For the first time, the incidence of breast cancer among African American women in the United States is equal to that of Caucasian women, according to a new report from the American Cancer Society

Historically, African American women have been less likely than Caucasian women to develop breast cancer, but it is more deadly. That appears to have changed. According to the report, the incidence rate of breast cancer has increased in African American women and remained stable in Caucasian women. African American women’s risk increased by 0.4% a year from 2008–2012, a much greater increase than in previous years. 

Overall, 124.3 African American women per 100,000 were diagnosed with breast cancer in those years, compared to 128.1 for Caucasian women. From 1989–2012, breast cancer death rates decreased by 36%, which translates to 249,000 breast cancer deaths averted in the United States. 

The decrease in death rates was found among all racial and ethnic groups except American Indians and Alaska Natives. However, the mortality disparity between African American and Caucasian women continued to widen and by 2012, death rates were 42% higher in African American women than in Caucasian women. African American women have a higher death rate from breast cancer at 31 per 100,000, compared to 21.9 per 100,000 for Caucasian women. 

African American women also tend to be diagnosed later, when the cancers are more likely to have spread, and they are more likely to be diagnosed with estrogen receptor-positive breast cancer. The authors suggested that this may be because of rising obesity rates. In 2012, 58% of African American women were obese, compared to 33% of Caucasian women. More fat increases estrogen levels in the body, which is a risk factor for some forms of breast cancer. Other risk factors may be involved, according to the researchers. 

Breast cancer incidence also increased slightly for Asian and Pacific Islander women, but their rates are still lower than Caucasian and African American women at 88.3 per 100,000. Hispanics also had lower rates at 91.9 per 100,000. According to the researchers, widening racial disparities in breast cancer mortality are likely to continue, at least in the short term, in view of the increasing trends in breast cancer incidence rates in African American women.