Less-Invasive Colorectal Screening Test May Detect Cancer as Effectively as Colonoscopy ► NCI Cancer Bulletin for March 6, 2012 - National Cancer Institute

NCI Cancer Bulletin for March 6, 2012 - National Cancer Institute

Less-Invasive Colorectal Screening Test May Detect Cancer as Effectively as Colonoscopy

Initial findings from a European clinical trial show that colonoscopy and fecal immunochemical testing (FIT), a type of stool test, detect a similar number of colorectal cancers. Investigators leading the COLONPREV trial are testing whether screening average-risk individuals only once with colonoscopy can reduce the number of deaths from colorectal cancer compared with biennial screening with FIT. The results from the trial’s first round of screening appeared February 23 in the New England Journal of Medicine.

More participants in the FIT group than the colonoscopy group complied with screening, 34.2 percent versus 24.6 percent. The two tests had similar cancer detection rates, and the stage of the cancers found did not differ between the groups. However, colonoscopy was better than FIT at detecting both advanced and, especially, nonadvanced adenomas. However, the extent to which nonadvanced adenomas are likely to progress to more advanced disease is not yet known.

“Since the primary outcome of this trial is the reduction in the rate of death from colorectal cancer at 10 years, the relative benefits and risks of the two strategies will be assessed at the end of the trial,” explained the authors. Follow-up will continue through 2021.

These results hold promise, noted Dr. Barry Kramer, director of NCI’s Division of Cancer Prevention, because the less-invasive FIT—which had better screening participation—picked up the same number of cancers as colonoscopy during the initial period of the trial.

“The final proof will be mortality, but it’s certainly conceivable that, as the trial goes on, FIT will continue to pick up potentially lethal cancers that are missed by a one-time [colonoscopy],” he explained. In the COLONPREV design, patients assigned to colonoscopy get a single test, whereas patients assigned to FIT receive the stool test every 2 years over a 10-year period.