Diagnostic accuracy of faecal biomarkers in detecting colorectal cancer and adenoma in symptomatic patients

Breath Fingerprint of Colorectal Cancer Patients Based on the Gas Chromatography-Mass Spectrometry Analysis

The human body emits a multitude of volatile organic compounds (VOCs) via tissues and various bodily fluids or exhaled breath. These compounds collectively create a distinctive chemical profile, which can potentially be employed to identify changes in human metabolism associated with colorectal cancer (CRC) and, consequently, facilitate the diagnosis of this disease. The main goal of this study was to investigate and characterize the VOCs' chemical patterns associated with the breath of CRC patients and controls and identify potential expiratory markers of this disease. For this purpose, gas chromatography-mass spectrometry was applied. Collectively, 1656 distinct compounds were identified in the breath samples provided by 152 subjects. Twenty-two statistically significant VOCs (p-xylene; hexanal; 2-methyl-1,3-dioxolane; 2,2,4-trimethyl-1,3-pentanediol diisobutyrate; hexadecane; nonane; ethylbenzene; cyclohexanone; diethyl phthalate; 6-methyl-5-hepten-2-one; tetrahydro-2H-pyran-2-one; 2-butanone; benzaldehyde; dodecanal; benzothiazole; tetradecane; 1-dodecanol; 1-benzene; 3-methylcyclopentyl acetate; 1-nonene; toluene) were observed at higher concentrations in the exhaled breath of the CRC group. The elevated levels of these VOCs in CRC patients' breath suggest the potential for these compounds to serve as biomarkers for CRC.

The performance of FIT-based and other risk prediction models for colorectal neoplasia in symptomatic patients: a systematic review

Background

Colorectal cancer (CRC) incidence and mortality are increasing internationally. Endoscopy services are under significant pressure with many overwhelmed. Faecal immunochemical testing (FIT) has been advocated to identify a high-risk population of symptomatic patients requiring definitive investigation by colonoscopy. Combining FIT with other factors in a risk prediction model could further improve performance in identifying those requiring investigation most urgently. We systematically reviewed performance of models predicting risk of CRC and/or advanced colorectal polyps (ACP) in symptomatic patients, with a particular focus on those models including FIT.

Methods

The review protocol was published on PROSPERO (CRD42022314710). Searches were conducted from database inception to April 2023 in MEDLINE, EMBASE, Cochrane libraries, SCOPUS and CINAHL. Risk of bias of each study was assessed using The Prediction study Risk Of Bias Assessment Tool. A narrative synthesis based on the guidelines for Synthesis Without Meta-Analysis was performed due to study heterogeneity.

Findings

We included 62 studies; 23 included FIT (n = 22) or guaiac Faecal Occult Blood Testing (n = 1) combined with one or more other variables. Twenty-one studies were conducted solely in primary care. Generally, prediction models including FIT consistently had good discriminatory ability for CRC/ACP (i.e. AUC >0.8) and performed better than models without FIT although some models without FIT also performed well. However, many studies did not present calibration and internal and external validation were limited. Two studies were rated as low risk of bias; neither model included FIT.

Interpretation

Risk prediction models, including and not including FIT, show promise for identifying those most at risk of colorectal neoplasia. Substantial limitations in evidence remain, including heterogeneity, high risk of bias, and lack of external validation. Further evaluation in studies adhering to gold standard methodology, in appropriate populations, is required before widespread adoption in clinical practice.

Funding

National Institute for Health and Care Research (NIHR) [Health Technology Assessment Programme (HTA) Programme (Project number 133852).

Fecal occult blood and calprotectin testing to prioritize primary care patients for colonoscopy referral: The advantage study

BACKGROUND

Colonoscopy is the gold standard for colorectal cancer (CRC) diagnosis and screening, but endoscopy services are usually overburdened. This study aims to investigate the usefulness of fecal hemoglobin (fHb) and calprotectin (FC) for the identification of patients with high probability of CRC who need urgent referral.

METHODS

In a multicenter prospective study, we enrolled symptomatic patients referred from primary care for colonoscopy. Prior to bowel preparation, fHb and FC quantitative tests were performed. The diagnostic performance was estimated for each biomarker/combination. We built a multivariable predictive model based on logistic regression, translated to a nomogram and a risk calculator to assist clinicians in the decision-making process.

RESULTS

The study included 1224 patients, of whom 69 (5.6%) had CRC. At the fHb cut-offs of >0 and 10 μg/g, the negative predictive values for CRC were 98.8% (95% confidence interval 97.8%-99.3%) and 98.6% (95%CI 97.7%-99.1%), and the sensitivities were 85.5% (95%CI 75.0%-92.8%) and 79.7% (95%CI 68.3%-88.4%), respectively. When we added the cut-off of 150 μg/g of FC to both fHb thresholds, the sensitivity of fecal tests improved. In the multivariate logistic regression model, the concentration of fHb was an independent predictor for CRC; age and gender were also independently associated with CRC.

CONCLUSIONS

fHb and FC are useful as part of a triage tool to identify those symptomatic patients with high probability of CRC. This can be easily applied by physicians to prioritize high-risk patients for urgent colonoscopy.

Fecal Calprotectin in Gastrointestinal Disease

BACKGROUND

Inflammatory bowel disease (IBD) comprises a group of chronic conditions characterized by relapsing and remitting inflammation of the gastrointestinal tract. The incidence is increasing worldwide, and the therapeutic options for management are expanding. Endoscopy is the gold standard investigation for diagnosis of IBD and for assessing mucosal healing, which is increasingly being used as a measure of disease control. However, it is an invasive procedure that is unpleasant for patients and expensive and time-consuming for hospitals. Fecal calprotectin has been shown to be an accurate surrogate marker of gastrointestinal inflammation in IBD.

