What is breast magnetic resonance imaging (MRI)?
Breast magnetic resonance imaging (MRI) uses magnetic fields to create an image of the breast.
Breast MRI is used in breast cancer screening for women at higher risk. It’s not recommended in breast cancer screening for women at average risk.
Breast MRI is also used in breast cancer diagnosis and staging. For example, some people have hard-to-find (occult) breast cancers. They may have cancer in the lymph nodes in the underarm area (axillary nodes) or metastases (spread) at diagnosis. In these cases, MRI may help find the original tumor in the breast.
Breast MRI vs. mammography
Compared to mammography, screening with breast MRI has some drawbacks [82-85]:
- Breast MRI is more invasive than mammography because a contrast agent (gadolinium) is given by vein (through an IV) before the procedure. In rare cases, people have a reaction to gadolinium.
- Gadolinium may build up in the brain over time in people who get MRIs on a regular basis, such as women at high risk of breast cancer who get regular breast MRI screening. Whether or not this build up has health risks is under study.
- Breast MRI has more false positive results than mammography. A false positive result shows a possible breast cancer, even though breast cancer isn’t present. The suspicious area must be checked with follow-up tests, and sometimes a biopsy, to be sure there’s no breast cancer.
- Breast MRI is also likely to cause over-diagnosis. For example, when used pre-operatively to make surgery decisions and when it finds small, invasive breast cancers that would have never caused symptoms or problems if left untreated.
- Some MRI centers don’t have the special magnets needed to do an MRI of the breast or don’t have radiologists specially trained to read breast MRIs.
- Breast MRI is expensive and isn’t always covered by insurance.
Breast MRI and breast cancer screening for women at higher risk
Compared to mammography alone, mammography plus breast MRI can increase detection of breast cancer in some women at higher risk of breast cancer [72-75].
- A BRCA1 or BRCA2 inherited gene mutation
- A first-degree relative (mother, sister, daughter) with a BRCA1/2 inherited gene mutation, but have not been tested for BRCA1/2 gene mutations themselves
- Li-Fraumeni syndrome or Cowden/PTEN syndrome (and first-degree relatives)
- A PALB2, PTEN, STK11 or TP53 inherited gene mutation
- Radiation treatment to the chest area between ages 10-30
- A greater than 20 percent lifetime risk of invasive breast cancer based mainly on family history (Estimate your lifetime risk or learn more about risk.)
The NCCN recommends some women at higher risk of breast cancer consider breast MRI as part of breast cancer screening, including those with [9,70]:
- Lobular carcinoma in situ (LCIS) who also have a 20 percent or greater lifetime risk of invasive breast cancer
- Atypical hyperplasia who also have a 20 percent or greater lifetime risk of invasive breast cancer
- An ATM, BARD1, CDH1, CHEK2, NF1, RAD51C or RAD51d inherited gene mutation
Both the NCCN and the American Cancer Society (ACS) recommend women at higher risk of breast cancer begin screening at an earlier age than women at average risk [8-9]. Figure 3.5 and Figure 3.6 outline their guidelines.
Talk with your health care provider about breast cancer screening. Together, you can make a screening plan that’s right for you.
|For a summary of research studies on breast cancer screening with breast MRI plus mammography and mammography alone for women at high risk of breast cancer, visit the Breast Cancer Research Studies section.
Timing of breast MRI screening
If you’re at high risk of breast cancer and getting a mammogram and breast MRI every year for screening, your health care provider may stagger the tests, so you get one test every 6 months.
Insurance coverage of breast MRI varies. You may want to check with your insurance company before getting breast MRI for screening to see if it’s covered.
Women with a personal history of breast cancer
Mammography plus breast MRI is under study for screening for new breast cancers in women with a personal history of breast cancer.
Some studies suggest, for women diagnosed with cancer in one breast, mammography plus breast MRI can find breast cancer in the opposite (contralateral) breast better than mammography alone [82-83,86].
One study found mammography plus breast MRI may also help find new cancers in the treated breast (in women who had lumpectomy) .
However, it’s still not clear whether or not screening with breast MRI offers a benefit to women who’ve had breast cancer. It’s also not clear whether any potential benefits outweigh the risks. So, it’s not routinely recommended.
Women with dense breast tissue
Mammography plus breast MRI is under study for screening in women with dense breast tissue [10,88-91,156].
In women with dense breasts, breast MRI plus mammography may find a few more breast cancers than mammography alone [10,90,156]. However, adding breast MRI increases false positive results and it’s unclear whether it improves breast cancer outcomes [10,90].
Both the NCCN and the ACS state there’s not enough evidence to make a recommendation for or against MRI screening for women who have dense breasts [8-9].
Learn more about breast density on a mammogram.
Learn more about breast density and breast cancer risk.
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