MRI helps detect breast cancer in women at high risk
If a woman has been newly diagnosed with cancer in one breast, MRI (magnetic resonance imaging) of the other breast may show cancer that would not be detected by a mammogram, according to a study by the American College of Radiology Imaging Network. This means that both cancers can be diagnosed at the same time, so women can have one round of treatment instead of two, says Dr. Constance Lehman, principal investigator of the study.
Lehman and other researchers studied the MRIs of 969 women with newly diagnosed breast cancer. All of the women had negative mammograms and negative clinical breast exams in the opposite breast. But, MRIs found 30 additional breast cancers that the mammograms missed.
When it was published last year, the study made headlines worldwide and led to new breast cancer screening guidelines for women at high risk by the American Cancer Society. Lehman, a UW professor of radiology and head of radiology for the Seattle Cancer Care Alliance, offers these additional insights about what her research means for women:
Q: Who should have a breast MRI?
A: Any woman who has a greater than 20 to 25 percent lifetime risk of developing breast cancer should have an MRI in conjunction with a mammogram.
Q: Which women fall into the high risk category?
A: According to the American Cancer Society, women with a greater than 20 percent lifetime risk of breast cancer include those who:
- have a known BRCA1 or BRCA2 gene mutation.
- have a first-degree relative (parent, brother, sister or child) with a BRCA1 or BRCA2 gene mutation and have not had genetic testing themselves.
- have a lifetime risk of breast cancer of 20 to 25 percent or greater, according to risk assessment tools that are based mainly on family history.
- had radiation therapy to the chest when they were between the ages of 10 and 30 years.
- have Li-Fraumeni syndrome, Cowden syndrome or Bannayan-Riley-Ruvalcaba syndrome, or have one of these syndromes in first-degree relatives.
Q: What about a woman who had breast cancer in one breast 10 years ago? Should she have an MRI on the other breast?
A: Many, but not all, women who have been treated for breast cancer have a 20 percent lifetime risk of recurrence. If a woman with a personal history of breast cancer never had an MRI, I think it’s a good idea to have one. It’s a discussion each woman with a history of breast cancer should have with her doctor.
Q: In what ways did your research challenge assumptions about MRI?
A: Our study challenged the prevailing view that MRI was only useful in young women, women with dense breast tissue or women with certain types of breast cancer. We found that the added benefit was not dependent on age, type of breast tissue or previous cancer history.
Q: Your study shows how MRI can be used to find breast cancer. What about news stories that question whether every woman should have a mammogram yearly after 40? How should women sort this information?
A: The recommendation that women between the ages of 50 and 69 should have routine mammograms is not argued by anyone with any scientific backing. Unfortunately, that’s not emphasized enough. So, for the first time in the history of screening, we’re seeing mammography rates decline. This is very concerning. We have decreased breast cancer mortality in the United States because of screening mammography’s ability to detect breast cancer at an early stage. My fear is that women are being misled to think that mammography is not an important tool. And that is really a disservice to women.
Mammography is also strongly recommended for women in their 40s. This is when cancers grow more rapidly and can be more aggressive. When possible, younger women should have digital mammography, which has proven to be more effective in cancer detection for this age group compared to film screen methods.
Q: Where is more information available?
A: The National Cancer Institute has a tool to determine your lifetime risk for breast cancer at www.cancer.gov/bcrisktool. For more information on the Seattle Cancer Care Alliance, visit www.seattlecca.org. For the American Cancer Society, visit www.cancer.org.