August 16, 2019
2 min read

Multiple FIT rounds offer better diagnostic yield for advanced neoplasia

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Multiple rounds of fecal immunochemical tests sent to patients through the mail had a higher diagnostic yield for advanced neoplasia among invitees compared with one-time flexible sigmoidoscopy or one-time colonoscopy, according to study results.

Manon C.W. Spaander, MD, PhD, of the department of gastroenterology and hepatology at Erasmus University Medical Center in the Netherlands, and colleagues wrote that it is unclear which screening technique offers the largest effect on colorectal cancer morbidity and mortality.

“It is of key importance for policy makers to know the impact of different screening programs over multiple rounds with long-term follow up,” they wrote. “For this reason, we aimed to compare the diagnostic yield of once-only colonoscopy, once-only flexible sigmoidoscopy and four rounds of FIT in population-based CRC screening, including interval cancer rate.”

Researchers invited 30,007 asymptomatic individuals aged between 50 and 74 years to participate in a CRC screening program. They assigned these individuals to three groups; the first received four rounds of mailed FIT (n = 15,046), one group underwent one-time flexible sigmoidoscopy (n = 8,407) and the last underwent one-time colonoscopy (n = 6,600).

Investigators referred patients to colonoscopy if they had a positive FIT or had evidence of large polyps or adenoma during sigmoidoscopy. Primary outcome of the study was number of advanced neoplasms detected by each test, defined as CRC, adenomas of at least 10 mm, adenomas with high-grade dysplasia or adenomas with a villous component of at least 25%. Researchers also included number of colonoscopies needed to detect advanced neoplasia and number of interval CRCs found during each primary screening test as secondary outcomes.

The FIT screening group had the highest cumulative participation rate (77%) compared with 31% in the sigmoidoscopy group and 24% in the colonoscopy group. The sigmoidoscopy group had the lowest percentage of colonoscopies among individuals invited (3%) compared with the FIT (13%) and colonoscopy (24%) groups.

In their intention-to-screen analysis, researchers found that the cumulative diagnostic yield for advanced neoplasia was higher with FIT (4.5%; 95% CI, 4.2%–4.9%) than both colonoscopy (2.2%; 95% CI, 1.8%–2.6%) or sigmoidoscopy (2.3%; 95% CI, 2%–2.7%). In their as-screened analysis, investigators found that colonoscopy had the best diagnostic yield (9.1%; 95% CI, 7.7%–10.7%) compared with sigmoidoscopy (7.4%; 95% CI, 6.5%–8.5%) and FIT (6.1%; 95% CI, 5.7%–6.6%).

All three screening modalities detected a similar proportion of patients with CRC.

“Since many countries are considering to implement screening programs, the findings of this study aid in deciding on choice of screening strategies worldwide, based on expected participation rates and available colonoscopy resources,” Spaander and colleagues wrote. by Alex Young

Disclosures: The authors report no relevant financial disclosures.