Repeat FIT Detects More Colon Cancers, Advanced Adenomas Compared With Sigmoidoscopy

colon cancer
colon cancer, CRC, colorectal neoplasia
A team of investigators report on the findings of a randomized clinical trial that compared sigmoidoscopy to repeated fecal immunochemical testing for colorectal cancer.

Repeat fecal immunochemical testing (FIT) was found to detect more colorectal cancers (CRCs) and advanced adenomas than once-only sigmoidoscopy in older patients undergoing CRC screening; however, both methods appear feasible with good participation rates, according to the results of a study published in Gastroenterology.

Investigators recruited people from Norway between the ages of 50 and 74 years (N=139,291) to undergo once-only flexible sigmoidoscopy (n=69,195) or FIT screening repeated every second year (n=70,096) for a total of 4 screenings. Patients with polyps measuring at least 10 mm, at least 3 adenomas, any advanced adenomas, or CRC were recommended to undergo colonoscopy after sigmoidoscopy. Outcome measures of this study included participation, neoplasia detection, and adverse events.

Participation rates for sigmoidoscopy and the first FIT round were 52% and 58%, respectively, and the participation rate for the 3 cumulative FIT rounds was 68%. The CRC detection rate in the first FIT round was similar to that with sigmoidoscopy (0.25% v 0.27%, respectively; odds ratio [OR], 0.92; 95% CI, 0.75-1.13; P =.410), but the CRC detection rate was higher after 3 FIT rounds relative to sigmoidoscopy (0.49% vs 0.27%; OR, 1.87; 95% CI, 1.54-2.27).

Although the rate of advanced adenoma detection was lower in the first FIT round compared with sigmoidoscopy (1.4% vs 2.4%; OR, 0.57; 95% CI, 0.53-0.62; P <.001), it was higher following 3 cumulative FIT rounds (2.7% vs 2.4%; OR, 1.14; 95% CI, 1.05-1.23; P =.001). No significant difference was noted between the sigmoidoscopy and FIT groups with regard to the rate of serious adverse events (0.05% vs 0.07%, respectively; P =.13).

Limitations of the study include incomplete data available for the third round of FIT (63%) as well as the inclusion of only patients from Norway, which may limit generalizability of the findings.

Although the researchers caution that “long-term follow-up data on CRC mortality and incidence are not expected until 10 years of follow-up,” they state that “results from large

randomized trials like ours will offer important information for policy makers with regard to the upcoming screening program in Norway, and in other countries where screening programs are already in place or imminent.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Randel KR, Schult AL, Botteri E, et al. Colorectal cancer screening with repeated fecal immunochemical test versus sigmoidoscopy: baseline results from a randomized trial. Published online November 20, 2020. Gastroenterology. doi:10.1053/j.gastro.2020.11.037