared the beta blocker use of more than 1,700 colon cancer patients to that of about the same number of cancer-free people.
After accounting for weight, smoking status and other patient factors, the researchers found no link between beta blocker use and colon cancer risk.
The finding held true even after the researchers broke down their analyses by duration of beta blocker use, specific types of beta blockers, and sites within the colon or rectum where colorectal cancer developed in patients.
The authors conclude that their findings do not support the theory that using beta blockers cuts colon cancer risk.
That didn't surprise Robbins. "The few studies on this matter have been contradictory and it's unlikely that we'll ever see this sort of protective effect, since cancer is an incredibly complex disease driven by a myriad of unique biologic pathways," he said.
Another expert added that even though beta blockers might not help prevent colon tumors, people have other means of doing so.
"Men and women at average risk should start getting screened at age 50," said Dr. Mark Pochapin, director of the division of gastroenterology at NYU Langone Medical Center in New York City. "Those with certain risk factors, such as a family history of colorectal polyps or cancer, should talk to their doctors about screening at a younger age."
Pochapin also added that "lifestyle modifications -- such as quitting smoking, avoiding excess intake of red or processed meats, ensuring adequate vitamin D intake, and maintaining a healthy body weight and regular exercise -- can be very beneficial in reducing one's risk for colorectal cancer."
The U.S. National Cancer Institute has more about colorectal cancer risk factors and prevention.