Introduction

Quantitative faecal immunochemical testing (FIT) is used in primary care to triage symptomatic patients for two-week-wait (TWW) colorectal cancer (CRC) referral, advised for use in all symptoms by specialty associations. FIT may effectively rule out CRC in FIT negative patients with rectal bleeding, with the potential to reduce endoscopy demand for patients with very low risk of CRC. Nottingham incorporated FIT (OC Sensor) into the TWW CRC diagnosis pathways for patients with rectal bleeding in November 2021. General Practitioners were advised to complete TWW referral for FIT ≥10 µgHb/g faeces (≥4 in the presence of anaemia or thrombocytosis).

Aims & Methods

Evaluate the demographics, investigations and early outcomes of the patients completing a FIT for rectal bleeding and compare to a reference group of TWW patients with rectal bleeding prior to the implementation of FIT.
Patients with rectal bleeding undertaking FIT after its introduction in this pathway (November 2021 to July 2022) had data collected in the Trust Enterprise Data Warehouse, allowing the formation of aggregate data (FIT group). Demographic, endoscopy, and cancer diagnosis was recorded with linkage to trust endoscopy and histology databases. A database of patients with rectal bleeding referred on a TWW pathway prior to the introduction of FIT (November 2017 to August 2019) was used as a comparison (pre-FIT group). In the pre-FIT group, investigation/outcome data was entered directly into the database by the nursing team managing referrals.

Results

2490 patients undertook a FIT for rectal bleeding after its introduction into the pathway, with 1497 patients in the reference pre-FIT group. There were more females in the FIT group than pre-FIT group (52.6% vs 48.9% respectively). The median age was lower in the FIT group (58 years vs 63.2 years). 75% of patients with rectal bleeding undertaking FIT had a negative (<10 µgHb/g faeces) FIT, 4% a value 10-19.9 µgHb/g faeces, 8% 20-99.9 µgHb/g faeces and 12.4% ≥100 µgHb/g faeces.
65.6% of patients with a FIT ≥ 10 µgHb/g faeces underwent endoscopy, compared to 81.2% in the pre-FIT group. The proportion of patients having endoscopy increased with rising FIT result (50% at a result 10-19.9µgHb/g faeces, 74.2% ≥100 µgHb/g faeces). 13.3% of patients with a FIT <10 µgHb/g faeces underwent endoscopy.
24 (3.9%) of patients with a FIT ≥10 µgHb/g faeces had histological diagnosis of CRC. There were no diagnoses of CRC in FIT <10 µgHb/g faeces. 10 extra-colonic cancers were diagnosed in the FIT group (0.4%), all FIT <10 µgHb/g faeces. 93 (6.2%) of the pre-FIT group had a histological diagnosis of CRC, 9 (0.6%) had a diagnosis of extra-colonic cancer.

Conclusion

FIT’s role in rectal bleeding remains unclear. In the limited follow-up of this study FIT appears to rule out CRC – 75% of patients returned a result <10 µgHb/g faeces and no CRC was found in these patients. However, CRC detection rates were almost 60% higher pre-FIT than in the FIT positive group; this may be explained by FIT being used for lower risk patients or the limited follow-up. Even in rectal bleeding a negative FIT may signpost towards extracolonic cancer, all found in FIT <10, suggesting appropriate investigations are required for these patients with low risk of CRC. Longer-term follow-up is required to assess whether any CRCs have been missed in “FIT-negative” patients to gauge the effectiveness of FIT for rectal bleeding and impact on endoscopy demand.

Introduction

Aims & Methods

Aims: To assess for evidence of association between a symptomatic FIT ≥10μgHb/g and 1 year risk of other GI cancers and influence of age and anaemia on these associations.
Methods: A regional cohort study inclusive of all patients who underwent a symptomatic FIT between 2017-2023 in Nottingham. Heatmaps, stratifying by age group and blood results were constructed to display the cumulative 1-year cancer risks using Kaplan-Meier estimates.

