First comprehensive study of the relationship between racial subgroups and colorectal cancer outcome

Jun 27 2005

A new study finds wide variations in colorectal cancer stage of diagnosis and mortality, with some ethnic groups having 10 to 60 percent higher risks of stage III or IV colorectal cancer compared to non-Hispanic whites, and 20 to 30 percent higher risk of death from the disease.

The report, the first comprehensive study of the relationship between racial subgroups and colorectal cancer outcome, appears in the August 1, 2005 issue of CANCER.

Colorectal cancer is common, causing 11 percent of all cancer-related deaths in the United States. Prognosis is dependent on the stage of disease at diagnosis, treatment, and, according to many studies, race. Studies have found that African Americans and Native Americans are more likely to be diagnosed with advanced disease and die of their disease compared to Asian Americans and non-Hispanic whites. A few studies that look at a few specific subgroups compared to non-Hispanic whites suggest more variation in cancer risks than the broader categories imply.

Led by Chloe Chien, M.S., researchers from the Fred Hutchinson Cancer Research Center in Seattle, reviewed patient data from the Surveillance, Epidemiology and End Results (SEER) program to evaluate the relationship between 18 racial categories and stage of disease and mortality.

Analysis across conventional racial categories demonstrated that African Americans, Native Americans, Asians/Pacific Islanders, and Hispanic whites were more likely to be diagnosed with advanced stages of colorectal cancer compared to non-Hispanic whites. In addition, African Americans, Native Americans, and Hispanic whites had higher risks of dying from colorectal cancer, while Asians/Pacific Islanders had a lower risk compared to non-Hispanic whites. However, dividing these broad categories demonstrated much more variation. Within the category of Asian/Pacific Islander, risk of stage IV disease and/or death was lower for Chinese, Japanese, and Indian/Pakistanis but elevated for Filipinos and Hawaiians compared to non-Hispanic whites. Within the category of Hispanic white, risk of stage IV disease and/or death compared to non-Hispanic whites was similar for Cubans and Puerto Ricans but elevated for Mexicans and South/Central Americans.

"We observed numerous differences in the risks of advanced stage CRC and mortality across individuals in different Asian/Pacific Islander and Hispanic white subgroups," conclude Ms. Chien and her colleagues, "suggesting that it is important to take into account the heterogeneity of broad racial/ethnic categories when evaluating risks in these populations."