Risk vs age: Which mammography screening method is better?

Proponents of risk-based mammography screening claim the method successfully emphasizes its benefits and minimizes its harms, but new research has found it may not be as effective as age-based screening.

Elizabeth S. Burnside, MD, with the University of Wisconsin-Madison School of Medicine and Public Health, and colleagues compared two hypothetical screening scenarios: An age-based screening program for women 45 and older and a risk-based situation that examined five-year breast cancer risk.

Their results were published June 11 in Radiology.

“Virtually all mammography screening trials use an age-based rather than a risk-based recruitment strategy, emphasizing the importance of studying the effectiveness of risk-based breast cancer screening strategies prior to implementation,” Burnside et al. explained. “Growing interest in risk-based screening creates an urgent mandate to determine effectiveness.”

The team compared the two methods in a group of 71,148 mammograms among 24,928 women screened between January 2006 and December 2013.

Age-based screening, in this hypothetical scenario, was defined as 45 and older, while risk-based screening was five-year risk of breast cancer greater than that of the average 50 year-old woman. The researchers looked at cancer detection, false positives and benign biopsy findings.

Overall, in women 40 to 49 years old, usual care resulted in 50 screening-detected cancer, 1,787 false-positive mammograms and 385 benign biopsies. Aged-based screening detected more cancers than the risk-based scenario, but also resulted in more false positives and benign biopsies.

Specifically, the two hypothetical scenarios produced the following results: Age-based screening resulted in 34 detected cancers, 899 false-positive mammograms and 175 benign biopsies; risk-based screening produced 13 screening-detected cancers, 216 false-positive mammograms and 49 benign biopsies.

“In conclusion, we demonstrated that outcomes in an age-based (≥45 years) screening strategy versus a risk-based screening strategy in a high-quality screening practice differed significantly in the 45–49-year age group but not in the 40–44-year age group,” the authors wrote. “The risk-based screening strategy exposed more women to delays in diagnosis prior to eligibility, and these delays were, on average, longer than those with age-based (≥45 years) screening.”

Those delays, the authors went on to say, could impact the breast cancer mortality rate in younger patients and increase healthcare costs.

Despite their results, Burnside and colleagues argued that when deciding on a screening strategy stakeholders will have to weigh the positives and negatives of each in relation to short-term and long-term outcomes.