Background: Breast cancer mortality in black women is disproportionately high; reasons for this phenomenon are still unclear. In addition to socioeconomic factors, the biology of the tumor may play a role.

Methods: We analyzed 1,097 incident invasive breast cancer cases diagnosed between 2000 and 2010 in black US women from Long Island and Brooklyn. Kaplan-Meier curves were calculated and fitted for cancer mortality; when data were stratified, the log-rank test was used to assess statistical differences in survival across strata. A multivariable Cox hazard model was applied to assess the independent contributions to survival of several factors such as age, histology, stage at diagnosis, and hormone receptor status.

Results: Thirty-five percent of women had an estrogen receptor (ER) negative tumor, 46% a progesterone receptor (PR) negative tumor. ER, PR negative tumors were diagnosed at an earlier age (55.8 vs 55.3 yrs), at a later stage (p= 0.06), were larger in size (p=0.04), and more frequently treated with neoadjuvant chemotherapy (p=0.06) than ER, PR positive tumors. Determinants of shorter survival were: ER, PR negativity (HR: 2.2, 95% CI: 1.4-3.4), age, and stage at diagnosis (HR: 2.0; 95% CI: 1.5-2.7). ER, PR negative women born outside of the US experienced significantly worse survival than ER, PR negative women who were born in the US. There were no differences in survival based on therapeutic strategy (radiation, chemotherapy, or surgery).

Conclusions: ER, PR negative tumors in black women born outside the US, mainly in the Caribbean, are biologically more aggressive than the same tumor size and age matched tumors in black women born in the US. Our study suggests that environmental exposures in the country of origin may impact on host cancer interactions and cancer outcome.

Citation Format: Marlene Camacho-Rivera, Tricia Kalwar, Jasotha Sanmugarajah, Iuliana Shapira, Emanuela Taioli. Heterogeneity of breast cancer clinical characteristics and outcomes in U.S. black women - effect of place of birth. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr B32. doi:10.1158/1538-7755.DISP13-B32

©2014 American Association for Cancer Research.
2014