CONTENT

Fecal calprotectin was initially used for the diagnosis of IBD but is now recognized as having a role in assisting in assessment of disease activity, prediction of relapse, and informing decisions around therapy and may help to minimize requirement for endoscopy. However, there are various preanalytical and analytical factors that can affect interpretation of the results; these need to be understood to optimize clinical care.

SUMMARY

Preanalytical and analytical factors that can potentially influence fecal calprotectin concentrations are examined, and an overview is provided of clinical situations in which fecal calprotectin is commonly measured.

The usefulness of fecal hemoglobin and calprotectin tests in diagnosing significant bowel diseases: a prospective study

OBJECTIVES

Although colonoscopy remains the gold standard for determining bowel diseases, it's invasive and expensive. New non-invasive diagnostic methods are urgently needed as an initial screening modality. We aimed to investigate the value of fecal calprotectin (FC) and fecal immunochemical test (FIT) in differentiation of significant and non- significant bowel diseases.

METHODS

In this prospective study, consecutive individuals were included if they underwent colonoscopy for symptoms of lower gastrointestinal (GI) tract, positive fecal occult blood test, surveillance for IBD or colorectal cancer (CRC) screening. Diagnostic value of FC and FIT in discriminating significant bowel diseases (advanced neoplasia, active inflammatory bowel diseases or bowel inflammation due to other causes) and non-significant bowel diseases (normal, asymptomatic diverticulum, non-adenomatous polyp, or non-advanced neoplasia) were evaluated.

RESULTS

Among 201 individuals included, 107 patients had significant bowel diseases. FC and FIT had an area under the curve (AUC) of 0.722 (95% confidence interval [CI] 0.653-0.792) and 0.797 (95%CI 0.734-0.860), respectively, for determining significant bowel diseases. Combination of FC and FIT predicted significant bowel diseases with an AUC, sensitivity, specificity, and accuracy of 0.832 (95% CI 0.775-0.890), 77.6%, 74.5%, and 76.1%, respectively. Moreover, combination of FC and FIT was more sensitive among patients with lower GI symptoms than asymptomatic individuals (80.8% vs. 74.1%) to identify significant bowel diseases.

CONCLUSIONS

A single measurement of FC or FIT is not sufficiently accurate to identify patients with significant bowel disease. However, combination of FC and FIT can help increase the sensitivity, especially in patients with lower GI symptoms.

A Point-of-Care Faecal Test Combining Four Biomarkers Allows Avoidance of Normal Colonoscopies and Prioritizes Symptomatic Patients with a High Risk of Colorectal Cancer

Most colonoscopies performed to evaluate gastrointestinal symptoms detect only non-relevant pathologies. We aimed to evaluate the diagnostic accuracy of a qualitative point-of-care (POC) test combining four biomarkers (haemoglobin, transferrin, calprotectin, and lactoferrin), a quantitative faecal immunochemical test (FIT) for haemoglobin, and a quantitative faecal calprotectin (FC) test in symptomatic patients prospectively recruited. Colorectal cancer (CRC), adenoma requiring surveillance, inflammatory bowel disease (IBD), microscopic colitis, and angiodysplasia were considered significant pathologies. A total of 571 patients were included. Significant pathology was diagnosed in 118 (20.7%), including 30 CRC cases (5.3%). The POC test yielded the highest negative predictive values: 94.8% for a significant pathology and 100% for CRC or IBD if the four markers turned negative (36.8% of the patients). Negative predictive values of FIT, FC, and its combination for diagnosis of a significant pathology were 88.4%, 87.6%, and 90.8%, respectively. Moreover, the positive predictive value using the POC test was 82.3% for significant pathology when all biomarkers tested positive (6% of the patients), with 70.6% of these patients diagnosed with CRC or IBD. The AUC of the POC test was 0.801 (95%CI 0.754-0.848) for the diagnosis of a significant pathology. Therefore, this POC faecal test allows the avoidance of unnecessary colonoscopies and prioritizes high risk symptomatic patients.

Impact of faecal haemoglobin based triage of bowel symptoms presenting to primary care on colorectal cancer diagnosis

AIM

Faecal immunochemical testing (FIT) for faecal haemoglobin was introduced into primary care in National Health Service Tayside in 2015 as an adjunct to clinical assessment of new bowel symptoms. We aimed to assess the impact of FIT-based triage in primary care on colorectal cancer (CRC) diagnosis.

METHOD

Cancer audit data between January 2016 and December 2019 were reviewed to identify all patients diagnosed locally with CRC. The mode of presentation and stage at diagnosis were noted and patient records were interrogated to identify whether FIT and full blood count (FBC) had been performed prior to referral. Results were compared between the FIT and non-FIT groups.

RESULTS

In all, 1245 patients were diagnosed with CRC of whom 581 (46.7%) presented through primary care. FIT was performed prior to referral in 440/581 (75.7%), with the proportion increasing from 62.3% in 2016 to 85.8% in 2019. At faecal haemoglobin ≥10 μg Hb/g faeces, sensitivity for CRC was 94.1%. Over the study period the annual proportion of non-emergency presentations increased significantly; presentations from primary care increased from 43.1% to 53.5% (P = 0.0096). After excluding non-FIT patients who had an overt CRC at referral, there was no difference in stage at diagnosis between FIT and non-FIT cancers. Safety-netting with FBC was widely used in our cohort with 97.3% of FIT patients having also had FBC.

