About

The Gail Model is the standard clinical tool used by healthcare providers to estimate a woman's risk of developing invasive breast cancer. This calculator evaluates personal medical history, reproductive factors, and family history to provide a statistical forecast. It compares the individual's risk against the average risk for a woman of the same age and race. This tool is designed for women age 35 and older who have no history of breast cancer.

Formulas

The algorithm computes the combined relative risk (RR) and applies it to baseline hazard rates h₁(t).

Risk(t) = 1 − exp− ∫ h₁(t)RR(1−AR) dt

Where AR is the attributable risk for the population.

Reference Data

Factor	Why it matters	Relative Risk Contribution
Age	Primary risk factor; risk increases with time.	Baseline Hazard
Age at Menarche	Early exposure to estrogen (<12y) increases risk.	1.1 - 1.2x
Age at First Birth	Late childbirth (>30y) or nulliparity increases risk.	1.2 - 1.7x
Family History	First-degree relatives (mother/sister) imply genetic factors.	2.0+ x
Biopsy History	Previous benign biopsies, especially with hyperplasia.	1.5 - 4.0x

Frequently Asked Questions

Atypical hyperplasia is a condition where cells in the breast increase in number and look abnormal under a microscope. It is not cancer, but having it increases the risk of developing breast cancer in the future.

This tool is not accurate for women who carry a known mutation in BRCA1 or BRCA2, or those who have had a previous history of invasive breast cancer or DCIS.

It means that out of 100 women with your exact risk profile, roughly 1 or 2 are expected to develop breast cancer in the next 5 years. The average 5-year risk for a 40-year-old woman is roughly 0.6%.