Regardless of their socioeconomic status, black women seemed nearly twice as likely as white women to be diagnosed with triple-negative breast cancer, a subtype that has a poorer prognosis, suggests an analysis of a large nationwide dataset. The analysis also found that Asian/Pacific Islander women were more likely to be diagnosed with another subtype of breast cancer: so-called human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer. The study appears early online in Breast Cancer Research and Treatment.
Triple-negative breast cancers are those whose cells lack estrogen receptors and progesterone receptors, and do not have an excess of the HER2 protein on their surfaces. Triple-negative breast cancers tend to grow and spread more quickly than most other types of breast cancer, and a lack of these receptors limits treatment options.
Previous studies have indicated that non-Hispanic blacks and Hispanics were more likely to be diagnosed with triple negative breast cancer than non-Hispanic whites. Some studies 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 their small and incomplete sampling.
"The excess odds of triple negative breast cancer in blacks compared to whites were remarkably similar, about 80% higher, in each socioeconomic group," said Dr. Sineshaw. "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."