Topic Overview

Is this topic for you?

This topic is for women who have been diagnosed with breast cancer for the first time. If you are looking for information on breast cancer that has spread or come back after treatment, see the topic Breast Cancer, Metastatic or Recurrent.

For male breast cancer, see the topic Breast Cancer in Men.

What is breast cancer?

Breast cancer occurs when abnormal cells grow out of control in one or both breasts. They can invade nearby tissues and form a mass, called a malignant tumor. The cancer cells can spread (metastasize) to the lymph nodes and other parts of the body.

Breast cancer that begins in the ducts of the breast is called ductal carcinoma. It is the most common type of breast cancer. This topic focuses on breast cancer that begins in the ducts.

Breast cancer is many women’s worst fear. But experts have made great progress in treating cancer. If it is found early, breast cancer can often be successfully treated, and it is not always necessary to remove the breast.

What causes breast cancer?

Doctors don't know exactly what causes breast cancer. But some things are known to increase the chance that you will get it. These are called risk factors. Risk factors that you cannot change include getting older and having changes to certain genes. Risk factors you can change include using certain types of hormone therapy after menopause, being overweight, and not getting enough physical activity.¹

But many women who have risk factors don't get breast cancer. And many women who get breast cancer don't have any known risk factors other than being female and getting older.

What are the symptoms?

Breast cancer can cause:

• A change in the way the breast feels. The most common symptom is a painless lump or thickening in the breast or underarm.
• A change in the way the breast looks. The skin on the breast may dimple or look like an orange peel. There may be a change in the size or shape of the breast.
• A change in the nipple. It may turn in. The skin around it may look scaly.
• A fluid that comes out of the nipple.

See your doctor right away if you notice any of these changes.

How is breast cancer diagnosed?

During a regular physical exam, your doctor can check your breasts to look for lumps or changes. Depending on your age and risk factors, the doctor may advise you to have a mammogram, which is an X-ray of the breast. A mammogram can often find a lump that is too small to be felt. Sometimes a woman finds a lump during a breast self-exam.