CONCLUSION

FIT-based triage of new bowel symptoms in primary care is associated with increased non-emergency presentation of CRC but this did not influence stage at diagnosis.

Role of the faecal immunochemical test in patients with risk-stratified suspected colorectal cancer symptoms: A systematic review and meta-analysis to inform the ACPGBI/BSG guidelines

Background

The UK National Institute for Health and Care Excellence (NICE), recommended in 2017 the use of the faecal immunochemical test (FIT) to guide investigations in patients presenting with NICE-defined low-risk symptoms suspicious for colorectal cancer (CRC). At that time, NICE did not recommend FIT use for high-risk symptoms. This is the first systematic review to evaluate the diagnostic accuracy of FIT in NICE-defined high and low-risk symptoms and was designed to inform the joint ACPGBI/BSG guidelines.

Methods

We performed a systematic literature review and meta-analysis. PROSPERO registration number CRD42021224674. Medline and EMBASE databases were searched from inception to 31st March 2022. We included studies recruiting adult patients presenting with suspected CRC symptoms in whom FIT was performed and diagnostic accuracy data for CRC detection could be derived at a limit of detection (LoD) and/or 10 µg haemoglobin/gram faeces threshold in four commonly used analysers. FIT performance was assessed for high-risk, low-risk and individual symptoms where possible. Bivariate meta-analysis was performed where study numbers allowed.

Findings

Thirty-one studies (79566 patients) met inclusion criteria. At 10 µg/g, for "all symptoms" (n = 35,945) sensitivity and specificity were 91.0% (95% CI: 88.9, 92.7) and 75.2% (95% CI: 69.6, 80.1); for "high-risk" symptoms (n = 18,264), 88.7% (95% CI: 84.4, 92.0) and 78.5% (95% CI: 73.0, 83.2); and for "low-risk" symptoms (n = 2161), 88.7% (95% CI: 78.1, 95.3) and 88.5% (95% CI: 87.1, 89.9), respectively. At LoD, for "all symptoms" (n = 26,056) sensitivity and specificity were 94.7% (95% CI: 90.5, 97.1) and 66.5% (95% CI: 58.7, 73.6); for "high-risk" symptoms (n = 16,768), 92.8% (95% CI: 86.4, 96.3) and 70.3% (95% CI: 66.5, 73.8); and for "low-risk" symptoms (n = 2082), 94.7% (95% CI: 85.4, 98.9) and 71.9% (95% CI: 69.9, 73.9), respectively. Summary estimates were similar across different analysers.

Interpretation

FIT sensitivity for CRC detection is maximised at the LoD; its performance is similar in high and low-risk symptoms, and across different analysers where a common threshold is used. FIT performance for CRC detection is adequate and transferrable to clinical diagnostic pathways.

Funding

This review was part-funded by NHS England awarded to RM Partners. RB and RC were funded by research fellowships awarded by Croydon University Hospital.

The role of faecal calprotectin in diagnosis and staging of colorectal neoplasia: a systematic review and meta-analysis

Introduction

The presence of inflammation is a key hallmark of cancer and, plays an important role in disease progression and survival in colorectal cancer (CRC). Calprotectin detected in the faeces is a sensitive measure of colonic inflammation. The role of FC as a diagnostic test that may categorise patients by risk of neoplasia is poorly defined. This systematic review and meta-analysis aims to characterise the relationship between elevations of FC and colorectal neoplasia.

Methods

A systematic review was performed using the keywords (MESH terms) and a statistical and meta-analysis was performed.

Results

A total of 35 studies are included in this review. CRC patients are more likely than controls to have an elevated FC OR 5.19, 95% CI 3.12–8.62, p < 0.001 with a heterogeneity (I² = 27%). No tumour characteristics significantly correlated with FC, only stage of CRC shows signs that it may potentially correlate with FC.

Conclusion

FC levels are significantly higher in CRC, with high sensitivity. Its low specificity prevents it from being used to diagnose or screen for CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02220-1.

REducing Colonoscopies in patients without significant bowEl DiseasE: the RECEDE Study - protocol for a prospective diagnostic accuracy study

INTRODUCTION

Demand for colonoscopies and CT colonography (CTC) is exceeding capacity in National Health Service Trusts. In many patients colonoscopies and CTCs show no significant bowel disease (SBD). Faecal Immunochemical Testing (FIT) is being introduced to prioritise patients for colonoscopies but is insufficient to identify non-SBD patients meaning colonoscopy and CTC demand remains high. The REducing Colonoscopies in patients without significant bowEl DiseasE (RECEDE) study aims to test urine volatile organic compound (VOC) analysis alongside FIT to improve detection of SBD and to reduce the number of colonoscopies and CTCs.

METHODS AND ANALYSIS

This is a multicentre, prospective diagnostic accuracy study evaluating whether stool FIT plus urine VOC compared with stool FIT alone improves detection of SBD in patients referred for colonoscopy or CTC due to persistent lower gastrointestinal symptoms. To ensure SBD is not missed, the dual test requires a high sensitivity, set at 97% with 95% CI width of 5%. Our assumption is that to achieve this sensitivity requires 200 participants with SBD. Further assuming 19% of all participants will have SBD and 55% of all participants will return both stool and urine samples we will recruit 1915 participants. The thresholds for FIT and VOC results diagnosing SBD have been pre-set. If either FIT or VOC exceeds the respective threshold, the participant will be classed as having suspected SBD. As an exploratory analysis we will be testing different thresholds. The reference comparator will be a complete colonoscopy or CTC. Secondary outcomes will look at optimising the FIT and VOC thresholds for SBD detection. An economic evaluation, using a denovo decision analytic model, will be carried out determine the costs, benefits and overall cost-effectiveness of FIT +VOC vs FIT followed by colonoscopy.