Results

370 (0.54%) out of 68,538 patients were diagnosed with a non-colorectal GI cancer within 1-year of symptomatic FIT. 242/54,855 (0.44%) patients diagnosed with non-colorectal GI cancer had a FIT<10μgHb/g compared to 128/13,683 (0.94%) with a FIT≥10μgHb/g (p<0.0001). A FIT≥10μgHb/g was associated with increased risk of oesophagogastric (p<0.0001) and small bowel (p<0.0001) cancer compared to FIT<10μgHb/g, yet the absolute risks of each were low (<0.5%). There was no association between FIT result and subsequent hepatopancreatobiliary malignancy. When stratified by FIT result, age and blood results the highest risks were seen in patients with anaemia (Table 1). The cumulative risk of small bowel cancer with a FIT≥10μgHb/g in patients under 40 years with anaemia was 0.8% (95%CI: 0-2.35%). The cumulative risk of oesophagogastric cancer with FIT≥10μgHb/g and anaemia in the age group 71-85 was 0.85% (95%CI: 0.49-1.2%).

Conclusion

Introduction

The United Kingdom National Institute for Health and Care Excellence recommends Faecal Immunochemical Testing (FIT) for all patients presenting to primary care with symptoms suggestive of colorectal cancer. How use of this test varies across England is unknown, which this study aimed to quantify.

Aims & Methods

Routinely-collected primary care records (Clinical Practice Research Datalink Aurum) were used to assess variations in symptomatic FIT use in adults (≥18 years) between regions and over time in England from 2019 to 2023. Rates were calculated using the population registered to each primary care practice as the denominator, with analysis split by calendar year.
The first coded FIT test with a numerical result per patient each year was extracted from the primary care records. Rates of testing were calculated using Poisson regression, adjusted for other confounders. Results were described between groups, regions and years at the recommended threshold of ≥10 µgHb/g faeces (results above this threshold henceforth referred to as FIT10), describing the proportions likely to have a secondary care referral based on national guidance. Logistic regression was used to compare the impact of year, region, gender and age on the differences in FIT10.

Results

Between 01/01/2019 and 05/06/2023 there were 531,735 FIT results among 495,121 patients and a denominator population of 17,910,681. The number of completed FITs increased from 8,395 in 2019 to 237,708 in 2022 (the last complete year within the study), with a corresponding ~thirty-fold increase from 0.69 tests per 1000 person-years in 2019 (95%CI 0.68-0.71) to 19.57 per thousand person-years in 2022 (95%CI 19.50-19.65). There was large variation in testing between regions, with rates 3.6 times higher in the North East compared to the West Midlands (17.05 per thousand person-years, 95%CI 16.87-17.23 versus 4.72 per thousand person-years, 95%CI 4.67-4.76). These differences persisted to 2022, with less than half the rate in the West Midlands (11.32) compared to the North East (31.85 per thousand person-years).
20.4% of results were FIT10. Despite increased testing, the overall proportion FIT10 did not change over time. 51.7% of all tests FIT10 were in those over 70 years of age. The percentage FIT10 was lower in regions with higher rates of FIT testing, for example FIT10 ranged from 16.7% in the South West (rate of testing 14.62 per thousand person-years) to 25.3% in the South East (rate of testing 8.00 per thousand person-years). After adjusting for year, region, gender and age, this difference persisted (adjusted OR 0.57, 95%CI 0.55-0.58) comparing FIT10 in the South West to the South East. The difference in proportions FIT10 between regions showed some convergence over time, from a range of 16.6%-26.7% (10.1%) in 2021 to 15.8%-23.7% (7.9%) in 2023.

Conclusion

There has been a marked increase over time in the use of FIT for patients with symptoms in primary care, with large and persistent variations between regions of England. The overall proportion FIT10 has not decreased over time with increasing use, however there were large differences in FIT10 between regions that correlated with rates of testing. These regional differences persisted but reduced over time as testing rates increased nationally. It is likely that clinical pathway differences in the implementation of FIT over time and between regions explain the variations we have observed. If used as a guide to referral, such variation could lead to inequalities in colorectal investigation and diagnosis.

