 Screening Ultrasound: During this test, a handheld device that resembles a microphone, called a transducer, is moved over each breast to transmit sound waves, which “see” through the skin into the body. The waves appear as images on a computer monitor, which can be recorded and reviewed later. The painless procedure takes five to 15 minutes in the doctor’s office.
Pros/Cons: Studies show that compared with mammography alone, adding a screening ultrasound can nearly double the detection rate of cancer in women with denser breast tissue. “It’s the single most effective tool to find additional cancers above and beyond what mammography misses,” says Dr. Kolb.
Experts don’t recommend using ultrasound without mammography, however, unless you’re under 30 and you have a palpable lump or nipple discharge. In such cases, ultrasound is typically used first, possibly in lieu of mammography, because less-mature breast tissue is more sensitive to the potential cancer-causing effects of low-dose radiation. Ultrasound also tends to miss fully half the time a very early form of cancer that starts in the milk duct, known as ductal carcinoma in site (DCIS), says Wendie Berg, M.D., Ph.D., a breast-imaging consultant in Baltimore and ACRIN-affiliated researcher. And screening ultrasound can sometimes result in a false-positive reading. Several individual studies found it involved a 2 to 6 percent risk of having unnecessary biopsy or aspiration (the removal of breast fluid or cells using suction). A large clinical trial sponsored by the Avon Foundation and the National Cancer Institute to investigate this screening technique is currently under way.
Should You Ask for It? Ultrasound isn’t the standard of care for screening purposes (though it is used for diagnostic tests). “But patients may want to ask for it in addition to mammogram if they have dense breast tissue,” says Dr. Berg. If you’re at high risk but you don’t have dense breasts, a mammogram should suffice. Because screening ultrasound is still in its infancy, insurance providers don’t typically pay for the test, which costs from $75 to $150, though more states now require that it be covered (check your policy). Also, ultrasound is not as stringently regulated as mammography: For instance, radiologists aren’t mandated to read a certain number of screening ultrasounds per year to keep their skills sharp. For better accuracy, “seek out a technologist or physician who does a minimum of five screening breast ultrasounds daily,” Dr. Kolb advises.
MRI (Magnetic Resonance Imaging): This tool employs magnetic and radio waves instead of X-rays to create high-definition cross-sectional images of breast tissue. For the test itself, the patient is injected with safe, nonradioactive contrasting salt solution in the arm, then lies facedown on a table with both breasts positioned into cushioned coils that contain signal receivers. The entire bed is then sent through a tube-like magnet. In areas where there might be cancer, the contrasting agent pools and is illuminated on computer-generated images. The machine is noisy, so it’s important to wear ear protection.
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Pros/Cons: Several studies have shown that MRI finds 2 to 6 percent more cancers than mammograms and clinical breast exams in high-risk women. A woman is considered high risk if she has a strong family history (a mother or sister diagnosed with breast cancer before age 50) or carries a genetic mutation (BRCA1 or BRCA2), among other factors. Talk to your doctor about whether your risk of breast cancer indicates you may benefit from MRI screening in addition to mammography. Like ultrasound, MRI can’t detect calcifications (a frequent sign of DCIS), which is why it’s used as a complement to mammography, not a replacement. MRI has also a significant risk of false positives. Screening breast MRI costs $1,000 to $2,000, though many insurance carriers now cover it.
Should You Ask for It? “Even if you have as little as a 2 percent risk of breast cancer over the next five years, talk to your doctor about adding MRI,” says Dr. Berg. MRI breast-imaging centers are springing up across the country, but the technology isn’t federally regulated or as widely available as ultrasound. Know-how counts, so “seek out practitioners with more experience,” says Etta Pisano, M.D., professor of radiology and biomedical engineering at the University of North Carolina, in Chapel Hill. It’s also important to seek out a facility that has MRI-guided biopsy capability, so a tissue sample can be retrieved for diagnosis at the time of your scan if a questionable mass is spotted.
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