Employee & Community Health

Did you know? Learn the latest about breast cancer

10/19/2015 by Dr. Summer Allen


Breast cancer is the second-most common cause of cancer in women with one in eight women (12%) in the U.S. being diagnosed during their lifetime, according to the Center for Disease Control and Prevention (CDC) and National Cancer Institute (NCI). October is Breast Cancer Awareness Month, and your Care Team wants to share current information regarding breast cancer screening, mammography and self-care. 

When should you start screening?

The United States Preventive Services Task Force (USPSTF) released the latest guidelines in 2009 on mammography screening. Another update is in progress, but the current recommendations include: 

  • Women most likely to benefit from screening are those ages 50-74. Screening is most likely to be beneficial if done every two years. 
  • Women in their 40's have a lower risk of developing breast cancer, so the benefits of screening is smaller than for women 50 and older. Screening before age 50 should be based on a woman's personal values, preferences, health history and through a discussion with their health care provider. 
  • For women age 75 and older, the evidence for the benefit of screening is limited, so a recommendation for or against it cannot be made at this time. 

These recommendations are intended to provide the greatest benefit to patients while reducing potential harm from screening, which can include: 

  • False-positive results. Screening exam shows potential concern, but additional imaging, tests or procedures reveal negative results. 
  • Over-diagnosis. Being diagnosed and receiving treatment for a type of breast cancer that would have no effect on a women's life.
  • Health-related anxiety. Caused by awaiting results from initial screening or when additional testing is needed.

These recommendations are different from other organizations, such as the American Cancer Society, the American College of Obstetrics and Gynecology and the National Comprehensive Cancer Network. All of these organizations recommend annual screening mammography starting at age 40. 

Mayo Clinic continues to offer annual screening mammography starting at age 40, and we encourage you to have a discussion with your healthcare provider regarding your individual preferences and health history in order to make an informed and shared decision regarding mammography screening. We also are working on a decision aid to help our patients better understand the potential benefits and limitations related to breast cancer screening and to facilitate the discussion with their provider. 

What are the main risk factors?

The top-two risk factors for breast cancer are gender (female) and age (risk increases with age). Recommendations for screening will be different for women with a history of breast cancer (including a diagnosis of ductal carcinoma in situ of the breast), genetic mutations known to place women at higher risk (for example, BRCA 1 and 2), and those with a history of chest radiation. Women with a mother, sister or daughter diagnosed with breast cancer have a different risk than other women. They should talk to their health care provider about recommendations for when to start screening and how often they should be screened. 

What is the link between breast density and cancer? 

Breast density, which is the proportion of milk glands and ducts to fat, is determined by a mammogram and the radiologist reading the image. The density levels are: A (fatty breast), B (mild density), C (moderate density) or D (extremely dense tissue). 

Those with dense breasts are at increased risk for developing breast cancer compared to women with primarily fatty breast tissue. As a result, many states have developed legislation to ensure that women are informed of their breast density following a mammogram. 

The USPSTF recently reviewed the evidence regarding additional screening in women with dense breasts and found that it doesn't clearly indicate that additional screening is beneficial. Consequently, the organization doesn't make a recommendation for or against more screening. Options for additional screening include: tomosynthesis, molecular breast imaging, ultrasound or breast magnetic resonance imaging (MRI). 

Watch this video of specialists in our Breast Diagnostic Clinic discussing breast density. 

Questions about breast cancer? Talk with us!

Please contact your Employee and Community Health (ECH) Care Team with any questions about breast cancer, screening, mammography or self-care. 

Dr. Summer Allen is a Family Medicine physician within Employee and Community Health's Division of Family Medicine. She has an interest in women's health (with a special interest in breast cancer, screening and preventive health), obstetrical care and population health. She also serves as a leader for Mayo Clinic in the area of Patient Engagement with a goal of understanding what our patients desire from health and healthcare.