The last 3D scanning technology detect more breast cancers and more accurately than traditional mammograms. This is demonstrated by a new large studioperformed by the Radiology Department of the University Hospital of Pennsylvania (Philadelphia, USA) and published in the prestigious American journal Radiologywhich has had the participation of more than a million women.
Breast cancer is the most common cancer in cancer patients and, although mortality has decreased since the late 1980s thanks to improvements in early detection and treatment, it remains the leading cause of death from cancer between women. Seeing it in time is essential: when it is detected early in its localized stage, the 5-year relative survival rate is 99%according to the American Cancer Society.
Mammography has its limitations; 3D tomosynthesis sees the “hidden”
Periodic screening has proven to be the most reliable method for early detection of breast cancer today. And digital mammography remains the standard of care at many centers. However, has its limitations and is unable to detect some cancers. In fact, there is increasing evidence that the latest screening technology significantly outperforms traditional mammography.
Specifically, the solution studied in the investigation is called digital breast tomosynthesis. This tool, available in more and more health centers, uses low-dose X-rays and computer reconstructions to create three dimensional images of the breasts in order to detect cancers. The main difference is that it is done from different angles, rather than the typical single image obtained with a standard 2D mammogram.
The new study included data from 1,100,447 women between the ages of 40 and 79 who underwent 3D or 2D digital mammography between January 2014 and December 2020 at five major US health systems. Most of the women underwent at least two screening tests during the study period, for a total of about 2.5 million screening tests.
Reduction of the feared false positives in cancer
The results of the analysis showed that tomosynthesis detected 5.3 breast cancers per 1,000 women screened, versus 4.5 per 1,000 women examined with 2D digital mammography. In addition, with tomosynthesis the rate of the dreaded false positivesas well as that of requests for additional images.
False positives occur when the patient is told to have follow-up tests, but no breast cancer is detected. “This can cause tremendous anxietyand there are increased costs and risks associated with additional testing,” says study author Dr. Emily Conant, chief of the division of breast imaging at the Hospital of the University of Pennsylvania.
Although 3D technology detects cancer better in large, dense breasts than traditional 2D mammograms. “Very dense breasts they look like a blizzard in some pictures and because of the whiteness, you can’t find the lesions,” he explained. He added: “The cancers are more difficult to see because they are masked by the white glandular tissue.”
With tomosynthesis, the X-ray beam takes “multiple low-dose images in an arc overhead and the computer reconstructs the breast so that I can move through the layers of breast tissue“, Conant explains. “I can go through the tissue layer by layer to see if it is a real lesion or not.” Despite this advance, the doctor emphasizes that ultrasound or MRI of the breast after any type of mammography they will still be needed to detect cancer in really dense breasts.
“We have demonstrated the most important results of mammographic screening: increased cancer detection, fewer false positives, and a significant improvement in efficacy. Therefore, women should look for centers that routinely offer breast cancer screening with digital tomosynthesis,” she says. “For women at high risk of breast cancer, it represents a very important option that is worth pursuing.”
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