NEW YORK (Reuters Health) Mar 22 - Women taking digoxin have an increased risk of breast cancer, according to a study of more than 2 million
NEW YORK (Reuters Health) Mar 22 - Women taking digoxin have an increased risk of breast cancer, according to a study of more than 2 million Danes.
The inotropic agent digoxin resembles estrogen chemically and is known to have estrogen-like effects. That led researchers to wonder if it might increase cancer risk the same way estrogen treatment does in older women.
About 2% of the women who took digoxin at any point during the study eventually developed breast cancer, the authors reported online March 21st in the Journal of Clinical Oncology.
Former users had the same risk as those who had never taken the drug, while those currently on it were about 40% more likely to develop breast cancer.
That extra risk is "worth noting," said Dr. Timothy Lash of Aarhus University Hospital in Denmark, a breast cancer expert who was not involved in the study. But he added that it's less impressive when you consider how few women actually developed the disease.
For the new study, researchers led by Dr. Robert Biggar of Statens Serum Institut in Copenhagen, Denmark, tapped into two national databases for prescriptions and cancer statistics.
About 100,000 women age 20 and older took digoxin at some point during the course of the study, which tracked women for an average of 12 years.
The chance of getting breast cancer was highest in women who were in their first year of digoxin therapy. Then the risk declined, but it slowly crept up again after 3 years or more on the drug.
A study like this one can't show whether digoxin leads to breast cancer in some women. And even if it does, the heart benefits might still outweigh that risk, the researchers said in their paper.
So the findings don't mean digoxin should be avoided in women, Dr. Lash told Reuters Health. Those who are on the drug "are receiving digoxin because they already have a fairly serious chronic disease," he said.
J Clin Oncol 2011.From Reuters Health Information