Dataset Information

Optimal diagnostic accuracy of quantitative faecal immunochemical test positivity thresholds for colorectal cancer detection in primary health care: A community-based cohort study.

ABSTRACT:

Background

Optimizing colonoscopy resources is challenging, and information regarding performing diagnostic quantitative faecal immunochemical test (FIT) in daily clinical practice in primary health care is still limited. This study aimed to assess the sensitivity, specificity, positive predictive value and negative predictive value of varying FIT positivity thresholds on colorectal cancer (CRC) detection in primary health care.

Methods

A retrospective cohort study of 38,675 asymptomatic and symptomatic patients with a FIT (OC-Sensor™) performed between 2012 and 2016 in a primary health-care setting, using a clinical laboratory database of two Spanish areas linked with the National Health System's Hospital Discharge Records Database. The primary outcome was 2-year CRC incidence.

Results

The mean age of the participants was 63.2 years; 17,792 (46.0%) were male. CRC prevalence was 1.7% (650/38,675). The percentage of patients with a FIT result above the threshold was 20.7% and 14.6% for 10 μg Hb/g faeces and 20 μg Hb/g faeces thresholds, respectively. Sensitivity was 90.5% (95% confidence interval 88.0%-92.5%) at a 10 μg Hb/g faeces threshold, and this decreased by 3.1% when a 20 μg Hb/g faeces threshold was used. The negative predictive value for CRC was at least 99.2% in any subgroup analysed. At a 20 μg Hb/g faeces threshold, less than one additional CRC would be missed per 1000 patients investigated, while approximately 1.3 times more colonoscopy examinations were needed to identify an incidence of CRC using the lowest threshold for any situation analysed.

Conclusions

In primary health care, a quantitative FIT threshold should be tailored to colonoscopy capacity and CRC prevalence in specific populations.

SUBMITTER: Pin-Vieito N

PROVIDER: S-EPMC8259257 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundThere is increasing evidence supporting the use of faecal immunochemical tests (FIT) in patients reporting symptoms associated with colorectal cancer (CRC), but most studies until now have focused on selected subjects already referred for investigation. We therefore set out to determine the accuracy and predictive values of FIT in a primary care population.MethodA prospective, multicentre, single-gated comparative diagnostic study on quantitative FIT in patients aged 40 years and above presenting in primary care with symptoms associated with CRC will be conducted. Patients representing the whole spectrum of severity of such symptoms met with in primary care will be eligible and identified by GPs. Participants will answer a short form on symptoms during the last month. They will provide two faecal samples from two separate days. Analyses will be performed within 5 days (QuikRead go®, Aidian Oy). The analytical working range is 10-200 μg Hb/g faeces. Reference test will be linked to the Swedish Colorectal Cancer Registry up to 2 years after inclusion. Accuracy, area under ROC curves, and predictive values will be calculated for one FIT compared to the highest value of two FIT and at cutoff < 10, 10-14.9, 15-19.9 and ≥ 20 μg Hb/g faeces. Subgroup analyses will be conducted for patients with anaemia and those reporting rectal bleeding. A model-based cost-effectiveness analysis based on the clinical accuracy study will be performed. Based on previous literature, we hypothesized that the sensitivity of the highest value of two FIT at cutoff 10 μg Hb/g faeces will be 95% (95% CI + / - 15%). The prevalence of CRC in the study population was estimated to be 2%, and the rate of non-responders to be 1/6. In all, 3000 patients will be invited at 30 primary care centres.DiscussionThis study will generate important clinical real-life structured data on accuracy and predictive values of FIT in the most critical population for work-up of CRC, i.e. patients presenting with at times ambiguous symptoms in primary care. It will help establish the role of FIT in this large group.Trial registrationNCT05156307 . Registered on 14 December 2021-retrospectively registered.

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Project description:ImportanceThe potential role of the fecal immunochemical test (FIT) for screening patients at increased risk for colorectal cancer (CRC) has not yet been elucidated.ObjectiveTo assess the diagnostic accuracy of FIT for CRC or advanced neoplasia (AN) in asymptomatic patients at above-average risk.Data sourcesMEDLINE, EMBASE, Cochrane Library, and gray literature sources through August 2016.Study selectionDiagnostic studies evaluating the accuracy of FIT for CRC or AN in patients with a personal or familial history of CRC using colonoscopy as the reference standard.Data extraction and synthesisTwo authors (A.K. and P.P.) independently extracted data and evaluated study quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, and evaluated the quality of the body of evidence by means of GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Hierarchical models were used to synthesize available evidence.Main outcomes and measuresThe primary outcome was the diagnostic performance of FIT for detecting CRC or AN.ResultsWe included 12 studies (6204 participants). Seven studies were deemed at high or unclear risk of bias. The average sensitivity of FIT for CRC was 93% (95% CI, 53%-99%), and the average specificity was 91% (95% CI, 89%-92%), yielding a positive likelihood ratio (LR+) of 10.30 (CI 7.7-13.9) and a negative likelihood ratio (LR-) of 0.08 (95% CI, 0.01-0.75) (GRADE: very low). The average sensitivity of FIT for AN was 48% (95% CI, 39%-57%); and the average specificity was 93% (95% CI, 91%-94%), yielding an LR+ of 6.55 (95% CI, 5.0-8.5) and an LR- of 0.57 (95% CI, 0.48-0.67) (GRADE: very low). Subgroup analyses indicated that FIT cutoff values between 15- and 25-μg/g feces provided the best combination of sensitivity and specificity for the diagnosis of CRC (93% and 94%, respectively). Quantitative and 1-sample FIT showed adequate test performance, but data on other FIT brands and multiple samples were insufficient.Conclusions and relevanceThe FIT has high overall diagnostic accuracy for CRC but moderate accuracy for AN in patients at above-average personal or familial risk. Heterogeneity and wide confidence intervals limit the trustworthiness of our findings.