Blacks have a disproportionately higher cancer burden than other races, according to a study published in Hormones and Cancer (2010;1(1):55-62).

The study led by researchers from the Public Health Sciences Division at the Fred Hutchinson Cancer Research Center included data on 7,237 women with newly-diagnosed distant-stage breast cancer. Of the study population, 1,364 women were black and 5,873 women were white. In addition to studying the incidence of advanced breast cancer and colon cancer, researchers also looked at rates of advanced-stage colorectal and prostate cancer in an attempt to determine which screening practices may have influenced the magnitude of racial disparities in these malignancies during this 12-year period

The findings revealed that the incidence of advanced breast cancer diagnosis among black women remained 30% to 90% higher compared to white women between 1992- and 2004. Additionally, the disparity in the incidence of advanced colorectal cancer actually widened over this period as rates dropped among whites but increased slightly among blacks.

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The study’s senior author, Christopher Li, MD, PhD, offered a possible explanation for the study results, stating that overall, black women have more aggressive tumors that are more difficult to detect and treat compared to non-Hispanic white women. “While we could not determine the exact contributors to the trends we saw in this study, it is interesting to note that for breast cancer, mammographic screening rates were quite similar among African American and white women in the United States during the time period we studied,” Dr. Li noted. “This suggests that factors other than screening may be contributing to this persistent disparity, including differences in both lifestyle and genetics.

When researchers studied 8,920 people with distant-stage colorectal cancer, they found a widening of the racial disparity gap for colorectal cancer, with distant-stage incidence rates among non-Hispanic whites declining over time but increasing somewhat among blacks. Black colorectal cancer patients were slightly younger at diagnosis and were more likely to be female compared to white participants. In 1992, blacks were 60% more likely to be diagnosed with late-stage colorectal cancer as compared to whites, and by 2004 that likelihood had doubled.

“Epidemiologic studies such as this one are an important first step in understanding trends in disease rates on a population level,” concluded lead author Jean McDougall, MPH. “However, we cannot draw strong conclusions regarding the factors contributing to the trends observed from this study, as its goal was to describe trends over time without using detailed data on individual cases and the complex factors that contribute to disease.”