When Katie Couric shared the news of her breast cancer diagnosis, the former co-host of NBC’s “Today” show said she considered this new health challenge to be a teachable moment to encourage people to get needed cancer screenings.
“Please get your annual mammogram,” she wrote on her website in September. “But just as importantly, please find out if you need additional screening.”
In the essay, Couric, 65, explained that because she tends to have dense breast tissue, she gets an ultrasound test in addition to a mammogram when screening for breast cancer. A breast ultrasound, sometimes called a sonogram, uses sound waves to take images of the breast tissue. It can sometimes identify malignancies that are hard to spot on a mammogram in women whose breasts are dense – that is, having a high proportion of fibrous tissue and glands vs. fatty tissue.
Ms. Couric, who famously underwent a colonoscopy on live television after her first husband died of colon cancer and who lost her sister to pancreatic cancer, has long pushed for cancer screening and better detection options.
“We don’t have evidence that auxiliary screening reduces breast cancer mortality or improves quality of life,” said Dr. Carol Mangione, a professor of medicine and public health at the University of California, Los Angeles, who chairs the U.S. Preventive Services Task Force, a group of medical experts who make recommendations for preventive services after weighing their benefits and harms.
Ms. Couric’s office did not respond to requests for comment.
In addition to an annual mammogram, some women with dense breasts get a breast ultrasound or MRI to help identify cancerous cells missed by the mammogram. Dense fibrous tissue appears white on a mammogram and makes it harder to see cancers, which also appear white. Fatty breast tissue, which appears dark on the mammogram, doesn’t obscure breast malignancies.
As digital breast tomosynthesis, or 3-D mammography, has become more widely available, a growing number of women are getting that screening test rather than the standard 2-D mammography. The 3-D mammography has been found to reduce the number of false-positive results and identify more cancers in some women with dense breasts, though the impact on mortality is unknown.
The task force gives an “I” rating to supplemental screening for women with dense breasts whose mammogram results don’t indicate a problem. That means the current evidence is “insufficient” to assess whether the benefits outweigh the harms of the extra screening. (The task force is updating its recommendation for breast cancer screening, including supplemental screening for women with dense breasts.)
One key harm that researchers are concerned about, besides the possible extra cost, is the chance of a false-positive result. Supplemental imaging in women who aren’t at high risk for breast cancer may identify potential trouble spots, which can lead to follow-up testing such as breast biopsies that are invasive and raise cancer fears for many patients. But research has found that very often these results turn out to be false alarms.
If 1,000 women with dense breasts get an ultrasound after a negative mammogram, the ultrasound will identify two to three cancers, studies show. But the extra imaging will also identify up to 117 potential problems that lead to recall visits and tests but are ultimately determined to be false positives.
“On the one hand, we want to do everything we can to improve detection,” said Dr. Sharon Mass, an ob.gyn. in Morristown, N.J., and the former chair of the American College of Obstetricians and Gynecologists’ New Jersey section. “But on the other hand, there are lots of costs and emotional distress” associated with false-positive results.
The professional group doesn’t recommend supplemental screening for women with dense breasts who don’t have any additional risk factors for cancer.
Many other professional groups take a similar position.
“We recommend having a conversation with a health care provider, and for patients to understand whether their breasts are dense,” Dr. Mass said. “But we do not recommend everyone get tested.”