Researchers comparing the effectiveness of cancer treatments among people of different races have found that African Americans do not respond as well as white Americans to therapies for breast, ovarian and prostate cancers, and that black women are more likely than white women to die after being diagnosed with breast cancer.
The findings suggest that while cancer survival rates overall are the same for blacks and whites, certain hormone-driven cancers pose special risks for African Americans.
For years, experts have noticed that African Americans have a greater chance of dying of certain kinds of cancers than white Americans.
In a study of 19,000 U.S. men and women treated identically by the same doctors for breast, ovarian and prostate cancer between 1974 and 2001, researchers led by oncologist Kathy Albain of Loyola University Medical Center in Maywood, Illinois found that African Americans were at a significantly higher risk of dying from those cancers than whites Americans.
According to Dr. Albain, the increased risks ranged from 21 percent higher for prostate cancer to 61 percent higher for ovarian cancer.
"It's a little bit of an unsettling final result here for that piece because we don't have the answer yet. We are vigorously, not just our group but other groups, working on trying to understand why that may be so," she said.
Dr. Albain says the research points to biological reasons why blacks do not respond to treatment as well as whites for breast, ovarian and prostate cancers.
"I think we are going to come up with a profile that's not going to be black versus white, so to speak. It's going to define an interaction among the hormonal levels, your metabolizing enzymes that you inherit from your parents and your tumor's biology, Albain said. "That profile is going to need a different attack than say the other profile that may have a much more favorable outcome."
The study, conducted by the Southwest Oncology group, a large U.S. clinical research organization with facilities around the country, explored outcomes between African Americans and Caucasians treated for 10 common forms of cancer -- including lung and colon cancer, leukemia and lymphoma.
Patients enrolled in 35 clinical trials received identical, state-of-the-art care. Except for the ovarian, breast and prostate cancers, researcher Kathy Albain says there was no difference in outcomes between African Americans and Caucasians.
"Adjusting for all of those factors, in each of these groups of patients on identical treatment we found some very reassuring news for a lot of the common cancers. There was no racial disparity in survival. They did equally as well in terms of race," she said.
Sociologists have pointed to the fact that African Americans, on average, are less affluent than white Americans, making them less likely to seek out expensive screening tests to detect cancer early. Experts also point to studies which show that poor African Americans do not have access to the same level of medical care as whites.
Another study by Idan Menashe and his colleagues at the National Institutes of Health looked at breast cancer mortality among 245,000 women. They found that African American women were twice as likely as white women to die within the first few years of diagnosis.
Menashe says the finding could be due to lifestyle factors, such as higher rates of obesity among African Americans, and biological differences between blacks and whites.
"We would like to gather up some real evidence to make sure that it's one or the other, to know what percentage of contribution these factors [make] to this disparity," he said.
Both studies exploring the survival of black and white cancer patients in the United States were published in the Journal of the National Cancer Institute.