Temporal changes in breast cancer lifetime risk and implications for personalised surveillance in high-risk women

To evaluate temporal changes in breast cancer lifetime risk (BC-LTR) over a 10-year period among women with clinically elevated risk but without known pathogenic genetic mutations, using the International Breast Cancer Intervention Study (IBIS) breast cancer risk evaluation tool, and to assess implications for personalised surveillance strategies.

In this retrospective study, women referred for elevated risk assessment in 2014 underwent BC-LTR estimation using IBIS (v8.0b). Risk was recalculated in 2024 using the same model without recalibration. Women who developed breast cancer, underwent bilateral mastectomy, died during follow-up, were older than 85 years in 2024, or carried pathogenic genetic mutations were excluded, as IBIS BC-LTR recalculation is not applicable in these contexts. Risk factor temporal changes were evaluated using paired statistics. A linear mixed model assessed predictors of IBIS BC-LTR and their association with temporal changes.

Among 362 eligible women, mean IBIS BC-LTR decreased from 23% in 2014 to 19% in 2024 (mean absolute change = 6.5, p < 0.001). Risk group reclassification occurred in 44%: 36% shifted to a lower risk category and 8% to a higher category. Increase in IBIS BC-LTR was associated with increasing density (p < 0.0001), higher BMI (p = 0.002), current HRT use (p = 0.007), and additional affected relatives (p < 0.03), whereas downward reclassification was mainly linked to decreasing density (p < 0.0001).

IBIS BC-LTR estimates change over time in women with elevated clinical risk. Periodic reassessment may better align estimated risk with tailored screening strategies, supporting more precise, individualised surveillance.

Variation in IBIS BC-LTR scores over time highlights the need for periodic recalculation to improve individual risk stratification and guide more appropriate, personalised imaging and screening pathways.

Breast cancer risk models identify women most likely to benefit from supplemental screening. IBIS BC-LTR estimates changed over 10 years, reclassifying over 40% of women with elevated baseline risk into a different risk category. Periodic IBIS BC-LTR recalculation is essential to optimise risk stratification and screening pathways.