In computer-aided detection (CAD), a radiologist uses a computer program to help find breast cancer in a mammogram. The study reviewed here found that CAD was used in 74% of screening mammograms paid for by Medicare in 2008, almost twice as many screening mammograms that used CAD in 2004. CAD was used in 50% of mammograms done to confirm breast cancer (called diagnostic mammograms) in 2008. In 2004, only 20% of diagnostic mammograms used CAD.
Even when very experienced radiologists read mammograms, cancer can sometimes be missed. At the same time, a suspicious area may be considered cancer when it's not (called a false positive). Because of these shortcomings, radiologists have been taking steps to make mammogram readings more precise.
Double reading is one step that's been taken. Double reading means that two different radiologists read each mammogram. This approach is common in European countries. Research had shown that double reading improves the accuracy of screening mammogram readings.
CAD is another approach to improving the accuracy of mammogram readings. The CAD computer program is designed to identify patterns in a mammogram that suggest cancer and to alert the radiologist to these suspicious areas. CAD programs often are included with digital mammography machines, which increasingly are replacing film mammography machines. Digital mammography uses the same technique as film mammography, but the image is recorded into a computer instead of onto x-ray film. A digital mammography image can then be enlarged, highlighted, and evaluated by a CAD program.
Some doctors question the benefits of CAD and some research suggests that CAD actually increases the likelihood of false positive readings. Some doctors also think that if radiologists come to rely on CAD to read mammograms, these radiologists may be less careful when reviewing mammograms, which would mean less accurate readings. Still, more and more radiologists are routinely using CAD to read mammograms. Because CAD requires only one radiologist (as opposed to the two needed for double reading), CAD can be a less expensive way to improve mammogram accuracy. A 2008 study showed that CAD and double reading were equally good at improving screening mammogram accuracy.
Mammograms aren't perfect, but they're the best way to find breast cancer early, when it's most treatable. As you and your doctor develop your breast cancer screening plan, you may want to ask these questions:
- Are any of the mammography centers near you better the others?
- Is digital mammography available? (Research has shown that digital mammography can be more accurate than film-based mammography.)
- Is your most recent mammogram compared to your older mammograms when it's being read? (Comparing the new to the old has been shown to improve reading accuracy.)
- Does a second radiologist routinely review any suspicious mammograms before a final interpretation is made? (Second readings improve mammogram accuracy.)
In the Breastcancer.org Screening and Testing section you can learn more about mammograms and other ways to screen for breast cancer.