At Mayo Clinic, doctors offer mammograms beginning at age 40 and continuing annually. When to begin mammogram screening and whether to repeat it every year or every other year it is a personal decision based on your preferences.

Mayo Clinic recommends that you discuss the benefits, risks and limitations of mammograms with your doctor and decide together what is best. Your doctor can guide you in balancing the benefits of screening with the limitations and risks.

Breast cancer screening guidelines are issued by various medical organizations in the United States. The organizations don't all agree on when to begin screening mammograms and how often to repeat them. But most emphasize meeting with your doctor to discuss what's right for your particular situation.

Balancing benefits and concerns

Mayo Clinic supports screening beginning at age 40 because screening mammograms can detect breast cancer early. Findings from randomized trials of women in their 40s and 50s have demonstrated that screening mammograms reduce the risk of dying of breast cancer.

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

Doctors can't tell which breast cancers will spread beyond the breast and which cancers will remain confined to the breast. So annual mammograms remain the best option for detecting cancer early, providing a greater chance for a cure and reducing the risk of death from breast cancer.

The main concern about mammograms for breast cancer screening is the chance of a false-positive result. This means that something unusual is detected but, after additional testing, it turns out to not be cancer. False-positives are more likely to occur in your 40s and 50s.

If an area of concern is detected on a mammogram, you'll be asked to undergo additional mammogram imaging and, possibly, ultrasound imaging. These tests may determine that the area of concern that was detected isn't likely to be cancer.

In certain situations, you may need to undergo a biopsy procedure to remove a sample of breast tissue for testing. Often, having a biopsy that confirms there isn't any cancer present is reassuring and doesn't increase anxiety.

Working with your doctor

If you're concerned about when to start mammograms and how often to repeat them, 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, your family 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