Introduction

In colorectal cancer (CRC) the pathway to diagnosis has rapidly evolved over the past 5 years incorporating Faecal Immunochemical Testing (FIT) as the chosen biomarker in the field. A FIT cut off of ≥10 µg Hb/g faeces is recommended by NICE for investigation of colorectal cancer (CRC) on an urgent pathway based on an expected CRC risk threshold of 3% in England. It is crucial to balance the risk of CRC against the ability of the health service to investigate and diagnose cancer in an appropriate and timely manner.

Aims & Methods

Our aim was to determine the empirical thresholds of CRC risk in a representative population at different FIT cut offs to assess optimal use of FIT in patients with symptoms of CRC. Cohort study of a symptomatic CRC pathway from primary care with a FIT test in Nottingham, UK (November 2017-2021) with 1-year follow-up. Heat maps showed the cumulative 1-year CRC risk using Kaplan-Meier estimates stratified by FIT (fHb <4 µg Hb/g faeces, 4-9.9 µg Hb/g faeces, 10-19.9 µg Hb/g faeces, 20 – 39.9 µg Hb/g faeces, 40- 99.9 µg Hb/g faeces and ≥100 µg Hb/g faeces), age, anaemia (≤130g/l in men; ≤120g/l in women), and thrombocytosis (≥400 x10⁹/l). We estimated the number of investigations that could potentially be re-purposed if a threshold of ≥3% 1-year risk of CRC was instigated.

Results

In total 514 (1.5%) CRC’s were diagnosed following 33694 index FIT tests. Individuals with a FIT ≥10 µg Hb/g faeces had a greater than 3% risk of CRC, except patients under the age of 40 years (CRC risk 1.45% (95% CI 0.03-2.86%)). Non-anaemic patients with a FIT <100 µg Hb/g faeces had a CRC risk of less than 3%, except those between the age of 70-85 years (CRC risk 5.26% 95% CI 2.72-7.73%). Non-anaemic patients do not meet the 3% threshold set by NICE for investigation until they have a FIT ≥40 µg Hb/g faeces. In contrast, those patients with anaemia meet the 3% threshold at a FIT of ≥20 µg Hb/g faeces. Using a ≥3% CRC threshold in patients < 55 years calculated using FIT, age and anaemia would allow 160-220 colonoscopies per 10000 FIT tests to be re-purposed, at a cost of missing 1-2 CRCs.

Conclusion

CRC risk varies by FIT, age and anaemia when fHb levels are below 100 µg Hb/g faeces. Tailored FIT cut offs for investigation on a CRC pathway could reduce the number of investigations needed at a 3% CRC risk threshold rather than a single cut off of ≥10 µg Hb/g faeces.

Disclosure

none to declare

Introduction

NICE recommend FIT (faecal immunochemical test) in almost all suspected colorectal cancer (CRC) cases. FIT-based prediction models perform well [1], but it is unclear how levels change along the adenoma-carcinoma sequence and how lesion type and location affect results. We previously reported retrospective FIT data from CRC patients at a single site [2]. We have re-evaluated this two years later and, utilising our regional trainee network, have included five more sites.

Aims & Methods

Our aim was to evaluate FIT results at various time points and in different tumour types/locations.
This was a multicentre, retrospective evaluation involving 6 hospital sites. All patients diagnosed with a malignant lesion of colon, rectum or anus in a 6-month period were identified using cancer registries. Data were collected from medical records.

Results

856 CRC patients were included. Where histology was available, 90% were adenocarcinoma. Referrals were 85% symptomatic, 14% BCSP and 1% surveillance. 492 patients had ≥1 non-BCSP FIT prior to diagnosis. 530 individual results were recorded with a mean of 178 days pre-diagnosis. Overall, 11% were <10μg/g, however the proportion increased as time from diagnosis increased (≤30 days 5.2%; 31-90 days 7.4%; 91-180 days 22.2%; 181-365 days 21.7%; >366 days 47.2%). When limited to ≤90 days, 6.3% were <10μg/g. This reduced to 5.3% in proven adenocarcinoma. The proportion varied according to lesion location (Table 1).
Table 1: Results by lesion location

Conclusion

Time since FIT is relevant clinically and in research. FITs >90 days old may not be suitable for guiding clinical decisions, however our sample for this time point was small. Prospective, sequential testing would more accurately study the change in FIT along the adenoma-carcinoma sequence. Studies assessing the value of repeat testing at different time points would help guide clinicians. The highest proportion of results <10μg/g was in right colon lesions, consistent with existing literature. However, we identified more false negatives in rectal lesions compared to left colon and recommend further research assessing this.

