Detection of serrated lesions in proximal colon by simulated sigmoidoscopy vs faecal immunochemical testing in a multicentre, pragmatic, randomised controlled trial

Abstract

Background The diagnostic yield of the faecal immunochemical test and sigmoidoscopy in detecting proximal serrated polyps in a colorectal cancer screening programme has not been fully assessed. Aim We determined the detection rate of proximal serrated polyps by simulated sigmoidoscopy and faecal immunochemical test compared with total colonoscopy in a population-based, multicentre, nationwide, randomised controlled trial (ColonPrev study). Methods Sigmoidoscopy yield was simulated based on the UK-Flexible Sigmoidoscopy Trial for total colonoscopy referral. Definitions were: proximal serrated polyp (proximal serrated polyp): sessile serrated polyp or hyperplastic polyp of any size and proximal at-risk serrated polyp (at-risk proximal serrated polyp): sessile serrated polyp of any size or hyperplastic polyp ≥ 10 mm, both located proximally to the splenic flexure. Results A total of 10,611 individuals underwent faecal immunochemical test and 5059 underwent total colonoscopy and were evaluated by simulated sigmoidoscopy. Sigmoidoscopy and faecal immunochemical test were less accurate in detecting proximal serrated polyps (odds ratio: 0.13; 95% confidence interval: 0.10–0.18 and 0.13; 0.09–0.18, p < 0.0001, respectively). Both tests were inferior to colonoscopy in detecting at-risk proximal serrated polyps, and sigmoidoscopy was inferior to faecal immunochemical test in detecting these lesions (odds ratio: 0.17; 95% confidence interval: 0.10–0.30 and 0.25; 0.17–0.37, p < 0.0001, respectively). Conclusion Sigmoidoscopy and faecal immunochemical test are less accurate in detecting proximal serrated polyps than colonoscopy, particularly in women.

Relatively low risk and nonaggressive stage of colorectal cancer in individuals with negative baseline fecal immunochemical test results: A cohort study

“…FIT has major limitations in detecting serrated polyps compared with total colonoscopy. 24,25 In addition, colonoscopy was found to be superior to FIT for detecting advanced adenomas. 23 In patients in whom cancer developed, median stool hemoglobin values from the baseline FIT were found to be higher in left-sided than in right- 26 which may be related to hemoglobin breakdown during transit through the colon.…”

“…Recent studies have reported that FIT-based screening was less sensitive in detecting advanced proximal colon neoplasia. [22][23][24] This may be because more proximal colon cancers develop from nonadenomatous lesions, such as sessile serrated polyps and flat (nonpolypoid) lesions. FIT has major limitations in detecting serrated polyps compared with total colonoscopy.…”

“…Besides, the sensitivity of FIT is different according to CRCs location. Recent studies have reported that FIT‐based screening was less sensitive in detecting advanced proximal colon neoplasia 22–24 . This may be because more proximal colon cancers develop from nonadenomatous lesions, such as sessile serrated polyps and flat (nonpolypoid) lesions.…”

Simulated performance of flexible sigmoidoscopy-based screening for advanced neoplasia detection in a Greek population

“…This was valid for both sexes; however, the difference was particularly pronounced in women, in whom all 4 criteria equally led to a particularly low sensitivity for ASLs (30%). In a post-hoc analysis of the ColonPrev study, the authors evaluated the diagnostic performance of FS visualizing the rectosigmoid followed by colonoscopy (UK referral criteria), focusing on detection of proximal serrated neoplasms [23]. In keeping with our findings, they determined that such a strategy would have detected 86% fewer individuals with proximal serrated polyps compared to total colonoscopy (odds ratio 0.13, 95%CI 0.10-0.18), with the performance being particularly low among women.…”

Future Prospects of Colorectal Cancer Screening: Characterizing Interval Cancers

“…However, the natural history of these lesions to CRC and programmatic screening are opportunities to detect them [ 18 ]. The sensitivity is significantly higher for polyps with advanced histology, a larger size, and a pedunculated shape, and lower for serrated lesions [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Some studies [ 29 , 30 , 31 ] have evaluated the differences in the diagnostic performance of the FIT in detecting neoplasia located in the proximal or right-sided colon (colon above the level of the splenic flexure) versus the distal colon.…”