A longstanding myth argues that bras cause breast cancer by obstructing the breast’s lymph system, causing the accumulation of toxins inside the breast leading to breast cancer. The myth was started by a 1995 book titled ‘Dressed to Kill’ based on the authors’ observations (not results of scientific studies) that women in western cultures who wore bras had a higer rate of breast cancer than women in traditional cultures who rarely wore bras. This myth is based on a number of illogical assumptions. Problems with the theory include:
- The authors’ observations did not take into account differences between these cultures in known risk factors for breast cancer, such as diet, weight, exercise, the age at which menstruation starts, pregnancies, and breast feeding.
- The suggested mechanism is inconsistent with scientific concepts of breast physiology and pathology. The breast lymph system does not drain into the main part of the breast. The lymph system drains out of the breast into the underarm lymph nodes; and bras do not prevent the circulation of blood and lymph from the breast.
- There are no well-designed research studies that demonstrate that wearing a bra causes breast cancer. The single epidemiological study that investigated the possible link between bra use and breast cancer suggested that breast cancer might be less common among women who do not wear bras. This result was not statistically significant and the researchers note that the connection is most likely due to indirect factors, such as women who are obese (a known risk factor for breast cancer) and have large breasts are less likely to go braless. There are no epidemiological studies published in scientific journals that suggest that bras directly contribute to breast cancer risk.