Published online Oct 14, 2021. doi: 10.3748/wjg.v27.i38.6415
Peer-review started: April 7, 2021
First decision: June 26, 2021
Revised: June 27, 2021
Accepted: August 16, 2021
Article in press: August 16, 2021
Published online: October 14, 2021
Processing time: 187 Days and 10.4 Hours
Faecal immunochemical tests (FITs) are the most widely colorectal cancer (CRC) diagnostic biomarker available. Many population screening programmes are based on this biomarker, with the goal of reducing CRC mortality. Moreover, in recent years, a large amount of evidence has been produced on the use of FIT to detect CRC in patients with abdominal symptoms in primary healthcare as well as in surveillance after adenoma resection. The aim of this review is to highlight the available evidence on these two topics. We will summarize the evidence on diagnostic yield in symptomatic patients with CRC and significant colonic lesion and the different options to use this (thresholds, brands, number of determinations, prediction models and combinations). We will include recommendations on FIT strategies in primary healthcare proposed by regulatory bodies and scientific societies and their potential effects on healthcare resources and CRC prognosis. Finally, we will show information regarding FIT-based surveillance as an alternative to endoscopic surveillance after high-risk polyp resection. To conclude, due to the coronavirus disease 2019 pandemic, FIT-based strategies have become extremely relevant since they enable a reduction of colonoscopy demand and access to the healthcare system by selecting individuals with the highest risk of CRC.
Core Tip: Faecal immunochemical test (FIT) is a colorectal cancer (CRC) diagnostic biomarker used widely in CRC screening programmes. In recent years, a large body of evidence has appeared that enables recommending its use in different scenarios. For the evaluation of symptomatic patients in primary healthcare, FIT improves use of available endoscopic resources, avoiding unnecessary colonoscopies, predicts the risk of CRC and may have an impact on prognosis. Furthermore, although endoscopic surveillance after adenoma resection is widely extended, there are relevant doubts over its efficiency in the context of high-quality baseline colonoscopies and a FIT-based surveillance strategy could be an alternative.