(http://www.nationalpartnership.org/) February 14, 2011 — FDA on Friday announced its approval of the Selenia Dimensions System, the first three-dimensional X-ray mammography device for breast cancer screening, which regulators say may reduce the number of women who need second-round testing for issues that often are non-cancerous, the Los Angeles Times reports (Zajac, Los Angeles Times, 2/11).
The device manufacturer, Hologic, had to push back its U.S. launch of the device in 2009 after FDA officials said they were not prepared to approve it. The move allowed Hologic to conduct additional clinical trials (Weisman, Boston Globe, 2/12). In two studies that asked radiologists to review 2-D and 3-D images from more than 300 mammography exams, the radiologists had a 7% improvement in distinguishing cancerous from non-cancerous abnormalities when viewing both exams, compared with viewing the 2-D images alone, according to an FDA statement (Los Angeles Times, 2/11). Currently, about 10% of women who receive a mammogram are called back for additional testing due to cells that appear to be cancerous but ultimately are benign. If both tests are used, that rate would fall slightly to 9.3% (Kotz, “Daily Dose,” Boston Globe, 2/11).
The new technology, called digital tomosynthesis, allows radiologists to see through overlapping tissue, a common problem with 2-D technology (Weisman, Boston Globe, 2/12). FDA expressed concern over increased radiation exposure among women who undergo both 2-D and 3-D screening, saying the two tests used together “approximately doubled the radiation dose the patient received” and “there is uncertainty for radiation risk estimates” (“Daily Dose,” Boston Globe, 2/11). Several hundred medical centers have a Hologic 2-D system that can be upgraded to 3-D through the purchase of software costing $150,000 (McCullough, Philadelphia Inquirer, 2/12). Hologic said the cost of the test and whether insurance will cover it is unknown (“Daily Dose,” Boston Globe, 2/11).