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Questions around mammography screening

Created date

February 21st, 2017

The fortieth anniversary of the Nurses’ Health Study presents a wonderful opportunity to pause and reflect on our current understanding of breast cancer and how to prevent it. This study, which began with over 120,000 nurses, many of whom continue to participate, has provided valuable insights. Alongside 40 years of medical advances and technology, the study gives us real capability in making personal care decisions about breast cancer prevention. 

In 2016, there is little debate that the mainstay exam for early detection and prevention of breast cancer is mammography, but difficult questions remain as to what age to start testing, how frequently to get the test, and finally, at what age to stop screening. 

To answer these questions, as with all medical testing, it is important to understand your risk of developing the disease, the capability of the test and the risks associated with it, and then finally, to put it all in the context of your personal situation in conversation with your physician. This can be a complex decision that becomes more nuanced as we age.

Here is some of what we know. Breast cancer tops the list as the most common cancer diagnosed in women and occurs most frequently above the age of 65. While mammography screening does prevent breast cancer deaths, the numbers may not be quite as dramatic as you might expect. Over a period of ten years, 8 breast cancer deaths are prevented per 10,000 women age 50–59 who are screened, and 21 deaths are prevented among 10,000 women age 60–69 who are screened. Data above the age of 70 are limited, but it appears that mammography continues to be effective for women age 70–74, preventing 10–15 deaths per 10,000 women screened over a ten-year follow-up period. Over the age of 75, there is just not enough data to draw confident conclusions about screening mammography’s effectiveness. It is also important to remember that mammography is not 100% accurate. Testing will in some instances result in unnecessary worry and biopsies of normal breast tissue. 

Determining your risk

Guiding principles to consider as you weigh the risks and benefits of mammography include what your underlying risk for the disease may be. Risk factors for breast cancer include personal or family history of breast cancer, genetic factors, never having children, having dense breasts, having your first child after age 35, or going through menopause at age 55 or later. Modifiable risks include being overweight, drinking moderate amounts of alcohol, and being sedentary; and some studies indicate that smoking may also be associated with breast cancer. A great way to calculate your risk of breast cancer is the Breast Cancer Risk Assessment Tool, which you can find at

As with all screening tests there are differences of opinion about the appropriate frequency for mammography testing. Experts from the U.S. Preventive Services Task Force and the American Cancer Society say having mammograms every two years is sufficient, while experts from the American College of Obstetrics and Gynecology say every year is best. Ultimately there are many factors to consider in your personal decision about mammography. Take your time, consider your options, and discuss it with your doctor. There is no right or wrong decision on this subject, just the one that makes sense for you.

Matt Narrett, M.D., is chief medical officer for Erickson Living and leads the medical team at all Erickson Living communities. He received his medical degree from Harvard Medical School and has been providing care for seniors for over three decades.