Many tools for the early detection of breast cancer are under study. These include magnetic resonance imaging (MRI), ultrasound, breast tomosynthesis (3D mammography), molecular breast imaging (MBI), positron emission tomography (PET) and thermography. At this time, it is not clear if these tools will play a role in breast cancer screening in all women or certain groups of women at higher risk.
If you are interested in joining a clinical trial studying one of these screening methods, talk to your health care provider. Learn more about clinical trials.
Magnetic resonance imaging (MRI)
Magnetic resonance imaging (MRI) uses magnetic fields to create an image of the breast. MRI is mostly used in breast cancer diagnosis and staging.
There is growing evidence that MRI in combination with mammography, compared to mammography alone, can increase detection of breast cancer in certain groups of women at higher risk [53-57,59]. For example, the American Cancer Society and the National Comprehensive Cancer Network currently recommend women with a BRCA1 or BRCA2 genetic mutation get an MRI in combination with their annual mammography screening [57-58]. Susan G. Komen for the Cure® recommends that women at higher risk of breast cancer ask their health care provider which screenings tests are right for them. Learn more about MRI as a screening tool for women at higher risk.
Some findings also suggest that for women diagnosed with cancer in one breast, MRI with mammography can find breast cancer in the opposite breast better than mammography alone [60-61]. MRI with mammography is also under study for screening in women with dense breast tissue [56,59,62]. Learn more about breast density.
Whether screening MRI offers benefit to women at average risk of breast cancer is under study and, at this time, is not recommended for these women. Screening MRI has some drawbacks.
- MRI is more invasive than mammography because a contrast agent is given through an IV during the procedure.
- Like mammography, MRI has false positive results, which need follow-up, but may turn out to be benign (not cancer).
- Not all centers doing MRI have radiologists specially-trained to read images of the breast.
- If there is an abnormal finding that can only be seen on MRI (and not other imaging like mammography), not all centers have the means to do an MRI-guided biopsy.
- MRI is expensive and not always covered by insurance.
Learn more about MRI as a screening tool for women at higher risk.
Learn more about MRI and the diagnosis of breast cancer.
Ultrasound
Ultrasound uses sound waves to make images of the breast. It is often used as a follow-up test to an abnormal mammogram, MRI or clinical breast exam.
Studies show ultrasound alone is not a good breast cancer screening tool and has many false positive and false negative results [27,59,63]. Because image-making with ultrasound is not yet automated, the quality of the image can vary greatly depending on the skill and experience of the person doing the ultrasound. Automated ultrasound may help improve image quality and is under active study [64]. However, at this time, it is not widely available or routinely used.
Ultrasound is better than mammography at distinguishing dense breast tissue from tumors. Studies have shown ultrasound combined with mammography can find more breast cancers than mammography alone in women with dense breasts [59]. However, ultrasound plus mammography leads to more false positive results.
For women at higher risk of breast cancer, there does not appear to be added benefit of using ultrasound for women screened with MRI and mammography [59,65]. However, ultrasound may be a useful addition to screening mammography among women at higher risk of breast cancer for whom MRI is not yet recommended [59]. Ultrasound is less expensive and less invasive than MRI. More research on the benefits of ultrasound in combination with mammography and MRI is needed before recommendations can be made on its use for screening women at average or higher risk of breast cancer.
Screening tools under active study and not widely available
Breast tomosynthesis (3D digital mammography)
Advances in digital mammography machines and software can create a three dimensional (3D) X-ray image of the breast (called breast tomosynthesis). The machine takes multiple two dimensional (2D) X-ray images. Computer software combines the 2D images into a 3D image. While it is not yet clear whether breast tomosynthesis will become a standard breast cancer screening tool, this new technology is under study [66-67]. Breast tomosynthesis is not widely available in the United States.
Nuclear medicine imaging of the breast (molecular breast imaging)
Nuclear medicine breast imaging (you may also hear the term molecular breast imaging) uses short-term radioactive agents that are given through an IV and absorbed into tissues, including the breast. Breast cancer cells appear to absorb more of agents than healthy cells and these cancer cells can be imaged with a special camera. Nuclear medicine breast imaging is being studied in combination with mammography screening for women with dense breasts [68].
Two types of nuclear medicine imaging techniques are:
- Breast-specific gamma imaging (BSGI). The radioactive agents used in BSGI emit gamma rays that are tracked by the special camera.
- Positron emission mammography (PEM). The radioactive agents used in PEM are sugars. PEM uses positron emission tomography (PET), a test that shows how much sugar is consumed by cells, along with the special camera to image cells. Cancer cells tend to consume more sugar than normal cells and this can help identify tumors. PET does not have the special camera needed for PEM, so PEM cannot be done on a regular PET scan machine. PET alone cannot provide a detailed enough image to find early stage breast cancers [69].
Although still under study, BSGI and PEM are used in clinical practice, but are not widely available.
Nuclear medicine breast imaging gives a higher dose of radiation than mammography [70]. Ways to lower the amount of radiation exposure are under study.
Thermography
Thermography uses infrared light to measure temperature differences on the surface of the breast. Although breast cancer can cause abnormal heat patterns, many benign conditions also cause abnormal heat patterns. Thermography cannot distinguish between benign and cancerous patterns [71]. And, because thermography measures heat at the surface of the breast, it is not good at finding cancers deeper within the breast tissue.
Neither the U.S. Food and Drug Administration (FDA) nor the American College of Radiology views thermography as a valuable breast screening or imaging tool [72-73]. In June 2011, the FDA issued an alert warning the public about misleading claims by thermography practitioners and manufacturers on the screening benefits of the tool [73]. To read the full alert, visit the FDA website.
Updated 04/25/12
