Mammography remains an effective method for breast cancer screening in women ages 65 and older, with the addition of the 3D technique tomosynthesis improving screening performances even more, according to a study published in the journal Radiology.
In the new study, researchers at Massachusetts General Hospital (MGH) sought to learn more about the performance of screening mammography in the older population and the added value of tomosynthesis. They compared screening mammograms from more than 15,000 women (mean age 72.7 years) who underwent digital 2D mammography (DM) with those of more than 20,000 women (mean age 72.1 years) who underwent tomosynthesis.
Both approaches were highly effective at detecting cancer, but tomosynthesis had some advantages over the 2D approach, including a reduction in false-positive examinations. Tomosynthesis also had a higher positive predictive value, the probability that women with a positive screening result will have breast cancer, and higher specificity, or the ability to distinguish cancer from benign findings, than DM.
“We’ve shown that screening mammography performs well in older women, with high cancer detection rates and low false-positives, and that tomosynthesis leads to even better performance than conventional 2D mammography,” says study lead author Manisha Bahl, MD, MPH, radiologist at MGH and assistant professor of radiology at Harvard Medical School. “For example, the abnormal interpretation rate, which is the percentage of women who are called back for additional imaging after a screening mammogram, is lower with tomosynthesis than with conventional 2-D mammography. We also found that fewer cancers detected with tomosynthesis were lymph node-positive, suggesting that we are detecting cancers at an earlier stage. Detecting breast cancers at an early stage is the goal of screening mammography.”
The study results do not support a specific age cutoff age for mammography screening, according to Bahl. She says that guidelines for screening in older women should be based on individual preferences, life expectancy, and health status rather than age alone. “Our research demonstrates that screening mammography and tomosynthesis perform well in older women with regard to cancer detection and false-positives,” she says. “So, if a woman is healthy and would want her cancer to be treated if it were detected, then she should continue screening.”
Bahl expects the combination of DM and tomosynthesis to eventually become the standard for screening at all practices. Since tomosynthesis is still a relatively new technology, more research is needed to determine its impact on long-term patient outcomes, Bahl says.
Caption: Images in a 72-year-old woman with screening-detected invasive carcinoma. (a) Tomo¬synthesis image from left craniocaudal view demonstrates architectural distortion in lateral aspect of left breast at anterior depth (arrow). (b) Finding is not as well demonstrated on two-dimensional left craniocaudal view. Patient underwent image-guided core biopsy and subsequent lumpectomy, which revealed grade 2 invasive lobular carcinoma.
