Using Breast Density at Age 40 to Guide Screening Mammography cost effective: Study

The risk of breast cancer is four to five times greater in women who have increased density in more than 75% of their breast tissue, than in women with little or no density in the breast. One-third of all breast cancers are found in women who have increased breast density in over 50% of their breast tissue. Current recommendations from the United States Preventive Services Task Force (USPSTF) suggest that women in their 40s can choose to undergo screening mammography based on their personal preference.

Researchers of America conducted a study, using computer-based microsimulation model to generate the natural history of breast cancer for women with and those without dense breasts and assessment of the cost-effectiveness of strategies tailored to breast density and nontailored strategies. They used model parameters from the literature; statistical modelling; and the analysis of Surveillance, Epidemiology, and End Results–Medicare data. They included 500,000 women born in 1970 who had no known genetic risk factors or family history of the disease and a breast cancer incidence that matched age-specific incidence in 2017. The major outcome assessed was lifetime costs and quality-adjusted life-years (QALYs), discounted at 3% annually.

Intervention method:

Researchers assessed the subjects in the following screening strategies:

• no screening;
• biennial or triennial mammography in women aged 50 to 75 years;
• annual mammography in women aged 50 to 75 years who were determined to have dense breasts at age 50 years and biennial or triennial mammography in women aged 50 to 75 years who did not have dense breasts at age 50 years; and
• annual mammography in women aged 40 to 75 years who were determined to have dense breasts at 40 years and biennial or triennial mammography in women aged 50 to 75 years who did not have dense breasts at 40 years.

Key findings of the study were:

♦ Upon base-case analysis, the researchers found that assessing breast density at age 40, followed by annual screening for those with dense breasts (i.e., heterogeneously and extremely dense breasts) and biennial screening starting at age 50 for those without dense breasts was associated with the greatest reduction in breast cancer mortality.

♦They noted that this method yielded an incremental cost-effectiveness ratio of $36,200per quality-adjusted life-years (QALY) compared with the currently recommended biennial screening strategy.

♦ Upon sensitivity analysis, they found among those who are willing to pay threshold of $100000per QALY, the likelihood of the density-stratified strategy at age 40 years being the optimal strategy was 56% compared with the other approaches.

♦ The findings suggest baseline breast density assessment in women aged 40years, followed by annual screening for those with dense breasts may be more cost-effective than biennial screening starting at age 50years.

The authors concluded, "The study findings advocate for breast density–stratified screening with baseline mammography at age 40 years".

The editorialists wrote: "The screening strategy proposed ... would do annual screening on 60% of women, which raises questions about how it could be cost-effective." In addition, they note that "not everyone with dense breasts is at increased risk for breast cancer." For now, they support a strategy in which all women are screened biennially between ages 50 and 75.

For further information:

https://www.acpjournals.org/doi/10.7326/M20-2912