Should breast cancer screening for women younger than 50 include DBT and mammography?

For patients under the age of 50, digital breast tomosynthesis (DBT) in addition to digital mammography is associated with a decrease in recall rates, according to a new study published by the American Journal of Roentgenology. DBT was also associated with increased cancer detection rates in women from that same age group with dense breast tissue.

“Women younger than 50 years old are more likely than older women to have heterogeneously or extremely dense tissue,” wrote Stephen L. Rose, MD, and Julie L. Shisler of Solis Mammography in Addison, Texas. “Increased breast density can lead to later diagnosis of breast cancer, with potentially larger tumor burden and poorer prognosis. To determine whether digital mammography with tomosynthesis improves screening mammography effectiveness, we designed our study to specifically evaluate screening performance metrics for digital mammography alone compared with combined digital mammography and tomosynthesis for women younger than 50 years old in a community-based mammography screening practice.”

The authors studied data from more than 59,000 patients. All patients were younger than 50 years old and screened by one of 31 sites in North Carolina, Texas, Ohio and Arizona that belong to a community-based screening network.

Overall, DBT plus digital mammography was found to have a recall rate of 108 per 1,000 screenings, down from 117 per 1,000 screenings for digital mammography alone. The biopsy rate of DBT plus digital mammography was 16.6 per 1,000 screenings, up from 13.5 per 1,000 screenings for digital mammography alone. In addition, the cancer detection rate for DBT plus digital mammography was 2.6 per 1,000 screenings, an increase from 1.9 per 1,000 screenings for digital mammography alone.

When just examining the effect of DBT on patients with dense breast tissue, the cancer detection rate increased from 2.1 per 1,000 screenings to 3.5. “The improvement in cancer detection rate in our study did not reach statistical significance for the entire cohort of women younger than 50 years old, but for the subgroup of women with dense breast tissue, the improvement in cancer detection rate was significant,” the authors wrote.

Rose and Shisler noted that debates about beginning breast cancer screening for women younger than 50 often include concern about potential harms such as false-positive recalls or biopsies. However, they added, their findings “address some of the harms of screening women younger than 50 years old.”

“The biopsy rate increased after the addition of tomosynthesis, but some of this increase was because of the additional cancers found,” the authors wrote. “Although more biopsies were performed after the addition of tomosynthesis, the positive predictive value for biopsy increased by 1.5 percent for all women and by 3.2 percent for women with dense breasts, but these differences were not statistically significant. The mean size of invasive cancers diagnosed for women screened with tomosynthesis decreased by a mean of 3 mm over digital mammography alone, indicating a shift toward detecting smaller malignancies, which tend to have a better prognosis.”

Rose and Shisler concluded that these results “argue strongly” for using DBT to screen women younger than 50 years old.