There were 127 patients who had one or more flat adenomas of any size in the analyzed sample of 428 (313 nonsmokers and 115 heavy smokers). Heavy smoking, age and male gender were all statistically associated with any flat adenomas of any size. In addition, researchers observed that heavy smoking, body mass index, gender and red meat consumption had associations with having an advanced flat adenoma. After a multivariate analysis, heavy smoking was the only variable that was found to be predictive of advanced flat colorectal neoplasia.

The researchers concluded that smoking is an important risk factor for flat colorectal adenomas. Not only was smoking associated with all flat adenomas, it was also a risk factor for those patients who only had flat adenomas that were greater than 6 mm in diameter. These patients did not have any polypoid adenomas. The study may explain the observation that smokers often present with colorectal cancer at a younger age and at a more advanced stage than nonsmokers.

They also state that their findings are important because detecting these adenomas may require special high-definition colonoscopes. The researchers observed that most flat adenomas were found on the right side of the colon, suggesting advanced imaging, such as chromoendoscopy, may help identify these lesions in smokers. Chromoendoscopy, an endoscopic technology, is performed by spraying specialized nonpermanent stains or dyes on the lining of the intestine during the endoscopic procedure to improve visualization.

In an accompanying editorial, Dayna Early, MD, Washington University School of Medicine, St. Louis, Mo., states "Few would argue that flat lesions are more difficult to identify than polypoid lesions, and although the Anderson et al study suggests that more advanced imaging should be used in smokers to detect flat colorectal neoplasia, data to support this approach are not available from their study."

"Ongoing emphasis should be placed on high-quality screening examinations and good bowel preparation because these are critical in detecting right-sided lesions. Finally, we should be on the lookout for flat adenomas not only in smokers, but in all patients undergoing screening colonoscopy and use the best technology available to us to do so," said Dr. Early. In addition, the editorial points out that these data can be used by physicians in counseling patients about the risks of smoking and colorectal cancer screening for smokers.

Source: American Society for Gastrointestinal Endoscopy