The death rate from breast cancer has been dropping since 1990, and a major reason for this is early detection of the disease through medical imaging technology. The earlier breast cancer is detected, the greater the likelihood of successful treatment.
The National Cancer Institute, the US Preventive Services Task Force, and the American Cancer Society have somewhat different guidelines on medical imaging screening for breast cancer. The National Cancer Institute recommends a mammogram every one to two years for women 40 and over, as does the US Preventive Services Task Force.
The American Cancer Society recommends an annual mammogram for women 40 and over, and also now recommends magnetic resonance imaging (MRI) in addition to an annual mammogram for women with lifetime risk of breast cancer of greater than 20%. The American Cancer Society says that women whose histories or genetics put them at a 15% to 20% lifetime risk of breast cancer should discuss the benefits and drawbacks of having an annual MRI along with a mammogram to determine if it’s a good idea.
Should Some Women Have an Annual MRI in Addition to a Mammogram?
Ellen Warner, MD, a medical oncologist at Toronto Sunnybrook Regional Cancer Center in Ontario says that women who have a mutation in the BRCA 1 or BRCA 2 gene that puts them at increased risk of breast cancer should have a breast MRI every year along with a mammogram. Warner studied 236 high-risk women, and found that MRI detected 77% of cancers, compared with just 36% detected by traditional mammography.
The American Cancer Society designates women at “high risk” for breast cancer as those whose lifetime risk of breast cancer is at least 20% based on family history or BRCA 1 or BRCA 2 mutations. Women with a first-degree relative with one of the mutations who have not had genetic testing themselves should also be considered high risk. These women can benefit from an annual MRI in addition to their annual mammogram.
Why MRI Is Valuable in Detecting Breast Cancer
MRI is a type of medical imaging that uses magnetic fields instead of radiation to create an image. The reason it is valuable in detecting breast cancer is because it provides superior soft tissue contrast. While MRI has been used in medical imaging of breasts since around 1990 (when it was often used to detect ruptured breast implants), it has only more recently demonstrated that it may have great value as a first-line technology for detecting breast tumors.
A 2004 Dutch study published in the New England Journal of Medicine followed 1,900 women with greater than 15% lifetime risk of breast cancer due to family history or genetics. For three years, the women received yearly MRIs in addition to clinical breast exams and mammograms. Mammography missed 22 cancers that were detected on MRI, while MRI missed only eight cancers that showed up on mammograms. A 2007 Italian study of 278 high risk women reported that 17 of the 18 cancers found showed up on MRI, and that included six cancers that all other screening methods missed.
Another 2007 study in the US of high risk women found that MRI detected all six of the cancers diagnosed by biopsy in the study group, whereas mammography only detected two, and that only MRI detected the four cancers diagnosed in study participants with dense breast tissue.
Why MRI Isn’t Appropriate for Screening All Women
If MRI is so great at detecting breast cancer, shouldn’t all women be screened with it? The answer is no, for three main reasons. For one thing, MRI is so sensitive to any abnormal tissue that it can detect tissues that are not cancerous. In fact, MRI yields many more false positives than mammography does. Second, MRI is an expensive and time-consuming type of medical imaging.
Third, mammography continues to improve. Digital mammography in particular improves detection of abnormalities in women with dense breast tissue, and is increasingly available and less expensive and time-consuming than MRI. The digital images produced by digital mammography can be processed to make it easier for radiologists to detect subtle changes that may not have shown up on traditional film mammography.
What About Ultrasound in Addition to Mammography?
Can ultrasound be used to detect breast cancer? Ultrasound alone is not that good at detecting breast cancer, but it does have value when used along with mammography in women with dense breast tissue. A 2012 study of 2,309 women with dense breast tissue and higher-than-average breast cancer risk found that alone, screening mammograms or screening ultrasound found just over half of cancers. Together, however, mammography and ultrasound found 82% of the cancers. Breast MRIs found another 8% of cancers not detected by other tests. These results were encouraging because ultrasound is a relatively inexpensive type of medical imaging and is widely available.
Medical imaging has long been used in screening women for breast cancer, with traditional x-ray mammography being used most. Over the past two decades, MRI has become more important in detection of cancer in women with higher risk of developing breast cancer. Ultrasound has also shown utility when used alongside traditional mammography in detecting cancer in women with dense breast tissue.
However, MRI is not being promoted as a general screening tool for women without elevated lifetime risk of breast cancer. MRI is expensive and time-consuming, and it tends to find more false positives than traditional mammography. But for women who have elevated lifetime risk of breast cancer, MRI in addition to mammography can be a very valuable form of medical imaging, allowing doctors to find cancers when they are smaller, and when more treatment options are available.
SteleRAD has four breast imaging radiology specialists on its staff, and is owned and operated by radiologists certified by the American Board of Radiology. SteleRAD is proud to have four breast imaging radiology specialists on staff: Dr. Michael Alboucrek, Dr. Deborah Guilbaud, Dr. Lisa Abrams, and Dr. Terrence Barrett.
SteleRAD’s team of radiologists is dedicated to providing the highest quality of patient-centered care in many radiological specialties, including breast radiology. Our breast imaging radiologists are qualified and ready to fulfill your hospital or large physician practices’ needs for mammography, breast MRI, ultrasound, and other medical imaging needs. To learn more about how SteleRAD‘s radiologists can help your practice or facility, contact us online, or call (954) 358-5250.