Incorporation of Breast Density Affects Cancer Risk Models

The incorporation of volumetric breast density into a common breast cancer risk classification model increases the number of women considered at high risk for the disease, according to research presented Sunday by a leading expert in breast imaging.

Both Tyrer-Cuzick and the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) are well-known and commonly used models for predicting a woman’s risk of developing breast cancer. The models use a variety of factors, such as family history, to estimate risk.

Recent National Comprehensive Cancer Network guidelines emphasize the inclusion of breast density in breast cancer risk assessment. Both Tyrer-Cuzick and BOADICEA include volumetric breast density, but BOADICEA incorporates a more detailed family history component with additional genes and single nucleotide polymorphisms (SNPs) not captured in Tyrer-Cuzick.

Researchers studied the impact of these inclusions on high-risk classification in the two models.

“Different models don’t always give us the same risk score for the patient,” said study lead author Stamatia Destounis, MD, managing partner of the Elizabeth Wende Breast Care Center in Rochester, NY, and RSNA Public Information Committee chair. “Once breast density was included, we wanted to know how the risk assessment evaluations compared between these two models.”

Models Help Patients Make Informed Decisions

Dr. Destounis and colleagues collected risk factor data during screening mammography over five months on 44,651 women aged 40 to 75 with no prior history of breast cancer. They defined high risk as a 20% lifetime risk of developing cancer.

The Tyrer-Cuzick model classified 14.8% of patients as high risk, compared with 9.8% for BOADICEA.

“Tyrer-Cuzick identified more women as high risk because it had greater influence from volumetric breast density and family history,” Dr. Destounis said. “The BOADICEA model classified fewer patients as high risk if the patient did not have a very strong family history, so it needed a very high volumetric breast density in order to offset the non-contributory family history.”

Dr. Destounis said radiologists should be cognizant of the possibility that Tyrer-Cuzick will give higher risk scores than the BOADICEA model.

“If you’re trying to manage the percentage of high-risk patients, you’re going to have to look at these two models and decide which one would work best for you,” she said. “Because it appears that with BOADICEA, if you the patient does not have strong contributory family history but does have high-density breasts, the relative risk will not be as high.”

The ramifications are significant, as patients considered high risk may have more frequent screening as well as supplemental screening, such as US. “If you want to be more inclusive and make sure you’re not missing any high-risk patients, you may want to utilize the Tyrer-Cuzick model, but you have to understand that you may be running into the possibility of overexaggerating the patient’s breast cancer risk,” Dr. Destounis said.

Awareness of the differences in the risk models is important for patients too, Dr. Destounis emphasized, as it could help them choose a screening regimen more tailored to their preferences. “We want to provide personalized care for each patient, and these models are one way of helping patients make informed decisions,” she said.

Access the session, “Comparing High Risk Estimations Using Volumetric Breast Density with Tyrer-Cuzick and BOADICEA Risk Models,” (S5-SSBR02-1) on demand at RSNA.org/MeetingCentral.