ETHICS AND DISSEMINATION

Ethical approval was obtained by Liverpool Central Research Ethics Committee (20/NW/0346).

TRIAL REGISTRATION NUMBER

RECEDE is registered on Clinicaltrials.gov NCT04516785 & ISRCTN14982373. This protocol was written and published before results of the trial were available.

Quantification of fibrinogen-to-pre-albumin ratio provides an integrating parameter for differential diagnosis and risk stratification of early-stage colorectal cancer

Background

Circulating fibrinogen to pre-albumin ratio (FPR) and albumin to fibrinogen ratio (AFR) are effective factors for predicting the prognosis of colorectal cancer (CRC). However, the role of these two ratios in diagnosing early-stage CRC and identifying the stage II CRC subgroup with high relapse risk remains unknown. This study aimed to assess the potential of FPR and AFR in differential diagnosis and risk stratification of early-stage CRC.

Methods

A discovery (694 and 512 patients with benign colorectal polyps and stage I–II CRC, respectively) and validation (201 benign colorectal polyps cases and 202 stage I–II CRC individuals) cohorts were enrolled in this study. Receiver operating characteristic curve (ROC), Kaplan–Meier curve, and time-dependent ROC were used to evaluate the diagnostic efficacy of AFR and FPR in the two cohorts and overall population, and the discriminating role of FPR in identifying clinical high-relapse risk patients in comparison with common clinical characteristics in stage II CRC patients.

Results

The area under the curve (AUC) of the preoperative circulating FPR was higher than that of AFR in the diagnosis of stage I–II CRC from colorectal adenomas and benign colorectal polyps in the discovery and validation cohorts and overall population. Carcinoembryonic antigen (CEA) combined with FPR could effectively discriminate early-stage CRC from colorectal adenomas or benign polyps. Preoperative FPR could effectively distinguish stage II subgroups with high and low relapse risk. It was superior to common clinical characteristics in identifying high-risk surgical patients who could benefit from adjuvant chemotherapy (CT) [time-dependent AUC: 0.637 vs. 0.511, p < 0.001 for predicting recurrence-free survival (RFS); 0.719 vs. 0.501, p < 0.001 for predicting overall survival (OS)]. Furthermore, CT treated stage II patients with FPR > 20 had the highest recurrence (31.16%) and death rates (21.88%), with similar highest recurrence (30.70%) and death (26.82%) rates found in non-CT-treated patients with FPR > 20. Stage II CRC patients with 20 ≥ FPR > 15 could significantly benefit from postoperative CT, as the recurrence (33.30%) and death (35.71%) rates within non-CT treated patients were approximately five times higher than those of the CT-treated cases (6.77% and 7.41% for the recurrence and death rates, respectively). No significant difference in recurrence rate was observed between L-FPR (≤ 15) patients with (10.00%) or without CT (9.76%), indicating that these patients might not require to receive adjuvant CT after curative resection.

Conclusions

Preoperative FPR combined with CEA is superior to common tumor biomarkers, FPR, or AFR in distinguishing early-stage CRC from benign colorectal polyps. Circulating FPR can be an effective biomarker for identifying high-risk patients and choosing suitable therapeutics for early-stage CRC.

Pre-diagnostic faecal calprotectin levels in patients with colorectal cancer: a retrospective study

BACKGROUND

Faecal calprotectin (FC) is a potential biomarker for colorectal cancer (CRC) screening. There is uncertainty if tumor characteristics are associated with FC levels. We investigated how tumor stage and tumor localization influence the extent of FC levels in patients with CRC in clinical practice.

METHODS

In two cohorts of patients with CRC, we retrospectively analyzed FC tests (CALPRO®) performed within three months prior to diagnosis. One hundred twenty-four patients with CRC were included (mean age 68 years, 44% women).

RESULTS

Ninety-eight patients with CRC (79%) had a FC ≥ 50 µg/g. FC correlated positively with tumor stage (UICC based on WHO TNM classification) (r_s 0.24; p = 0.007) and with CRP levels (r_s 0.31, p = 001), and a negatively with B-haemoglobin (r_s -0.21; p = 0.019). The patients with right-sided CRC had significantly more often a FC ≥ 50 µg/g than patients with left-sided CRC (92% vs 74% p = 0.027). In a binary logistic regression analysis, tumor stage III/IV (adjusted OR 3.47; CI 1.27-9.42) and right-sided tumor localization (adjusted OR 3.80; CI 1.01-14.3) were associated with FC ≥ 50 µg/g. Tumor stage III/IV (adjusted OR 2.30; CI 1.04-5.10) and acetylsalicylic use (adjusted OR 3.54; CI 1.03-12.2) were associated with FC ≥ 100 µg/g. In a cox regression analysis, a FC ≥ 100 µg/g was not associated with survival (Hazard OR 0.61; CI 0.24-1.52).

CONCLUSIONS

Elevated pre-diagnostic FC levels were common in patients with CRC in close proximity to diagnosis. Right-sided localization and tumor stage were significantly associated with a rise in FC levels.

