Tailoring Breast Cancer Screening Intervals by Breast Density and Risk for Women Aged 50 Years or Older: Collaborative Modeling of Screening Outcomes

Abstract

Background Biennial screening is generally recommended for average-risk women aged 50–74 years, but tailored screening may provide greater benefits. Objective To estimate outcomes for varying screening intervals after age 50 based on breast density and risk. Design Collaborative simulation modeling using national incidence, breast density, and screening performance data. Setting U.S. population. Patients Women ages ≥50 with combinations of breast density and relative risk (RR: 1.0, 1.3, 2.0, 4.0). Interventions Annual, biennial, or triennial digital mammography screening from age 50 to 74 (versus no screening) and age 65 to 74 (versus biennial 50–64). Measurements Lifetime breast cancer deaths, life expectancy and quality-adjusted life years (QALYs), false-positives, benign biopsies, overdiagnoses, cost-effectiveness and ratio of false-positives to breast cancer deaths averted. Results Screening benefits and overdiagnosis increase with breast density and risk. False-positives and benign biopsies decrease with increasing risk. Among women with fatty or scattered fibroglandular breast density and RR=1.0–1.3, breast cancer deaths averted were similar for triennial versus biennial screening for both age groups (medians: age 50–74, 3.4–5.1 vs. 4.1–6.5; age 65–74, 1.5–2.1 vs. 1.8–2.6). Breast cancer deaths averted increased with annual versus biennial screening for ages 50–74 years with all levels of breast density and RR=4.0, and ages 65–74 years with heterogeneously or extremely dense breasts and RR=4.0, but harms were almost 2-fold higher. Triennial screening for average-risk and annual screening for highest-risk subgroups cost <$100,000 per QALY gained. Limitations Models did not consider ages <50, RR< 1, or other imaging modalities. Conclusions Average-risk/low-breast density women undergoing triennial screening and higher-risk/high-breast density women receiving annual screening will maintain a similar or better balance of benefits and harms compared to biennial screening of average-risk women. Primary Funding Source National Cancer Institute

Population-Attributable Risk Proportion of Clinical Risk Factors for Breast Cancer

“…These factors represent clinically available information that can and should be used by clinicians to stratify breast cancer risk for improved risk-based screening and primary and secondary prevention efforts. 4 …”

“…1,2 Although it is impossible to determine the cause of breast cancer in any individual case, 3 easily assessed risk factors that explain a substantial proportion of incident breast cancers can be used to stratify breast cancer risk for targeted screening 4 and primary prevention 5 and improve public health interventions to reduce breast cancer risk.…”

Trends in breast cancer mortality by stage at diagnosis among young women in the United States

“…6–8 Biennial screening results in less benefit in terms of mortality reduction, but also fewer false-positive results, compared with the annual mammography in women aged 50 to 74 years. Screened and unscreened women both experience reductions in breast cancer mortality 9–11 implying that other factors (eg, cancer treatment) are also responsible for the reduced mortality.…”

Breast Cancer Incidence by Stage Before and After Change in Screening Guidelines

“…Comparative modeling analyses indicate that biennial screening in women aged 50–74 years retained 78.2% of breast cancer mortality reduction of annual screening (25.8% reduction in biennial screening versus 33.0% reduction in annual screening compared with no screening), 84.5% of years of life gained of annual screening (122.4 years of life gained per 1,000 women screened by biennial screening versus 144.8 years by annual screening compared with no screening), and 86.4% of quality-adjusted life years (QALYs) gained of annual screening (86.0 QALYs gained per 1,000 women screened by biennial screening versus 99.5 QALYs by annual screening compared with no screening). 18,20 Multiple factors including trust in consensus guidelines, previously established screening patterns, physician financial incentives, and willingness to change preventive care patterns have prevented the full adoption of biennial screening recommendations. 11 Nevertheless, since the USPSTF screening guideline changes in 2009, annual mammography rates have declined significantly among U.S. adult women, 11,13,14 indicating at least some level of responsiveness to this guideline change.…”

“…15–17 Collaborative models of breast cancer screening strategies suggested that a reduction in screening frequency would result in less benefit (mortality reduction) but also fewer false-positive results in the biennial mammography as compared with the annual mammography in women aged 50 to 74 years. 18–20 …”