Public Release: 

Advances in screening and markers improve early detection of colorectal cancer

American Gastroenterological Association

WASHINGTON, D.C. (May 23, 2007) -- Although colorectal cancer is the second leading cause of cancer death in the United States, when detected early, it has one of the highest cure rates. For this reason, innovative and improved methods to screen for and detect this disease are essential. Research presented today at Digestive Disease Week® 2007 (DDW®) demonstrates the breadth of technological and research advances that are helping to decrease both the number of deaths and the number of new cases of colorectal cancer diagnosed in the United States. DDW is the largest international gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

A New Benchmark in the Colorectal Neoplasm Miss Rate During Colonoscopy: Results of a Randomized Controlled Trial of Wide Angle View (170 degrees) Colonoscopy Comparing Narrow Band Imaging and White Light (Abstract #821)

Although the colonoscopy is considered the most effective means to detect precursors of colon cancer, the overall reported rate of missing colorectal tumors is 24 percent, as reported in 1997. In the past 10 years, significant advances in screening technologies have led to the development of colonoscopes (long, flexible, lighted tubes with attached cameras) that have a wider angle of view and non-white light capabilities, such as narrow band imaging (NBI). Researchers from the Veterans Affairs Palo Alto Medical Center in Palo Alto, Calif. utilized current technologies to study the colonoscopic polyp miss rate, comparing NBI to white light imaging.

NBI changes the white light normally emitted by the colonoscope to a bluish light, providing a narrower wavelength and enhancing visual contrast of the surface structure of the colon. In this study, two consecutive, same-day colonoscopies were performed in 276 patients. All colonoscopies used a wide angle of view (170 degrees compared to standard 140) and high resolution capabilities. The patients were randomly assigned to white light (141 patients) or NBI (135 patients) during the first withdrawal, and then immediately underwent a second examination by the same physician using white light.

The study found an overall miss rate of 12 percent for tumors of any size and three percent for tumors greater than or equal to six millimeters. No lesion larger than one centimeter was missed and all missed tumors were tubular adenomas, or non-cancerous tumors. Based on these results, researchers established the colorectal tumor miss rate as zero percent (up to 2%) for significant tumors and 12 percent for all tumors. However, no significant difference of missed lesions was found between NBI and white light.

"Our findings suggest that technological advances have led to a significant reduction in the overall colorectal tumor miss rate, establishing a new benchmark for more accurate screening and detection," said Roy Soetikno, M.D., of Stanford University in Stanford, Calif., and senior author of the study. "Our study reaffirms the role of colonoscopy as the gold standard method to screen for colorectal cancer."

Dr. Soetikno will present this study on Wednesday, May 23, at 8:35 a.m. in Ball Room AB.

The Association of Elevated C-Reactive Protein Levels with Synchronous and Advanced Colorectal Adenoma (Abstract #S1987)

Inflammation has been implicated in numerous diseases through recent research. High levels of C-reactive protein (CRP) - a protein found in the blood that can be used to detect or grade inflammation - are often associated with cardiovascular disease and cancers, such as colorectal cancer. Little is known, however, about CRP levels and non-cancerous colorectal tumors (adenomas) that precede colorectal cancer. Researchers from National Taiwan University Hospital in Taipei, Taiwan, examined levels of CRP in both men and women, finding that elevated levels may be associated with increased risk of colorectal adenoma, but only in men.

Study authors conducted a cross-sectional study of plasma CRP levels in 6,695 Chinese patients. All patients underwent a complete total colonoscopy and thorough health check-up. Results were adjusted for age, gender, history of colon polyp, diabetes, hypertension, hypertriglyceridemia, hypercholesterolemia, physical activity, alcohol intake, smoking, white blood cell counts and abdominal obesity.

Results demonstrated that plasma CRP levels were significantly higher in patients in whom colorectal tumors were forming when compared to patients without tumor development. The presence of tumors forming at the same time, known as synchronous neoplasia, and advanced tumor development were associated with elevated levels of plasma CRP. However, while researchers found that high CRP levels are associated with the risk of colorectal tumor formation in male patients, the study did not find a corresponding association with female patients.

"These findings support the crucial role of chronic inflammation in the development of colorectal cancer," said Han-Mo Chiu, M.D., of the National Taiwan University Hospital, and senior author of this study. "These data warrant further investigations that will continue to evaluate C-reactive protein levels as an indicator of colorectal cancer and examine the gender differences found in our study."

Dr. Chiu will present this study on Sunday, May 20, at 8:00 a.m. in Hall E.

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Digestive Disease Week® (DDW®) is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. Jointly sponsored by the American Association for the Study of Liver Diseases (AASLD), the American Gastroenterological Association (AGA) Institute, the American Society for Gastrointestinal Endoscopy (ASGE) and the Society for Surgery of the Alimentary Tract (SSAT), DDW takes place May 19-24, 2007 in Washington, D.C. The meeting showcases more than 5,000 abstracts and hundreds of lectures on the latest advances in GI research, medicine and technology.

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