Antibiotic use may raise risk for breast cancer

A study of more than 10,000 women shows that antibiotic use may be linked with the development of breast cancer, with the study subjects who used antibiotics the most during their lives having the highest risk for the disease, The Washington Post reports. Women who had more than 25 prescriptions for antibiotics over a 17 year period were shown to have twice the risk of cancer than women who had taken no antibiotic medications, according to the study. The risk of breast cancer development increased with the number of prescriptions received, but even women who had between 1 and 25 prescriptions were 50% more likely to have developed cancer. The risk was consistent with all forms of antibiotics. Although the researchers are unsure of precisely how antibiotics seem to raise the risk of breast cancer, they theorized that the drugs could affect bacteria in the digestive tract and alter the way the body uses foods that protect against cancer. It's also possible the drugs affect the immune system's ability to fight off the development of breast cancer cells. Health experts say that women should not stop taking antibiotics to treat infections, including sexually transmitted diseases and other serious conditions. They say that although the study does show a link between antibiotic use and breast cancer, additional studies need to be done to rule out any other possible causes for the increased cancer risk. The study also did not rule out the possibility that women who take antibiotics more often have other risk factors for the disease, such as a family history of breast cancer or hormonal imbalances. "We need to follow up and find out if this is a real association," Stephen H. Taplin, a senior scientist at the National Cancer Institute, told the Post. However, the researchers say the study does provide another reason for doctors to prescribe antibiotics sparingly, and avoid prescribing them in situations where other treatments are available. Breast cancer is diagnosed in more than 211,000 American women each year and kills more than 40,000, making it the most common form of cancer and second leading cancer killer among women.