African-Americans are less likely than whites to survive breast, prostate and ovarian cancer even when they receive equal treatment, according to a large study that offers provocative evidence that biological factors play a role in at least some racial disparities.
The first study of its kind, involving nearly 20,000 cancer patients nationwide, found that the gap in survival between blacks and whites disappeared for lung, colon and several other cancers when they received identical care as part of federally funded clinical trials. But disparities persisted for prostate, breast and ovarian cancer, suggesting that other factors must be playing a role in the tendency of blacks to fare more poorly.
For decades, studies have shown that poor people and minorities are more likely to live shorter, sicker lives, and are less likely to survive a host of illnesses, including many cancers. Studies have indicated that the disparities were largely the result of poor people and minorities getting inferior care; they are less likely to have health insurance and receive routine preventive care, they frequently get diagnosed later, and they often undergo less aggressive treatment once they are diagnosed.
"There is good news and puzzling news in our results," said Kathy Albain of Loyola University, whose findings were published online Tuesday by the Journal of the National Cancer Institute.
"When there's a level playing field with the same quality of care, African-Americans survive just as well as other races from some of our most common cancers, which is reassuring news and points us nationally toward a need to make sure there is quality of care and equal access to all," Albain said. "But for prostate, ovarian and breast (cancer), it's not access to care. There's something else. And we need to sort that out."
Because these three cancers are related to gender, the survival gap may be the result of differences in the biology of the tumors and inherited variations in genes that control metabolism of drugs and hormones, she said.
Some experts worried the findings could reinforce old prejudices. "When I hear scientists talking about racial differences, I worry that it starts to harken back to arguments about genetic inferiority," said Otis Brawley, chief medical officer of the American Cancer Society.
"We certainly aren't talking about 'genetic inferiority' or stereotypes in our study," Albain wrote in an e-mail. "What we are saying is that there is something that 'tracks' with African ancestry only in these three diseases."
But Brawley and others argued that access to high-quality care remains the dominant problem. Socioeconomic factors that occur earlier in life may explain the findings, Brawley said. For example, poor people and minorities are more likely to grow up in polluted neighborhoods and have been hit hardest by the obesity epidemic, which could lead to more difficult-to-treat cancers, he said.