What is breast cancer?

Breast cancer is a kind of cancer that starts in the breast. It can start in the skin of the breast, the nipple, or—usually—the parts inside the breast such as milk ducts and lobes. Cancer that starts in the breast acts and grows in a different way than cancer that starts in another body part.

Women have a 1-in-70 chance of getting breast cancer at age 40, and the risk through a woman’s whole life is 1 in 8. Less than 1 percent of breast cancer cases happen in men. The chances of getting breast cancer go up as you get older.

Types of Breast Cancer

There are many types of breast cancer. Without treatment, the most common types will form a lump called a tumor.

The most common type for both men and women starts in the lining of the milk ducts of the breast and is called ductal carcinoma. The second most common type for women starts in the lobes, which are the glands that make milk, and is called lobular carcinoma. Other types of breast cancer include:

  • Tubular carcinoma
  • Medullary carcinoma
  • Papillary carcinoma
  • Cribriform carcinoma
  • Inflammatory breast cancer
  • Paget’s disease of the nipple
  • Phyllodes tumors

Understanding Breast Cancer


Because there are many kinds of breast cancer, the symptoms can vary. Very early on, you may not have any symptoms.

Breast cancer symptoms that you should look for on your own include:

  • Swelling
  • Skin redness or irritation
  • Thickening of the skin
  • Dimpling of the skin
  • Pain, in the breast or nipple
  • Changes in the nipple, such as it turning inward
  • Discharge from the nipple that’s not breast milk
  • A lump in the breast, in or near the armpit, or near the collar bone

Breast Cancer Awareness
To get an idea of how your breast feels and looks normally, it is a good idea to do a self-exam every month. Changes in your body, including breastfeeding and aging, can change the way your breasts look and feel. Some doctors recommend doing this exam within 2 or 3 days of your period’s end. Talk with your doctor about what is timing is right for you, and make a habit of it.

A more important part of breast cancer awareness is seeing your doctor regularly to be screened for breast cancer. This screening will involve an exam of your breast by your doctor, and it may also include a mammogram, an ultrasound, or an MRI of your breast.