Colon pathology influenced by ethnicity

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There is a marked ethnic variation in the prevalence of colonic neoplastic lesions in asymptomatic patients at average-risk for colorectal cancer who undergo screening with flexible sigmoidoscopy, researchers report in the April issue of the American Journal of Gastroenterology.

As senior investigator Dr. Edward J. Bini told Reuters Health, "we found that the prevalence of neoplastic lesions in the distal colon was highest in Asians and lowest in African Americans. In contrast, Asian patients who had a follow-up colonoscopy after a positive flexible sigmoidoscopy had the lowest prevalence of neoplastic lesions in the proximal colon."

Dr. Bini of New York University School of Medicine and colleagues prospectively studied more than 2200 patients who underwent sigmoidoscopy in New York City. The group consisted of 970 Caucasians, 765 African Americans, 395 Hispanics and 77 Asians.

The prevalence of neoplasia in the distal colon was 24.7% in the Asians, 15.9% in the Hispanics, 12.6% in the Caucasians and 11.2% in the African Americans.

However, in 290 patients with neoplasia who underwent follow-up colonoscopy showed neoplasms in the proximal colon in 66.7% of Hispanics, 63.9% of Caucasians, 59.3% of African Americans and only 26.3% of Asians. The team also found that advanced neoplasms were highest in the African Americans (34.9%) and lowest in the Asians (10.5%).

Given these differences, Dr. Bini recommends that "screening colonoscopy studies be performed in order to explore ethnic variation in prevalence and location of colonic neoplastic lesions, since ethnic variation could lead to tailored colorectal cancer screening strategies."