Blacks and Hispanics at higher risk for precancerous colorectal polyps

"Our data suggest that we need to redouble our efforts to increase colon cancer screening in areas with large numbers of racial and ethnic minorities," said lead author Benjamin Lebwohl, MD, MS, assistant professor of clinical medicine and epidemiology at NewYork – Presbyterian Hospital/Columbia University Medical Center and Columbia University's Mailman School of Public Health.

The study also found that blacks and Hispanics have a higher risk of developing polyps in the upper portion of the colon, compared with whites. "These lesions would have been missed had these patients undergone sigmoidoscopy, which examines only the lower half of the colon," said Dr. Lebwohl. "Therefore, colonoscopy, which examines the entire colon, may be preferable to sigmoidoscopy as a screening test for blacks and Hispanics."

Colorectal cancer caused an estimated 51,370 deaths in 2010 – the last year for which data are available. This type of cancer is largely preventable if caught early, in the form of precancerous polyps, or adenomas. Such polyps are effectively treated with removal during colonoscopy.

The researchers looked at rates of advanced adenomas — polyps 10 mm or larger that exhibited aggressive features under microscopic examination. "These are the kinds of polyps that we are most concerned may eventually develop into cancer," said Fay Kastrinos, MD, MPH, assistant professor of clinical medicine at NewYork – Presbyterian Hospital/Columbia University Medical Center and senior author of the study. "We found that blacks and Hispanics were roughly twice as likely to have advanced adenomas, compared with whites, after adjusting for factors such as age and family history."

Previous studies had shown that colorectal cancer incidence and mortality are higher in blacks than in whites, and that blacks are typically younger at the time of diagnosis than are whites. Little was known about the risk of adenomas among Hispanics.

In the current study, the first to compare adenomas in white, blacks, and Hispanics, the investigators analyzed data from 5,075 men and women age 50 or older who underwent first-time colonoscopy at NewYork – Presbyterian Hospital/Columbia University Medical Center from 2006 to 2010. The study population was 70 percent white, 18 percent Hispanic, and 12 percent black, with a mean age of 62. None of the subjects had signs or symptoms of colon cancer at the time of screening. At least one adenoma was detected in 19 percent of whites, 22 percent of Hispanics, and 26 percent of blacks, the researchers reported.

The findings run counter to existing statistics showing that Hispanics have a lower rate of colon cancer compared with whites. "Surprisingly, we found that Hispanics have a slightly higher rate of precancerous polyps," said Dr. Lebwohl. "This adds to other recent evidence that the rate of colorectal cancer among Hispanics may be increasing with acculturation."

Doctors generally advise patients to get an initial screening test at age 50, when overall rates of colon cancer begin to increase.

Provided by Columbia University Medical Center