There are several persistent email and internet rumors about potential causes of breast cancer. One is that wearing a bra, or wearing an underwire bra, causes the disease.
The idea that bras may cause cancer was fueled by the 1995 book called Dressed to Kill by Sydney Ross Singer and Soma Grismaijer. It claims that women who wear underwire bras for 12 hours a day have a much higher risk of developing breast cancer than women who do not wear bras.They maintain that bras restrict the lymph system, which results in a build-up of toxins in the breasts.+ However, according to the American Cancer Society, there is no evidence that compression of the lymph nodes by bras causes breast cancer; in reality, body fluids travel up and into the underarm lymph nodes, not towards the underwire. Similarly, there is no sufficient evidence that any types of bras cause breast cancer.
In The Dr. Susan Love’s Breast Book, Love claims that the hypothesis about bras causing cancer stems from our desire to have control over areas of life where we have a lot of uncertainty or fear. People want something to blame, and also hope that by avoiding bras they can avoid breast cancer. While there are geographic variations in breast cancer rates, there are many, many factors, including diet, exercise, lifestyle, childbearing practices, as well as other behaviors and exposures that are more plausible explanations for these regional differences in breast cancer than bras. In places where people have less access to medical care, breast cancer will not be diagnosed as often, even though it might be present. And because the risk of breast cancer increases as women get older, breast cancer rates will be lower in parts of the world where people die of other causes at younger ages, whether they have worn bras or not.
Even if women who wear underwire bras are more likely to be diagnosed with breast cancer, a likely explanation would be that many women with larger breasts also tend to be heavier. Being overweight or having a lot of body fat puts a woman at increased risk for breast cancer. It would make sense that women with larger breasts are both more likely to wear underwire bras and more likely to develop breast cancer. But this doesn’t mean that underwire bras cause breast cancer!
In a study published in 2014, researchers interviewed postmenopausal female participants about their lifetime bra wearing patterns. Evaluating more than 1,000 women with breast cancer and almost 500 who did not have breast cancer, the researchers found no evidence of a connection between the number of hours spent wearing a bra or wearing an underwire bra and increased breast cancer risk.
The bottom line: well-designed studies have not convinced experts that wearing bras or underwire bras increase your chances of developing breast cancer.