Deadly Breast Tumors Higher in Blacks

Sept. 6, 2007 - African-American women are more likely than white women to develop aggressive breast tumors that are notoriously difficult to treat, U.S. researchers report.

An analysis of national data on nearly 100,000 cases of invasive breast cancer shows that 39% of African-American women have tumors that are not fueled by estrogen, compared with 22% of white women.

Tumors that are not fueled by estrogen, referred to as estrogen receptor (ER)-negative tumors, are associated with a less favorable prognosis than those that are fueled by estrogen, or ER-positive.

That’s partly because the antihormone drugs such as aromatase inhibitors and tamoxifen that are credited with significantly reducing the risk of recurrence only work against estrogen-fed tumors. But even before the antihormone drugs were introduced, studies showed that ER-negative tumors came back sooner.

Findings Hold True Regardless of Age or Income

For the study, the researchers analyzed data on 170,079 cases of breast cancer included in the National Cancer Data Base, a multi-institutional tumor registry that collects cancer data from 1,600 hospitals in all 50 states.

Of the total, about 95,000 women had invasive cancer; the rest had ductal carcinoma in situ (DCIS), a noninvasive, condition of abnormal cells in the breast ducts that can progress to become invasive cancer. Ninety percent of the women were white, and the rest were African- American.

Results showed that regardless of their stage of disease, age, or income, black women with invasive cancers were more likely than their white counterparts to have ER-negative tumors.

Among women with either invasive cancer or DCIS, blacks were diagnosed at a younger age: 57 years, on average, vs. 62 years for whites.

African-American women also had larger tumors at diagnosis: 2.0 centimeters in diameter vs. 1.5 centimeters for white women.

White women, on the hand, were diagnosed at an earlier stage of disease, with 42% having stage I tumors that are still confined to the breast and therefore easier to treat vs. 29% of African-American women.

The study is being presented here this week at the 2007 Breast Cancer Symposium, co-sponsored by the American Society of Clinical Oncology and four other cancer care groups.