Faecal immunochemical test to triage patients with possible colorectal cancer symptoms: meta-analysis

This review evaluated the utility of single quantitative faecal immunochemical test (FIT) as a triaging tool for patients with symptoms of possible colorectal cancer, the effect of symptoms on FIT accuracy, and the impact of triaging incorporating FIT on service provision.

Five databases were searched. Meta-analyses of the extracted FIT sensitivities and specificities for detection of colorectal cancer at reported f-Hb thresholds were performed. Secondary outcomes included sensitivity and specificity of FIT for advanced colorectal neoplasia and serious bowel disease. Subgroup analysis by FIT brand and symptoms was undertaken.

Fifteen prospective cohort studies, including 28 832 symptomatic patients were included. At the most commonly reported f-Hb positivity threshold of ≥ 10 µg Hb/g faeces (n=13), the summary sensitivity was 88.7% (95% c.i. 85.2 to 91.4) and the specificity was 80.5% (95% c.i. 75.3 to 84.8) for colorectal cancer. At lower limits of detection of ≥ 2 µg Hb/g faeces, the summary sensitivity was 96.8% (95% c.i. 91.0 to 98.9) and the specificity was 65.6% (95% c.i. 59.0 to 71.6). At the upper f-Hb positivity thresholds of ≥ 100 µg Hb/g faeces and ≥ 150 µg Hb/g faeces, summary sensitivities were 68.1% (95% c.i. 59.2 to 75.9) and 66.3% (95% c.i. 52.2 to 78.0), with specificities of 93.4% (95% c.i. 91.3 to 95.1) and 95.1% (95% c.i. 93.6 to 96.3) respectively. FIT sensitivity was comparable between different assay brands. FIT sensitivity may be higher in patients reporting rectal bleeding.

Single quantitative FIT at lower f-Hb positivity thresholds can adequately exclude colorectal cancer in symptomatic patients and provides a data-based approach to prioritization of colonoscopy resources.