Environmental co-benefits of WISDOM risk-based breast cancer screening: A multi-institutional pathway-based life cycle assessment.

Abstract

e23224 Background: The WISDOM randomized clinical trial demonstrated that risk-based breast cancer screening incorporating population-based genetic testing safely stratified screening intensity and was noninferior to annual screening for stage ≥IIB cancers while reducing mammography utilization. Breast cancer screening also represents a substantial national expenditure, estimated at approximately US$11B annually in recent years.The environmental consequences of screening guideline intensity and downstream diagnostic cascades—relevant to population health and environmental justice—remain under-characterized. Methods: We conducted a pathway-based life cycle assessment (LCA) to quantify environmental impacts of hypothetical breast cancer screening–diagnostic cascades under (1) population-based annual screening and (2) WISDOM-aligned risk-stratified screening pathways. The modeled clinical sequence included screening mammography, recall, diagnostic imaging, biopsy, and pathology. Pathways were parameterized for four clinically defined risk groups (low, average, elevated, high), with procedure volumes and intensities informed by WISDOM trial screening assignments and supporting empirical evidence. A cradle-to-grave boundary captured energy use, consumables, equipment manufacturing, and waste. Primary data inputs were derived from audit and process inventories across three US academic centers. Environmental outcomes were expressed as kg CO₂-equivalents (CO₂e) per patient pathway and summarized across risk strata. Results: Compared with population-based annual screening, risk-stratified pathways were associated with an approximate 30% reduction in total greenhouse gas emissions. Emissions were dominated by routine mammography (approximately 65% of total pathway emissions) and downstream diagnostic imaging and biopsy (approximately 20%). Per-patient emissions increased with escalating risk intensity: +30%, +163%, and +400% for average-, elevated-, and high-risk pathways, respectively, relative to low-risk pathways. The average-risk group accounted for approximately 52% of total pathway emissions due to its prevalence. Conclusions: WISDOM-aligned risk-based screening may offer clinically safe screening intensity while reducing the environmental footprint of breast cancer screening pathways by approximately 30%, largely through decreased routine mammography volume and associated downstream diagnostic cascades. Incorporating environmental impact metrics into screening policy evaluations could strengthen value-based, equitable guideline modernization by jointly considering outcomes, costs, and environmental externalities.