The Biology and Socioeconomics of Breast Cancer

Breast tumors in Hispanic women more resistant to chemotherapy

(RxWiki News) While white women in the United States are diagnosed more frequently with breast cancer, women of color are more likely to die of the disease. New research confirms this.

Breast cancer is more likely to be fatal in Hispanic women than it is in non-Hispanic white women. These are the findings of recent University of Louisville research.

"Have regular breast cancer screenings."

Kathy B. Baumgartner, Ph.D., professor of epidemiology and associate dean for faculty affairs in the School of Public Health and Information Sciences at the University of Louisville in Kentucky, says the difference may have to do with the fact that tumors in Hispanic women tend to be more resistant to standard therapies.

Baumgartner and colleagues conducted the New Mexico Women's Health Study (NMWHS) between 1992 and 1996. This research looked at the difference in risk factors between Hispanic and white women. A total 692 women diagnosed with a first primary breast cancer participated.

In this new study, researchers followed 577 women with invasive breast cancer through 2008. These women had participated in the original NMWHS study. The objective was to examine the differences in long-term survival between Hispanic and white women.

Baumgartner's group found that Hispanic women had a 20 percent greater likelihood of dying from breast cancer than white women. This is consistent with other study findings.  However, when researchers adjusted for age, stage of cancer, lymph node involvement and estrogen receptor status, the Hispanic women had risks similar to t those of their white counterparts.

Baumgartner thinks, "the ethnic difference in breast cancer mortality may be mostly biologically based,"

Hispanic women who received chemotherapy were also about 1.5 times more likely to die from breast cancer than white women who received the therapy.

Cary Kaufman, M.D., a breast surgeon and specialist at Bellingham Regional Breast Center in Washington state, told dailyRx, "It’s difficult to separate the socioeconomic issues from the medical issues, despite case controlled studies. In the New Mexico study, white and Hispanic women, stage for stage had similar survival, but Hispanic women had more late stage cancers. Lack of screening mammograms and lack of insurance may contribute significantly to these differences," Dr. Kaufman said.

Baumgartner agrees. "Some studies suggest that Hispanic women are more likely to develop ER-negative tumors that are resistant to chemotherapy," she added. And the fact that Hispanic women respond worse to chemotherapy may partly explain the disparity.

She added, "Altered response to chemotherapy may partly explain the Hispanic vs. non-Hispanic white disparity in breast cancer survival."

Baumgartner and her team will continue monitoring this group.

This research was supported by a grant from the National Cancer Institute and the James Graham Brown Cancer Center.

Findings from the study were presented at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium.

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Review Date: 
December 6, 2011