Location Plays a Role in DBT Cost-Effectiveness

August 7, 2020

Nations with lower breast imaging recall rates and high mammography compliance are less likely to view digital breast tomosynthesis as a cost-effective screening option.

Country of residence could play a significant role in whether digital breast tomosynthesis (DBT) is considered more effective in breast cancer screening than digital mammography (DM). And, there is also a price tag associated with that tipping point in efficacy, a new study has revealed.

In an article published in the Aug. 4 Radiology, investigators from The Netherlands detailed their research with a simulated population of women. Through their endeavors, which ran from March 2018 to February 2019, they generated 10,000 outcomes.

They determined that DBT could be considered cost-effective at a willingness-to-pay threshold of $38,500 per life-year gained, but not at $22,000. In addition, they found countries with higher breast imaging recall rates, such as the United States, were more likely to experience DBT’s benefits. Nations, such as The Netherlands, where recall rates are low and mammography compliance is high are less likely to consider DBT as a cost-effective option.

“With current data, biennial DBT screening between 50 and 74 years of age is not expected to be cost effective at the Dutch willingness-to-pay threshold of [$22,000] per life year gained and 3.5-percent annual discounting,” wrote the team, led by Valérie Sankatsing, Ph.D. candidate and researcher with the Erasmus department of public health.

For this study, Sankatsing’s team used a micro-simulation model to create 10,000 model runs with a simulated group of 1 million women per run. According to the team, the women were born in 1970 and underwent biennial screening between ages 50 and 74, and the team assigned half the women to DBT and half to DM.

During the study, the team applied the actual screening compliance rate from The Netherlands of 80 percent to the simulated cohort. For DBT, they estimated it bolstered sensitivity by 18 percent, had a 30-percent positive predictive value, and cost $100 more than DM. 

Each of the 10,000 model runs created an incremental cost-effective DBT-DM pair, and their analysis determined DBT is both the more effective and expensive screening option. According to the data analysis, per 1,000 women, DBT provided a 7-percent rise – 13 years – in life-years gained, prevented 6-percent additional deaths from breast cancer, and resulted in 2.5-percent drop in false positives. But, it did cost more than DM with a mean lifetime cost of $151,311.

To determine whether DBT was truly cost-effective, the team said, they examined the willingness-to-pay threshold. The lower the threshold, the lower the cost-effectiveness, they said. For a willingness-to-pay threshold of $22,000, DBT was only deemed cost-effective in 36 percent of cases, but when the threshold rose to $38,500, it was considered cost-effective in 66 percent of situations.

This difference among thresholds, they said, underscores the likelihood that countries with lower recall rates may not turn to DBT as much as a viable screening option.

“A meta-analysis evaluating recall rates with DBT compared with DM showed that the reductions in recall rates were prominently found in studies from the United States that reported high baseline recall,” Sankatsing’s team wrote. “The decrease in recall rates and the number of false-positive results with DBT, thus, depends on the initial recall rate.”