Washington: In a new study, smoking was found to have a strong association with the presence of flat adenomas (precancerous polyps) in the colon and may explain the earlier onset of colorectal cancer in smokers, as well as the advanced stage with which they present when compared to nonsmokers.
Flat adenomas are more difficult to detect and have more aggressive pathology than the typical raised type of polyp detected during colorectal cancer screening.
Colorectal polyps, which are growths residing in the lining of the colon or rectum, start as a small colorectal polyp known as an adenoma and their removal is the key to prevent colorectal cancer.
"Little is known regarding the risk factors for these flat lesions, which may account for over one-half of all adenomas detected with a high-definition colonoscope. Smoking has been shown to be an important risk factor for colorectal neoplasia in several screening studies," said study lead author Joseph C. Anderson, MD, Neag Comprehensive Cancer Center, University of Connecticut Health Center, Farmington, Conn.
The study found that in 600 asymptomatic patients who underwent screening colonoscopy, smoking was associated with the presence of flat adenomas. The patients were examined using colonoscopy and divided into groups of non-smokers, heavy smokers and low-exposure smokers. After a multivariate analysis, heavy smoking was the only variable that was found to be predictive of advanced flat colorectal neoplasia.
"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 Dayna Early, MD, Washington University School of Medicine, St. Louis, Mo.
The study appears in the June issue of GIE: Gastrointestinal Endoscopy, the monthly peer-reviewed scientific journal of the American Society for Gastrointestinal Endoscopy (ASGE).