Canadian study finds that colonoscopy is associated with lower death rates, but raises concerns about detection of colorectal cancer on the right side of the colon
OAK BROOK, Ill., Dec. 16 /PRNewswire-USNewswire/ -- A study released today in the Annals of Internal Medicine found that colonoscopy is associated with lower death rates from colorectal cancer, however, the procedure missed lesions more often on the right side of the colon versus the left side. The study highlights the importance of seeking a qualified gastrointestinal endoscopist to perform a thorough colonoscopy and that patients must take the bowel prep as directed by their physician allowing for a clear view of the colon to detect lesions. The American Society for Gastrointestinal Endoscopy (ASGE), representing the specialists in colorectal cancer screening, recommends that patients seek out an expertly-trained gastrointestinal endoscopist to perform a colonoscopy and to ask questions about their qualifications before the procedure.
"Colonoscopy is the gold standard for colorectal cancer screening for its ability to detect and remove polyps before they turn into cancer. Colonoscopy's effectiveness is evidenced in the recent decline in the incidence and death rates from colorectal cancer announced last month by leading cancer organizations," said John L. Petrini, MD, FASGE, president of the American Society for Gastrointestinal Endoscopy. "While colonoscopy is not a perfect test, this study should not deter anyone from undergoing a colonoscopy for colorectal cancer screening. Approximately 70 percent of the colonoscopies performed in this study were not done by gastroenterologists. Studies have shown that missed lesion rates are higher for internists and family practice physicians doing colonoscopy. We urge patients to log on to www.asge.org to find a qualified, expertly-trained gastrointestinal endoscopist to perform their colonoscopy and to ask questions about their qualifications."
Study participants included patients with colorectal cancer that was diagnosed between 1996 and 2001 in the province of Ontario, Canada, and died of colorectal cancer by 2003 (the case patients). Investigators found five individuals for each case patient who were similar but had not died of colon cancer by 2003 (the controls). The study looked at 10,292 case patients and 51,460 controls were identified; 719 case patients (7.0 percent) and 5,031 controls (9.8 percent) had undergone colonoscopy. Compared with controls, case patients were less likely to have undergone any attempted colonoscopy or complete colonoscopy. Complete colonoscopy was strongly associated with fewer deaths from left-sided colorectal cancer (33 percent reduction), but not from right-sided colorectal cancer (1 percent reduction).
ASGE, as the standard-setting society for endoscopy, has issued quality indicators for colorectal cancer screening that define measures for improving quality in colonoscopy. ASGE provides training and education to physicians to ensure that patients are receiving the highest quality of care possible. The Society offers a "Find a Doctor" feature at www.asge.org, as well as a list of questions patients should ask their gastrointestinal endoscopist before undergoing a colonoscopy or endoscopy procedure.
"Bowel prep and withdrawal time are key to a complete and thorough colonoscopy. Experts in gastrointestinal endoscopy will need to be more vigilant than ever in encouraging their patients to take their bowel prep as directed before the colonoscopy. A proper bowel prep allows the physician to clearly see the colon," said Petrini. "The missed lesions in this study were mostly on the right side of the colon, which often harbors flat lesions that are more difficult to detect than the more typical raised polyp and more likely to be cancerous. This fact highlights the importance of not withdrawing too soon during the procedure, allowing the physician enough time to thoroughly examine the colon. According to ASGE quality indicators, average withdrawal time should be six minutes or more."
"There are many factors that go into prevention, detection, diagnosis and treatment of colorectal cancer. Patients need to find a qualified gastrointestinal endoscopist, ask questions before the procedure and work with their physician to identify an appropriate screening schedule based on the individual's medical history as well as family history," said Petrini. "Colorectal cancer is preventable and treatable when caught at an early stage. ASGE recommends colonoscopy screening beginning at age 50 for those at average risk, sooner if there are certain risk factors."
Colonoscopy is a common and very safe procedure that examines the lining of the lower intestinal tract called the colon or large intestine. Colonoscopy means "to look inside the colon." Physicians specially trained in the procedure use a flexible tube that has a light and miniature TV camera on the tip. This instrument, often referred to as the "scope," is placed in the rectum and advanced through the colon. It is connected to a television monitor that the physician watches while performing the test. Various miniaturized tools can be inserted through the scope to obtain biopsies (samples) of the colon and to perform a wide range of maneuvers for diagnosis and treatment. When used as a colon cancer prevention method, colonoscopy can find potentially precancerous conditions before they turn into cancer. Colonoscopy is the only procedure that visualizes the entire colon and allows for the detection and removal of lesions and polyps before they turn into cancer. New advances in endoscopic technology are improving detection of colorectal cancer and precancerous polyps.
About Colorectal Cancer
Each year nearly 150,000 people are diagnosed with colon cancer and almost 50,000 die from the disease annually in the United States. Colorectal cancer, also known as colon cancer, is the third most commonly diagnosed cancer in men and women and the third leading cause of cancer-related deaths in men and women in the United States. Many of those deaths could be prevented with earlier detection. Colorectal cancer screening's effect on early detection and prevention through polypectomy (performed during colonoscopy) has been identified as a main contributing factor for the declining rates of colorectal cancer incidence and deaths from the disease.
About the American Society for Gastrointestinal Endoscopy
Founded in 1941, the mission of the American Society for Gastrointestinal Endoscopy is to be the leader in advancing patient care and digestive health by promoting excellence in gastrointestinal endoscopy. ASGE, with nearly 11,000 members worldwide, promotes the highest standards for endoscopic training and practice, fosters endoscopic research, recognizes distinguished contributions to endoscopy, and is the foremost resource for endoscopic education. Visit www.asge.org and www.screen4coloncancer.org for more information.
Endoscopy is performed by specially-trained physicians called endoscopists using the most current technology to diagnose and treat diseases of the gastrointestinal tract. Using flexible, thin tubes called endoscopes, endoscopists are able to access the human digestive tract without incisions via natural orifices. Endoscopes are designed with high-intensity lighting and fitted with precision devices that allow viewing and treatment of the gastrointestinal system.
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SOURCE American Society for Gastrointestinal Endoscopy