'Unmasking' lurking cancer with 3-D mammograms

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'Unmasking' lurking cancer with 3-D mammograms

New study highlights cost effectiveness of adding 3-D imaging for women with dense breast tissue

Oct. 28, 2014
Dr. Christoph Lee

Dr. Christoph Lee, a researcher with the Hutchinson Institute for Cancer Outcomes Research, led a new study that evaluated the cost effectiveness of adding 3D mammography to standard digital imaging for women with dense breasts.

Photo by Robert Hood / Fred Hutch News Service

Women with dense breast tissue have long been in a quandary.

Dense tissue slightly elevates the risk for developing breast cancer and it can also be difficult to read. Unfortunately, 2-D digital mammograms alone may not spot a hidden cancer so many women opt for additional screening. But what is the most effective screening method to catch a potential cancer? And will this additional screening be covered by insurance?

A new study out of Fred Hutchinson Cancer Research Center has laid key groundwork to solve this cancer Catch-22.

“Our study was trying to figure out, if we add tomosynthesis [3-D mammography] to screening women with dense breasts, will the benefits outweigh the costs?” said Dr. Christoph Lee, a researcher with the Hutchinson Institute for Cancer Outcomes Research (HICOR). “What we’ve found is extremely promising.”

A radiologist at Fred Hutch’s treatment arm, Seattle Cancer Care Alliance, Lee looked at the cost effectiveness of offering a one-two screening punch – using both 2-D digital mammograms and 3-D tomosynthesis – compared with digital mammography alone for women with dense breast tissue.

“We found that the benefits of increasing cancer detection rates and decreasing false positives is well likely to be worth the additional cost of tomosynthesis for screening women with dense breasts from age 50 to 74,” he said.

Breast screening can involve a number of different methods: film-screen mammography, 2-D digital mammography, 3-D mammography or tomosynthesis, ultrasound and MRI. While digital mammography picks up more tumors than film-screen mammography in women with dense breasts, it is not perfect. Fatty tissue appears gray on a mammogram, and fibro-glandular tissue – dense tissue – appears white. Unfortunately, tumors also appear white on a mammogram, so the denser the breast, the more it can potentially mask a cancer.

‘It’s like finding a snowflake in a snowstorm’  

“It’s like finding a snowflake in a snowstorm,” said breast cancer oncologist and clinical researcher Dr. Julie Gralow of trying to find small cancers amid dense tissue.

MRIs can help, but they have drawbacks: Not only are they more expensive and invasive than mammography, they can read normal tissue as abnormal, prompting additional unnecessary tests.

As a result, many women – and their doctors – have opted for ultrasounds in addition to their digital mammograms. But those, too, can be flawed.

“The problem with screening ultrasound right now is it more than doubles the biopsy rates for patients,” said Lee. “Moreover, only about 7 percent of women who undergo a biopsy after screening ultrasound actually have breast cancer. The large majority of people undergoing biopsy end up having benign results.”

Tomosynthesis, approved by the Food and Drug Administration in 2011, offers an alternative screening method. Its 3-D imaging appears to give a more complete, layer-by-layer picture of the breast, “unmasking” cancers that may be lurking in dense tissue. Tomosynthesis and 2-D digital mammography can also be done on the same machine at the same time, adding only a few seconds to the patient’s imaging procedure. In comparison, a screening ultrasound could add an additional 20 minutes to the patient’s clinic visit.

Fred Hutch researchers used effectiveness data from European trials – 3-D tomosynthesis screening was adopted by regulators there in 2008 – to estimate the effects of adding it to the screening repertoire for women in the U.S. with dense breasts. They then projected what the effect of this mammographic double whammy would be on women with dense breasts by creating a breast cancer simulation model based on data and metrics from the National Cancer Institute’s Breast Cancer Surveillance Consortium, Medicare reimbursement rates and medical literature.

Decreasing false-positive diagnoses, increasing cost effectiveness

According to their findings, for every 2,000 women, a combined mammography and tomosynthesis screening led to one less breast cancer death and 810 fewer false-positives after 12 rounds of screening.

“Unlike ultrasound, it’s actually decreasing the recall rate and the false positives,” said Lee, who is also on the Department of Radiology faculty at the University of Washington.

“That alone will drive cost effectiveness,” he said. “That’s going to save women the anxiety of going through a false-positive exam and all the repercussion of having to pay for additional workup of benign findings. Overall, those benefits will far outweigh the additional cost per exam.”

These findings are particularly significant in light of new laws regarding the reporting of breast density. Currently, 19 states have laws that make it mandatory for mammogram reports to include information regarding a woman’s breast density, and both the U.S. Senate and House of Representatives are considering bills that would make this the national norm.

But the findings are preliminary, especially with regard to determining whether insurance might pay for this alternative form of screening, said Fred Hutch internist and health care economist Dr. Scott Ramsey, director of HICOR and a co-author of the study.

“It’s a promising alternative, but it’s a model and we need more data from the U.S. to really help us understand whether it’s going to be cost effective,” he said. “It’s an important step but it’s a little preliminary to make a policy or reimbursement decision using just this model.”

What should you do if you have dense breasts?

The answer remains the same: talk to your doctor to see what this might mean for you (here’s a report from the American Cancer Society, as well). And perhaps be on the lookout for a sea change with regard to screening recommendations.

Related news:

Diane Mapes is a staff writer at Fred Hutchinson Cancer Research Center. She has written extensively about health issues for NBC News, TODAY, CNN, MSN, Seattle Magazine and other publications. A breast cancer survivor, she also writes the breast cancer blog doublewhammied.com. Reach her at dmapes@fredhutch.org.

Solid tumors, such as those of the breast, are the focus of Solid Tumor Translational Research, a network comprised of Fred Hutchinson Cancer Research Center, UW Medicine and Seattle Cancer Care Alliance. STTR is bridging laboratory sciences and patient care to provide the most precise treatment options for patients with solid tumor cancers.

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