Priority stratification for colonoscopy based on two-sample faecal immunochemical test screening: results from a cross-sectional study at an endoscopy clinic in Japan

Abstract

ObjectivesLittle has been reported on the yield and characteristics of colorectal neoplasia detected by the two-sample faecal immunochemical test (FIT), particularly the difference between subjects with two-positive results on the two-sample FIT and those with one-positive results. We aimed to assess risk stratification among patients with positive two-sample FIT to prioritise colonoscopy.DesignA retrospective cross-sectional study.SettingA single-centre, representative endoscopy clinic in Japan.ParticipantsConsecutive patients who underwent colonoscopy were enrolled. Indications for colonoscopy included two-positive results on the two-sample FIT (FIT (+/+)), one-positive results on the two-sample FIT (FIT (+/−)), and other reasons (non-FIT group, including presence of symptoms, screening or surveillance).Primary and secondary outcome measuresPrimary outcomes were detection rates of colorectal cancers, including in situ (all cancers) and invasive cancers, based on the indications for colonoscopy. Secondary outcomes were cancer features, such as location, size, T stage and histological subtype.ResultsOf the 8724 patients, 264 underwent colonoscopy following FIT (+/+), 1018 following FIT (+/−) and 7442 for reasons other than positive FIT. Detection rates of all (and invasive) cancers in the FIT (+/+), FIT (+/−) and non-FIT groups were 12.1% (8.3%), 1.9% (0.3%) and 0.4% (0.2%), respectively. The cancer detection rates were much higher in the FIT (+/+) group than in the FIT (+/−) group, which in turn had higher rates than the non-FIT group. Moreover, the FIT (+/+) group showed more advanced T stages on tumour, node, metastasis (TNM) classification (Tis/T1/T2/T3/T4: 10/7/4/10/1) than the FIT (+/−) group (16/1/2/0/0, p<0.001).ConclusionsTwo-positive results for two-sample FIT showed a much higher yield for more advanced colorectal cancers than the one-positive result. High priority for diagnostic colonoscopy should be assigned to patients with two-positive-FIT results.

A cohort study of duplicate faecal immunochemical testing in patients at risk of colorectal cancer from North-West England

“…The utility of a two-sample FIT strategy has previously been evaluated in the literature 26–29. While it has been suggested that it may be a useful tool for clinicians to risk stratify patients referred for urgent colonoscopy,26 29 other groups suggest that the performance of FIT is not improved with repeated sampling 27 28.…”

“…The utility of a two-sample FIT strategy has previously been evaluated in the literature 26–29. While it has been suggested that it may be a useful tool for clinicians to risk stratify patients referred for urgent colonoscopy,26 29 other groups suggest that the performance of FIT is not improved with repeated sampling 27 28. Some of this evidence is from asymptomatic patients in screening programmes and is therefore arguably not directly relevant to symptomatic patients,27 and while other studies performed suggest that repeat FIT sampling does not have additional benefit at a threshold 12 µgHb/g, a significant proportion of CRC patients were FIT negative, raising concerns about the safety and acceptability of a single sample strategy alone to risk stratify patients outside of secondary care 28…”

Double faecal immunochemical testing in patients with symptoms suspicious of colorectal cancer

“…Both this previous work and the present study included referred populations, and are therefore different from unselected patients attending primary care. Increased pathology yield with two positive tests is known to aid colonoscopy resource prioritization 16 . Previous smaller studies have compared one against two FITs in symptomatic patients with mixed results, from no benefit from a second test 17 , to improved sensitivity for colorectal cancer 18 and advanced colorectal neoplasia 19 .…”

One or two faecal immunochemical tests in an organised population-based colorectal cancer screening programme in Murcia (Spain)

“…In contrast to our work, the capacity of the health system to cope with the increase in colonoscopies due to the higher detection rate was not considered. 34 Turvill et al have also recently contributed showing no improvement in diagnostic yield using one or two FITs, but their study assessed 13 FIT in patients presenting with symptoms, not in an asymptomatic screening population. 35 A germane question is to what extent would a change in strategy that reduces the positivity and allows an increase in the participating population without changing the total number of participants with positive FIT results (and therefore the same colonoscopy requirement) affect neoplasia detection rates.…”

“…In contrast to our work, the capacity of the health system to cope with the increase in colonoscopies due to the higher detection rate was not considered. 34 Turvill et al have also recently contributed showing no improvement in diagnostic yield using one or two FITs, but their study assessed FIT in patients presenting with symptoms, not in an asymptomatic screening population. 35…”