"This study is very significant, as these flat lesions are more difficult to detect than the typical polyp during colorectal cancer screening," said Grace H. Elta, MD, FASGE, president of the American Society for Gastrointestinal Endoscopy (ASGE). "Researchers identified these lesions in their study through colonoscopy, which has the ability to detect lesions of all sizes and is the only procedure that allows for the removal of lesions and polyps. Studies have shown that other imaging methods are ineffective at identifying even small polyps and miss flat lesions entirely. This study highlights the importance of quality colonoscopy screening. ASGE, as the standard-setting society for endoscopy, has issued quality indicators for colorectal cancer screening that define measures for improving quality in colonoscopy."
Flat lesions are challenging to detect because subtle findings through examination can be difficult to distinguish from the normal mucosa. As compared with the surrounding normal mucosa, the flat lesions appear to be slightly elevated, completely flat or slightly depressed.
The study examined data from a group of 1,819 patients, almost all men with an average age of 64, from July 2003 to June 2004 undergoing elective colonoscopy to estimate the prevalence of non-polypoid colorectal neoplasms (NP-CRNs), or flat lesions, and to characterize their association with colorectal cancer. Patients were divided into three groups; screening, surveillance and a group of patients with symptoms for colorectal cancer. Flat lesions were found in 170 people, approximately 10 percent. The surveillance group had the highest incidence with more than 15 percent who had flat lesions. Approximately six percent of the screening and symptoms groups had flat lesions. Researchers found that the flat growths were five times more likely to be cancerous than polyps.
"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. Proper bowel prep is important so that the physician can clearly see the colon. This study also 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, withdrawal time should be six minutes or more. ASGE will continue to provide training and education to physicians to ensure that patients are receiving the highest quality of care possible," said Elta.
About Colonoscopy
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.
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 second leading cause of cancer-related deaths in the United States. Many of those deaths could be prevented with earlier detection. The five-year relative survival rate for people whose colon cancer is treated in an early stage is greater than 90 percent. Unfortunately, only 39 percent of colon cancers are found at that early stage. Once the cancer has spread to nearby organs or lymph nodes, the five-year relative survival rate decreases dramatically.
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.
