Using digital breast tomosynthesis technology, a more advanced form of mammography, can help increase breast cancer detection rates for women with dense breast tissue, according to a new study.
“Our results show that implementation of tomosynthesis might indicate a new era in breast cancer screening,” Dr. Per Skaane, the study's co-author and a radiologist at Oslo (Norway) University Hospital, said in a news release. The study's authors reported receiving financial support from Hologic, a manufacturer of imaging equipment used in breast cancer screening.
Tomosynthesis, also called 3-D mammography, creates a 3-D image of the breast. Traditional mammography creates a two-dimensional image. But there are still questions about higher doses of radiation associated with the newer technology and whether the higher costs are offset by improvement in detection rates.
The study, released Tuesday at the Radiological Society of North America's annual meeting in Chicago, found that using a combination of digital mammography and tomosynthesis caught 80% of cancers in women with dense breasts, compared to the 59% of cancers diagnosed in women who only underwent mammography.
Women with dense breast tissue are at higher risk of getting breast cancer. It's also more difficult to identify their cancers in a mammogram, where tumors appear white. Dense breast tissue also appears white and can shield tumors from being detected by radiologists.
Efforts have been underway in recent years to better educate women and clinicians about the differences in breast cancer screening for these women. Nineteen states have passed laws requiring healthcare providers to notify a patient if she has dense breast tissue. That's up from 13 states that had passed breast density notification laws at this time last year.
Other screening modalities, including ultrasound and MRI, also are considered adjunct screening methods for women with dense breast tissue. They are more expensive and can produce higher rates of false-positives than mammography.
Tomosynthesis is the newest of the adjunct screening modalities. Hologic, a Bedford, Mass.-based manufacturer, received approval from the Food and Drug Administration for its tomosynthesis technology in 2011.
The study compared the detection rates for about 25,000 women aged 50 to 69 years old.
During a news conference, Skaane said it was the “best and most practical solution” to better screening women with dense breast tissue, in part because there is less training needed to teach radiologists familiar with mammography to use tomosynthesis when compared to other modalities.
A second study of breast cancer screening also released Tuesday looked at a more controversial issue in the radiology community—at what age a woman should start undergoing screening for breast cancer.
Debate persists about whether women should continue to start undergoing mammograms at age 40, as many patient groups and clinicians recommend, or get screened every two years starting at age 50, unless a strong family history or dense breast tissue are present.
The U.S. Preventive Services Task Force made the second recommendation in 2009 and has been criticized by cancer groups as well as some radiologists.
Researchers at the University of California at San Francisco conducted a retrospective study of 136 patients who had been diagnosed with breast cancer from 1997 to 2012. They found that 90% of the patients did not have a very strong family history, and 86% of the patients did not have extremely dense breast tissue.
Breast tissue density is split into four categories. About half of the women in the U.S. have dense breast tissue, which are categorized as a “3” or “4” under the American College of Radiology's scoring system.
If a healthcare provider implemented a risk-based screening system based on the task force's recommendations, this would mean about 75% of breast cancers in women in their 40s would be missed, the researchers concluded.
“Neither family history nor breast density in combination or alone are sufficient risk factors to safely triage patients in risk-based screening,” Dr. Bonnie Joe, chief of women's imaging at UCSF, said in a statement.
It's not the first time that researchers have presented data at RSNA to make the case against encouraging women to wait until age 50 to begin receiving breast cancer screenings.
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