No matter who you are, where you live or your age, you have a 1 in 8 chance of being impacted by breast cancer. Breast cancer is the most common cancer among women in the U.S. and around the world. Men can also get breast cancer.

There is good news. Progress in treatment and early detection has led to improved survival for people of all ages, races and with all stages of breast cancer. In fact, there are more than 3.8 million breast cancer survivors in the U.S. today: that’s more than any other group of cancer survivors!

What is Breast Cancer?

Breast cancer occurs when cells in the breast divide and grow without their normal control.

Tumors in the breast tend to grow slowly. By the time a lump is large enough to feel, it may have been growing for as long as 10 years. However, some tumors are more aggressive and will grow much faster.

Between 50-75 percent of breast cancers begin in the milk ducts, about 5-15 percent begin in the lobules and a few begin in other breast tissues.

Learn about breast anatomy.