Breast Cancer Risk Calculator

What Is the Gail Model?

The Gail model (Breast Cancer Risk Assessment Tool) estimates a woman's probability of developing invasive breast cancer over the next five years using age, reproductive history, biopsy history, family history, and race-specific baseline hazards from NCI data. Women at or above 1.67% 5-year risk are often considered for preventive counseling. See also the Breast Cancer Recurrence Risk Calculator and Heart Disease Risk Calculator.

Gail Model Formula

Relative risk comes from a logistic regression of personal factors. Absolute 5-year risk integrates age-specific breast cancer hazards ($\lambda_1$) and competing mortality ($\lambda_2$) over the projection interval:

$$P = 1 - \exp\left(-\sum \frac{\lambda_1 \cdot RR}{\lambda_1 \cdot RR + \lambda_2} \cdot \Delta t\right)$$

where $RR$ is the relative risk multiplier from the Gail covariates and $\Delta t$ is time spent in each age band.

High-Risk Threshold

A 5-year risk of 1.67% or higher meets the FDA guideline used when discussing risk-reducing medications such as tamoxifen for eligible women.