It's clear that DBT's sensitivity is superior to that of mammography, said session moderator Dr. Sylvia Heywang-Köbrunner of Breast Diagnostics Munich. However, finding more cancers doesn't necessarily translate into reduced mortality rates, since increased detection could be caused by overdetection of "harmless" malignancies, she said.
"We need further data to estimate the technology's effectiveness and its potential for overdiagnosis," she told session attendees. "And there are logistical problems such as longer reading time and how to optimize hanging protocols and comparison with both digital mammography and DBT priors."
In addition, more evidence is needed regarding how tomosynthesis does with interval cancers.
"Several trials show that tomosynthesis has excellent sensitivity and good specificity, but we still don't know how it performs with interval cancers," Heywang-Köbrunner said. "So although tomosynthesis is promising, we need more interval cancer data."
More from Malmö
The need for more interval cancer data for tomosynthesis was on the list of "lessons learned" from the Swedish Malmö Breast Tomosynthesis Screening Trial, which Dr. Kristina Lång, PhD, of Lund University presented during the session.
Lång outlined key takeaways from the study, which recruited 15,000 women between 2010 and 2015. The women were between the ages of 40 and 74 and underwent one-view DBT and two-view digital mammography. Lång and colleagues have published preliminary results that include data from 7,500 women; they are in the process of analyzing data for the total study cohort.
These preliminary results have shown the following:
All of these findings suggest that tomosynthesis could indeed replace digital mammography for screening. But like Heywang-Köbrunner, Lång emphasized that more data on DBT and interval cancers are needed. Her team plans to work with researchers from the Screening With Tomosynthesis or Standard Mammography (STORM) trial and the Oslo Tomosynthesis Screening Trial (OTST) to tackle the issue.
"We're planning a joint effort with [researchers from the] other prospective, population-based trials to do an individual participant data meta-analysis and evaluate whether tomosynthesis reduces the interval cancer rate," Lång said. "When we have analyzed interval cancer rates, let's use tomosynthesis in screening -- with the aid of artificial intelligence."