In a 2018 study, researchers tested the efficacy of the Tyrer-Cuzick Lifetime risk model for identifying women at increased or high risk of hereditary breast cancer. In doing so, 100,318 women underwent genetic testing and those results were compared against each patient's respective Tyrer-Cuzick risk score. The results? The Tyrer-Cuzick model failed to identify about 40 percent of women eligible for changes in their medical management, like increased MRI screening.
This means many women are missing the opportunity to engage in simple preventive care services that support cancer detection as early as Stage 0.
Here we will explore the Tyrer-Cuzick Lifetime risk model, the National Comprehensive Cancer Network (NCCN) Guidelines in Clinical Oncology, and why you should be using both the NCCN Guidelines and Tyrer-Cuzick to ensure your breast imaging center flags all high-risk breast cancer patients.
What is the Tyrer-Cuzick Lifetime Risk Model?
Tyrer-Cuzick Lifetime, or the IBIS tool, is a risk model that calculates a woman's likelihood for developing breast cancer in 10 years and over her lifetime, up to 85 years old. As well, it estimates the the likelihood of a being a BRCA1 or BRCA2 mutation carrier. A female-oriented risk model, Tyrer-Cuzick Lifetime focuses primarily on breast cancer, ovarian cancer, and reproductive history.
Using Tyrer-Cuzick Lifetime, a woman's risk for breast cancer is expressed as a percentage, with 20 percent being the threshold in which changes in medical management for additional screenings are determined (e.g., MRI eligibility). Because of its specific utility for identifying women who are at risk of developing breast cancer, the risk model is heavily used in breast imaging centers.
What are the NCCN Guidelines?
The NCCN Guidelines are considered the standard of care in oncology. Reviewed annually by thousands of multidisciplinary clinicians and researchers, NCCN Guidelines are among the most thorough and up-to-date guidelines in medicine. Specifically, NCCN Guidelines include recommendations that identify high-risk patients who would benefit from genetic counseling and testing.
When determining if a patient is eligible for genetic counseling, providers use "referral" guidelines. These are less stringent and more all encompassing than the guidelines used to determine a patient’s eligibility for genetic testing, which are known as the "testing" guidelines. The testing guidelines are more restrictive on, for example, age ranges and family history. At its core, these sets of guidelines provide a framework for individualized preventive care pathways.
How Does NCCN Differ From Tyrer-Cuzick?
Whereas Tyrer-Cuzick uses non-genetic risk factors in its model to help indicate a women's eligibility for MRI, the NCCN Guidelines focus on eligibility for genetic testing. Though the NCCN Guidelines and Tyrer-Cuzick are both risk assessment tools, they are used for very different purposes — underscoring the need to use both.
If your breast center only uses one risk assessment framework, you may be over- or underestimating patient risk:
- ● A 35-year-old woman with atypical hyperplasia on a breast biopsy — but has no other inputs — would have a Tyrer-Cuzick 8 Lifetime score of over 43 percent. In this case, the patient would be flagged as eligible for MRI surveillance, because they exceed the 20 percent threshold. However, the woman would not meet NCCN Guidelines with that information alone, and she would not be eligible for referral to genetic counseling or genetic testing. Researchers have demonstrated this before, showing that the Tyrer-Cuzick model significantly overestimates risk of breast cancer for women with atypia.
- ● A 45-year-old woman with a family history of cancer on her father’s side, including a paternal grandmother with ovarian cancer and a paternal uncle with pancreatic cancer, wouldn’t be flagged as high-risk with the Tyrer-Cuzick model. Because Tyrer-Cuzick is female-focused, the risk score only emphasizes breast and ovarian cancers. This means she would not receive a breast MRI, potentially leading to a late-stage cancer diagnosis. With the NCCN guidelines, this patient would be flagged for genetic testing — and as a BRCA2 mutation carrier — she would be given a preventive care plan for breast MRIs and prophylactic oophorectomy. This would make it possible to detect breast cancer as early as Stage 0.
These examples highlight how Tyrer-Cuzick alone can generate inappropriate referrals, and thus over- or underestimate risk for patients.
If your breast center is in the business of early detection and prevention, don't take a light pass at evaluating which of your patients are high risk. Using NCCN Guidelines helps flag more of the right patients who are eligible for testing, and from there, you can truly know a patient's risk for inherited breast cancer. Tyrer-Cuzick provides non-genetic risk factors that are used for determining MRI eligibility. Both serve a purpose in cancer prevention and early detection. .
Read now to discover how you can design and implement your high-risk cancer screening program to drive better clinical and financial outcomes.