Breast Cancer Risk Factors: Hyperplasia and Other Benign Breast Conditions

Benign breast conditions (also called benign breast diseases) are non-cancerous breast disorders. They may be found on a mammogram and may be diagnosed with a biopsy.

Some benign breast conditions are linked to an increased risk of breast cancer and others are not.

To assess breast cancer risk, benign breast conditions are classified as:

• Proliferative (those with quickly growing cells)
• Non-proliferative (those without quickly growing cells)

Learn about other factors linked to the risk of breast cancer.

Proliferative breast conditions

Proliferative breast conditions aren’t cancerous, but they are linked to an increased risk of breast cancer [188-191].

The most common proliferative breast condition is hyperplasia. There are 2 types of hyperplasia: usual hyperplasia (more common) and atypical hyperplasia (less common). Some women may have both usual and atypical hyperplasia.

Usual hyperplasia

With usual hyperplasia (the most common form of hyperplasia), the proliferating (dividing) cells look normal under a microscope.

Women with usual hyperplasia have about twice the breast cancer risk of women without a proliferative breast condition [188-189].

For a summary of research studies on usual hyperplasia and breast cancer, visit the Breast Cancer Research Studies section.

Atypical hyperplasia

With atypical hyperplasia, the proliferating (dividing) cells look abnormal.

Atypical hyperplasia is less common than usual hyperplasia.

Women with atypical hyperplasia have about 3 to 5 times the breast cancer risk of women without a proliferative breast condition [188-191].

For a summary of research studies on atypical hyperplasia and breast cancer, visit the Breast Cancer Research Studies section.

Breast cancer screening for women with atypical hyperplasia

For women with atypical hyperplasia who also have a 20% or greater lifetime risk of invasive breast cancer, there are special breast cancer screening recommendations. (Estimate your lifetime risk or learn more about risk.)

The National Comprehensive Cancer Network (NCCN) recommends women with atypical hyperplasia who also have a 20% or greater lifetime risk of invasive breast cancer [163]:

• Have a clinical breast exam and risk assessment every 6-12 months, starting by age 25
• Have a mammogram with digital breast tomosynthesis every year, starting at age 30
• Talk with a health care provider about screening with breast MRI every year, starting at age 25

Screening helps make sure if breast cancer does develop, it’s caught early when the chances of survival are highest.

Learn more about breast cancer screening for women at higher risk.

Risk reduction for women with atypical hyperplasia

The NCCN strongly recommends women with atypical hyperplasia take a risk-reducing drug (such as tamoxifen) to lower their risk of developing breast cancer [54].

These drugs can lower the risk of breast cancer in women with atypical hyperplasia by about 86% [54].

Learn more about risk-reducing drugs.

Non-proliferative breast conditions

Non-proliferative breast conditions (such as cysts) are not linked to an increased risk of breast cancer.

Learn more about benign breast conditions. 

SUSAN G. KOMEN®‘S BREAST SELF-AWARENESS MESSAGES

1. Know your risk Talk with both sides of your family to learn about your family health history. Talk with a health care provider about your risk of breast cancer. 2. Get screened Talk with a health care provider about which screening tests are right for you if you’re at higher risk. Have a mammogram every year starting at age 40 if you’re at average risk.* Have a clinical breast exam at least every 3 years starting at age 25, and every year starting at age 40.* * Per National Comprehensive Cancer Network Guidelines 3. Know what is normal for you See a health care provider if you notice any of these breast changes: Lump, hard knot or thickening inside the breast or underarm area Swelling, warmth, redness or darkening of the breast Change in the size or shape of the breast Dimpling or puckering of the skin Itchy, scaly sore or rash on the nipple Pulling in of the nipple or other parts of the breast Nipple discharge that starts suddenly New pain in one spot that doesn’t go away To see illustrations of these warning signs, please visit the Warning Signs of Breast Cancer page. 4. Make healthy lifestyle choices Maintain a healthy weight. Make exercise part of your routine. Limit alcohol intake. Limit menopausal hormone therapy (postmenopausal hormone use). Breastfeed if you can.

Updated 12/18/24

This content is regularly reviewed by an expert panel including researchers, practicing clinicians and patient advocates.