Rates of new or missed colorectal cancer after barium enema and their risk factors: a population-based study.

OBJECTIVE: Double-contrast barium enema (DCBE) is widely used in clinical practice to detect colorectal cancer (CRC). Our objective was to evaluate the rate of new or missed CRC following DCBE and the associated risk factors in a population-based study.

METHODS: All patients (> or =20 yr old) with a new diagnosis of CRC between April 1, 1997, and March 31, 2004, in Ontario were identified. Data were extracted from the Ontario Health Insurance Program, the Canadian Institute for Health Information, the Registered Persons Database and the Ontario Cancer Registry. Patients who had a DCBE examination 36 months prior to the diagnosis of CRC were divided into two groups: detected cancers (DCBE within 6 months prior to diagnosis) and new or missed cancers (DCBE 6-36 months prior to diagnosis). Multivariate analysis was used to evaluate factors associated with new or missed CRC.

RESULTS: We identified 13,849 patients who had a DCBE 36 months prior to the diagnosis of CRC. The overall rate of new or missed cancers following DCBE was 22.4%. Independent risk factors for new or missed cancers were older age, female sex, previous abdominal or pelvic surgery, diverticular disease, right-sided CRC, and having the DCBE in an office setting.

CONCLUSIONS: Physicians who use DCBE to evaluate the colon must inform their patients that if a cancer is present, there is an approximately one in five chance that it will be missed. Given the recent endorsement of CT colonography by the U.S. Multi-Society Task Force on Colorectal Cancer as an option for CRC screening, it may be time to reconsider the use of DCBE to detect CRC.