When screening for colorectal cancer, there are many different test options; however, there has been no consensus on the most appropriate screening method for specific subsets of patients.
In this study, researchers evaluated tests to detect advanced neoplastic lesions (lesions with high risk of progression to cancer or actual cancer), seeking to identify possible racial disparities between Caucasian and African American patients in detecting and diagnosing colorectal cancer, as well as the usefulness of colonoscopies in detecting colorectal cancer in patients without cancerous symptoms.
Investigators reviewed 16,737 colonoscopies performed at Emory University Hospital and Grady Memorial Hospital between January 2000 and December 2005. Colonoscopies give clearer pictures of bends in the colon than another screening tool called flexible sigmoidoscopy, which uses a slender hallow lighted tube to detect cancer. Researchers studied procedure results for abnormally sized and shaped polyps and adenomas (benign tumors) larger than 10 millimeters.
One-third (n=5,597) of the patients screened had an average risk for colorectal cancer and eight percent (n=462) were confirmed to have advanced neoplastic lesions. For more than half of the patients with advanced neoplastic lesions (57%, n=262), the lesions were confined to the proximal colon, making it very difficult for the flexible sigmoidoscopy to detect. Notably, Caucasian patients had a higher risk for proximal tubular adenoma while African American patients had a higher risk for proximal adenocarcinoma and proximal tubulovillous adenoma. Tubulovillous adenomas have a higher rate of progression to cancer. There was a trend towards females having more advanced neoplastic lesions. However, this was not statistically significant.
“These results direct doctors to perform colonoscopies rather than other methods, such as the flexible sigmoidoscopy, as they detect more colon tumors that may have been missed with flexible sigmoidoscopy,” said Mohammed A. Wehbi, M.D., of Emory University in Atlanta, Ga., and lead author of this study. “Additionally, the study shows racial differences in detecting and diagnosing advanced neoplastic lesions/cancer, suggesting a possible need for earlier and more aggressive screening of African American patients.”