Breast cancer happens when cells in your breast grow abnormally and out of control. The cancer cells can spread to other parts of your body.
You're more likely to get breast cancer as you get older. But the disease can affect women in their 40s and, rarely, women in their 30s.
Breast cancer is the most common type of cancer in women, but it can often be treated successfully if it is found early.
eMedicineHealth Medical Reference from Healthwise
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