Using CT colonography as an additional primary colorectal cancer screening test could lead to substantially greater participation in screening programmes compared with conventional colonoscopy, according to research published in The Lancet Oncology.

"The issue with screening for colorectal cancer is not related to the test efficacy per se, but rather to the willingness of patient participation. By offering the additional option of CT colonography for screening, overall patient outcomes will be positively affected by the equivalent (or greater) yield for advanced neoplasia coupled with a decrease in complications and costs", explains Perry Pickhardt from the University of Wisconsin-Madison, Madison, USA, in an accompanying Comment.

Although most colorectal cancers develop from polyps and are essentially preventable and treatable, colorectal cancer remains the second leading cause of cancer deaths in Europe. Screening by colonoscopy saves lives by identifying and removing polyps before they become cancerous, but participation is generally low. Because CT colonography is less invasive than standard colonoscopy and does not require sedation, it might encourage more people to be screened.

A team led by Evelien Dekker and Jaap Stoker from the Academic Medical Centre, Amsterdam, and Ernst Kuipers from the Erasmus Medical Center, Rotterdam, The Netherlands compared participation and diagnostic yield** between screening with conventional colonoscopy and CT colonography. The study included average-risk individuals 50–75 years of age from the general Dutch population in Amsterdam and Rotterdam, who were randomly allocated to be invited for colorectal cancer screening by colonoscopy or by CT colonography.

CT colonography improved participation in screening by more than 50% compared with conventional colonoscopy. "The most probable reason for the significant difference in participation rate is a difference in the expected burden or procedure-related complications", say the authors.

Colonoscopy identified significantly more advanced neoplasia (abnormal growth of cells) per 100 participants than CT colonography, but the overall programme yield (per invitee) for advanced neoplasia was similar for both procedures.

The authors conclude: "Both techniques can be used for population-based screening for colorectal cancer. Other factors such as cost-effectiveness and perceived burden should be taken into account when deciding which technique is preferable."

"The additive yields of having both colonoscopy and CT colonography available as primary screening options could have a profound effect on the incidence and mortality of colorectal cancer in the future", adds Perry Pickhardt in the accompanying comment.

Source: The Lancet