Mammograms are probably the most important tool doctors have to help them diagnose, evaluate, and follow women who've had breast cancer. Safe and highly accurate, a mammogram is an X-ray photograph of the breast. The technique has been in use for about 30 years.
Still, mammograms aren't perfect. Normal breast tissue can hide a breast cancer, so that it doesn't show up on the mammogram. This is called a false negative. And mammography can identify an abnormality that looks like a cancer, but turns out to be normal. This "false alarm" is called a false positive.
The number of mammogram false positives have caused some debate about when breast cancer screening should start. Besides worrying about being diagnosed with breast cancer, a false positive means more tests and follow-up doctor visits. The process can be extremely stressful and upsetting.
Digital mammography uses the same technique as film mammography, except that the image is recorded directly into a computer. Stereoscopic digital mammography gives a three-dimensional view of breast tissue. But stereoscopic digital mammography is very new and is not widely available yet. A study found that stereoscopic digital mammography helps reduce false positives.
Until stereoscopic digital mammography is available to more women, and to make up for mammography's limitations, more than mammography is needed. Women also need to:
- practice breast self-examination
- get regular breast examinations by an experienced health care professional
- in some cases, get another form of breast imaging, such as ultrasound or MRI scanning
Concern about false positives is NOT a good reason to skip mammograms. Work with your doctor to get the best quality mammogram you can:
- Ask if one mammography center is better than another. Staff members' skill and the technology available can affect mammogram accuracy.
- Insist that your new mammogram be compared with your older mammograms when it's being read. This has been shown to improve the accuracy of mammogram readings.
- Ask if a second person routinely reviews any suspicious mammograms before a final interpretation is made. A second reading also has been shown to improve mammogram accuracy.
For more information on mammograms and other tests to detect breast cancer, visit the breastcancer.org Screening and Testing section.