Objective Faecal immunochemical tests (FITs) are replacing guaiac faecal occult blood tests (gFOBTs) for colorectal cancer (CRC) screening. Incidence of interval colorectal cancer (iCRC) following a negative stool test result is not yet known. We aimed to compare incidence of iCRC following a negative FIT or gFOBT.
Design We searched Ovid Medline, Embase, Cochrane Library, Science Citation Index, PubMed and Google Scholar from inception to 12 December 2017 for citations related to CRC screening based on stool tests. We included studies on FIT or gFOBT iCRC in average-risk screening populations. Main outcome was pooled incidence rate of iCRCs per 100 000 person-years (p-y). Pooled incidence rates were obtained by fitting random-effect Poisson regression models.
Results We identified 7 426 records and included 29 studies. Meta-analyses comprised data of 6 987 825 subjects with a negative test result, in whom 11 932 screen-detected CRCs and 5 548 gFOBT or FIT iCRCs were documented. Median faecal haemoglobin (Hb) positivity cut-off used was 20 (range 10–200) µg Hb/g faeces in the 17 studies that provided FIT results. Pooled incidence rates of iCRC following FIT and gFOBT were 20 (95% CI 14 to 29; I2=99%) and 34 (95% CI 20 to 57; I2=99%) per 100 000 p-y, respectively. Pooled incidence rate ratio of FIT versus gFOBT iCRC was 0.58 (95% CI 0.32 to 1.07; I2=99%) and 0.36 (95% CI 0.17 to 0.75; I2=10%) in sensitivity analysis. For every FIT iCRC, 2.6 screen-detected CRCs were found (ratio 1:2.6); for gFOBT, the ratio between iCRC and screen-detected CRC was 1:1.2. Age below 60 years and the third screening round were significantly associated with a lower iCRC rate.
Conclusion A negative gFOBT result is associated with a higher iCRC incidence than a negative FIT. This supports the use of FIT over gFOBT as CRC screening tool.
- colorectal cancer screening
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Contributors EW, EHS and MCWS conceptualised and designed the study. Responsible for data acquisition were EW and EHS. Data analyses were done by EW and DN. Interpretation of data was done by EW and EHS with contribution of all co-authors. The manuscript was drafted by EW and EHS. All co-authors provided critical revision for important intellectual content. Statistical analyses were done by DN. Supervised execution of the study was done by MCWS. All authors read and approved the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
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