ScienceDaily (Sep. 29, 2008) — Compared with white patients, black patients undergoing screening colonoscopy have a higher prevalence of colon polyps, according to a study in the September 24 issue of JAMA.

Colorectal cancer incidence and death are higher in black patients compared with white patients. Death rates for black men and women are 38 percent to 43 percent higher than for white men and women, and incidence rates are 15.5 percent to 23 percent higher in black individuals, according to background information in the article. Since 1985, as incidence rates have declined in white individuals, rates in black men have increased and remained unchanged in black women. "Colorectal cancer screening might be less effective in black individuals, if there are racial differences in the age-adjusted prevalence and location of cancer precursor lesions," the authors write.

David A. Lieberman, M.D., of Portland VA Medical Center, Portland, Ore., and colleagues measured the prevalence and location of colon polyps sized more than 9 mm in diameter in black (n = 5,464) and white (n = 80,061) patients who had undergone colonoscopy screening at 67 practice settings across the United States.

The researchers found that a total of 422 black patients (7.7 percent) and 4,964 white patients (6.2 percent) had 1 or more polyps sized more than 9 mm. These differences extended across all age groups in women and men. Compared with white patients, black men had a 16 percent increased odds of having polyps sized more than 9 mm; black women had a 62 percent increased odds.

There was an increased risk associated with age older than 50 years and also a significant increase in risk when patients age 60 to 69 years were compared with those age 50 to 59 years. In a subanalysis of patients older than 60 years, proximal (situated nearest to point of origin) polyps sized more than 9 mm were more likely prevalent in black men and women compared with white men and women.

"In summary, we find that asymptomatic black men and women undergoing colonoscopy screening are more likely to have 1 or more polyps sized more than 9 mm compared with white individuals. The differences were especially striking among women. These findings emphasize the importance of encouraging all black men and women to be screened," the authors write.

Editorial: Colorectal Cancer Risk - Black, White, or Shades of Gray?

In an accompanying editorial, Hemant K. Roy, M.D., and Laura K. Bianchi, M.D., of Evanston Northwestern Healthcare, Evanston, Ill., comment on the findings of Lieberman and colleagues.

"… it is becoming clear that as physicians and patients enter the era of personalized medicine, colorectal cancer screening will evolve from simply dichotomizing patients into average or increased risk to assigning more precise gradations ('shades of gray'). Through assessing both genetic and environmental risk factors, clinicians may be able to more rationally tailor screening strategies to maximize cost-effectiveness and risk benefit. While waiting for this field to mature, using the published guidelines with evidence-based judicious modifications (such as more aggressive screening of black patients) would seem to be prudent."

Journal reference:

1. Lieberman et al. Prevalence of Colon Polyps Detected by Colonoscopy Screening in Asymptomatic Black and White Patients. JAMA The Journal of the American Medical Association, 2008; 300 (12): 1417 DOI: 10.1001/jama.300.12.1417

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