Monday, June 16, 2008

Blacks are more likely than whites to die of breast and prostate cancer. Researchers want to know why.

[Source: Peter Wehrwein and Anthony L. Komaroff, M.D., NEWSWEEK] - Not so long ago, people were often uncomfortable discussing breast or prostate cancer. The science was also limited by a lack of funding. But with ribbons, walks, bicycle rides and fund-raising, advocacy groups generated resources for research and public-awareness programs. As a result, breast and prostate cancer are now very much on the map. Despite these laudable efforts, there's still a disturbing fact about the two cancers that many Americans don't know: AfricanAmericans—and especially young African-Americans—are much more likely to die of breast or prostate cancer than white Americans are, for reasons scientists still don't understand. Now a number of doctors, researchers and patient advocates want to see African-American breast and prostate cancer pushed to the top of the health-policy agenda.

The need is undeniably urgent. African-American men have the highest incidence of prostate cancer in the world; they get the disease about 60 percent more often than white American men. And they're twice as likely as white men to die of it. Black women face grim statistics as well. Although they get breast cancer less often than white women, they have a higher breast-cancer mortality rate, especially at a younger age. That may be because young African-American women with breast cancer are twice as likely as whites to have triple-negative tumors—particularly aggressive cancers that lack receptors for estrogen, progesterone and human epidermal growth factor-2 (HER2). Without those receptors, anti-estrogen drugs such as tamoxifen and the aromatase inhibitors, and the anti-HER2 drug Herceptin, have no targets and therefore can't be used—although combinations of conventional chemotherapy drugs can still be quite effective.

Dr. Lisa Carey, a University of North Carolina researcher and oncologist, and her colleagues have also found that young African-American women are disproportionately affected by a subset of triplenegative breast cancers—called basal-like carcinomas—that generally have an even worse prognosis. Robert Millikan, a professor of epidemiology at the University of North Carolina, estimates that 20 to 40 percent of breast cancers in young African-Americans are the basal-like form, compared with about 15 percent among whites. Based on research reported earlier this year, Millikan estimates that about two thirds of basal-like breast cancers in young African-American women could be prevented by breast-feeding and a reduction in abdominal obesity.

In general, less is known about the biology and genetic origins of prostate cancer. "We don't have a gene for prostate cancer like the BRCA1 gene for breast cancer or the APC gene for colon cancer," says John Carpten, a prostate-cancer researcher at the Translational Genomics Research Institute in Phoenix. Small studies suggesting that black men may have androgen receptors that respond more vigorously to testosterone, which could in turn stimulate the proliferation of prostate-cancer cells, have not been confirmed by larger studies.

Many experts believe that differences in education and income as well as access to health insurance and medical care are more important than biological explanations for the higher death rates among African-Americans. There is some good news on this front: the breast- and prostate-cancer screening gap between black and white Americans seems to be closing. The federal government's National Health Interview Survey found that black men between the ages of 40 and 49 are more likely to get a PSA test than white men in that age bracket—and found no racial disparity in PSA testing at other ages. The National Breast and Cervical Cancer Early Detection Program, which provides low-income women with access to screening services, seems to have helped increase the number of black women who get mammograms regularly.

But researchers have identified racial disparities elsewhere in the cancer-care system. It's been documented, for example, that there's more delay time between the discovery of a breast abnormality and follow-up tests for African-American women than for white women. A study of six New York City hospitals found that African-American and Hispanic women were twice as likely as white women not to get important radiation, hormonal or chemotherapy follow-up treatments after breast surgery. African-American men are less likely to receive aggressive treatment for prostate cancer—a difference that can't be entirely explained by the stage of the cancer, the age of the patient or other health conditions. (There is no strong evidence that treatments are less effective in African-Americans.)

In an effort to address barriers to screening, diagnosis and treatment, the National Cancer Institute has established the Center to Reduce Cancer Health Disparities, which funds community outreach projects and research. Programs uniting health professionals with community leaders have begun to form in some cities, like Chicago, where the goal is to improve mammography and treatment services. Groups in Houston and Baltimore may follow the Chicago group's example. More than 200 cancer centers around the country now have patient "navigators," health-care workers who help patients coordinate appointments and paperwork and arrange for transportation and babysitters. While new tests and therapies may save lives, they have also "made the path to the best treatment extremely complicated," says Dr. Karen Freund, chief of the women's health unit at Boston Medical Center. "You need someone to see you through it."

Although disparities are still unacceptably high, some researchers think there's reason to be optimistic. A deeper understanding of tumor biology has led to clear improvements in breast-cancer treatment, "and that is only going to continue," says Dr. Harold Burstein, a breast-cancer specialist at the Dana-Farber Cancer Institute in Boston. Just as significant is the fact that both the socioeconomic and biological issues underlying the higher death rates from breast and prostate cancer are now literally on the agenda at cancer research meetings. "There is increasing awareness, and people are finally getting motivated to do something about it," Burstein says. And as the history of the fight against these cancers shows, awareness is the first step to a cure.

Wehrwein is editor and Komaroff is editor in chief of the Harvard Health Letter. For more information go to .


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