When it comes to breast health, everyone understands the importance of mammograms. But as technology changes, it’s also important to understand the various technologies available for mammography. Which mammography methodology increases cancer detection and delivers fewer false positives? According to a five-year study at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, 3D Mammography or Digital Breast Tomosynthesis (DBT) screening help detect a higher proportion of poor prognosis cancers than digital mammography.
The procedure uses an X-ray tube that moves in an arc. It takes low radiation-dose projections of the breast from a variety of angles. By varying the angle, you can have multiple data points that allow reconstruction in different ways.
The study, which was published in the journal Radiology, looked at outcomes for patients over a five-year time period after they began imaging all their screening patients with DBT in the fall 2011. More than 56,000 Digital Breast Tomosynthesis exams were included in the study, along with 10,500 prior DM exams. Emily F. Conant, M.D., professor and chief of breast imaging in the Department of Radiology, Perelman School of Medicine at the University of Pennsylvania in Philadelphia and study lead author said, "As a radiologist, tomosynthesis allows viewing of the breast in multiple layers or slices. This ability to scroll through slices of otherwise overlapping breast tissue helps us not only detect more cancers but also better characterize benign or normal areas of the breast."
There are other studies that have shown that DBT is superior to DM for cancer detection and reducing recall rate (the rate at which women are called back for additional imaging based on suspicious initial findings.) Most of the published data, however, has been from the first round of DBT screening, when cancer detection rates and recall rates are expected to be higher than those in subsequent rounds of screening.
In the five-year study, cancer detection rates were 6 per 1,000 for DBT and 5.1 per 1,000 for DM alone. Screening recall rates for DBT were 8% compared to 10.4% for DM alone. These findings held steady across all five years of tomosynthesis screening. Almost one third of cancers detected with DBT screening were associated with a poorer prognosis. This is compared with a quarter of those detected with only DM.
The five-year study involved a diverse population of women. This is important since African American women are known to develop more aggressive breast cancer types at an earlier age. African American women comprised almost 50% of the study group.
"We found different types of biology in the cancers detected across our diverse population and that's an important takeaway of this paper," Dr. Conant said.
"Our results show that we can improve our screening outcomes for younger women with DBT by finding clinically important cancers earlier with fewer false positives."
Dr. Conant also said, "This is the longest follow-up with cancer registry matching that has been published thus far." She attributed the improved outcomes achieved with tomosynthesis to better visualization of both benign and malignant lesions as well as a reduction in tissue superimposition. "With tomosynthesis you can remove some of the overlapping or obscuring breast tissue so that both normal and abnormal findings are better seen," she said.
"That provides both improved cancer detection and decreased false positives."Dr. Conant added, "Our results show that we can improve our screening outcomes for younger women with DBT by finding clinically important cancers earlier with fewer false positives."
It’s true that more studies with diverse populations and long term follow-up are needed. However, the initial findings of this study underscore the strength of tomosynthesis in breast cancer screening.
Talk To An Expert
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Here are some blogs you may have missed:
- Choosing A Digital Mammography System: GE vs. Hologic
- When should you evaluate your mammography equipment?
- Mammography or Breast MRI? Which is More Effective?
- The Difference Between Digital Mammography and Tomosynthesis
- 3 Considerations When Choosing a Digital Mammo System
Meet the author: Vikki Harmonay