Home > Gastroenterology > Cancer detection likely similar for one-time colonoscopy or two fecal immunochemical tests

Cancer detection likely similar for one-time colonoscopy or two fecal immunochemical tests

The Lancet Gastroenterology and Hepatology
Reuters Health - 29/03/2022 - Colon cancer screening results were similar for a single colonoscopy or two closely timed fecal immunochemical tests (FIT), although colonoscopy detected more right-sided lesions, according to a preliminary report from an ongoing randomized trial. 

"This is the first report after recruitment and screening from SCREESCO (SCREEning of Swedish COlons), a national randomized controlled trial in 18 regions in Sweden," Dr. Anna Forsberg of the Karolinska Institute told Reuters Health by email. "The preliminary analysis of data collected from 2014-2020 suggests satisfactory participation, a low rate of adverse events, and on the intention-to-treat level, no difference in the two arms for colorectal cancer detection; however, colonoscopy performed better than FIT for right-sided lesions." 

"The approach - one-time colonoscopy at age 60 or two FIT tests two years apart, compared to no screening - was never tested before," she added. 

As reported in The Lancet Gastroenterology and Hepatology, Dr. Forsberg and colleagues randomized close to 280,000 individuals to either once-only colonoscopy (31,400); two rounds of FIT, two years apart using the OC-Sensor (60,300); or a control group with no intervention - only standard diagnostic pathways (186,840). 

The primary endpoints of the trial are colon cancer incidence and mortality. Measures for the current analysis included participation rates, baseline findings and adverse events up to the completion of the second FIT round. 

Participation rates were 35.1% for colonoscopy and 55.5% for one or both rounds of FIT. 

A total of 6,471 participants had a positive FIT (6.3%), and of those, most (90.8%) had a subsequent colonoscopy. 

In the intention-to-screen analysis, colorectal cancer was detected in 49 patients (0.16%) in the colonoscopy group versus 121 (0.20%) in the FIT group (relative risk, 0.78). 

Advanced adenomas were detected in 2.05% of the colonoscopy group and 1.61% of the FIT group (RR, 1.27). As Dr. Forsberg noted, colonoscopy detected more right-sided advanced adenomas than FIT. 

There were two perforations and 15 major bleeds in more than 16,500 colonoscopies. No intervention-related deaths occurred. 

Dr. Forsberg said, "Based on the colonoscopy quality, the overall diagnostic yield and the low number of adverse events in a routine clinical setting, the SCREESCO design can be transferred to a population-screening service." 

Dr. Jeffery Nelson, Surgical Director of Mercy's Center for Inflammatory Bowel and Colorectal Diseases in Baltimore, commented in an email to Reuters Health, "I agree with the findings from an academic point of view. However, all the study patients were 60 years old, (and), we know that colorectal cancer is increasing in people under age 50. This problem doesn't figure into the calculus of this study." 

"It would be advantageous from a resource perspective if we could just scope people once at a certain age or do stool testing, and then not have to repeat it," he said. However, "In this study, they used FIT testing (tests for blood in the stool just from a colonic source), but Cologard (stool DNA testing) is probably more prevalent in the U.S." 

He also expressed concern that the FIT testing arm missed more right-sided lesions than the colonoscopy arm. 

"Similar studies would need to be conducted in different age groups, perhaps using Cologard, as well, to determine the ultimate effectiveness and applicability of this strategy," he said. "It is encouraging, however, that in tens of thousands of patients, the colon cancer detection rate was only 0.4% to 0.5% in each treatment arm." 

The study was funded in part by Eiken Chemical. 

SOURCE: https://bit.ly/3tPc5xb  The Lancet Gastroenterology and Hepatology, online March 14, 2022. 

By Marilynn Larkin 

Posted on