Study Explores Racial/Ethnic Disparities in Incidence of Breast Cancer Subtypes

An analysis of a large, nationwide dataset has revealed that regardless of their socioeconomic status, black women are nearly twice as likely to be diagnosed with triple-negative breast cancer (TNBC) and Asian/Pacific Islander women are more likely to be diagnosed with HER2-overexpressing breast cancer compared with white women.

The study is published online in Breast Cancer Research and Treatment.

“The excess odds of triple-negative breast cancer in blacks compared to whites were remarkably similar, about 80% higher, in each socioeconomic group,” Helmneh Sineshaw, MD, MPH, lead author of the study, said in a statement. “That consistent increase suggests factors other than differences in socioeconomic status play a strong role in the excess odds seen in black women. Further studies are needed to identify those factors.”

The study analyzed data from 260,174 breast cancer cases recorded from 2010 to 2011 in the National Cancer Data Base (NCDB), a national hospital-based cancer registry database jointly sponsored by the American College of Surgeons and the American Cancer Society.

The results of the analysis showed that patients with low socioeconomic status had higher proportions of TNBC than did patients with high or moderate socioeconomic status. However, researchers found that after controlling for socioeconomic status, black women were still 1.84 times as likely to be diagnosed with TNBC.

Researchers also discovered that Asian/Pacific Islander women had higher odds of presenting with HER2-overexpressing breast cancer compared with white women. This was also observed across every level of socioeconomic status, the authors report.

Previous reports have shown that non-Hispanic blacks and Hispanics were more likely to be diagnosed with triple-negative breast cancer than non-Hispanic whites, whereas other reports have suggested that the higher odds of breast cancer subtypes with unfavorable prognoses in minority racial/ethnic groups could be explained by differences in socioeconomic status. However, these studies were limited by small and incomplete sampling.

Sineshaw H, Gaudet M, Ward E, et al. Association of race/ethnicity, socioeconomic status, and breast cancer subtypes in the National Cancer Data Base (2010-2011) [published online ahead of print May 3, 2014]. Breast Cancer Res Treat. doi: 10.1007/s10549-014-2976-9.