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Breast MRI —
Finding Its Role in Imaging Cancer Care New evidence on the efficacy of breast MRI has emerged since 2003 when the American Cancer Society (ACS) last issued screening guidelines for early breast cancer detection. After the organization’s expert panel reviewed the new evidence, the ACS updated its screening guidelines for women at an unusually high risk of developing breast cancer. The guidelines now recommend that women who have a 20% to 25% or greater lifetime risk of developing breast cancer undergo both mammography and MRI each year, either concurrently or alternately every six months. When the new guidelines were announced in late March, they received much media attention. Breast cancer screening is critical because when detected early, survival rates can approach 100%. That same week in March, a study led by Constance Lehman, MD, PhD, director of breast imaging at the University of Washington and the Seattle Cancer Care Alliance, was reported in The New England Journal of Medicine (NEJM) that found women newly diagnosed with cancer in one breast benefit from an MRI of the opposite breast. Lehman reported that MRI detected cancers clinically and mammographically occult in the contralateral breast in 30 of the 969 women (3.1%) enrolled in the study. Those who provide breast MRI services were likely not surprised by the updated guidelines or attention the modality has now been getting from medical and lay communities. “If you’re at all going to conferences and talking with colleagues across the country, you’re seeing how powerful a tool breast MRI is,” says Robin Shermis, MD, a radiologist at the Northwest Ohio Dedicated Breast MRI Center in Toledo, which is acquiring the Aurora 1.5-Tesla (T) Dedicated Breast Imaging System. “The images are spectacular. ... Breast MRI is opening up a profound new level of evaluating breast cancer, as well as different problems in the breast.” David Gruen, MD, a radiologist at the Norwalk Radiology & Mammography Center in Connecticut, agrees, “There is no question that right now, breast MRI is the most sensitive and specific imaging test of the breast that exists.” ‘About Time’ According to a 2006 IMV Medical Information Division, Inc. report, approximately 2,000 of the 11,000 facilities in the country with MRI are capable of performing breast MRI, although not all those facilities are trained to manage a comprehensive breast MRI program. The number of facilities with breast MRI capabilities was rising even before the most recent developments. Many breast specialists and providers of breast imaging equipment expect it to continue rising in light of the revised guidelines and the NEJM and other studies. However, because establishing breast MRI services is not a simple matter, they don’t expect to see a significant jump in facilities—at least not immediately. Aurora Imaging Technology was started in 1995, with the first installations of its dedicated breast MRI system in 1997. Today, it has 23 sites, 21 of which are in the United States. As of June, another 17 installations had been scheduled, which will bring its total by the end of the year to 40. “We are ramping up as we speak,” Cheng says. “Nevertheless, our lead time is six months.” Five years ago, Bellevue, Wash.-based Confirma, Inc. first launched CADstream, computer-aided detection (CAD) for breast MRI technology, which it developed to assist in the analysis, interventional guidance, and reporting of breast MRI studies. “Today, Confirma is considered the market leader in CAD for breast MRI with over 700 CADstream systems in clinical use throughout the world,” says Dan Bickford, executive vice president of sales and marketing for Confirma. Bickford says the recent headline-making news about breast MRI resulted in more queries, but it has not yet translated into a spike in sales because it takes time for facilities to decide, and then order and install the equipment and software necessary to perform breast MRI properly. Not for Everyone Breast MRI, which takes approximately 30 to 40 minutes, must be performed on a scanner with a magnet that is 1.5-T or higher. Breast MRI can be performed on a whole body machine, but it requires special breast coils that immobilize the breast and produce high-resolution images, Gruen says. Gruen uses a GE Healthcare 1.5-T MRI unit. Aurora’s dedicated breast imaging system costs roughly $1.5 million. Adding a breast coil and the necessary software to an existing whole body machine is less, but it is still approximately $500,000, “and still a lot of money,” Shermis says. Breast MRI also requires CAD software, Gruen says. “Breast MRI is a data-intensive and time-consuming study; CAD is essential to accurately and efficiently read studies,” adds Gruen, who has been using CADstream for nearly three years. CADstream is compatible with all MRI systems. The Aurora system has its own CAD. Gruen’s practice typically performs between eight and 15 breast MRI exams a day. “We’re acquiring between 2,000 and 3,000 images per study. When you’re looking at thousands of images per day, computer-aided detection with proper training and education are crucial for quality patient care.” Everyone agrees that there is a learning curve to interpreting breast MRI, but the more it is done, the better the interpreter becomes. A major criticism of breast MRI is that it is too sensitive and it leads to many more false positive results than mammography. However, Gruen says, those with experience