CT Colonography Has Higher Cancer Detection Rate Among Seniors

May 15, 2018

CT colonography detects cancer among seniors with no colorectal cancer symptoms.

Computed tomography colonography (CTC) detects more cancer among seniors without symptoms compared with younger adults, according to a study published in the American Journal of Roentgenology.

Researchers from the United States and Italy performed a systematic review of CTC studies to assess the rate of lesion detection among adults aged 65 years and older. They reviewed studies published between January 1994 and August 2017 containing data on senior-age adults and primary endpoint or the CTC-positive rate for large colorectal polyps (10 mm or larger) and masses. Secondary endpoints included lesions 6 mm or larger, proven advanced neoplasia, and colorectal cancer (CRC).

The researchers included 34 studies with 41,680 (18,798 senior-age) subjects. They found pooled CTC-positive rates among senior-age patients using the 10-mm size threshold were significantly lower in cohorts of patients with no symptoms (8.2 percent) compared with cohorts of patients with positive fecal occult blood tests (32.8 percent) and other symptoms of CRC (14 percent). “However, a uniformly high positive predictive value for advanced neoplasia at colonoscopy was seen for all senior-age cohorts using a 10-mm threshold (84.3 percent) where such data were available,” they wrote. The CTC sensitivity for CRC was 93 percent in senior-age patients compared with 92 percent in younger patients. Overall, the CTC detection rates were higher in senior-age adults compared with younger adults.

While CTC-positive rates were higher among older patients and those with CRC symptoms, on average, one in every 12 senior-age adults without symptoms of CRC who underwent screening would be referred to colonoscopy using the 10-mm threshold, with a high yield for advanced neoplasia and high sensitivity for cancer detection, the researchers concluded.