African Americans face higher risk of colorectal cancer

African Americans are at significantly higher risk of developing colorectal cancer, and being diagnosed with the disease at a later stage, than other ethnic groups. That's the finding of a paper being presented at the annual meeting of the American College of Gastroenterology in San Diego.

Robert Wong, M.D., and his colleagues at California Pacific Medical Center looked at records of more than 500,000 cases of colorectal cancer, diagnosed between 1973 and 2004, analyzing them for race and sex-specific disparities. In the study proximal colon cancers included the cecum, ascending colon, up to the point of the hepatic flexure, which is the point where the colon makes a turn to become the transverse colon. They found that African American males were more than twice as likely as Asian American males to be diagnosed with proximal cancer (25.2 per 100,000/year vs 11.7 per 100,000 year.). The rate among African American women was also twice that of Asian American women (21.9 vs 11.4). Similar disparities were seen between African Americans, both men and women, and whites and Hispanics.

"I was surprised at how big the differences were between the various groups," says Wong, the lead author of the study. "I had done similar research on liver cancer in the past and found that racial and ethnic differences were present, but not nearly as stark as this."

The differences were not just in numbers but also in the severity of the disease. African Americans had the highest rates of advanced cancer, with the rate among both African American men and women nearly double that of Hispanic men and women. The more advanced the disease is when diagnosed the poorer the outcome for the patient.

"I think access to care plays a huge role in determining who is at risk and how great that risk is," says Wong. "But access alone does not explain all the differences. It's likely that for some socio-economic groups education is also critical. Members of certain groups may not have enough information on education and the importance of screening."

Colorectal cancer is the third most common cancer and the second most common cause of death from cancer in the United States. The researchers hope that identifying which groups are at highest risk will help in guiding changes and improvements in cancer screening programs.