Using data from the Malmö Breast Tomosynthesis Screening Trial (MBTST), Dr. Kristin Johnson of Skåne University Hospital Malmö in Sweden and colleagues evaluated rates of interval breast cancers in 14,848 women. They also assessed the screening performance of DBT versus conventional mammography.
Johnson's group compared interval cancer rates from the trial with those of a cohort of women who underwent digital mammography screening at the same site. The team identified interval cancers and concurrent screens from the Swedish Cancer Registry and the country's National Quality Registry for Breast Cancer.
MBTST researchers identified 22 interval cancers, for a rate of 1.5 cancers per 1,000 screening exams. Among the control screening population, the interval cancer rate was 1.8 per 1,000 screening exams. This difference was not statistically significant, which led the researchers to conclude that more research is needed.
"The slightly lower interval cancer rate in the trial might indicate that DBT screening leads to the detection of clinically relevant cancers," the group concluded. "Analysis of interval cancers is important in order to elucidate the future value of DBT in screening."
