By Will Boggs MD
NEW YORK (Reuters Health) - 26/3/2019
Digital breast tomosynthesis (DBT) substantially reduces the rate of benign biopsies without hampering cancer detection, according to results from the U.K. National Health Service Breast Screening Program.
"Currently there is a lot of focus on whether DBT should be used as a screening tool, and there are many factors that need to be considered in this setting," Dr. Nisha Sharma from Leeds Teaching Hospital NHS Trust, in Leeds, England, told Reuters Health by email. "In practical terms, DBT can reduce the number of benign biopsies in the diagnostic setting by increasing the confidence of the radiologist interpreting the mammograms."
In the U.K. screening program, women are called for routine screening mammography every three years between ages 50 and 70. If an abnormality is detected, they are recalled for triple assessment of the abnormality (clinical examination, additional imaging and potential biopsy). DBT is an accepted additional imaging modality, but it is not used in routine screening.
Dr. Sharma and colleagues compared the use of DBT versus no DBT in 827 women recalled for screening assessment after full-field digital mammography (FFDM).
Among these women, 145 breast cancers were detected (142 identified during initial screening, two additional cancers seen only with DBT and one detected on surveillance MRI).
The cancer-detection rate was 17.2% with and without the addition of DBT, the researchers report in Radiology, online March 19.
Screening without the addition of DBT resulted in 571 biopsies, with 142 cancers identified. The use of DBT would have resulted in only 298 biopsies, with 142 cancers identified.
As a result, the positive predictive value was higher with DBT (47.7%) than with screening without DBT (24.9%).
The specificity with DBT assessment (77.5%) was about twice that with routine screening (38.2%).
Both DBT and routine screening would have missed two cancers, but all invasive cancers were identified with DBT.
"DBT is an important diagnostic imaging tool as it helps minimize the impact of tissue overlap from conventional digital mammography and can also help in reducing the masking effect," Dr. Sharma said. "I think that DBT should routinely be used in the diagnostic work up of women recalled from screening or attending the symptomatic clinic where a biopsy is being considered based on conventional imaging findings." "It is important to adhere to triple assessment, and DBT complements the imaging aspect of this process," she said.
Dr. Per Skaane from Oslo University Hospital, in Norway, who wrote an accompanying editorial, told Reuters Health by email, "Indeterminate densities in asymptomatic women should not undergo needle biopsies without DBT!"