Call-backs have always been a problem in mammography. They are a source of worry, added discomfort, well-founded patient complaints about the inefficiency of breast exams, and unnecessary cost. More than that, they call into question the credibility of an exam whose use depends on women’s belief in its value.
Now a study, published June 25 issue of the Journal of the American Medical Association (JAMA), has found that the addition of 3-D imaging, widely known as breast tomosynthesis, substantially decreases the proportion of patients who are called back, just as its use finds more cancers than the use of 2-D digital mammography alone — a 41 percent increase in the detection of invasive breast cancers and a 29 percent increase in the detection of all breast cancers.
While the data indicating improved performance due to the use of breast tomo is welcome, they come as no surprise. The FDA approved the sale of 3-D imaging systems for breast cancer screening in 2011 because studies showed its addition to standard digital mammography uncovers more cancers, just as it reduces false positives. Its effect on recall rates, however, has been largely anecdotal. The just published JAMA study changes that.
Data acquired at 13 U.S. centers performing 454,850 screening exams (61 percent of which involved only 2-D digital mammography for comparison) found that the addition of tomo dropped the recall rate from 107 to 91 per 1,000 screening exams — a 15 percent decrease. This translates to 16 fewer recalls per 1,000 screening exams.
The study is good news for women in general and Hologic in particular. The company’s Selenia Dimensions is the only breast tomography system currently approved by the FDA for sale in the United States. More than 1,000 of these systems are operating across all 50 states, according to the company, including those at the five academic hospitals and eight community-based sites participating in the study.
Hologic framed the study as addressing the two most frequently cited concerns about breast cancer screening — unnecessary recalls and finding cancers that do not need to be treated. The latter was demonstrated by the 41 percent increase in the detection of invasive breast cancers; the former by a double digit reduction in the recall rate.
It’s hard to overestimate the importance of these findings. Screening mammography exposes women with no known sign of disease to ionizing radiation, which itself can cause cancer. As such, they deserve the greatest possible assurance that the exam they undergo is done with the least chance of being wrong. The JAMA study documents that the routine use of tomosynthesis in breast cancer screening does exactly this, providing women the reason to believe that modern mammography truly is a potentially life-saving tool.