The Tyrer-Cuzick score measures the likelihood of specific gene mutations relating to breast cancer. A doctor can place people into three categories: average, intermediate, and high risk.

The Tyrer-Cuzick score helps doctors estimate an individual’s level of risk of developing breast cancer and may help when making recommendations about screening.

People also refer to it as the International Breast Intervention Study (IBIS) risk prediction model or IBIS tool.

While the Tyrer-Cuzick score can be a useful tool, it is not flawless. Results do not automatically indicate if someone will develop breast cancer or not, as there are many individual risk factors involved.

This article will discuss the Tyrer-Cuzick model, how scoring works, and what the results suggest.

A doctor reviewing the results of a person's Tyrer-Cuzick score.Share on Pinterest
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To calculate a person’s Tyrer-Cuzick score, the model considers their family health history and other potential risk factors.

Some factors that can influence an individual’s Tyrer-Cuzick score include their:

A person can use this online tool to determine their Tyrer-Cuzick score.

According to a person’s Tyrer-Cuzick score, a doctor will classify their risk of developing breast cancer into one of three categories.

Average risk

Doctors generally consider a person with a Tyrer-Cuzick score of under 15% at an average risk of developing breast cancer.

The American Cancer Society currently suggests that people at average risk for breast cancer consider beginning to have annual mammograms from age 40.

Those between the ages of 45 and 54 need to undergo a mammogram every year, switching to every other year from age 55 if they wish. Other personal factors may also influence the frequency of testing.

Intermediate risk

A score of 15% to 19% indicates an intermediate risk of developing breast cancer.

Doctors may recommend additional testing for some people at this risk level, such as those with dense breast tissue.

Before proceeding, doctors will explain the issues that can arise from additional testing, such as false positives and other risks of mammogram tests.

High risk

Doctors typically consider a score over 20% high risk. They may recommend that people in the high risk group get additional screening tests every year, such as a breast MRI and mammography.

Doctors may also have further recommendations for each individual, such as supplemental ultrasound testing for those with very dense breast tissue.

A 2016 article suggests the Tyrer-Cuzick model is the most comprehensive and sensitive model for detecting breast cancer risk. The authors add that it is the only model that considers both personal and extensive familial risk factors.

Research from 2018 explored the accuracy of the model using results from over 132,000 women. The study indicated that Tyrer-Cuzick assessments may provide useful data for at least 19 years, which doctors can use to design individualized screening and prevention strategies.

However, people need to be aware that two of the study authors received royalty payments for commercial use of the Tyrer-Cuzick model through Cancer Research UK.

The authors of a 2021 article suggest that while the Tyrer-Cuzick model is useful, other tools, such as the extended Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm, may be more accurate for certain populations.

Another study from 2019 indicated that the Tyrer-Cuzick model may overpredict invasive breast cancer risk in people with lobular carcinoma in situ, which is an atypical growth of cells in the breast.

An assessment of cancer risk is only a general estimate. People in average risk groups may still get breast cancer, and those in high risk groups may never develop the illness.

While the Tyrer-Cuzick model can be helpful, it may fail to take certain factors into account. For example, risk level varies by race and ethnicity, but a 2021 study notes that researchers developed the Tyrer-Cuzick model primarily in non-Hispanic white women. According to this study, the test is accurate for many racial and ethnic groups but may overestimate breast cancer risk in Hispanic women.

Another 2018 article states that while the Tyrer-Cuzick model seems to be the most consistently accurate tool for predicting breast cancer risk, its use of breast density as a risk factor does not have validation. Researchers are currently studying the factors of breast cancer risk further, and their results will help improve the test.

For all these reasons, doctors will not rely on a Tyrer-Cuzick score as their only screening tool.

Online assessment tests may help an individual gauge their risk of developing breast cancer. However, they are not diagnostic tools. Anyone who would like to understand their risk for breast cancer can speak with a doctor about a full screening.

Healthcare professionals generally recommend people begin having annual mammograms around age 40. This can help them understand their risk as they continue to age and get additional screening if necessary.

A doctor may recommend several other tools to help assess a person’s risk of breast cancer moving forward. As well as mammograms, a personalized screening plan may include:

Doctors may also recommend preventive measures, such as adjusting lifestyle factors where applicable. This may include:

A Tyrer-Cuzick score can give a general indication of a person’s risk of developing breast cancer over the next 10 years and throughout their lifetime.

These scores are not definitive but provide guidelines for doctors to help make decisions about screening and additional testing in each case.

Doctors may recommend that a person with a high Tyrer-Cuzick score undergo additional annual screening, including MRI and ultrasound tests.

Doctors will discuss the risks and benefits of any test with each person before making a recommendation.