What causes breast cancer? Cancer grows when a cell's DNA is damaged, but why and how that DNA becomes damaged is still unknown. It may be the result of genetic or environmental factors, but most people won't know exactly what caused their cancer.
Certain genetic factors that may put people at risk (including age, race, family history and personal health history) can't be changed, but they also do not guarantee you'll develop breast cancer. Environmental factors, though, can be changed: a sedentary lifestyle, poor diet, obesity and too much alcohol may all increase your risk of developing breast cancer — but again, they do not guarantee that you will. According to the National Breast Cancer Foundation, up to 70% of people with breast cancer have no connection to these risk factors at all, and other people with these risk factors will never develop cancer.
In October, be kind to your breasts: Exercise regularly. Enjoy a healthy diet. Don't smoke. Drink in moderation. Conduct monthly breast self-exams and follow the National Breast Cancer Foundation's tips for early detection of breast cancer. And continue to hydrate!
Breast cancer is the most common cancer among women worldwide, claiming the lives of hundreds of thousands each year.
In the U.S. in 2020, the National Breast Cancer Foundation estimates that more than 276,480 new cases of invasive breast cancer will be diagnosed in women, as well as 48,530 new cases of noninvasive or in situ breast cancer. (Noninvasive cancers are confined to the ducts or lobules and have not spread to surrounding tissues. Invasive breast cancer has spread outside the milk duct and into the normal tissue inside the breast. Noninvasive cancers can become invasive. Learn more about the anatomy of the breast.) Also in 2020, an estimated 42,170 of those women will die.
Men get breast cancer, too. The National Breast Cancer Foundation estimates 2,620 men will be diagnosed with breast cancer this year in the U.S. and approximately 520 will die.
The good news: Death rates from breast cancer have been declining since about 1990, due to better screening and early detection, increased awareness and continually improving treatment options.