The following article features coverage from the American Society of Clinical Oncology 2020 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

A model used to assess breast cancer risk validated in non-Hispanic white women provided similar risk discrimination in other racial/ethnic groups; however, it overestimated risk for Hispanic women, according to a recent study.

“Cancer risk estimates are important to guiding screening and prevention recommendations,” said Allison W. Kurian, MD, of Stanford University School of Medicine in California, who presented these findings during the ASCO20 Virtual Scientific Program. “The ASCO clinical practice guidelines, in terms of the use of endocrine therapy for breast cancer risk reduction, recommend using models such as the International Breast Intervention Study (IBIS) Tyrer-Cuzick Risk Calculator to make determinations about risk reducing medication.”

In this study, the Tyrer-Cuzick (TC) Model was used in 6836 women with newly diagnosed breast cancer among a group of 91,893 women in the Women’s Health Initiative. The group included 80,260 non-Hispanic white women, 5903 African American women, 2131 Asian women, 2368 Hispanic women, and 305 Native American women.

The TC model uses various parameters to predict risk such as genetic risk and nonfamilial factors including personal, hormonal, and lifestyle characteristics. Later versions of the model include polygenic risk and breast density.


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According to Dr Kurian, the TC model was well-calibrated overall in the more diverse population. The ratio of observed to expected breast cancer cases was 0.96 for non-Hispanic white women and 0.91 for African American women, with a desired ratio of 1.0. However, the model overestimated risk in Hispanic women with a ratio of 0.75.

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“Optimizing the factors included in the model did not explain this difference, but an exploratory analysis simulating a protective [single-nucleotide polymorphisms] more common among Hispanics did appear to explain some of it and warrants further study,” Dr Kurian said.

Dr Kurian also noted that the study suggested good calibration for the model among Asian/Pacific Islanders and Native Americans, but samples sizes for these populations were small.

Read more of Cancer Therapy Advisor‘s coverage of the ASCO 2020 meeting by visiting the conference page.

Reference

Kurian AW, Hughes E, Bernhisel R, et al. Performance of the IBIS/Tyrer-Cuzick (TC) Model by race/ethnicity in the Women’s Health Initiative. Presented at: ASCO20 Virtual Scientific Program. J Clin Oncol. 2020;38(suppl):abstr 1503.