NEW ORLEANS — Screening colonoscopy in asymptomatic black patients found a 4.5% rate of high-grade dysplastic polyps in those aged 45–49 years, according to the findings of a retrospective review.
The findings suggest that blacks should have their first colonoscopy before they reach age 50, said Dr. Frank Friedenberg, a professor of medicine at Temple University Hospital, Philadelphia.
About a month after the meeting, the American Society for Gastrointestinal Endoscopy issued separate guidelines suggesting that blacks begin screening colonoscopy at age 45. Developed by the ASGE's Standards of Practice Committee, the guidelines on ethnicity, gastrointestinal diseases, and endoscopic procedures appear in the June issue of GIE: Gastrointestinal Endoscopy (2010;71:1108–11). The document is available at www.giejournal.orgwww.asge.org
The guidelines, which are based on literature reviews, include “recommendations” as well as “suggestions,” with the latter term indicating that the quality of evidence is weaker.
The ASGE suggestion regarding screening for black patients reflects several risk factors: “African Americans with colon cancer have a 20% stage-adjusted increase in mortality risk, compared with European Americans,” are younger at presentation, have a higher proportion of cancers presenting before age 50, and generally more advanced stage at the time of diagnosis, the authors of the guidelines noted.
Many ethnic groups have low colon cancer screening rates; the guidelines support an increased emphasis on screening for those groups.
No studies have assessed the impact of modifying specific endoscopic standards based on ethnicity, but “it is logical to assume that increased awareness of differences in disease patterns and management among different ethnic groups could have beneficial impacts on the health-related quality of life of people in these groups,” said Dr. Jason A. Dominitz, chair of ASGE's Standards of Practice Committee.
“It is important to recognize that ethnic populations are not homogeneous and that additional factors, such as environment and behavior, also play important roles in disease,” Dr. Dominitz added in a statement.
In presenting his findings at Digestive Disease Week, Dr. Friedenberg noted that “several lines of evidence suggest we should be looking at screening blacks at an earlier age.”
“National data suggest that colorectal cancer is actually increasing in blacks, while it's declining in the general population. Blacks also seem to have a predilection for proximal colorectal neoplasia, suggesting that flexible sigmoidoscopy is not an appropriate screening tool.
“Finally, patients younger than 50 who develop colorectal cancer are twice as likely to be black as white. All these are very compelling reasons to think about earlier screening,” he said.
Dr. Douglas K. Rex, distinguished professor of medicine at Indiana University, Indianapolis, and director of endoscopy at Indiana University Hospital, commented in an interview that “the approach of screening colonoscopy starting at age 45 in African Americans was endorsed by the American College of Gastroenterology, but has been controversial. This study lends support to the ACG recommendation, but is unlikely to resolve the controversy.”
Dr. Friedenberg and his colleagues reviewed the charts of 109 black patients aged 45–49 years matched with 226 black patients aged 50–59 years, all of whom underwent a screening colonoscopy. All of the patients were asymptomatic, and none of them had a family history of colorectal cancer. The groups were well-matched in terms of gender and body mass index (mean, 31 kg/m
The older patients were significantly more likely than the younger patients to smoke (48% vs. 37%), drink alcohol (43% vs. 21%), and use aspirin regularly (26% vs. 15%).
Polyps were found in 22% of the younger group and 20% of the older group, not a significant difference. Thirty percent of each group had more than one polyp. The polyps were on the right side of the colon in about half of each group. “This is much more than you would expect, lending credence to the observation that blacks have a predilection for right-sided lesions,” Dr. Friedenberg said.
Significant differences emerged in polyp histology. High-grade dysplastic lesions occurred in 4.5% of the younger group and 0.4% of the older group. “Theoretically, this means that there were several younger individuals who, if they had waited until their 50s to have a colonoscopy, could have had a colon cancer by then,” Dr. Friedenberg said.
The significantly higher use of aspirin in the older group may have exerted a protective influence against high-grade lesions, he said, “although since that group smoked significantly more, it might have balanced out the risk.”
The study suggests that screening colonoscopy should begin earlier in black patients, Dr. Friedenberg said. “We are already swamped with colonoscopies, and to begin screening years earlier in this population would be a financial challenge,” he said. “Still, it is something that needs to be looked at on a larger scale.”