African American women are more likely to have breast cancer at a younger age, to die of their disease, and to have estrogen receptor (ER)-negative breast cancer that does not respond to tamoxifen. African American women are more likely to have breast cancer at a younger age, to die of their disease, and to have estrogen receptor (ER)-negative breast cancer that does not respond to tamoxifen, compared with white women, researchers reported recently.

The study findings, presented at a Breast Cancer Symposium in San Francisco, support previous research that has shown clear racial differences in breast cancer that are likely to be genetic in origin.

The study findings were unchanged by income, education, or insurance coverage, Dr. Catherine Lee of the University of Michigan Comprehensive Cancer Center said in a telephone briefing.

Dr. Lee's team analyzed data for 170,079 women with breast cancer seen at 1600 hospitals in all 50 states. White women accounted for 90% of the cases, with African American women making up nearly 10 per cent.

Thirty-nine percent of African American women had ER-negative tumors compared with 22 per cent of white women. African Americans were also diagnosed at an average age of 57 years compared with 62 for white women, yet their cancer was more advanced, with just 29 per cent having stage I tumors compared with 42 per cent of white women.

The findings bolster a growing body of evidence that shows breast cancer is different biologically in African-American women, Dr. Lee told participants of the Breast Cancer Symposium, co-sponsored by the American Society of Breast Disease, the American Society of Breast Surgeons and other groups.

"Differences in tumor biology have a significant impact on survival," Dr. Lee said in a statement.

"The fact that breast cancers in black women are more aggressive biologically suggests that we need to focus more of our research energy on developing better treatments targeting ER-negative tumors," she added.

"These findings also point to a need for improved cancer education and screening in black women, particularly those in younger age groups.