Another Racial Divide

Environment, Genetics: Which Causes More Breast Cancer Deaths In Blacks Than Whites?

July 27, 2009|By Kelly Brewington | Kelly Brewington,

A new study that suggests that racial differences in biology could be a key reason black women are more likely to die of breast cancer than white women has reignited an intense debate among medical experts about the role of genetics versus factors such as poverty, diet and unequal access to quality health care.

For nearly three decades, researchers have known about the disparity in death rates, but they have been puzzled over the reasons why. In Maryland, for example, the breast cancer death rate for black women is 15 percent higher than for white women, even though African-Americans have a lower incidence of the disease. State health officials, doctors and advocacy groups have long thought a combination of factors explained the disparity and have vowed to shrink the gap through better research, aggressive treatment and outreach efforts aimed at getting black women life-saving care.

But researchers worry that a biological explanation may eclipse the real barriers black women face to getting the early preventive care that might save their lives.

Robena Pope, a breast cancer survivor from Catonsville, thinks black women, regardless of income, are reluctant to be screened for breast cancer because they think a diagnosis is a death sentence.

Years ago, the former teacher at an early child development center in Baltimore took it upon herself to educate the mothers and grandmothers of her students about breast cancer - few had ever had a mammogram. Pope invited a doctor at her primary care practice to come to the school to offer education sessions on breast cancer with the women. The effort is now an annual outreach event.

"Even women who had insurance, they didn't want a mammogram," she said. "They just didn't want to know."

The newest national study on the problem examined some 20,000 adults with various cancers and found that blacks were more likely than whites to die of three gender-related cancers - ovarian, prostate and breast. The disparity persisted, even when patients received the same treatment and when researchers adjusted for factors such as age, income and the severity of the illness.

The risk of dying for blacks was 41 percent higher than whites for breast cancer before menopause, and 49 percent higher for post-menopausal breast cancer, according to the paper, published this month in the Journal of the National Cancer Institute.

The findings suggest that socioeconomic status and access to care alone can't explain the survival gap - as many researchers had speculated. Rather, the disparity is likely caused by interactions among hormones, differences in the biology of the tumors and racial differences in genes that control the metabolism of drugs, said Dr. Kathy S. Albain, breast and lung cancer specialist at Loyola University Medical Center in Maywood, Ill., and the study's lead author.

Despite the study's findings, some experts are skeptical that biology explains the disparity in death rates. The study had certain limitations: It did not explain whether other health problems might have contributed to the disparity or specify how participants adhered to their drug therapies. In addition, for years, other studies have shown that socioeconomic factors, social inequities and other barriers keep African-Americans from receiving quality health care. And some think that one's environment - from diet, chemical exposures and cultural influences - might impact biology.

"I am very concerned that folks will take this and walk away from it with the wrong impression," said Dr. Otis W. Brawley, chief medical officer for the American Cancer Society and an expert on racial disparities. "People might say, we don't have to worry about getting adequate care to blacks, because it doesn't matter. It's all biology."

Still, to other experts, the findings are important because they shed a little more light on the mystery behind the racial differences - a field that desperately needs more research.

"In my 30 years as a researcher ... only now people are awakening and addressing that there is a disparity," said Saraswati Sukumar, a professor of oncology and co-director of the Breast Cancer Program at the Johns Hopkins Kimmel Cancer Center. "Some people are still skeptical that there even is a disparity. That's why I like this paper. It's clear. Look at the numbers.

"We need to be asking how can we change this?" said Sukumar, who is researching how certain gene changes may make African-Americans more susceptible to getting breast cancer. She hopes the findings can help doctors detect the disease earlier in blacks. "How can we improve this? It's very, very important."

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