Metformin may affect risk of breast cancer in women with type 2 diabetes

A study of 44,541 women has found that there appears to be no association between type 2 diabetes and developing breast cancer overall. This may be because most women in the study with type 2 diabetes were taking metformin, a medication widely used to treat type 2 diabetes, whose actions may help to reduce the risk of developing oestrogen positive (ER-positive) breast cancer.