April 29, 2016
2 min read

CT colonography comparable to flexible sigmoidoscopy for CRC screening

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CT colonography performed with a comparable detection rate to flexible sigmoidoscopy as a screening test for colorectal cancer in two randomized clinical trials in Italy.

“No direct comparison between [CT colonography] and [flexible sigmoidoscopy] is available to date. To bridge this knowledge gap we have undertaken a study aimed at comparing [advanced neoplasia] detection rate ... and participation rate,” the researchers wrote.

They performed two randomized clinical trials in which randomly assigned average risk individuals aged 58 to 60 years underwent screening CT colonography or flexible sigmoidoscopy. Participation rate and detection rate of advanced neoplasia served as the respective primary outcome measures in each trial.

In the participation trial, 30.4% of the 980 patients randomly assigned CT colonography participated, and 27% of the 976 patients randomly assigned flexible sigmoidoscopy participated (RR = 1.12; 95% CI, 0.98-1.29). Men randomly assigned CT colonography had a higher participation rate than men randomly assigned flexible sigmoidoscopy (34.1% vs. 26.5%; RR = 1.3; 95% CI, 1.07-1.65).

“A higher screening uptake among men may enhance the health impact of screening, since men have a higher [advanced neoplasia] prevalence compared with women,” the researchers wrote. “However, measures to reduce the gender gap in screening coverage also need to be implemented when using [CT colonography], as is already the case with [flexible sigmoidoscopy].”

In the detection trial, 2,673 patients underwent flexible sigmoidoscopy and 2,595 underwent CT colonography. The respective advanced neoplasia detection rates were 4.8% and 5.1% (RR = 1.08; 95% CI, 0.85-1.37), although “the distribution of [advanced neoplasia] detected by the two tests showed a different pattern by colonic site,” with respective distal advanced neoplasia detection rates of 3.9% and 2.9% (RR = 0.72; 95% CI, 0.54-0.96), and respective proximal advanced neoplasia detection rates of 1.2% and 2.7% (RR = 2.06; 95% CI, 1.37-3.1).

“In a population-based screening trial, [CT colonography] showed a similar [advanced neoplasia] detection and acceptability as [flexible sigmoidoscopy],” the researchers wrote. “Comparative cost-effectiveness data are needed to assess the possible role of [CT colonography] in this setting.” – by Adam Leitenberger

Disclosure: Two of the researchers report they are employees of im3D, but the researchers who were not employees or consultants of im3D had control of all data and information that might present a conflict of interest.