Although the technology has demonstrated benefits such as reducing recall rates and improving cancer detection, it has remained unclear whether these results carry over in the long term, wrote a team led by Dr. Liane Philpotts.
So the group analyzed DBT's screening performance over a seven-year period, including 124,669 screening DBT exams performed between 2011 and 2018. The researchers assessed the modality's recall and cancer detection rates, as well as positive predictive value for screening recall (PPV1) and biopsy (PPV3). For comparison, they calculated these same metrics from digital mammography exams taken between August 2008 and July 2011.
Philpotts and colleagues obtained the following results:
- Over the seven-year period, DBT's recall rate decreased from 7.9% to 6.2%; the overall digital mammography recall rate was 11.4%.
- DBT's cancer detection rate per 1,000 screening exams remained stable, at 5.8 in the first year and 5.1 in the seventh year, while digital mammography's overall cancer detection rate was 3.8 per 1,000 exams.
- DBT's predictive value of screening recall (PPV1) improved over the seven-year timeline, from 7.2% to 8.2%; digital mammography's overall PPV1 rate was 3.3%.
- Finally, DBT's predictive value of biopsy (PPV3) increased over the years, from 35% in year 1 to 44% in year 7, compared with an overall digital mammography rate of 29%.
The use of DBT could dramatically shift the balance between screening mammography's harms and benefits, according to the researchers.
"Screening metrics with DBT over seven years were sustainably significantly improved over 2D rates and further demonstrate favorable trends of improvement over time," they wrote.
