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Study Finds MRI Effective at Screening Younger Women at High Breast Cancer Risk (dateline August 8, 2001)


A new study finds that screening younger women at high risk of breast cancer with magnetic resonance imaging (MRI) can be highly effective at detecting the disease. In fact, in the study, MRI was more accurate than mammography in screening this population of women for breast cancer. While mammography is the only exam approved by the U.S. Food and Drug Administration (FDA) to screen for breast cancer in women with no signs of the disease (such as a breast lump), MRI could one day become an established supplemental screening exam for young women who have a strong family history of breast cancer or other factors that put them at high risk of the disease. (MRI is now FDA approved as a diagnostic tool to evaluate breast abnormalities found with another exam).

In the study, lead researcher Mark J. Stoutjesdijk, MD and his colleagues from the University Medical Center St. Radboud in The Netherlands studied the medical records of 179 women who had an MRI of the breast and a subset of 75 women who had both MRI and mammography. Of 13 cancerous tumors detected among the 179 women, all were detected with MRI but seven of those 13 cancers were not detected with mammography.

"MRI was more accurate than mammography in annual breast cancer surveillance of women with a hereditary risk of breast cancer," wrote the researchers. Dr. Stoutjesdijk and his colleagues also said that larger studies should be conducted to determine whether MRI should be used as another screening tool for breast cancer. Currently, MRI is used as a diagnostic tool, to investigate a breast concern detected by other means (such as mammography) or to study women with breast cancer (to determine the extent of the disease, etc.).

The study also found that mammography yielded seven false-negative reports; in other words, it failed to detect breast cancer seven times. MRI, on the other hand, yielded no false-negative reports. The researchers also found that radiologists were more likely to detect breast cancer on MRI films than on mammography films.

The purpose of the study was to determine whether MRI might be particularly beneficial in screening younger women at high risk of breast cancer. All women are recommended to begin receiving annual mammograms at age 40 to help detect breast cancer. However, younger women at high risk of breast cancer, such as those with a strong family history or those who test positive for a mutated breast cancer gene (BRCA1 or BRCA2) are often recommended to begin receiving mammograms at an earlier age. Yet, younger women tend to have dense breast tissue, which can decrease the effectiveness of mammography. (Breast tissue becomes less dense in women as they age, increasing the effectiveness of screening mammography in that population). MRI, on the other hand, can be used effectively in women with dense breasts.

Additional studies are necessary before MRI can be recommended as a screening tool for women at high risk of breast cancer. Currently, MRI is used to investigate breast concerns in conjunction with mammography, to evaluate breast abnormalities detect with mammography or other exams, to image breast implants (including any breast tissue obscured by the implant on a mammogram), to determine the extent of breast cancer and help evaluate treatment options, and to help detect a recurrence of breast cancer after a lumpectomy.

However, there are also several limitations to breast MRI versus mammography. First, MRI cannot always distinguish between cancerous and non-cancerous abnormalities, which can lead to unnecessary breast biopsies. A biopsy of an MRI-detected abnormality can be particularly difficult, too, because physicians must learn how to use MRI to guide them to the abnormality. This is necessary because the abnormality found with MRI may not be visible with traditional image guidance techniques, such as mammography or ultrasound. MRI is also unable to image calcifications, tiny calcium deposits that can indicate breast cancer. Mammography, on the other hand, can reliably image calcifications, which are often associated with early-stage breast cancers such as ductal carcinoma in situ (DCIS).

Furthermore, MRI is an expensive exam; an average MRI of the breast costs $1000 versus $100 per screening mammogram. MRI, which involves the use of a contrast agent to ensure high quality images, also takes substantially longer than mammography: more than 30 minutes in addition to the administration of the contrast versus 10 to 15 minutes for a mammogram. Patients must also tolerate any claustrophobia (fear of small spaces) they may have in order to have an MRI. Finally, MRI is not widely available for breast imaging. Currently, it is performed mostly at research centers and is not often available for breast cases. Many community centers do not perform breast MRI.

Benefits of Breast MRI Limitations to Breast MRI
  • Sensitive to small abnormalities
  • Effective in dense breasts
  • Can image breast implants/ruptures
  • Can evaluate inverted nipples
  • Can locate primary tumor in women whose cancer spread to armpit lymph nodes
  • Can detect residual cancer after lumpectomy
  • Can determine what type of surgery is indicated: lumpectomy or mastectomy
  • Can detect cancer recurrence after lumpectomy
  • May be useful to screen women at high breast cancer risk
  • Non-specific; often cannot distinguish cancerous and non-cancerous tumors
  • May lead to unnecessary, difficult to perform biopsies
  • Cannot image calcifications, tiny calcium deposits that can indicate early breast cancers
  • Expensive and not widely available
  • Some patients who are claustrophobic may not tolerate MRI
  • Requires use of contrast agent
  • More time-consuming than mammography
  • MRI centers cannot always produce results cited in research studies

In summary, breast MRI is a very useful problem-solving technology used to investigate breast concerns first detected with mammography, physical exam, or other imaging exams. It is also excellent at imaging the augmented breast. MRI can also play a key role in staging cancer (to determine the most appropriate treatment) and follow-up. However, there are several limitations of breast MRI as a breast cancer screening tool, as illustrated in the above chart. As research and technological advances continue, breast MRI may play a greater role in screening young, high-risk women in the future (in addition to its current use as a breast cancer diagnostic tool).

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