This tool runs three independently validated breast cancer risk models simultaneously. Each uses different inputs and produces different outputs — understanding their strengths helps interpret results.
Developed by Mitchell Gail et al. (1989) and implemented by the National Cancer Institute as the Breast Cancer Risk Assessment Tool (BCRAT). It is the most widely used model in US clinical practice.
Outputs an absolute 5-year and lifetime risk of invasive breast cancer. The 1.67% five-year threshold is used clinically to assess eligibility for chemoprevention (tamoxifen, raloxifene).
Limitations: Does not include second-degree family history, breast density, hormonal factors, or BRCA status. Less accurate for women with strong hereditary risk.
Developed by Jonathan Tyrer and Jack Cuzick (2004) at the International Breast Cancer Intervention Study (IBIS). Considered the most comprehensive risk model available and recommended by NICE (UK) for high-risk assessment.
Outputs lifetime risk to age 80 plus 5-year and 10-year estimates. A lifetime risk ≥ 20% typically qualifies a patient for enhanced screening (annual MRI in addition to mammography) and genetic referral.
Strengths: Incorporates BRCA1/2 carrier probability, extended family history, hormonal exposures, BMI, breast density, and benign breast disease — making it the most sensitive model for hereditary risk.
Developed by the Breast Cancer Surveillance Consortium (Tice et al., 2008; updated 2019) using data from over 1 million mammography screening visits across six US registries.
Outputs a 5-year absolute risk calibrated to the US screening population. Its key differentiator is the direct inclusion of mammographic breast density (BI-RADS categories), which is one of the strongest independent risk factors.
Use case: Particularly useful in breast imaging settings where BI-RADS density is already recorded. Enables radiologists to communicate personalised risk at the point of screening.
Three validated models: Gail · Tyrer–Cuzick (IBIS) · BCSC — educational use only
Three models calculated from your inputs
Gail Model — Uses age, race, menarche, first birth, family history, biopsy history, and atypical hyperplasia. Published by Gail et al. (1989), implemented by NCI. Outputs 5-year and lifetime absolute risk.
Baseline hazard from NCI BCRAT tables (white women), adjusted for race. Competing mortality included implicitly via short time horizons.
Tyrer–Cuzick (IBIS) — Most comprehensive model. Includes BRCA probability, extended family history, hormonal factors, BMI, and breast density. Calibrated to ~12% population lifetime risk to age 80.
Combined RR applied to annual baseline hazard (0.00145). Lifetime risk computed as 1 − e^(−h × years remaining).
BCSC — Incorporates mammographic breast density alongside standard risk factors. Developed by Tice et al. (2008) from screening program data. Outputs 5-year risk.
Baseline risk stratified by age and race from BCSC cohort tables. Breast density RR from BI-RADS category.