Better Adherence to CT Colonography Might Not Trump Colonoscopy Advantages

In a randomized, controlled trial in the Netherlands, adherence to CT colonography was higher than to colonoscopy for colorectal cancer screening, but results might not be generalizable to the U.S.


Colorectal cancer screening tests are only effective if invited patients actually undergo the tests (i.e., adherence). In previous trials comparing the acceptance of computed tomographic colonography (CTC) versus conventional colonoscopy, only one study examined adherence, finding similar rates of about 18% (Am J Gastroenterol 2004; 99:1145). Now, results of the largest trial to date show better adherence rates for CTC than colonoscopy.

In this study, investigators randomized 8844 people aged 50 to 75 in the Netherlands to be offered colonoscopy or CTC in a 2:1 ratio. CTC was performed with a noncathartic preparation in which patients received only three 50-mL doses of iodinated contrast before the procedure.

The adherence rate was higher for CTC than colonoscopy (34% vs. 22%; P<0.0001). Among those screened, completion rates were 99% for CTC and 98% for colonoscopy. The yield of patients with advanced neoplasia was 6.1% with CTC versus 8.7% with colonoscopy (P=0.02). Yield per invitee was similar in the CTC and colonoscopy groups (2.1% and 1.9%). The detection rate of "serrated adenomas" was 12 times higher in patients receiving colonoscopy versus CTC (2.4% vs. 0.2%). Rates of cancer detection and complications were low and did not differ between groups.


Citation(s):

Stoop EM et al. Participation and yield of colonoscopy versus non-cathartic CT colonography in population-based screening for colorectal cancer: A randomised controlled trial. Lancet Oncol 2011 Nov 15; [e-pub ahead of print].

Pickhardt PJ. Strong evidence in support of CT colonography screening. Lancet Oncol 2011 Nov 15; [e-pub ahead of print].