5 FAQs about mammography screening for women of average risk

Posted by Fadi Yahya, M.D.
May 19, 2016


Are you of average risk for breast cancer and what does that mean exactly? Should you have a mammogram and if so, how often? Below are five top frequently asked questions (FAQs) and answers about breast screenings and recommendations.

  1. Does mammography really save lives? Yes, it does. Mayo Clinic supports screening beginning at age 40 because screening mammograms can detect breast abnormalities early in women in their 40s. Findings from randomized trials of women in their 40s and 50s have demonstrated that screening mammograms decrease breast cancer deaths by 15 to 29 percent. The down side is the possible harm that arises from screening. Harm includes “false alarms” and “over diagnosis.” A false alarm is when the mammogram is read positive and further workup is negative for cancer. While an over diagnosis is discovering and treating a cancer that would have never caused harm. It is important to note that while some cancers are not harmful due to tumor biology, currently there is no way to know if a cancer will progress or not so all cancers detected are treated. Over diagnosis leads to some patients receiving treatment for a cancer that, if undiscovered, would not have caused harm. Some studies show that fewer lives are saved by screening among women in the 40-49 age group, the risk-to-benefit analysis is controversial and the screening recommendations for this age group vary among medical societies.
  2. At what age should screening start? All major groups making recommendations about breast cancer screening endorse routine screening with mammography for women starting at age 50 and older. There is debate, however, about routine screening for younger women (age group 40-49), with some groups encouraging shared decision-making with patients, because of trade-offs of benefits and harms.  As of May 2016, Mayo Clinic recommends annual screening mammography beginning at age 40 years for women at average risk of breast cancer. Average risk of breast cancer means women with no family history of breast cancer and no other risk factors for breast cancer. Women with a family history of breast cancer or other risk factors for breast cancer require an individualized approach to screening.
  3. When should screening be discontinued? The recommendations vary between organizations. Some recommend discontinuing at the age of 74 years, while others recommend assessing life expectancy and if it is less than 5 to 10 years, then screening can be discontinued.
  4. How often should mammograms be done? The recommended frequency of mammography is variable among organizations. In general, government-sponsored groups, such as the U.S. Preventive Services Task Force, recommend screening every 2 to 3 years, while medical societies recommend screening every 1 to 2 years. This variation is related to balancing the benefits and harms of mammography. The longer intervals are associated with less harm from false alarms and over diagnosis, and also leads to slightly less lives saved.
  5. What is the significance of increased breast density? The presence of dense breast tissue on mammography both decreases the sensitivity of mammography and increases the risk of breast cancer. Additional screening strategies are available that can improve the detection of cancer in women with increased breast density.

We encourage women to inquire about the benefits as well as the harms of mammography and to ask their providers about recommendations from all the major groups and medical societies. While not all organizations agree on breast cancer screening guidelines, most do emphasize working with your doctor to determine what's right for your particular situation.

Fadi Yahya, M.D., is an OB-GYN on the Albert Lea campus of Mayo Clinic Health System – Albert Lea and Austin.

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