Perspectives on self-sampling for cancer screening among rural and urban women: Multilevel factors related to acceptability

PURPOSE

Self-sampling tests may be used to overcome barriers to screening that are more prevalent in rural populations compared to urban populations. This study aims to qualitatively examine the attitudes toward established and novel self-sampling tests for cervical and colorectal cancer among women, comparing themes from rural versus urban areas.

METHODS

We recruited women (ages 45-65) from 28 counties in Pennsylvania. Four focus groups were conducted with women from metropolitan counties, and 7 focus groups were conducted with women from nonmetropolitan counties. A brief survey was conducted prior to the focus group regarding general health and willingness to complete self-sampling tests for cervical and colorectal cancer.

FINDINGS

We identified 3 themes about the potential for self-sampling for cancer screening: advantages and disadvantages of self-sampling compared to traditional testing, impact of self-sampling on patient interactions with their health care providers/clinics, and implications for improving/worsening access to quality health care services. We detected differences in responses from rural versus urban participants in the potential impact of self-sampling for cancer screening.

CONCLUSIONS

There are several barriers and facilitators at the individual, interpersonal, and organizational levels that influence the feasibility of implementing self-sampling for cancer screening in routine clinical practice. Rural participants face unique barriers to cancer screening across all levels. These findings can be used to guide interventions aimed at increasing the use of self-sampling methods.

Evaluation of fecal SYPL1 as a diagnostic biomarker in colorectal cancer

BACKGROUND

At present, there is still no ideal non-invasive biomarker for colorectal cancer (CRC) screening. Previously, we foundserum synaptophysin like 1 (SYPL1) served as a potential biomarker for CRC diagnosis. However, whether fecal SYPL1 (fSYPL1) are more sensitive and specific for CRC remains unclear.

METHODS

We analyzed fSYPL1 in controls (n = 70), adenoma patients (n = 80), CRC patients (n = 150) and postoperative CRC patients (n = 25) by ELISA.

RESULTS

SYPL1 was stable in feces. The fSYPL1 levels were significantly higher in CRC patients than in either controls or adenoma patients (P < 0.0001). ROC curves showed that fSYPL1 performed superbly in distinguishing CRC patients from controls (AUC = 0.947; 95% CI: 0.920 - 0.974, P < 0.0001, sensitivity: 80.67%, specificity: 100.00%), which showed much stronger performance than the traditional biomarkers (FOBT, CEA and CA19-9). Meanwhile, the fSYPL1 level positively correlated with tumor size, tumor invasion, lymph node invasion and clinical stage (P < 0.05). In addition, the detection rate of fSYPL1 was high in early CRC (75.00% in stage I and II). The fSYPL1 levels in CRC patients declined substantially after surgery (P = 0.0002). By means of a lower cut off level, 73.58% of high-risk adenomas were detected. The combination of fSYPL1 and FOBT performed better than the combination of plasma SYPL1, CEA and CA199 in distinguishing CRC patients from controls.

CONCLUSION

The fSYPL1 might be a potential biomarker for CRC screening, early diagnosis, prognosis prediction and therapeutic effect monitoring.

Comparison of faecal protein biomarkers' diagnostic accuracy for colorectal advanced neoplasms: a systematic review and meta-analysis

Early diagnosis of colorectal advanced neoplasms (ANs), including colorectal cancer (CRC) and advanced adenoma (AA), has a positive effect on the survival rate. As a first attempt, the aim of this meta-analysis was to compare the diagnostic accuracy of faecal protein biomarkers for the detection of colorectal neoplasms with consideration of a wide range of covariates. A systematic literature search was performed up to Jun 10, 2021 on Web of Sciences, Scopus and PubMed. The diagnostic accuracies were calculated using the bivariate/hierarchical random effect model. Biomarkers were determined to be clinically applicable (CA) if they had areas under the curve > 0.70 and positive and negative likelihood ratios > 2 and < 0.5, respectively. A total of 47,059 test results were extracted from 16 immunochemical faecal occult blood test (iFOBT), 26 pyruvate kinase-M2 (PK-M2) and 23 faecal calprotectin (FC) studies. Only iFOBT, PK-M2 and FC for CRC plus iFOBT and PK-M2 for AN were CA. iFOBT had significantly superior accuracy (P = 0.02 versus PK-M2 and P < 0.01 versus FC for CRC; P < 0.01 versus PK-M2 for AN). Regarding covariates, the lateral flow method of PK-M2 measurement increased its accuracy for CRC detection compared to the enzyme-linked immunosorbent assay (P < 0.01). iFOBT is recommended as the most accurate faecal biomarker for CRC and AN diagnosis.

The role of faecal calprotectin in the identification of colorectal neoplasia in patients attending for screening colonoscopy

AIM

Although the relationship between colorectal neoplasia and inflammation is well described, the role of faecal calprotectin (FC) in clinical practice to diagnose or screen patients for colorectal neoplasia is less defined. This prospective study characterizes the relationship between FC and colorectal neoplasia in patients within the faecal occult blood testing (FOBT) positive patients in the Scottish Bowel Screening Programme.

METHODS

All FOBT positive patients attending for colonoscopy between February 2016 and July 2017 were invited to participate. Patients provided a stool sample for FC before commencing bowel preparation. All demographics and endoscopic findings were collected prospectively.

