Colorectal cancer is the second-leading cause of cancer deaths, affecting both men and women nearly equally and is one of the most preventable cancers. The American Gastroenterological Association (AGA) Institute supports clinically proven technologies that increase the number of patients screened for colon cancer.
The AGA Institute offers the following comments on the study by Kim et al., “CT Colonography Versus Colonoscopy for the Detection of Advanced Neoplasia,” published in the Oct. 4, 2007, issue of the New England Journal of Medicine.
“This study expands our knowledge about computerized tomographic colonography (CTC), or virtual colonoscopy,” said Robert Sandler, MD, MPH, AGAF, president-elect of the AGA Institute. “The AGA Institute welcomes research that will help to clarify the role CT colonography will play in the screening and detection of colorectal cancer and polyps, but many questions remain. This study by Kim and colleagues shows that CT colonography may be another tool in encouraging patients who have not already done so to get screened for colon cancer.”
When a polyp is found during an optical colonoscopy, the physician can remove it immediately. In the study by Kim, diminutive polyps (<5 mm) were not deemed dangerous enough for removal. There are no long-term, adequately controlled studies that define whether leaving small polyps is safe. The AGA Institute recommends that all patients with diagnosed polyps, regardless of size, should be referred for optical colonoscopy.
"Fortunately, small polyps often aren’t cancerous – but some are,” said Don Rockey, MD, AGAF, chair of the AGA Institute Task Force on CT Colonography. “If patients are comfortable not having small polyps removed, then CTC might be the test for them. Those who want to have their polyps removed – all of them, not just the big ones – might choose optical colonoscopy. Since the natural history of small polyps is not fully understood, the AGA has asked the National Institutes of Health to pursue a study to establish the clinical significance of diminutive polyps (<5mm) using adequate controls and long term follow up. We clearly need data that provides physicians with information on the natural history of polyps and guidance on their management."
According to recommendations put forth in September by the AGA Institute Task Force on CT Colonography:
- Any polyp >6 mm in size (i.e., widest diameter) should be reported and the patient referred for consideration of endoscopic polypectomy.
- Patients with three or more polyps of any size in the setting of high diagnostic confidence should be referred for consideration of endoscopic polypectomy.
- The appropriate clinical management of patients with one to two lesions no greater than 5 mm in diameter is unknown. In the absence of data, the follow-up interval recommended for these patients should be based on individual characteristics of the patient and procedure.
Colon cancer screening rates in eligible populations remain low. The AGA Institute supports all clinically proven options for colon cancer screening and encourages patients to discuss them with their physicians.
The AGA Institute will host a course on CT Colonography on March 7-8, 2008, in Washington, DC. To learn more about AGA Institute initiatives on CTC, please visit the AGA Web site at www.gastro.org.
Guidelines from multiple agencies and professional societies, including the AGA Institute, underscore the importance of colorectal cancer screening for all individuals 50 years of age and older (younger for certain groups known to be at higher risk). The U.S. Preventive Services Task Force, the U.S. Multi-Specialty Task Force and others have published recommendations for screening for colorectal cancer, the second-leading cause of cancer deaths in the United States. Currently, recommended screening tests include colonoscopy, flexible sigmoidoscopy, barium enema and fecal occult blood tests. We look forward to the updated recommendations on screening for colorectal cancer from the U.S. Multi-Society Task Force and the U.S. Preventive Services Task Force in November.
About the AGA Institute
The American Gastroenterological Association (AGA) is dedicated to the mission of advancing the science and practice of gastroenterology. Founded in 1897, the AGA is one of the oldest medical-specialty societies in the United States. Comprised of two non-profit organizations—the AGA and the AGA Institute—our more than 16,000 members include physicians and scientists who research, diagnose and treat disorders of the gastrointestinal tract and liver. The AGA, a 501(c6) organization, administers all membership and public policy activities, while the AGA Institute, a 501(c3) organization, runs the organization’s practice, research and educational programs. On a monthly basis, the AGA Institute publishes two highly respected journals, Gastroenterology and Clinical Gastroenterology and Hepatology. The organization's annual meeting is Digestive Disease Week®, which is held each May and is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. For more information, please visit www.gastro.org.