using CADstream are able to thoroughly review morphology and kinetics and accurately determine those areas that need to be biopsied or can be dismissed as normal breast tissue. Using CAD Lehman also led a study reported last year in the American Journal of Roentgenology that found CAD evaluation of breast MRI could assist radiologists in determining the need to biopsy MR-detected lesions in women at high risk for breast cancer. The study used CADstream technology. While only a limited number of facilities are currently offering breast MRI and the opportunity for expansion is great, some believe it would not be appropriate for every practice. Daniel Garner, MD, a radiation oncologist and associate medical director of MedSolutions, a radiology management solutions firm in Franklin, Tenn., believes practices that offer breast MRI need to be larger groups. “Preferably, it is not something that should be undertaken by either a solo practitioner or a very small group of radiologists who all practice general diagnostic imaging,” he says. “It should be in a setting where some physicians in the group focus on breast imaging. That’s very important because those doing breast MRI need to be conversant with the other modalities for breast imaging—mammography and ultrasound—as well.” While MRI is improving and emerging as an important screening and diagnostic tool, mammography and ultrasound still have a very important role in breast care, Garner says. “They continue to be very good and very cost-effective modalities.” Garner’s colleague at MedSolutions, Jennifer B. Meko, MD, a general thoracic surgeon, agrees that a practice needs to be large enough to be able to be dedicated to breast care. “I do think that a focus on breast imaging is important because you do want to do breast MRI in conjunction with mammography and ultrasound. It should not be a totally isolated test,” she says. Meko notes that the American College of Radiology (ACR) is developing an accreditation program for breast MRI as it has for other modality-specific accreditation programs, including mammography. The program will determine what training is necessary for performing and reading breast MRI. “I think once that criteria comes out it will be a good format for facilities to follow, if they want to go ahead and be capable of doing breast MRI,” she says. MRI Biopsy “MR-directed biopsy absolutely needs to be done on the same machine that found it the first place,” Garner agrees. Not only is MRI proving useful for breast cancer screening in high-risk women, but it also plays an increasingly significant role in determining the extent of disease (staging) and monitoring response to therapy in breast cancer patients. Garner says many women, especially younger women, who have breast cancer often feel compelled to have bilateral mastectomies with reconstruction, assuming that cancer may be lurking in the contralateral breast. “They think, ‘Why not take care of the problem by doing bilateral mastectomy?’” Hopefully, Garner says, the NEJM study will lead to a reduction in the number of unnecessary mastectomies of the opposite breast. “One of the points the study was stressing was that breast MRI has a higher-than-expected specificity, meaning that a negative result is a true negative,” Garner explains. Thus, if a woman undergoes MRI of the contralateral breast and it is negative, she can be nearly 100% certain she does not have cancer in the opposite breast and does not need to have a bilateral mastectomy. Reimbursement “By and large, most insurance companies are reimbursing for breast MRI in the right setting,” Shermis adds. Cheng believes many insurers are willing to reimburse for diagnostic breast MRI because it is so useful in determining whether the chosen treatment is working. Spending $1,000 for a breast MRI study is far less than treating a patient with a $30,000 chemotherapy regime only to find out five weeks later that it didn’t work for her, she says. The new ACS guidelines are specific about who is considered at unusually high risk and who should receive annual screenings via breast MRI. They include symptomless women aged 30 and older who have a mutation in the BRCA1 or BRCA2 genes; those who received radiation treatment to the chest between the ages of 10 and 30, such as for Hodgkin’s disease; and those with a strong family history of the disease, such as women with two or more first-degree relatives who were diagnosed with breast or ovarian cancer before the onset of menopause. The ACS estimates that some 1.4 million women fall into the affected group. Others believe as many as 2 million women would benefit from additional screening with MRI. The new guidelines do not suggest that women at normal risk undergo screening breast MRI. However, Shermis believes that as breast MRI becomes more widely available, the definition of who is at high risk will expand. Meko says the new guidelines beg physicians to ask and pay close attention to their patients’ answers to questions about their family history and for more genetic counseling so women at an unusually high risk can be identified. “It’s not that we have to run out and set up lots more breast MRI facilities,” she says, “though we do need high-quality breast MRI facilities, and we need for women to recognize that they may be at very high risk.” — Beth W. Orenstein is a freelance medical writer and regular contributor to Radiology Today. She writes from her home in Northampton, Pa. |
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