Underwire bras do not increase the risk of breast cancer

The lymphatic system removes waste products from all tissues, including breast tissue. These waste products may contain carcinogenic substances. According to some, the underwire in an underwire bra could constrict lymphatic drainage, leading to a buildup of potentially toxic substances in the breast. This is nonsense for several reasons. Lymph from the breast is drained along fixed pathways to the armpit, not downward toward where the underwire is located. Furthermore, lymph vessels are not located near the surface, and pressure from an underwire has no effect whatsoever on lymph flow. If lymph were to accumulate in the breast, the breast would swell (edema): wearing an underwire bra definitely does not make your breasts bigger. And for anyone who still has doubts: the impact of bras on breast cancer risk was once investigated in a study* involving approximately 500 women with breast cancer, who were compared to a control group of an equal number of women without breast cancer. Wearing any type of bra has absolutely no impact on the risk of breast cancer.

*Chen L, Malone KE, Li CI. Bra wearing is not associated with breast cancer risk: a population-based case-control study. Cancer Epidemiol Biomarkers Prev 2014;23(10):2181-2185