JAMA

22 Jan Breast Cancer: Genome Assays May Need Recalibration for Racial and Ethnic Groups

MedicalResearch.com Interview with: [caption id="attachment_56433" align="alignleft" width="150"] Dr. Hoskins[/caption] Kent Hoskins, MD Eileen Lindsay Heidrick Professor in Oncology Division of Hematology/Oncology University of Illinois at Chicago Director of Cancer Genetics Co-Leader, Breast Cancer Research Group University of Illinois Cancer Center MedicalResearch.com: What is the background for this study? Response: The racial disparity in breast cancer mortality emerged in the US in the late 1980s in the wake of widespread implementation of mammography screening and the development of successful systemic adjuvant therapies for early breast cancer. Unfortunately, more than three decades later, Black women in the US still have a 40% higher mortality rate from breast cancer compared with non-Hispanic White women despite similar disease incidence. Health disparities research has primarily focused on the fact that Black women have a higher incidence of the aggressive triple-negative subtype, and that they are more likely to present with more advanced stages of disease. As important as those factors are, in recent years our group and others reported that Black women with hormone receptor-positive breast cancer have worse survival than non-Hispanic white women even after adjustment for stage at diagnosis and treatment. Since nearly 2/3 of breast cancers in Black women are hormone receptor-positive, this is a significant contributor to the overall mortality disparity. Importantly, these studies also suggested that Black women disproportionately develop biologically aggressive forms of hormone-dependent breast cancer, which is typically considered a more favorable disease subtype. Using data on more than 70,000 patients from the SEER registry that is linked to data from Genomic Health Laboratory, which provides the Oncotype DX recurrence score (the most commonly ordered prognostic/predictive multi-gene expression assay for early breast cancer), we set out to address three questions: 1) is there evidence of disproportionately aggressive tumor biology among Black women with hormone receptor (HR)-positive breast cancer, as reflected in the Oncotype DX recurrence score? 2) Is there a racial survival disparity even among patients with early stage, axillary node-negative tumors with comparable recurrence scores on the Oncotype assay? and 3) Is there is a difference in the prognostic accuracy of the Oncotype assay between Black and non-Hispanic white patients, since there was limited representation of Black women in the development and validation of the Oncotype assay and other prognostic/predictive assays?