Breast MRI monitoring in women who have previously been diagnosed with breast cancer finds more cancers than mammography, but also leads to more biopsies, according to a study.
The research was published in July 2019 by the journal Radiology. Read the abstract of “Surveillance Breast MRI and Mammography: Comparison in Women with a Personal History of Breast Cancer.”
About the study
National guidelines differ on whether MRI should be used to routinely monitor women with a personal history of breast cancer. The American College of Radiology recommends annual breast MRI for women with dense breasts who were first diagnosed with breast cancer before age 50, but not much research has been done on the risks and benefits of doing this.
According to the researchers who did the study, radiologists aren’t sure which routine screening method to recommend to women with a history of breast cancer.
"You have women who've been diagnosed and treated for breast cancer, some of whom have been recommended to get breast MRI, and some of whom that haven't," said lead author, Karen Wernli, of Kaiser Permanente Washington Health Research Institute, in an interview. "So it's important to understand whether or not additional imaging with breast MRI is important in finding second breast cancers in women who have a previous breast cancer history."
So the researchers compared routine surveillance mammography with routine surveillance breast MRI.
To do the study, the researchers used information on 13,266 women who had been diagnosed with stage 0 to stage III breast cancer in the Breast Cancer Surveillance Consortium, a database of breast cancer screening records, which is funded by the National Cancer Institute.
Of the 13,266 women:
- 11,745 were monitored with mammography alone, with a total of 33,938 mammograms done
- 1,521 were monitored with breast MRI, with a total of 2,506 MRIs done; these women also had mammograms
The researchers found that breast MRI had a higher cancer detection rate — finding 10.8 cancers per 1,000 exams compared to mammography alone, which found 8.2 cancers per 1,000 exams.
Breast MRI also had a higher biopsy rate — 10.1% of women who had MRI had a biopsy compared to mammography alone, where 4.0% of the women had a biopsy.
Still, there were no statistically significant differences between breast MRI and mammography in sensitivity for breast cancer detection or interval cancer rates.
Sensitivity for breast cancer detection is the ability of a test to detect breast cancer. Interval cancers are cancers that are found within 12 months of a screening test that comes back normal.
So while breast MRI found more cancers than mammography, the two imaging techniques were equally likely to find breast cancer.
"…[The] radiologic interpretation of mammography does not appear to miss more second cancer events that would become clinically detectable during the screening interval of 12 months compared with the radiologic interpretation of breast MRI," the researchers concluded in an article.
What this means for you
If you have a personal history of breast cancer, it makes sense to talk to your doctor about the risks and benefits of adding MRI to your breast cancer screening plan.
While MRI may be a good option, it also can lead to more false positives — results showing an abnormal area that looks like a cancer but turns out to be normal. Ultimately the news is good: no breast cancer. But the suspicious area usually requires follow-up with more than one doctor, extra tests, and extra procedures, likely including a biopsy. There are psychological, physical, and economic costs that come with a false positive.
Together, you and your doctor can decide on a screening plan that is best for your unique situation.
For more information on the tests and tools used to screen for breast cancer, visit the Breastcancer.org Screening and Testing pages.
Written by: Jamie DePolo, senior editor