The Fast Track FIT study: diagnostic accuracy of faecal immunochemical test for haemoglobin in patients with suspected colorectal cancer

Abstract

Background: The faecal immunochemical test (FIT) is now available to support clinicians in the assessment of patients at low risk of colorectal cancer (CRC) and within the Bowel Cancer Screening Programme. Aim: To determine the diagnostic accuracy of FIT for CRC and clinically significant disease in patients referred because they were judged by their GP to fulfil NICE NG12 criteria for suspected CRC. Design and Setting: Patients referred from primary care with suspected CRC, meeting NG12 criteria, to 12 secondary care providers in Yorkshire and Humber were asked to complete a FIT prior to investigation. Method: The diagnostic accuracy of FIT based upon final diagnosis was evaluated using receiver operating characteristics analysis. Clinicians and patients were blinded to the FIT results. Results: 5040 patients were fully evaluated and CRC was detected in 151 (3%). An optimal cut-off value of 19 g Hb/g faeces for CRC was determined, giving a sensitivity of 85.4% (78.8-90.6%) and specificity of 85.2% (84.1-86.2%). The negative predictive value at this cut-off value was 99.5% (99.2-99.7%) and the positive predictive value 15.1% (12.8-17.7%). Sensitivity and specificity of FIT for CRC and significant premalignant polyps at this cut-off value were 62.9% (57.5-68.0%) and 86.4% (85.4-87.4%) respectively and when including all organic enteric disease were 35.7% (32.9-38.5%) and 88.6% (87.5-89.6%). Conclusions: FIT used in patients fulfilling NICE NG12 criteria should allow for a more personalised CRC risk assessment. FIT should permit effective, patient-centred decision-making to inform the need for, type and timing of further investigation.

Faecal immunochemical testing (FIT) in patients with signs or symptoms of suspected colorectal cancer (CRC): a joint guideline from the Association of Coloproctology of Great Britain and Ireland (ACPGBI) and the British Society of Gastroenterology (BSG)

“…Bailey et al 10 found 33% were detected at early stage when using FIT in those that satisfied DG30 criteria specifically. Turvill et al 29 Other studies have shown obstructing tumours and higher stage CRC are also common in FIT 'negative' CRC.…”

“…In summary, a meta-analysis informing these guidelines61 and four prior meta-analyses of over 48 000 patients, which include the largest three studies from NICE FIT, qFIT and the York groups on FIT diagnostic accuracy reported an FIT sensitivity for CRC in symptomatic patients to be greater than 87% at a threshold of 10 µg/g28 29 62 (table 1). Therefore, based on the studies reviewed in this section, FIT should be considered in patients presenting with lower GI symptoms irrespective of their nature, to support referral or triage to appropriate investigations if there are concerns about a cancer diagnosis.…”

A cohort study of duplicate faecal immunochemical testing in patients at risk of colorectal cancer from North-West England

“…In 2017 the National Institute of Health and Care Excellence (NICE) recommended faecal immunochemical testing (FIT) for the detection of CRC in patients with low risk symptoms 7. Subsequently, several large trials have suggested that FIT also performs well in patients with high-risk symptoms for CRC (87%–94% sensitivity, 80%–89% specificity, 12%–18% positive predictive value (PPV) and 99% negative predictive value (NPV) at a threshold of 10 µgHb/g 4 8–13. However, given the prevalence of CRC in patients presenting to primary care, up to 10% of patients with CRC will not be detected at a threshold of 10 µgHb/g,4 11–13 raising concerns about how the risk associated with managing this group of patients should be managed.…”

Combining the quantitative faecal immunochemical test and full blood count reliably rules out colorectal cancer in a symptomatic patient referral pathway

“…Emerging data has proven the utility of FIT in symptomatic patients with sensitivity and specificity reportedly ranging from 85 to 100% and 56 to 91% respectively for colorectal cancer detection at a threshold of ≥ 10 µg Hb/g faeces [8][9][10][11][12][13][14][15]. FIT has proven equally valid in determining cancer risk in patients meeting high risk (NG12) or low risk (DG30) symptom criteria [6,8,16], and in patients with and without rectal bleeding [17]. Most studies to date have examined such FIT programmes and only included referred patients.…”