Tyrer-Cuzick Score: A Comprehensive Guide to Your Breast Cancer Risk
Key points
- Personal Information: Age, height, and weight (to calculate Body Mass Index, or BMI).
- Reproductive and Hormonal History:
- Age at your first menstrual period (menarche).
- Age at the birth of your first child.
- Whether you have gone through menopause and at what age.
- Use of Hormone Replacement Therapy (HRT).
When actress Olivia Munn revealed her breast cancer diagnosis in 2023, she credited a risk assessment tool for saving her life. That tool calculated her lifetime risk at 37%, prompting an MRI that found the cancer despite a clear mammogram. Months later, she urged her mother to take the same test, which led to her mom's own early-stage diagnosis. The tool at the center of her story is the Tyrer-Cuzick score.
This powerful model is transforming breast cancer prevention from a one-size-fits-all approach to a personalized strategy. By understanding your score, you and your doctor can make more informed decisions about screening and prevention, potentially catching cancer at its earliest, most treatable stage.
What is the Tyrer-Cuzick Score?
The Tyrer-Cuzick score, also known as the IBIS (International Breast Cancer Intervention Study) model, is a comprehensive risk assessment tool used to estimate a woman's probability of developing invasive breast cancer over the next 10 years and throughout her lifetime.
Developed by scientists at the Wolfson Institute of Preventive Medicine in London, it is designed for women who have not had a previous breast cancer diagnosis. Its purpose is to identify individuals who may benefit from enhanced screening protocols, genetic counseling, or preventive therapies.
What Factors Does the Tyrer-Cuzick Model Consider?
The strength of the Tyrer-Cuzick model lies in its comprehensive nature. Unlike simpler models, it integrates a wide array of personal and family health information to create a highly detailed risk profile.
Key factors include:
- Personal Information: Age, height, and weight (to calculate Body Mass Index, or BMI).
- Reproductive and Hormonal History:
- Age at your first menstrual period (menarche).
- Age at the birth of your first child.
- Whether you have gone through menopause and at what age.
- Use of Hormone Replacement Therapy (HRT).
- Personal Medical History:
- History of breast biopsies and their results, specifically noting conditions like atypical hyperplasia or lobular carcinoma in situ (LCIS).
- History of ovarian cancer.
- Breast Density: An increasingly important factor, as dense breast tissue can both increase risk and make tumors harder to see on mammograms. The model can incorporate BI-RADS density categories.
- Genetic Factors:
- Known mutations in the BRCA1 or BRCA2 genes.
- Ashkenazi Jewish ancestry, which is associated with a higher prevalence of BRCA mutations.
- Detailed Family History: Extends to first-degree relatives (mother, sister, daughter) and second-degree relatives (aunt, grandmother) with breast or ovarian cancer, noting their age at diagnosis.
Understanding Your Tyrer-Cuzick Score: What Do the Results Mean?
After your information is entered into the calculator, the model generates a percentage representing your 10-year and lifetime risk of developing breast cancer. Healthcare providers typically group these scores into three categories to guide clinical decisions.
| Risk Category | Lifetime Risk Percentage | Recommended Actions |
|---|---|---|
| Average Risk | < 15% | Continue with standard annual screening mammography. |
| Intermediate Risk | 15% - 19% | Your doctor may recommend supplemental screening, like a breast ultrasound. |
| High Risk | ≥ 20% | You may be advised to undergo more intensive screening, such as an annual breast MRI in addition to a mammogram. A referral to a high-risk breast clinic or genetic counselor may also be recommended to discuss preventive strategies. |
It's important to remember that having a high-risk score is not a diagnosis. It is a statistical tool that empowers you and your healthcare team to create a proactive surveillance plan tailored to your specific needs.
How Accurate is the Tyrer-Cuzick Model?
The Tyrer-Cuzick model is widely regarded as one of the most accurate risk assessment tools available, particularly for women with a significant family history. A 2018 study published in JAMA Oncology found the model accurately predicted breast cancer risk for at least 19 years.
However, like any predictive tool, it has limitations.
Strengths and General Accuracy
- Comprehensive: Its inclusion of numerous risk factors makes it more robust than many other models.
- Long-term Validation: Its predictive ability has been validated over long periods in large populations.
- Identifies High-Risk Patients: It is effective at identifying women who would be missed by less detailed assessments.
Key Limitations and Considerations
- Data Dependent: The accuracy of the score is only as good as the information provided. Incomplete or incorrect family history can lead to an inaccurate result.
