Gail Model – Breast Cancer Risk Factors (Educational)
Simplified educational calculator using Gail model risk factors to generate a qualitative risk factor score. For trained health professionals only.
- Current age
- Age at menarche
- Age at first live birth (or nulliparity)
- Number of first-degree relatives with breast cancer
- Number of prior breast biopsies and atypical hyperplasia
- Race/ethnicity (recorded here but not used to change the score)
The score and bands below are heuristic and not derived from the original Gail coefficients. They should never be used alone to make preventive or screening decisions.
Score & Interpretation
Complete the fields above and click “Calculate Risk Factor Score” to see a qualitative risk band based on Gail model risk factors.
This calculator is an educational adjunct for health professionals. It simplifies the Gail model concept into a non-calibrated risk factor score and is not a substitute for the official NCI Breast Cancer Risk Assessment Tool or other validated models. It must not be used by patients for self-assessment or to make decisions about screening, chemoprevention, or surgery. Always use validated tools and shared decision-making in clinical practice.
The Gail Model, also known as the Breast Cancer Risk Assessment Tool (BCRAT), is a statistical model used to estimate a woman’s absolute risk of developing invasive breast cancer over a defined time period—typically the next 5 years and up to age 90 (lifetime risk).The Breast Cancer Risk Assessment Tool+1
It was originally developed in the late 1980s by Dr. Mitchell Gail using data from large US screening cohorts and has since been updated and recalibrated.PMC+1 The model is widely used in clinical practice and research, especially in the US, to help:
- Identify women who might benefit from risk-reducing medications (e.g. SERMs, AIs)
- Guide screening intensity and follow-up
- Decide eligibility for prevention trials
Risk factors included in the Gail Model
The NCI Breast Cancer Risk Assessment Tool uses a set of personal and family factors:Susan G. Komen®+2The Breast Cancer Risk Assessment Tool+2
- Current age
- Age at menarche (first menstrual period)
- Age at first live birth (or no live births)
- Number of first-degree relatives with breast cancer (mother, sisters, daughters)
- History and number of prior breast biopsies
- Whether any biopsy showed atypical hyperplasia
- Race/ethnicity
From these, the Gail model estimates the absolute probability of developing invasive breast cancer over a given period, using baseline population incidence and relative risk coefficients.The Breast Cancer Risk Assessment Tool+1
A commonly used clinical threshold is 5-year risk ≥ 1.67%, originally used to define “high risk” for entry into chemoprevention trials and for considering risk-reducing medication.Susan G. Komen®+2AACR Journals+2
Limitations
- It does not apply to women with prior invasive breast cancer or DCIS/LCIS, or those with BRCA1/BRCA2 or other high-penetrance mutations.The Breast Cancer Risk Assessment Tool+1
- It performs best in US and European populations and may over- or under-estimate risk in some other ethnic groups.The Breast Cancer Risk Assessment Tool+1
- It only includes a limited set of risk factors and is not highly accurate at the individual level—it’s better for stratifying groups.
