While a direct cause has not been fully identified, experts know that breast cancer happens when the cells begin rapidly dividing and multiplying. As these cells accumulate, they form lumps or abnormal tissue. Usually, breast cancer starts within the milk-producing ducts or the glandular tissue, known as lobules. However, it can also begin in other tissues in the breast.

Inevitably, more research is needed to further understand breast cancer. It has been theorized that environmental, lifestyle, and genetic factors may play a role in the development of breast cancer. Yet, these are more so defined as risk factors, which we explore in the next section.

There are many factors that researchers have identified as ‘high risk’ in the development of breast cancer. However, these risk factors, as outlined below, don’t necessarily guarantee one will develop breast cancer.

About 5-10% of breast cancer cases are estimated to be linked to genetic or inherent causes [2]. This may be due to genetic mutations, including certain genes linked to breast and ovarian cancer. Usually, if a person has a family history of breast cancer, their doctor will recommend regular testing to ensure that if it does happen, it’s caught early on.

While breast cancer can happen in males, it is rare. Unfortunately, being female poses a higher risk of developing this disease.

Any radiation exposure to the chest or torso may increase your odds of developing breast cancer. This particularly increases the risk for adults who, as children or young adults, were exposed to radiation.

If you are on hormonal therapy, such as postmenopausal estrogen or progesterone medications, to help reduce the symptoms associated with menopause, you may be at a higher risk of developing breast cancer. Ceasing to take this medication will decrease risks of developing breast cancer.

Obesity is associated with a number of chronic diseases and conditions, including breast cancer. In addition, giving birth at an older age, early menstruation, never being pregnant, and menopause starting at a later age also increases your risk of developing breast cancer.