RESULTS

In all, 352 patients were included. 210 patients had FC > 50 µg. Colorectal cancer (CRC) patients had a higher median FC (138.5 μg/g, P < 0.05), in comparison to those without CRC, and 13/14 had an FC > 50 µg/g (93%). FC had a high sensitivity (92.8%) and negative predictive value (99.3%) for CRC, but with a low specificity (41.7%) and positive predictive value (6.2%). FC sensitivity increased sequentially as neoplasms progressed from non-advanced to malignant neoplasia (48.6% non-advanced adenoma vs. 92.9% CRC). However, no significant relationship was observed between FC and non-cancer neoplasia.

CONCLUSION

In an FOBT positive screening population, FC was strongly associated with CRC (sensitivity 92.8%, specificity 41.7% for CRC, at 50 µg/g). However, although sensitive for the detection of CRC, FC failed to show sufficient sensitivity or specificity for the detection of non-cancer neoplasia. Based on these results we cannot recommend routine use of FC in a bowel screening population to detect cancer per se, but it is apparent that, with further optimization, faecal assessments including quantification of haemoglobin and inflammation could form part of a risk assessment tool aimed at refining the selection of patients for colonoscopy in both symptomatic and screening populations.

Biomarkers to Detect Early-Stage Colorectal Cancer

Colorectal cancer is a leading cause of mortality worldwide. The high incidence and the acceleration of incidence in younger people reinforces the need for better techniques of early detection. The use of noninvasive biomarkers has potential to more accurately inform how patients are prioritised for clinical investigation, which, in turn, may ultimately translate into improved survival for those subsequently found to have curable-stage CRC. This review surveys a wide range of CRC biomarkers that may (alone or in combination) identify symptomatic patients presenting in primary care who should be progressed for clinical investigation.

Faecal immunochemical test for patients with 'high-risk' bowel symptoms: a large prospective cohort study and updated literature review

Background

We evaluated whether faecal immunochemical testing (FIT) can rule out colorectal cancer (CRC) among patients presenting with ‘high-risk’ symptoms requiring definitive investigation.

Methods

Three thousand five hundred and ninety-six symptomatic patients referred to the standard urgent CRC pathway were recruited in a multi-centre observational study. They completed FIT in addition to standard investigations. CRC miss rate (percentage of CRC cases with low quantitative faecal haemoglobin [f-Hb] measurement) and specificity (percentage of patients without cancer with low f-Hb) were calculated. We also provided an updated literature review.

Results

Ninety patients had CRC. At f-Hb < 10 µg/g, the miss rate was 16.7% (specificity 80.1%). At f-Hb < 4 µg/g, the miss rate was 12.2% (specificity 73%), which became 3.3% if low FIT plus the absence of anaemia and abdominal pain were considered (specificity 51%). Within meta-analyses of 9 UK studies, the pooled miss rate was 7.2% (specificity 74%) for f-Hb < 4 µg/g.

Discussion

FIT alone as a triage tool would miss an estimated 1 in 8 cases in our study (1 in 14 from meta-analysis), while many people without CRC could avoid investigations. FIT can focus secondary care diagnostic capacity on patients most at risk of CRC, but more work on safety netting is required before incorporating FIT triage into the urgent diagnostic pathway.

Diagnostic accuracy of point of care faecal immunochemical testing using a portable high-speed quantitative analyser for diagnosis in 2-week wait patients

AIM

Laboratory-based faecal immunochemical testing (FIT) is the gold standard for detecting the presence of blood in the stool. The aim was to perform a diagnostic accuracy study to confirm if a point of care (POC) analyser for FIT could be safely used as an adjunct in the triage and management of 2-week wait (TWW) colorectal patients.

METHODS

The Point of Care Faecal Immunochemical Testing (POC FIT) prospective observational cohort study was designed for TWW patients at a regional referral centre. Between July 2019 and March 2020, patients were invited to perform and bring a FIT sample to clinic. FIT was completed within the clinic appointment using a POC quantitative analyser that has a 2-min processing time (QuikRead go®). Patients and clinicians were blinded to results within the clinic appointment. The results were compared with subsequent diagnostic outcomes. Faecal haemoglobin of <10 µg haemoglobin/g of faeces was considered a negative result. Sensitivities for colorectal cancer (CRC) and combined serious bowel disease (SBD) were calculated using this pre-determined cut-off.

RESULTS

A total of 553 patients were included for analytical comparison with diagnostic outcomes. There were 14 (2.5%) patients with CRC and 52 (9.4%) with SBD. The sensitivities for CRC and SBD were 92.9% (95% CI 68.5%-98.7%) and 76.9% (95% CI 63.9%-86.3%) respectively. 379 (68.5%) patients had a negative FIT result (negative predictive value for CRC was 99.7%).

CONCLUSIONS

This POC FIT device is a useful adjunct to better manage TWW patients. The high observed sensitivity for CRC offers opportunities, within a single consultation, for improved triage and rationalization of investigation for those with bowel symptoms.

Non-Invasive Detection and Staging of Colorectal Cancer Using a Portable Electronic Nose

Electronic noses (e-nose) offer potential for the detection of cancer in its early stages. The ability to analyse samples in real time, at a low cost, applying easy-to-use and portable equipment, gives e-noses advantages over other technologies, such as Gas Chromatography-Mass Spectrometry (GC-MS). For diseases such as cancer with a high mortality, a technology that can provide fast results for use in routine clinical applications is important. Colorectal cancer (CRC) is among the highest occurring cancers and has high mortality rates, if diagnosed late. In our study, we investigated the use of portable electronic nose (PEN3), with further analysis using GC-TOF-MS, for the analysis of gases and volatile organic compounds (VOCs) to profile the urinary metabolome of colorectal cancer. We also compared the different cancer stages with non-cancers using the PEN3 and GC-TOF-MS. Results obtained from PEN3, and GC-TOF-MS demonstrated high accuracy for the separation of CRC and non-cancer. PEN3 separated CRC from non-cancerous group with 0.81 AUC (Area Under the Curve). We used data from GC-TOF-MS to obtain a VOC profile for CRC, which identified 23 potential biomarker VOCs for CRC. Thus, the PEN3 and GC-TOF-MS were found to successfully separate the cancer group from the non-cancer group.

