Breast Imaging in a New Dimension
Tomosynthesis is gaining popularity among breast imaging specialists. Will it overtake mammography?
New technology always causes a splash in its particular community. In breast imaging, tomosynthesis (tomo) is creating ripples.
Since its FDA approval in 2011, studies have examined everything from detection to preference among radiologists. Early results suggest that digital breast tomosynthesis may improve cancer detection over conventional full-field digital mammography, as well as reduce screening recall rates. Some radiologists believe we're entering a whole new world in breast imaging. Others think that although tomo will help some women, it will not help every woman. Although tomo reduces recalls, opponents argue, its benefit is felt only by the relatively small number of women who would have been recalled without it.
Margarita L. Zuley, MD, director of breast imaging at the University of Pittsburgh Medical Center, has begun to implement tomo in her practice. Her recent study, "Digital Breast Tomosynthesis versus Supplemental Diagnostic Views for Evaluation of Non-Calcified Lesions," found that the use of tomo improves accuracy and reduces false-positive rates when compared against standard mammography. In fact, the high false-positive rate is perhaps one of the greatest criticisms of conventional mammography.
For Zuley, the positives of tomo are important to note, particularly with respect to patient care. "It's reducing recall rates, which is mitigating the potential harm of recalling normal patients," she says. "It's increasing cancer detection, which is mitigating the harm of a missed cancer. It's decreasing the number of biopsies because it's clearer when lesions are benign. So it's beginning to directly address some of the criticisms of mammography."
Despite its promise, however, the role of digital breast tomo is not entirely clear. Currently, the radiation dose for a combined examination of conventional mammography and tomo is slightly more than twice the dose of mammography alone. While this is still below the FDA-allowed dose, it is something to contemplate very carefully when considering a modality for possibly tens of millions of women each year. To help resolve the issue, one vendor has used innovative techniques to utilize the tomosynthesis data set to generate a synthetic planar mammogram, thereby eliminating the need to do a mammogram and reducing the dose.
Studies are underway to answer important questions about tomosynthesis. A trial conducted in Oslo by Per Skaane, MD, PhD, and colleagues released preliminary data that seems promising. As this trial comes to fruition, radiologists hope to learn more about the target population and whether the benefits accrued in the first screening round hold up in subsequent rounds. Another concern being addressed is the length of time needed to interpret tomo exams compared with standard mammography. Early experience shows that it takes 50 to 100 percent longer to read tomo exams, taking up more of a radiologist's valuable time.
Some radiologists also have concerns about reimbursement. Currently, there is no separate billing code for reimbursement. It has taken years for data to be published about the use of tomo, hindering the process of creating new billing codes. Some facilities use an unspecified code in conjunction with the mammogram code, but this has mixed success with providers — and if patients have to make up the cost, they are likely to opt out of the procedure. New technology is expensive, so radiologists have to ascertain if the technology is going to be both helpful to the patient and affordable for the system.
Another consideration about tomo, or any new technology, is the learning curve. Not only will radiologists have to become comfortable and proficient in its interpretation, but patients and their referring providers will need to be educated about its utility. To educate patients and referring physicians, Zuley believes it is important to be proactive and to have a plan. Distributing flyers, speaking directly with referring physicians, contacting the local media, and having a list of commonly asked questions on hand are all good ways to keep individuals informed. Direct communication can help answer questions and reduce patient anxiety. Zuley, for instance, encourages patients and referring physicians to email her directly with questions about tomo. The concerns expressed have so far been fairly basic — cost, time, and radiation dose are all common topics.
The future of tomo is uncertain, and the College continues to pay attention to studies that are designed to yield definitive data. It continues to encourage breast imagers to educate their patients about getting regular mammography screenings starting at age 40. For more information, visit www.mammographysaveslives.com.
By Meghan Edwards