Roxanne Nelson

November 24, 2008

November 24, 2008 — Black women are more likely than white women to be diagnosed with estrogen- or progesterone-receptor (ER/PR) negative breast cancer. In addition to race, socioeconomic status and other tumor characteristics are important predictors of this disease subtype.

Compared with white women, black women are 2.26 times more likely to be diagnosed with ER/PR-negative than with ER/PR-positive breast cancer. When the data were controlled for socioeconomic factors, including educational levels and insurance status, black women remained 1.97 times more likely to have ER/PR-negative tumors than white women.

The study results were presented at the recent Seventh Annual American Association for Cancer Research International Conference on Frontiers in Cancer Prevention Research, held in Washington, DC.

Breast cancer patients with ER/PR-positive tumors generally have a better prognosis, as indicated by a longer interval to disease recurrence and a longer overall survival, than women with ER/PR-negative tumors.

"Previous research has documented that black women are more likely to be diagnosed with receptor-negative breast tumors, compared with white women," said study coauthor Elizabeth Ward, PhD, director of cancer surveillance research at the American Cancer Society, during a press briefing. "However, there is still a need for more information about the association between these types of tumors and socioeconomic factors, as well as other tumor characteristics."

Dr. Ward and colleagues used the National Cancer Database, which collects information on demographic and clinical characteristics from approximately 1500 Commission on Cancer–approved hospitals, accounting for nearly 70% of all cancer patients treated in the United States, to evaluate the relation between race, socioeconomics, and breast cancer.

They identified a total of 175,820 women between the ages of 18 and 99 years, who were diagnosed with breast cancer during 2004 and 2005. Frequency distributions were used to assess the relation between hormone-receptor status and demographic and clinical variables, and multivariate logistic regression models were used to examine these associations while controlling for age, race, insurance status, educational attainment, stage, histology, and tumor size.

"We found that 35% of breast cancers among African American women were ER/PR negative, compared with 20% among white women," said Dr. Ward. "This is consistent with what has previously been shown in the literature."

Black women were also more likely to be diagnosed with breast cancer at a younger age (<50 years), with late-stage tumors, larger tumors, and higher-grade tumors. "All of these tumor characteristics are associated with poorer prognosis," she explained.

"Women who were uninsured or Medicaid insured and those living in areas with lower educational attainment also had higher odds of being diagnosed with ER/PR-negative breast tumors," said Dr. Ward. "After controlling for socioeconomic factors, African American women were still almost 2 times as likely to have hormone-receptor-negative tumors as white women."

Investigation into tumor characteristics, such as stage, size, and histology, further attenuated the odds ratio (relative risk,1.85).

Dr. Ward reiterated that these results confirm previous reports that black women are more likely to be diagnosed with ER/PR-negative breast cancer, but a third of this excess risk was explained by differences in socioeconomic factors, stage at diagnosis, tumor size, and histology type. "Associations of race, socioeconomic status, and insurance status with hormone-receptor status merit further study," she concluded. "These differences could be related to different exposures to breast cancer risk factors, including reproductive factors, obesity, and access to medical care."

American Association forCancer Research's Seventh Annual International Conference on Frontiers in Cancer Prevention Research: Abstract B122. Presented November 18, 2008.


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