Facing Prostate Cancer
Prostate cancer in black men:
Focusing on disparities
By Richard Saltus
Colleagues Gary Bennett, PhD, and Glorian Sorensen, PhD, MPH
For reasons that are complicated and poorly understood, a black man in the United States is more likely to be diagnosed with prostate cancer than a white man. Chances are his disease will be more aggressive and advanced when it's caught, and his risk of dying is double that of non-blacks. In fact, prostate cancer is the second-leading cause of cancer death (after lung cancer) among black males in this country.
"Prostate cancer presents challenges from a disparities perspective unlike those of any other cancer," says Dana-Farber's Gary Bennett, PhD, a behavioral scientist. "We don't understand enough about what creates these disparities — and what we do know makes for enormous complications for intervention."
There's mounting evidence that prostate tumors in blacks are inherently more aggressive, and Bennett cites the causes as biological differences combined with environmental and lifestyle factors. For example, black men tend to eat more red meat and dairy products and fewer foods containing lycopene, a substance in tomato sauce that is believed to reduce cancer risk, than do non-blacks.
Early detection is therefore key. It appears that blacks are less likely to undergo PSA (prostate-specific antigen) blood tests and digital rectal exams, although the reasons for this disparity are not entirely clear, and the value of PSA screening for early detection remains controversial. Screening is recommended beginning at age 45 in blacks — five years earlier than in non-blacks — and even earlier for those with a family history of prostate cancer.
Bennett leads a support group for prostate cancer survivors at Dana-Farber. He is also working with colleagues Jennifer Allen, DSc, and Christopher Lathan, MD, to develop a Web-based tool kit that would help men make more informed decisions about undergoing PSA testing. The goal is to take such a decision aid into workplaces and other community sites, says Bennett, who joined the Institute's Center for Community-Based Research in 2003 and focuses his research on racial, ethnic, and other disparities in cancer risk behaviors.
There's a promising lead for reducing prostate cancer risk in blacks: vitamin D. Large studies have revealed a link between too-little vitamin D and a higher risk of several cancers, including prostate. "We know that blacks in general don't synthesize vitamin D from sunlight as well as whites because of the melanin pigment in their skin," Bennett says, "and this is particularly true in the Northeast, where we're farther from the equator and spend more time indoors. Many blacks are vitamin D-deprived."
An upcoming study headed by Charles Fuchs, MD, of Dana-Farber aims to find appropriate cancer-preventing doses of vitamin D. In addition, Bennett's colleagues Karen Emmons, PhD, and Glorian Sorensen, PhD, MPH, have developed strategies for getting multiethnic populations to take more multivitamins.
"Our eventual goal will be to combine the appropriate vitamin D dosage with intervention strategies to raise awareness and utilization," says Bennett. "I predict that in 10 years, there will be an enormous focus on vitamin D's role in cancer prevention among blacks."
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