Many women dislike the annual ritual but do it anyway: They trudge off to the doctor for a mammogram, even though it misses breast cancer about half the time.
Now a new study offers a way to better the odds. Adding an ultrasound scan helps find cancer in high-risk women.
The two tests together found 55 percent more cancers than mammograms alone. Investigators say the trial, the largest U.S. study to combine the two, may prompt more ultrasound screenings.
"My hope is that this study … will convince everybody that ultrasound is valuable, in the right setting, for detecting additional breast cancers," said Dr. Stuart S. Kaplan, section chief of breast imaging at the Comprehensive Breast Center at Mount Sinai Medical Center in Miami.
The test does come with a downside — a significantly higher risk of a false positive test, requiring a breast biopsy.
The study may be part of a move toward more personal decisions about testing, said an editorial in the Journal of the American Medical Association, which published the study Tuesday.
"Individualized screening schemes tailored to the individual risk and to the personal preferences" of the woman tested may become more common, the journal said.
One woman might get a mammogram every other year. Another, a mammogram plus ultrasound every year. A third, a mammogram and MRI.
In November, Sheila Grenitz got an ultrasound as well as a mammogram because, like the women in the study, she has dense breast tissue. It was the ultrasound that found cancer. Grenitz had a lumpectomy and radiation treatment.
"All I can tell you is, I am very lucky," said Grenitz, 70, a retiree who lives in the Fort Lauderdale suburb of Weston. "Who can tell how long it would have taken before it showed up on a mammogram?"
Having dense tissue is relatively common. About half of women under 50, and a third of women over 50, have such tissue. But "it's a double-edged sword," said Dr. Wendie Berg, the study's lead author and a radiologist at an outpatient center in the Johns Hopkins Health System.
Women with dense tissue are more likely to get breast cancer, and it's harder to spot those cancers on a mammogram.
The study, done by the American College of Radiology Imaging Network, included more than 2,700 women with dense tissue and other risk factors, such as a personal or family history of breast cancer.
During the study, 40 participants were diagnosed with cancer. Mammography alone found half of those cancers. Combining mammograms with ultrasound improved the odds to 78 percent.
Put another way, the combination found an extra 4.2 cancers for every 1,000 women screened.
But mammograms found a false positive reading in about 4.4 percent of patients, compared with 10.4 percent of women getting both tests. So to find those 4.2 extra cancers with ultrasounds, 100 women would be told they had abnormal readings and go through the anxiety and discomfort of a breast biopsy.
"It's not a big deal for many women, but it is a big deal for some," Berg said. "Everybody has to be aware of this risk to have this test."
The ultrasound combination isn't as accurate as combining MRI with mammograms. But it's much cheaper and also more comfortable for patients, Berg said.
Kaplan and others have done smaller studies showing ultrasound's benefits, but it hasn't been widely adopted. That's partly because of a concern that most cities won't have enough staff trained to perform the test, Berg said.
"It depends on the person doing the scanning to see the abnormality while they're doing the scan," Berg said.
Berg hopes that this study, with 100 investigators participating at 21 sites in three countries, will show that the skill can be learned.
Kaplan hopes the study will encourage more insurers to cover the test.
"Mammography is an excellent way to screen for breast cancer," he said. "And certainly the best way. But it's not perfect, and we can all use some assistance."
Lisa Greene can be reached at firstname.lastname@example.org or (813) 226-3322.