A study found that women who are at high risk for breast cancer benefit more from screening with a mammogram AND breast ultrasound than from a mammogram alone.
In high-risk women who got only a mammogram, only half of the breast cancers that were present were found. When both a mammogram and breast ultrasound were done, about 80% of the breast cancers were found. Ultrasound was very good at finding small breast cancers that hadn't spread to the lymph nodes yet. It's always good to find breast cancer early, when it's most treatable.
Finding more breast cancers earlier by adding another screening method, such as ultrasound, is important. But adding another screening test also increases the risk of a "false positive." False positives happen when a screening test identifies an area that looks like cancer, but turns out to be normal.
Research has shown that when more than one screening test is used, there's a greater risk of false positives. In the study reviewed here, women who had both mammogram and ultrasound screening were 4 times more likely to have a false positive than women who had only a mammogram. Besides the fear of being diagnosed with breast cancer, a false positive also means more tests (including biopsies) and follow-up doctor visits. The process can be very stressful and upsetting.
For women who have an average risk of breast cancer, getting a mammogram every year starting at age 40 is a very good way to screen for breast cancer. Women at high risk:
- who have an abnormal BRCA1 or BRCA2 gene
- who have a strong family history of breast cancer
may need different screening plans.
Adding ultrasound is one way to increase the chances of finding a breast cancer early in high-risk women, but it also increases the risk of a false positive. Other studies have shown that a breast MRI scan may be better than mammograms for finding very early breast cancer in high-risk women. Adding MRI also increases the rate of false positives, but this higher rate is considered acceptable by women and their doctors because of the benefits of MRI. The American Cancer Society recommends using MRI screening instead of mammography in certain groups of women at high risk for breast cancer.
If you have a higher-than-average risk of breast cancer, you might want to ask your doctor about:
- the type of screening that's best for you
- the value of digital and 3-dimensional mammograms, if they're available in your area
- the benefits of being screened more often than once a year
- the risk of false-positives
No matter what your risk of breast cancer is, you and your doctor can work together to create a screening plan that's best for you.
For more information on mammograms, ultrasounds, MRIs, and other tests to find breast cancer, visit the breastcancer.org Screening and Testing section.