- Overestimation in Specific Groups: Studies have shown the model can significantly overestimate risk in women with specific high-risk benign breast conditions, such as atypical hyperplasia and LCIS.
- Population Variances: The model's calibration may not be perfect for all ethnic groups. Some research suggests it may overestimate risk in Hispanic women, and its accuracy in other non-White populations is still being studied due to underrepresentation in validation cohorts.
- It's an Estimate, Not a Guarantee: The score represents a probability, not a definitive prediction of who will or will not get cancer.
Tyrer-Cuzick vs. Other Risk Models (like the Gail Model)
The Tyrer-Cuzick model is often compared to the Gail model, another common risk assessment tool. The primary difference is the level of detail.
- Comprehensiveness: The Tyrer-Cuzick model incorporates breast density, BRCA gene status, and a more extensive family history, which the Gail model does not.
- Best Use Case: Because of its detail, the Tyrer-Cuzick model is often preferred for determining eligibility for supplemental screening like breast MRI. The Gail model is frequently used to determine eligibility for chemoprevention (medications to reduce risk).
- Accuracy: For women with a strong family history of breast or ovarian cancer, the Tyrer-Cuzick model is generally considered more accurate, as the Gail model may underestimate their risk.
The Future of Risk Assessment: Integrating Genomics
Breast cancer risk assessment is continually evolving. Recently, leading healthcare technology companies like Ambry Genetics have updated their platforms to better integrate breast density directly into the Tyrer-Cuzick calculation within electronic health records (EHR), streamlining this critical process for clinicians.
The next frontier is the integration of Polygenic Risk Scores (PRS). A PRS analyzes hundreds or thousands of common genetic variations (called SNPs) to provide a more nuanced genetic risk profile beyond just the BRCA genes. Combining PRS with the clinical factors in the Tyrer-Cuzick model has been shown to significantly improve risk stratification, offering an even more precise and personalized prediction of breast cancer risk.
How to Get Your Tyrer-Cuzick Score
Many hospitals and imaging centers, like Avera Health, are now integrating the Tyrer-Cuzick assessment as a standard part of mammogram appointments. You may be asked to fill out a questionnaire on a tablet or via a link sent to you beforehand.
While online versions of the calculator, such as the IBIS Risk Assessment Tool, are available for individual use, it is crucial to discuss the results with a qualified healthcare professional. They can interpret the score in the context of your complete health profile and provide appropriate recommendations.
Conclusion: Empowering Women Through Personalized Risk Assessment
The Tyrer-Cuzick score is more than just a number; it's a key to unlocking a personalized approach to your breast health. By providing a comprehensive view of your individual risk, it facilitates meaningful conversations with your doctor about the best screening and prevention plan for you.
If you have a family history of breast or ovarian cancer or other concerns, talk to your doctor. Ask if a formal risk assessment using the Tyrer-Cuzick model is the right next step for you. It could be a life-saving conversation.
References
- Munn, O. (2024). Instagram Post. ABC News. https://abcnews.go.com/GMA/Culture/olivia-munn-reveals-mom-diagnosed-breast-cancer-after/story?id=123624969
- Ikonopedia. (n.d.). IBIS: Online Tyrer-Cuzick Model Breast Cancer Risk Evaluation Tool. https://ibis.ikonopedia.com/
- Ambry Genetics. (2025). Ambry Genetics Announces Improved EHR-Integrated Breast Cancer Risk Assessment Solution. Business Wire. https://www.businesswire.com/news/home/20251001225867/en/Ambry-Genetics-Announces-Improved-EHR-Integrated-Breast-Cancer-Risk-Assessment-Solution-with-Upgraded-Tyrer-Cuzick-Scoring-Approach-Incorporating-Breast-Density
- Avera Health. (2025). How Avera helps more women understand their breast cancer risk. SiouxFalls.Business. https://siouxfalls.business/how-avera-helps-more-women-understand-their-breast-cancer-risk/
- Brentnall, A. R., et al. (2018). Long-term Accuracy of Breast Cancer Risk Assessment Combining Classic and New Risk Factors. JAMA Oncology.
- MagView. (n.d.). Comparison of the Tyrer-Cuzick vs Gail Risk Assessment. https://magview.com/womens-health/tyrer-cuzick-vs-gail-risk-assessment-tools/
About the author
Sofia Rossi, MD, is a board-certified obstetrician-gynecologist with over 15 years of experience in high-risk pregnancies and reproductive health. She is a clinical professor at a top New York medical school and an attending physician at a university hospital.