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

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 as they were judged by their GP to fulfil National Institute for Health and Care Excellence guideline 12 (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 before investigation.

Method

The diagnostic accuracy of FIT based on final diagnosis was evaluated using receiver operating characteristics analysis. This permitted a statistically optimal cut-off value for FIT to be determined based on the maximisation of sensitivity and specificity. Clinicians and patients were blinded to the FIT results.

Results

In total, 5040 patients were fully evaluated and CRC was detected in 151 (3.0%). An optimal cut-off value of 19 µg Hb/g faeces for CRC was determined, giving a sensitivity of 85.4% (95% confidence interval [CI] = 78.8% to 90.6%) and specificity of 85.2% (95% CI = 84.1% to 86.2%). The negative predictive value at this cut-off value was 99.5% (95% CI = 99.2% to 99.7%) and the positive predictive value 15.1% (95% CI = 12.8% to 17.7%). Sensitivity and specificity of FIT for CRC and significant premalignant polyps at this cut-off value were 62.9% (95% CI = 57.5% to 68.0%) and 86.4% (95% CI = 85.4% to 87.4%), respectively; and when including all organic enteric disease were 35.7% (95% CI = 32.9% to 38.5%) and 88.6% (95% CI = 87.5% to 89.6%), respectively.

Conclusion

FIT used in patients fulfilling 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.

Performance of the faecal immunochemical test for the detection of colorectal neoplasms and the role of proton pump inhibitors in their diagnostic accuracy

AIM

The faecal immunochemical test (FIT) is currently utilized in both symptomatic and screening populations, but little is known about factors that affect its performance. For example, proton pump inhibitor (PPI) therapy has been purported to increase false negative rates. This has significant implications given the extent of PPI prescriptions. The aim of this work was to evaluate the performance of the FIT for the detection of colorectal neoplasms and the impact of PPI therapy on its diagnostic accuracy.

METHOD

Symptomatic patients referred on the suspected cancer pathway and those on polyp surveillance between 2015 and 2019 were approached to participate. Estimates of the accuracy of FIT at different cut-off levels in diagnosing colorectal neoplasms were made. Logistic regression was used to assess the effect of PPIs on the FIT results.

RESULTS

A total of 667 participants were eligible for the final analysis. At a cut-off of 10 μg/g faeces, the overall sensitivity and specificity of FIT for the detection of colorectal cancer (CRC) was 0.85 (95% CI 0.71-0.94) and 0.81 (95% CI 0.78-0.84), respectively. For the detection of advanced neoplasia, the sensitivity was 0.70 (95% CI 0.58-0.79) and the specificity was 0.83 (95% CI 0.80-0.86). At higher thresholds, the sensitivity steadily declined whilst specificity increased. PPI therapy did not have a significant effect on performance of the FIT.

CONCLUSION

FIT is a good rule-out test for the detection of CRC and advanced neoplasia at lower thresholds. PPI therapy does not appear to have an effect on its diagnostic performance.

Systematic review with meta-analysis: volatile organic compound analysis to improve faecal immunochemical testing in the detection of colorectal cancer

BACKGROUND

Faecal immunochemical test (FIT) is emerging as a valid test to rule-out the presence of colorectal cancer (CRC). However, the accuracy of FIT is dependent on the cut-off applied. An additional low-cost test could improve further detection of CRC.

AIMS

To evaluate the efficacy of combined FIT and volatile organic compounds (VOC) in the detection of CRC within symptomatic populations.

METHODS

Systematic reviews on the diagnostic accuracy of FIT and VOC, for the detection of CRC, were updated. Meta-analyses were performed adopting a bivariate model for sensitivity and specificity. Clinical utility of combined FIT and VOC was estimated using Fagan's nomogram. Post-test probability of FIT negatives was used as a pre-test probability for VOC.

RESULTS

The pooled sensitivity and specificity of FIT at 10 µg/g faeces, for the detection of CRC, were 0.914 (95% confidence interval [CI] = 0.894-0.936) and 0.783 (CI = 0.850-0.696), respectively. For VOC, the sensitivity was 0.837 (CI = 0.781-0.881) and the specificity was 0.803 (CI = 0.870-0.712). The area under the curve for FIT and VOC were 0.926 and 0.885, respectively. In a population with 5% CRC prevalence, the estimated probability of having CRC following a negative FIT was 0.5% and following both negative FIT and VOC was 0.1%.

CONCLUSIONS

In a FIT-negative symptomatic population, VOC can be a good test to rule-out the presence of CRC. The estimated probability reduction by 0.4% when both tests being negative offers adequate safety netting in primary care for the exclusion of CRC. The number needed to colonoscope to identify one CRC is eight if either FIT or VOC positive. Cost-effectiveness and clinical accuracy of this approach will need further evaluation.

Using the faecal immunochemical test in patients with rectal bleeding: evidence from the NICE FIT study

AIM

The aim of this work was to investigate whether the faecal immunochemical test (FIT) could safely rule out colorectal cancer (CRC) in patients with rectal bleeding (RB).

