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Contrary to popular belief, beta-blockers don’t prevent colorectal cancer
By Thomas H. Maugh II
Contrary to popular belief among physicians and patients, the family of hypertension drugs known as beta-blockers does not prevent development of colon and rectal cancer, German researchers reported Monday. In fact, long-term use of the drugs might even be associated with an increased risk of developing an advanced form of the disease, they said.
Beta-blockers are a family of drugs that reduce blood pressure and improve heart function by reducing the body’s response to stress hormones such as epinephrine and norepinephrine. Among the best known are atenolol (Tenormin), bisoprolol (Zebeta), metoprolol (Lopresor or Toprol) and carvedilol (Coreg). Because studies in animals and cell lines have shown that norepinephrine increases the growth rate of certain tumors, such as breast and colon cancer, researchers have speculated that beta-blockers might inhibit growth of the tumors by inhibiting norepinephrine response. Several small trials in humans, however, have produced mixed results.
Between 2003 and 2007, epidemiologist Michael Hoffmeister of the German Cancer Research Center in Heidelberg and his colleagues interviewed 1,762 patients with colorectal cancer and 1,708 healthy patients, asking about their use of the drugs and a variety of other potential complicating factors. Their survey was part of a larger study assessing the efficacy of colonoscopy screening in reducing the risk of colorectal cancer.
The team reported in the journal Cancer that they found no association between the drugs and colorectal cancer, even when they analyzed by duration of drug use, type of drug, specific ingredients and sites within the colon or rectum where tumors developed. The only potential link they observed was that patients who had used the drugs the longest had about double the normal risk of being diagnosed with stage IV (advanced) colon cancer. That finding, they emphasized, needs further exploration and confirmation.