Certain Factors Boost Risk of Post-Colonoscopy Cancer
Physicians urged to inform patients that they have a 2 percent to 6 percent risk of a new or missed cancer
FRIDAY, Jan. 26 (HealthDay News) -- In patients who undergo a colonoscopy with negative findings, there is a 2 percent to 6 percent chance that they will go on to develop a new or missed case of colorectal cancer, according to a study published in the January issue of Gastroenterology. Independent risk factors for a new or missed cancer include older age, diverticular disease, right-sided or transverse colorectal cancer, colonoscopy by an internist or family physician, and colonoscopy in an office.
Brian Bressler, M.D., of the University of Toronto in Ontario, Canada, and colleagues analyzed data from the Ontario Cancer Registry database to identify all the Ontario residents who had a new diagnosis of colorectal cancer between April 1, 1997 and March 31, 2002, and who had a colonoscopy sometime in the three years prior to their diagnosis.
They found that the respective rates of new or missed cancers were 5.9 percent for right-sided tumors (3,288 cases), 5.5 percent for transverse tumors (777 cases), 2.1 percent for splenic flexure/descending tumors (710 cases) and 2.3 percent for rectal or sigmoid colorectal cancers (7,712 cases).
"Because having an office colonoscopy and certain patient, procedure and physician characteristics are independent risk factors for new or missed colorectal cancer, physicians must inform patients of the small risk (2 percent to 6 percent) of these cancers after colonoscopy," the authors conclude.