April 9, 2007 -- Hispanic women get more aggressive breast cancers than non-Hispanic white women, an analysis of Kaiser Permanente data shows.
At first diagnosis, compared with non-Hispanic white women, Hispanic women:
- Are younger at the age of first breast cancer diagnosis.
- Are 2.7 times more likely to have stage IV breast cancer -- that is, cancer that has already spread beyond the breast.
- Have 2.25 times more poorly differentiated tumors -- that is, tumors with a cell type that means poorer prognosis.
- Have a twofold risk of larger tumors.
- Have a nearly twofold higher risk of estrogen-negative cancer, meaning that the cancer cannot be treated with some of the most effective cancer drugs.
University of Denver researcher A. Tyler Watlington, MD, MSPH, and colleagues looked at data on 139 Hispanic women and 2,118 non-Hispanic white women enrolled in a Kaiser Permanente health plan for at least three years.
Earlier research has suggested that Hispanic women get more aggressive breast cancer. But most experts thought that in the U.S., Hispanic women's lesser access to health care explained this disparity. Women who do not get appropriate breast cancer screening tend to have later-stage disease by the time they find out they have cancer.
But Watlington and colleagues found that the differences between Hispanic women and other women persist even when they get exactly the same health care.
"True biologic differences exist in breast cancer by ethnicity," they suggest.
Future research, Watlington and colleagues say, should explore these clinical and biological differences "as different strategies for breast cancer prevention may then be warranted for Hispanic women."
Watlington and colleagues report their findings in the May 15 issue of the American Cancer Society journal Cancer.