Genes, Poverty: Cancer Risks in Blacks
New Research Shows Race Itself Not to Blame
WebMD News Archive
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% of the women were black.
The study showed that 47% of black women had these most aggressive cancers, compared with just 22% 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% 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.
Olufunmilayo I. 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.