DBT, synthetic 2D mammogram beat digital mammography alone

Research published online March 2 in Radiology found digital breast tomosynthesis (DBT) and 2D synthetic mammography (SM) screening more effective in detecting histologically favorable tumors than digital mammography (DM) alone.

While the authors from Norway and the United States pointed out studies have shown DBT paired with DM increases breast cancer detection rates compared to DM on its own. The downsides include radiation exposure, extended compression time and increased data storage space.

A large team analyzed data from 37,185 women screened with DBT and SM and 61,742 women screened with DM—information was taken from the Norwegian Breast Cancer Screening Program.

Analysts used 11 performance measures to compare the cancer screening methods, including recall rate due to abnormal mammographic findings, rate of screen-detected breast cancer and tumor grade.

“We identified a significantly higher rate of screen-detected breast cancer in women screened with DBT and SM than in women screened with DM,” wrote corresponding author Solveig Hofvind, PhD, with the Cancer Registry of Norway in Oslo and colleagues.

Results of the study are as follows:

  • Recall rates were comparable for DBT and SM screening (3.4 percent), and DM screening (3.3 percent).
  • DBT and SM screening achieved a higher rate of screen-detected cancer (9.4 per 1,000 patients) compared to DM screening (6.1 per 1,000).
  • The rate of detection of tumors 10mm or smaller for DBM/SM (3.2 per 1,000 patients) was higher compared with SM (1.8 per 1,000).
  • DBT/SM achieved better performance in the rate of grade 1 tumors (3.3 per 1,000) compared to DM (1.4 per 1,000).

Researchers did cite what they deemed an important issue: Additional cancers detected with DBT and SM were typically smaller in diameter and of a lower histologic grade than those detected by DM. This suggests DBT-SM screening detects less aggressive invasive tumors than DM.

Further studies exploring breast tumor growth and access to long-term clinical follow-up data are necessary to fully understand this issue.