Poverty, Genetics Linked to Cancer Risks in Blacks

Published April 04, 2006

| WebMD

At a time when blacks share a disproportionate share of the nation’s cancer burden, new research suggests that poverty and genetics may be at least partly to blame.

“These studies dispel the myth that it’s all about race,” says Lucile L. Adams-Campbell, PhD, director of the Howard University Cancer Center in Washington. “Health disparities go beyond color and ethnicity.”

Nearly 138,000 new cancer cases occurred among blacks in 2005, and about 63,000 blacks died of cancer last year, according to the American Cancer Society (ACS). Black men are particularly hard hit, with a 20 percent higher rate of cancers and a 40 percent higher rate of death from all cancers combined compared with white men.

Yet blacks make up about 13 percent of the U.S. population based on U.S. census figures, says the ACS.

The new research was presented here at the annual meeting of the American Association for Cancer Research.

Poor, Uninsured Women at Higher Risk

In one study, researchers found that women with breast cancer are more likely to have aggressive, hard-to-treat tumors if they live in poverty -- regardless of race.

“African-American women are more commonly poor and uninsured, so some studies suggest socioeconomic status, not race, is associated with a poor prognostic profile,” says researcher Keith A. Dookeran, MBBS, of Stroger Hospital of Cook County in Illinois.

To test that hypothesis, the researchers studied 341 black and 94 white women treated at Cook County Hospital, a public hospital that serves largely poor, uninsured people. Fewer than 10% of women in both groups had health insurance.

After taking into account other risk factors for breast cancer, 40 percent of women of both races had highly aggressive tumors that are associated with poor survival, he says.

“These women were all treated at one hospital with standardized screening and treatment plans,” Dookeran tells WebMD. “It was not their race but the fact that they were poor, largely uninsured, and of low socioeconomic status that accounts for their poor prognosis.”

Genes Drive Bleak Outlook

Another study suggests that genetics may play a major role in explaining differences in breast cancer outcomes among black and white women.

Mary Jo Lund, PhD, and colleagues studied what she calls triple-whammy breast cancers -- those characterized by three biological components that make the disease more difficult to treat.

Doctors base crucial treatment decisions on the basis of three tumor biomarkers used to characterize breast cancers -- estrogen receptor, progesterone receptor, and HER2, she explains.

That’s because the most effective treatments for breast cancer, such as the drugs tamoxifen and Herceptin, target these receptors, inhibiting the growth of the tumor.

“Tumors with all three of these characteristics are angry, aggressive tumors with worse outcomes that preclude that use of common lifesaving treatments, such as tamoxifen and Herceptin,” says Lund, a researcher at Emory University in Atlanta.

Younger women are much more likely to be diagnosed with triple-whammy cancers; in fact, women under 55 account for nearly one-third of all such tumors, she says.

The study included nearly 500 women under age 55 diagnosed with breast cancer between 1990 and 1992. About 25 percent of the women were black.

The study showed that 47 percent of black women had these most aggressive cancers, compared with just 22 percent of whites.

“The fact that both younger women and blacks are much more likely to have tumors with aggressive features suggests a genetic predisposition,” Lund tells WebMD.

The Colorectal Cancer Treatment Gap

Yet other research shows that blacks are less likely than whites to be offered chemotherapy for colorectal cancer, regardless of whether they had early or late disease.

“Colorectal cancer is one of the very few preventable and one of the very few treatable cancers if detected and treated properly,” says Hanaa S. Elhefni, MS, MPH, of Wright State University in Dayton, Ohio. “But we found that blacks are 20 percent less likely to be given chemotherapy than whites.”

For the study, Elhefni reviewed the records of all black and white people diagnosed with colorectal cancer in Alabama between 1996 and 2002.

Seeking to find out why there exists such a disparity in practice, she could find no explanation. “We thought maybe blacks are not as accepting of the drugs, but there was no difference in compliance between the two races,” she tells WebMD.

“Obviously the differences in outcomes could be greatly reduced by changes in medical practice. We need further research to figure out why blacks are less likely to get chemotherapy,” Elhefni says.

Taking Charge

OlufunmilayoI. Olopade, MD, director of the Center for Clinical Cancer Genetics at the University of Chicago Medical Center, says that taken together, the research tells every woman with breast cancer that they need to know whether their tumors are fueled by hormones like estrogen and HER2.

And unless another medical condition precludes it, every person with colorectal cancer should be getting chemotherapy, regardless of race, income, or severity of disease, says Olopade, who was not involved with any of the research.

“If your doctor isn’t doing these things, take matters into your own hands and ask for them,” she tells WebMD.

By Charlene Laino, reviewed by Louise Chang, MD

SOURCES: American Association of Cancer Research annual meeting, Washington, April 1-6, 2006. Lucile L. Adams-Campbell, PhD, director, Howard University Cancer Center, Washington. Mary Jo Lund, PhD, Emory University, Atlanta. Hanaa S. Elhefni, MS, MPH, Wright State University, Dayton, Ohio. Olufunmilayo I. Olopade, MD, Director, Center for Clinical Cancer Genetics at the University of Chicago Medical Center. American Cancer Society, Cancer Facts and Figures for African-Americans 2005-06.

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