References

1. Hampton JS, Kenny RPW, Rees CJ, et al. The performance of FIT-based and other risk prediction models for colorectal neoplasia in symptomatic patients: a systematic review. EClinicalMedicine 2023; 64. DOI:10.1016/j.eclinm.2023.102204.
2. Manning S, Maxfield D, Bragg R, et al. P241 Is a negative FIT falsely reassuring? A retrospective evaluation. 2022 DOI:10.1136/gutjnl-2022-BSG.295.

Introduction

Colorectal cancer (CRC) and other bowel diseases is a significant health concern globally. In several countries, the fecal immunochemical test (FIT) is a cornerstone in CRC screening for early detection of cancer in asymptomatic individuals. Moreover, the utility of FIT extends beyond this, as it is increasingly recommended for evaluating symptomatic patients as part of the clinical pathway to render possible or rule out serious bowel pathology. Therefore, we aimed to quantify the findings of serious bowel conditions following a non-screening FIT test in the Danish population.

Aims & Methods

This study investigated use of FIT beyond the national CRC screening program in Denmark. We aimed (1) to assess utilization patterns of FIT in contexts other than screening and (2) to examine ensuing diagnoses. Our goal was to quantify the findings of CRC and other bowel diseases in symptomatic patients, thereby assessing its broader potential.
This cohort study was conducted within the Danish universal public healthcare system, delivered by five administrative regions. National CRC screening using FIT was initiated in 2014, but utilization of FIT for symptomatic patients varies between regions. The cut-off for a positive test is ≥10 µg haemoglobin/g faeces for symptomatic populations.
The study used data from the Danish Civil Registration System, the Danish National Patient Registry covering all Danish hospitals, and the Clinical Laboratory Information Register. The cohort included all patients who underwent FIT between 2014 and 2021 outside the Danish CRC screening program.
We employed descriptive statistics to examine FIT administration and demographic distributions across the Danish regions, as well as fecal haemoglobin levels among tested individuals. In addition, we estimated the cumulative incidence of CRC and inflammatory bowel disease (IBD) diagnoses following FIT, considering death as a competing risk and evaluated the proportion of diagnoses for CRC and IBD during the year following FIT.

Results

We identified 19,787 individuals who underwent FIT outside the national CRC screening program in 2014 to 2021. Of these, 4,283 (22%) individuals had a positive FIT result. Among tested individuals, 10,807 (55%) were female. Median age at testing was 64 years. Use of FIT varied across the regions, with 36% of the study cohort being from the Central Denmark Region, and 1.6% being from the Region of Southern Denmark.
Positive FIT cases had a shorter median time to CRC diagnosis (28 days) and any diagnosis (36 days) compared to negative FIT cases (711 and 58 days, respectively). Within one year of the FIT, 370 (1.9%) individuals were diagnosed with CRC, with higher occurrence for FIT positive individuals (7.9%) than for FIT negative individuals (0.2%) (risk difference: 7.7 percentage points [95% CI: -3.2, 11.1]).
Among individuals with a positive FIT result, 83 (1.9%) were diagnosed with IBD within one year, compared to 51 (0.3%) individuals with a negative FIT (risk difference: 1.6 percentage points [95% CI: -5.8, 7.3]).

Conclusion

We found that FIT used outside the national CRC screening program had over 20% positivity. A positive test indicated higher risk of CRC and IBD. Differences in diagnoses are expected due to varied follow-up procedures after positive and negative FIT results. A negative test, while not definitive, suggests a potential to rule out disease and could reduce unnecessary investigations when assessing symptomatic patients.