Abstract B41: Racial/ethnic differences in breast cancer survival by inflammatory and hormonal receptor states: An analysis of the Surveillance, Epidemiology, and End Results data
Authors: Poudrier Jill K. , Zahm Sheila H. , Jatoi Ismail , McGlynn Katherine A. , Gallagher Christopher , Enewold Lindsey , Schairer Catherine , Shriver Craig D. , Zhu Kangmin 
Published: May 2019

Background:Breast cancer survival differs by histologic subtype and hormone receptor status. Inflammatory breast cancer (IBC) has less favorable survival than non-IBC. IBC is more likely to be estrogen receptor (ER) and progesterone receptor (PR) negative, which is also associated with less favorable survival. While black women are more likely to have IBC and ER-/PR- tumors than white women and racial/ethnic disparities in breast cancer survival have been observed separately by IBC histology and hormone receptor status, it is unclear whether the racial disparity in IBC survival is explained by a greater proportion of ER-/PR- tumors among black IBC patients or whether the racial disparity in IBC survival is modified by ER/PR status. The objective of this study was to assess racial/ethnic differences in breast cancer survival by both histology and hormone receptor status.

Methods:This study was based on the National Cancer Institute's SEER-18 database for public use. Study subjects included non-Hispanic white (NHW), Hispanic white (HW), black and Asian/Pacific Islander (API) women diagnosed with histologically confirmed breast cancer between 1990 and 2004. The outcome of the study was breast cancer death, which was assessed through December 31, 2009. Kaplan-Meier survival curves and Cox proportional hazard ratios adjusted for age at diagnosis, marital status, stage, grade, surgery, and radiation, and stratified by histology or/and hormone receptor status were used to assess the relationship between race/ethnicity and survival. Cox model results were further stratified by age at diagnosis (&lt;50 vs. &gt;=50 years) to evaluate if racial/ethnic differences might vary by menopausal status.

Results:Black women had significantly worse survival than NHW women regardless of histology or/and hormone receptor status. The adjusted HRs were 1.32 (95% CI 1.21-1.44), 1.43 (95% CI 1.20-1.69), 1.30 (95% CI 1.16-1.47), and 1.22 (95% CI 1.00-1.50) for IBC, IBC with ER+/PR+, IBC with ER-/PR-, and IBC with ER+/PR- or ER-/PR+, respectively. The similar HRs were found for non-IBC with various hormone receptor status. API women had significantly lower hazard ratios compared to NHWs despite histology and hormone receptor status.

Conclusion: Black women had significantly poorer survival compared to NHW women regardless of histology and hormone receptor status, while API women had better survival. These results imply that factors other than histology and hormone receptor status, such as access to or use of medical care, and/or other biomarkers, may play a role in racial/ethnic disparities in breast cancer survival.

Citation Format: Jill K. Poudrier, Sheila H. Zahm, Ismail Jatoi, Katherine A. McGlynn, Christopher Gallagher, Lindsey Enewold, Catherine Schairer, Craig D. Shriver, Kangmin Zhu. Racial/ethnic differences in breast cancer survival by inflammatory and hormonal receptor states: An analysis of the Surveillance, Epidemiology, and End Results data. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr B41.