CT colonography often detects extracolonic abnormalities in older patients

November 20, 2007

NEW YORK (Reuters Health) - Two thirds of elderly patients undergoing CT colonography (CTC) for lower gastrointestinal symptoms will have one or more extracolonic abnormalities detected, which, in many cases, are clinically significant, new research shows.

"We were surprised at the high incidence of tumors outside the colon," lead author Dr. Damian Tolan, from St. James's University Hospital in Leeds, UK, told Reuters Health.

"About 7% of patients referred to our service were diagnosed with colon cancer, and 5.5% had other tumors," he said. "In patients without colon cancer over 70 in our study population, they had a 1 in 5 chance of having a potentially significant previously undiagnosed abnormality not involving the colon, and a 1 in 20 chance of having an extracolonic malignancy, which we found remarkable."

The study, which is reported in the American Journal of Roentgenology for November, involved an assessment of CTC findings in 400 consecutive patients, older than 70 years, who were evaluated over a 14-month period. Symptoms leading to CTC evaluation included weight loss, a change in bowel habits, rectal blood loss, abdominal pain, and anemia.

Overall, 505 extracolonic abnormalities were identified in 268 of the patients (67%), including 116 with lesions considered clinically significant. "Of these, 110 lesions were previously unknown in 96 of the 400 patients (24.0%)," Dr. Tolan and colleagues found.

One or more malignancies were detected in 49 patients (12.3%), including 29 cancers inside and 23 outside the colon. In 13 patients, the cancers had not yet spread to nearby lymph nodes.

In 20 patients with colon cancer, newly identified extracolonic abnormalities were also seen. Half of these extracolonic lesions were related to the primary tumor and half were not.

"We would recommend clinicians consider CT colonography in investigating symptomatic patients over 70, rather than using barium enema (and possibly colonoscopy) alone, because of the number of additional significant findings we can detect with this technique," Dr. Tolan said. "An additional benefit is that sedation is not required with its attendant risks and there is a very low associated complication rate."