Non-Hispanic black women diagnosed with breast cancer, specifically those with estrogen receptor-positive tumors, are at a significantly increased risk for breast cancer death compared with non-Hispanic white women.
"This difference was greatest in the first three years after diagnosis," said Erica Warner, M.P.H., Sc.D., a postdoctoral fellow at Harvard School of Public Health in Boston, Mass., who presented the data at the Fifth AACR Conference on The Science of Cancer Health Disparities, held here Oct. 27-30, 2012.
Prior research has shown that non-Hispanic black women have lower breast cancer survival rates relative to other racial/ethnic groups.
Warner and colleagues conducted a study of 19,480 women who presented to National Comprehensive Cancer Network centers with stage 1 to stage 3 breast cancer between January 2000 and December 2007. They compared breast cancer-specific mortality among 634 Asian women, 1,291 Hispanic women, 1,500 non-Hispanic black women and 16,055 non-Hispanic white women.
After a median follow-up of 6.9 years, the researchers found that non-Hispanic black women had a 48 percent higher risk for breast cancer death in the first three years after diagnosis compared with non-Hispanic white women. After three years, non-Hispanic black women had a 34 percent increased risk for breast cancer-specific mortality.
"The higher risk for early death among black women was more striking among women with estrogen receptor-positive tumors," Warner said.
Non-Hispanic black women with estrogen receptor-positive tumors were more than twice as likely to die from breast cancer within the first three years of diagnosis compared with non-Hispanic white women. This risk was also increased in non-Hispanic black women with luminal A and luminal B breast cancer subtypes.
"This finding is important because these are the types of tumors that we traditionally think of as more treatable," Warner said.
No difference in breast cancer mortality between non-Hispanic black and white women was found for estrogen receptor-negative, basal or HER2-overexpressing tumor subtypes.
Warner and colleagues also evaluated breast cancer survival among Asian and Hispanic women. Compared with non-Hispanic white women, data indicated that Asian women had a 40 percent lower risk for breast cancer death. The researchers observed this decreased risk in all breast cancers and in estrogen receptor-negative, luminal A and HER2-overexpressing tumors. They found no significant differences between non-Hispanic white women and Hispanic women for breast cancer mortality.
"The results of this study emphasize that clinical management and follow-up for patients with breast cancer, particularly black women, is important in the first few years after diagnosis," Warner said. "Although the difference between blacks and whites was highest for this time period, the risk for death was highest in the first few years after diagnosis for all groups."