Which women should get MRIs in addition to mammograms?

High Breast-cancer Risk

No one has a definite answer to how breast-cancer risk should be determined. "High risk" is typically defined as a 20 percent chance of getting breast cancer, but risk factors are pretty qualitative. Most guidelines state that high-risk women are those who are over 30 and have:

  • more than one close relative (mother, sister, daughter) who has had breast cancer
  • a genetic mutation linked to breast cancer (a mutated BRCA1, BRCA2, TP53 or PTEN gene)
  • a close relative with a genetic mutation linked to breast cancer
  • radiation treatment to the chest area after the age of 10 and before the age of 30

Even with these guidelines, the only way to know if you're really in the high-risk group is to discuss it with your doctor. Some woman who meet one or more of these criteria are actually in the average-risk group and should not be getting an MRI every year.

The second source promoting the regular use of MRI in breast-cancer testing is a new study published in the New England Journal of Medicine, and it really only applies to women who are diagnosed with breast cancer. This new research suggests that women who have been diagnosed with breast cancer in one breast should absolutely get an MRI of the other breast, even if the mammogram is clear, before beginning cancer treatment.

The study involved 969 women who had been diagnosed with a malignant tumor in one breast and had a mammogram of the other breast that revealed no cancer. Each of the women then received an MRI of the non-cancerous breast. In 30 cases, the MRI revealed that there was in fact cancer in the other breast. Without the MRI, those 30 women -- 3 percent of the subjects in the study -- would have begun treatment for cancer in one breast only to find out later it was also in the other breast. The second cancer would have been detected at a later stage, making it more serious, and the woman might have had to go through an entire second round of treatment involving surgery, chemotherapy and/or radiation. In cancer terms, a 3 percent chance of a false negative is unacceptable if it can be avoided with a non-invasive procedure that takes an hour.

With the back-to-back release of two credible recommendations for MRI as a regular breast-cancer detection method, it's likely that insurance companies that don't cover the procedure will start doing so very soon.

For more information on breast cancer, MRI and related topics, check out the links below.


Related HowStuffWorks Articles

More Great Links


  • "Breast MRIs urged for high-risk women." CNN.com. Mar. 28, 2007. http://www.cnn.com/2007/HEALTH/conditions/03/27/ breast.mri.ap/index.html
  • Grady, Denise. "Call to Increase M.R.I. Use for Breast Exam." The New York Times. Mar. 28, 2007. http://www.nytimes.com/2007/03/28/health/28mri.html? ex=1175745600&en=811b28ffc55cd3e9&ei=5070
  • "Magnetic Resonance Breast Imaging." Imaginis. http://www.imaginis.com/breasthealth/mri.asp
  • "MRI Detects Cancers In The Opposite Breast Of Women Newly Diagnosed With Breast Cancer." ScienceDaily. March 28, 2007. http://www.sciencedaily.com/releases/2007/03/070328073156.htm
  • "What is Breast MRI?" UCSF Department of Radiology. http://www.mrsc.ucsf.edu/breast/what_is_breast_mri.html