Will 3-D Mammograms Find More Cancer?
There’s a new form of mammogram on the market, but is it doing a better job at finding cancer?
It’s called breast tomosynthesis, or 3-D mammography and it was technically introduced by the Food and Drug Administration in 2011. But although the new type of scan has been touted by some radiologists, the technology is still largely untested to determine who, if anyone, it will be more useful for.
“I strongly encourage you to take advantage of this technology for your mammogram today,” the website of one radiology practice in Washington, D.C. says. “3-D mammography is helping us every day to find more early curable breast cancers.”
Obviously, it would be amazing if this were true, but the evidence just isn’t there yet. Because of this, many insurers aren’t paying for it. If you try and request the new mammogram, you may have to pay $50 or $100 out of pocket to have the extra scan added to your “normal” mammogram.
So what’s the most recent data tell us? “Adding the 3-D technique increased the cancer detection rate from 4.28 to 5.24 per 1,000 patients,” according to data presented recently at a Radiological Society of North America meeting in Chicago. It also reduced false positives from 10.40 percent to 8.78 percent.
“It really addresses a lot of the criticism of screening mammography by the U.S. Preventive Services Task Force and others,” says Emily Conant, a professor of radiology at the University of Pennsylvania Medical Center who led the study. “In 2009, that panel recommended that women under age 50 not get mammograms because of the high rate of false alarms. The decision was denounced by many in the cancer and women’s health communities.”
Conant’s team looked at results from 15,633 women who had 3-D scans at Penn in 2011. That year, the hospital ran the new technology on every woman who came in for a mammogram. They then compared all of those findings with women who had visited the hospital the year before and had the conventional mammograms.
“It’s an exciting platform,” Conant says. “I would highly recommend seeking out tomosynthesis.” Of course, it’s important to keep in mind that results may have been better in large part because the first time a new test is used it often picks up cancers that were missed by old technology. After the initial upswing, it quickly tapers off.
Many breast imaging experts are skeptical. “The gains seem to be modest in both directions,” says a diagnostic radiologist at Memorial Sloan-Kettering Cancer Center. “Is this something that will prove to be worth the additional time, expense and radiation exposure? I think that Dr. Conant’s study is encouraging, but it’s not the definitive study.”
“We need to wait and see if the next round shows the same benefit, and whether we can figure out if it’s for everybody, every year,” says a professor of radiology at the Washington University School of Medicine in St. Louis.
Here’s some more standout points from NPR.org:
- There’s been speculation that women with dense breasts may benefit more from 3-D mammograms because the usual mammogram isn’t good at seeing through dense tissue.
- Standard mammograms take two images of each breast, one vertical and one horizontal. In a 3-D mammogram, the X-ray machine swings in an arc to take about 60 1-millimeter-thick images. The radiologist then views them like a digital flipbook. That should up the odds of spotting tiny tumors.
- Right now, women have to get both a regular mammogram and the 3-D version, which means they get a double dose of radiation. That’s still within safe limits, Conant says, though not ideal.
- The FDA has approved an application from Hologic, Inc., manufacturer of a 3-D scanner, for a software module to make 2-D images from a 3-D scan. This would reduce women’s radiation exposure.
- In November, the Centers for Medicare and Medicaid Services posted an FAQ stating that breast tomosynthesis should be included in the cost of regular mammography for Medicare patients, which may pressure private insurers to start paying for it. But that won’t necessarily make women’s decisions any easier.
What do you think about this new information? Would you be willing to try the new 3-D equipment, or are you still skeptical? Tell us your thoughts in the comments below!