Several factors increase your risk for breast cancer. And all of these factors are somehow linked to the female hormone estrogen. Breast cancer has also been associated with the use of estrogen replacement therapy after menopause. Most physicians strongly believe this therapy does not cause breast cancer. However, they do suggest that it may accelerate the growth of a cancer that's already present.
All women are at risk for breast cancer.
However, the risk increases greatly after the age of 40. In fact, two-thirds of breast cancers are found in women over the age of 50. It also increases if a woman has a family history of the disease, has never had children, or had her first child after the age of 30. Women with a personal or family history of breast cancer are also at higher risk for breast cancer. For example, if you have already had breast cancer, you are more likely to develop it again in the opposite breast.