Scottsdale, Arizona - At Mayo Clinic, doctors offer mammograms to women beginning at age 40 and continuing annually. When to begin mammogram screening and how often to repeat it is a personal decision based on your preferences and values.

Mayo Clinic recommends women and their doctors discuss the benefits, risks and limitations of mammograms and decide together what is best. Balancing the benefits of screening with the limitations and risks is a key part of deciding when to begin mammograms and how often to repeat them.

Not all organizations agree on mammogram guidelines. For instance, the U.S. Preventive Services Task Force mammogram guidelines recommend women begin screening at age 50. The American Cancer Society, the National Comprehensive Cancer Network and other organizations recommend that women begin screening in their 40s. Some organizations recommend screening every year and others recommend screening every two years.

Reacting to changing evidence

Mayo Clinic doctors continue to review studies about mammogram guidelines to understand what the studies mean for women's health. Changes to mammogram guidelines might or might not be necessary in the future, as researchers continue studying this topic.

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.

But mammogram screening isn't perfect. Another study concluded that despite more women being diagnosed with early breast cancer due to mammogram screening, the number of women diagnosed with advanced breast cancer hasn't decreased. The study suggested that some women with early breast cancer were diagnosed with cancer that may never have affected their health.

Unfortunately doctors can't distinguish dangerous breast cancers from those that are non-life-threatening, so annual mammograms remain the best option for detecting cancer early and reducing the risk of death from breast cancer.

Other concerns about mammogram screening for breast cancer include:

  • Exposure to low levels of radiation
  • A chance of a false-positive result, which can lead to additional testing and, possibly, a breast biopsy

Working with your doctor

If you're concerned about when to start breast cancer screening and how often to repeat it, work with your doctor to make an informed decision. Together you can decide what's best for you based on your personal preferences, your medical history and your individual breast cancer risk.

Talk with your doctor about:

  • Your personal risk of breast cancer
  • The benefits, risks and limitations of screening mammograms
  • The role of breast self-exams for breast awareness in helping you become more familiar with your breasts, which may help you identify abnormalities or changes