DBT rapidly rising despite lack of clinical evidence, industry agreement

Although most studies demonstrating the benefits of digital breast tomosynthesis (DBT) have been observational, use of the modality has risen dramatically over the past few years, according to a study of more than nine million women published in JAMA Internal Medicine.

In fact, an analysis of Blue Cross Blue Shield (BCBS) claims data found breast cancer screening exams utilizing DBT rose from 12.9% in 2015 to 43.2% in 2017.

The analysis, which included data from 9,673,583 breast cancer screening exams in women ages 40 to 74 insured through BCBS, found the number of hospital referral regions (HRRs) using DBT as the primary screening method also increased from 4.6% in 2015 to 41.8% in 2017. These regions used the modality in more than 50% of screening exams.

“We found that in a large privately insured population, DBT was rapidly adopted into practice and became the predominant mode of screening in more than 40% of HRRs around the country,” wrote Ilana B. Richman, MD, with Yale School of Medicine in New Haven, Connecticut, and colleagues.

Overall, the rise was predominantly seen in areas with higher median household incomes, greater educational attainment and a larger proportion of white residents.

Joy Melnikow, MD, MPH, and Joshua J. Fenton, MD, MPH, both with the University of California Davis, tackled this issue in a related editorial, along with the gap between industry endorsements of DBT for clinical use and the dramatic rise in the modality compared to digital mammography.

They, along with Richman et al., noted that screening guidelines from the U.S. Preventative Services Task Force and American Cancer Society haven’t given the green light to DBT for routine screening due to insufficient evidence. But, the American Society of Breast Surgeons and American College of Radiology have each come out in support of DBT for mammography screening.

“Diffusion of medical technology ahead of definitive evidence is common in the United States,” the pair wrote. “Societal attitudes that place high value on innovation and technology create a fertile environment for the rapid adoption of novel but unproven interventions.”

What’s also potentially troubling is that disparities in breast cancer mortality could worsen depending on trials examining the effectiveness of DBT on patient outcomes, the editorialists wrote.

“Five randomized clinical trials with a combined recruitment goal of 430,000 women are currently under way in Europe, the United Kingdom, and North America; within 2 to 5 years, they should provide more reliable information about diagnostic characteristics and comparative rates of interval cancers,” the pair added.

“If trial findings show no benefits or possible harms, then those who have not received DBT may be better off,” Melnikow and Fenton concluded.