Blacks and other minorities in the U.S. face greater colorectal cancer risks than whites, according to a new study.

The results show that minorities are up to 60 percent more likely to have colorectal cancer diagnosed at an advanced stage — and up to 30 percent more likely to die from the disease — than whites.

Blacks are hardest hit by colorectal cancer, but researchers say this is the first study to compare colorectal cancer risks within smaller racial and ethnic subgroups.

Colorectal cancer is the third leading cause of cancer-related deaths in the U.S. The risk of death depends largely on the stage at which the disease is diagnosed, treatment, and as this study suggests, ethnic group.

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Risks Vary by Race and Ethnic Group

Blacks and American Indians are more likely to have colorectal cancer diagnosed at a later stage and die from the disease than Asians and whites. But researchers say information about other racial groups has been limited.

In this study, which appears in the Aug. 1 issue of the journal Cancer, researchers analyzed data on more than 150,000 people from 18 different races and ethnicities who were diagnosed with colorectal cancer from 1988 to 2000.

The results showed that the risks associated with colorectal cancer varied widely within different racial and ethnic subgroups, which suggests that risk assessments based on broad categories, such as non-Hispanic white or Asian/Pacific Islander, may not be entirely accurate.

For example, the results showed:

— Blacks, American Indians, Asians/Pacific Islanders, and Hispanic whites were more likely to be diagnosed with advanced stages of colorectal cancer than non-Hispanic whites.

— Blacks, American Indians, and Mexicans had higher risks of dying from colorectal cancer than non-Hispanic whites.

— Asians/Pacific Islanders had a lower risk than non-Hispanic whites.

But when researchers divided these broad categories into narrower ones they found much more variation in risk. Specifically, compared to the overall category of non-Hispanic whites:

The risk of death due to colorectal cancer was 20 percent-30 percent higher among blacks, American Indians, Hawaiians, and Mexicans. But Chinese, Japanese, and Indians/Pakistanis had a 10 percent-40 percent lower risk. Within the category of Asian/Pacific Islander, the risk of being diagnosed with colorectal cancer at the most advanced stage (stage IV) and/or death was lower for Chinese, Japanese, and Indians/Pakistanis but higher for Filipinos and Hawaiians. Within the category of Hispanic white, the risk of being diagnosed with colorectal cancer at the latest stage was similar for Cubans and Puerto Ricans but elevated for Mexicans and South/Central Americans.

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By Jennifer Warner, reviewed by Brunilda Nazario, MD

SOURCE: Chien, C. Cancer, Aug. 1, 2005; vol 104.