Breast cancer is the most common cancer in women and is second only to lung cancer as the leading cause of cancer deaths among women in the United States. It affects one of every eight American women.
The Centers for Disease Control and Prevention estimates that more than 192,370 women are diagnosed with breast cancer each year, and the number of new cases has declined over the past decade. More than 40,000 women lose their lives to this disease annually.
Men can develop breast cancer, but it happens much less often than in women. Nearly 2,000 men are diagnosed with breast cancer each year.
Breast Cancer Types
There are two main types of breast cancer. Breast tumors may have a single type of cancer, a combination of types, or a mixture of invasive and noninvasive (in situ) cancer.
Ductal carcinoma is the most common form of breast cancer. Tumors form in the cells of the milk ducts, which carry milk to the nipples. Ductal carcinoma can be invasive with the potential to spread or non-invasive (also called ductal carcinoma in situ or DCIS). About one in five new breast cancer cases are DCIS. The chance for successful treatment of DCIS usually is very high.
Lobular carcinoma occurs in the lobules, which are the milk-producing glands. Lobular breast cancer can be non-invasive (in situ or LCIS, also called lobular neoplasia) or invasive (have a tendency to spread). About one in 10 breast cancer cases are invasive lobular cancer.
Less common types of breast cancer
Inflammatory breast cancer (IBC) is a rare, aggressive form of breast cancer that affects the dermal lymphatic system. Rather than forming a lump, IBC tumors grow in flat sheets that cannot be felt in a breast exam. Read more about IBC.
Triple-negative breast cancer is usually an invasive ductal carcinoma with cells that lack estrogen and progesterone receptors and do not have an excess of HER2 protein on their surfaces. These types of breast cancers tend to spread more quickly and do not respond to hormone therapy or drugs that target HER2.
Recurrent breast cancer is cancer that has returned after being undetected for a time. It can occur in the remaining breast tissue or at other sites such as the lungs, liver, bones or brain. Even though these tumors are in new locations, they still are called breast cancer.
Breast Cancer Risk Factors
If you have any of the risk factors listed below, talk to your doctor about getting these tests more often and adding more tests, including breast MRI (magnetic resonance imaging) and genetic testing. If you are concerned about inherited family syndromes that may cause breast cancer, we offer advanced genetic testing to let you know your risk.
Anything that increases your chance of getting breast cancer is a risk factor.
- Age: While most cases occur in women 50 or older, breast cancer sometimes develops in women in their 20s. Age is the main risk factor.
- Family history (especially mother, sister, daughter) of ovarian and/or breast cancer
- Hormones/childbirth: Your risk of breast cancer is higher if you:
- Had your first period before age 12
- Began menopause after age 55
- Never had children
- Had your first child after age 30
- Used hormone therapy after menopause
- History of radiation to the chest area
- Previous abnormal breast biopsy results
- Breast diseases such as atypical hyperplasia, or lobular or ductal carcinoma
- Obesity or weight gain after menopause
- Inherited susceptibility genes BRCA1 and BRCA2 account for about 5% to 10% of breast cancer cases. Tell your doctor if other women in your family have had breast cancer
Other breast cancer risk factors include:
- Oral contraceptive use (birth control pills)
- Diet high in saturated fats
- Not getting enough exercise
- Drinking more than one alcoholic drink a day
Not everyone with risk factors gets breast cancer. However, if you have risk factors, it’s a good idea to discuss them with your doctor.
Research shows that many cancers can be prevented. Visit our Prevention site to learn more.