Higher Fecal Immunochemical Test Cutoff Levels: Lower Positivity Rates but Still Acceptable Detection Rates for Early-Stage Colorectal Cancers

Abstract

Background: Adjusting the threshold for positivity of quantitative fecal immunochemical tests (FIT) allows for controlling the number of follow-up colonoscopies in a screening program. However, it is unknown to what extent higher cutoff levels affect detection rates of screen-relevant neoplasia. This study aimed to assess the effect of higher cutoff levels of a quantitative FIT on test positivity rate and detection rate of early-stage colorectal cancers (CRC).Methods: Subjects above 40 years old scheduled for colonoscopy in 5 hospitals were asked to sample a single FIT (OC sensor) before colonoscopy. Screen-relevant neoplasia were defined as advanced adenoma or early-stage cancer (stage I and II). Positivity rate, sensitivity, and specificity were evaluated at increasing cutoff levels of 50 to 200 ng/mL.Results: In 2,145 individuals who underwent total colonoscopy, 79 patients were diagnosed with CRC, 38 of which were with early-stage disease. Advanced adenomas were found in 236 patients. When varying cutoff levels from !50 to !200 ng/mL, positivity rates ranged from 16.5% to 10.2%. With increasing cutoff levels, sensitivity for early-stage CRCs and for screen-relevant neoplasia ranged from 84.2% to 78.9% and 47.1% to 37.2%, respectively.Conclusions: Higher FIT cutoff levels substantially decrease test positivity rates with only limited effects on detection rates of early-stage CRCs. However, spectrum bias resulting in higher estimates of sensitivity than would be expected in a screening population may be present.Impact: Higher cutoff levels can reduce strain on colonoscopy capacity with only a modest decrease in sensitivity for curable cancers. Cancer Epidemiol Biomarkers Prev; 20(2); 272-80. Ó2010 AACR.

Faecal immunochemical tests to triage patients with lower abdominal symptoms for suspected colorectal cancer referrals in primary care: a systematic review and cost-effectiveness analysis

“…After initial screening of titles and abstracts, 113 papers were considered to be potentially relevant and ordered for full-paper screening; of these, 21 papers 13,[52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71] were included in the review.…”

“…The authors of two studies 56,58 provided additional test accuracy data, which were included in our review.…”

“…Additional data were supplied by the authors of two studies. 56,58 In the case of Terhaar sive Droste et al, 58 the authors provided overall data for symptomatic study from the master database, which holds data for all of their publications (e-mail from Sietze van Turenhout, University Medical Center, Amsterdam, to Marie Westwood, KSR Ltd, 12 June 2016, personal communication). The results section of this report cites studies using the primary publication and, where this is different, the publication (shown in bold text in Table 3) in which the referenced data were reported.…”

Using the Cancer Risk Management Model to Evaluate Colorectal Cancer Screening Options for Canada

“…Sigmoidoscopy parameters were assumed to be the same as those for colonoscopy in the distal colon and rectum. Sensitivities and specificities for fecalbased tests were taken from published comparative studies that included colonoscopy evaluation of all subjects [38][39][40][41][42][43][44][45][46][47] and assumed that the fecal immunochemical test (fit) uses a single sample. For other parameters, the model provides base-case values, but users can specify their own values.…”

A new insight into fecal hemoglobin concentration‐dependent predictor for colorectal neoplasia

“…While the fecal immunochemical test (FIT) is widely used in population-based screening for colorectal neoplasia and is effective in reducing colorectal cancer mortality through early detection, [1][2][3][4][5][6][7][8][9][10][11][12] it has been not yet known whether the detailed information on quantitative fecal hemoglobin concentration (FHbC) available with the FIT might also be of use for predicting the risk of colorectal neoplasia. Unfortunately, because clinical practice is to select subjects with FHbC greater than a set cut-off for further clinical investigation the precise value of FHbC, although measured and often reported, is largely neglected.…”