METHOD

This was a multicentre, double-blinded diagnostic accuracy study in 50 National Health Service hospitals. Patients referred from primary care with suspected CRC on an urgent 2-week-wait pathway were asked to perform a FIT prior to colonoscopy. The primary outcome measure was the sensitivity of the FIT for CRC in patients with RB versus nonrectal bleeding symptoms (NRB). The secondary outcome measures included the diagnostic accuracy of the FIT for CRC and other serious bowel disease.

RESULTS

Of 9822 patients included in the study, 3143 (32.0%) were referred with RB. CRC was present in 4.7% of patients with RB versus 2.7% of patients with NRB (p < 0.05). Faecal haemoglobin (f-Hb) was detectable (>2 µg/g) in 44.1% of patients with RB and 33.9% with NRB (p < 0.05). In RB patients, CRC was present in 10.4% when f-Hb was >2 µg/g compared with 0.1% when f-Hb was not detected. Flexible sigmoidoscopy in this group would further reduce the risk of CRC to 0.03%. The sensitivity of the FIT for CRC in RB versus NRB groups was 98.6% (95% CI 95.2%-99.8%) vs 95.6% (91.5%-98.1%) for f-Hb >2 µg/g and 96.6% (92.2%-98.9%) vs 86.3 (80.4%-90.9%) for f-Hb >10 µg/g.

CONCLUSION

Faecal haemoglobin is not always detectable in patients with RB; 56% of patients had undetectable f-Hb (<2 µg/g) and CRC was present in 0.1%. The high sensitivity of the FIT can be used to rule out CRC in patients with RB and triage them more appropriately for investigation.

The Addition of Other Fecal Biomarkers Does Not Improve the Diagnostic Accuracy of Immunochemical Fecal Occult Blood Test Alone in a Colorrectal Cancer Screening Cohort

Background: Screening with fecal occult blood test reduces colorectal cancer (CRC) incidence and mortality, and is currently implemented in most countries. However, around 40% of screening colonoscopies are normal. Thus, strategies to avoid these colonoscopies are highly necessary. Adding other fecal biomarkers, such as fecal calprotectin (FC), lactoferrin, and transferrin may be useful, but evidence is scarce.

Aims: To evaluate the diagnostic accuracy of fecal occult blood immunochemical test (FIT), FC, and a one-step combo card test for the simultaneous semi-qualitative detection of human hemoglobin (hHb), transferrin (hTf), calprotectin (hCp) and lactoferrin (hLf) in a CRC screening program population.

Methods: Single-center, prospective observational study, enrolling patients included in a CRC screening program, referred for a colonoscopy due to a positive FIT test. Participants collected a stool sample prior to bowel preparation, and FIT, FC and the combo semi-qualitative tests were performed on the sample. Sensitivity, specificity, positive and negative predictive values and area under receiver operator curve (AUC) for diagnosis of advanced neoplasia, advanced adenoma and CRC were estimated for each biomarker and their combinations. The primary endpoint of the study was to assess whether these biomarkers could improve the diagnostic accuracy of FIT alone.

Results: 336 consecutive patients (64% males) were recruited. Advanced neoplasia was found in 129/336 (38.4%) patients, and of these, 22/336 (6.5%) were diagnosed of CRC. 153/336 (45.5%) colonoscopies were completely normal. The AUC for the diagnosis of advanced neoplasia were 0.725 (95%CI 0.665–0.784) for FIT, 0.477 (95%CI 0.413–0.541) for FC and 0.732 (95%CI 0.674–0.791) for the combination of both (FIT + FC) quantitative tests. The AUCs for the combo test were 0.70 (95%CI 0.641–0.760) for hHb, 0.625 (95%CI 0.562–0.698) for hTf, 0.532 (95%CI 0.469–0.595) for hCp, 0.531 (95%CI 0.466–0.595 ) for hLf and 0.681 (95%CI 0.620–0.741) for the combination of the four biomarkers.

Conclusion: In average-risk population, FIT appears to be the best fecal marker for the diagnosis of CRC and advanced adenoma. None of the other biomarkers explored or their combinations provided a better diagnostic accuracy. Only hTF showed an acceptable diagnostic accuracy. FC and hLF were not useful in this setting.

Breast health screening: a UK-wide questionnaire

Background

Currently, there is an unmet clinical need in identifying and screening women at high risk of breast cancer, where tumours are often aggressive and treatment intervention is too late to prevent metastasis, recurrence and mortality. This has been brought into sharp focus by the SARS-CoV-2 global pandemic, constantly changing hospital policies and surgical guidelines in reducing access to established screening and treatment regimens. Nipple aspirate fluid (NAF), is thought to provide a unique window into the biological processes occurring within the breast, particularly in the context of a developing neoplasm. Evaluation of NAF in asymptomatic women, for novel chemical biomarkers of either early disease and/or cancer risk offers tremendous promise as a tool to facilitate early detection and to supplement screening. However, it is acceptability as a method of collection and screening by women is critical and yet unknown. A breast health questionnaire was disseminated to women through breast cancer charities, patient support groups and social media platforms, with the aim of collecting opinions on the acceptability of use of NAF as a potential screening tool.

Method

Following ethical approval a questionnaire was prepared using online surveys consisting of four parts: (a) introduction on breast health screening in the UK, (b) core demographic data, (c) questions regarding screening and the acceptability of using NAF and (d) opinions about the process of collecting and using nipple fluid for screening. The voluntary and anonymous questionnaire was disseminated through social media, professional networks, charity websites and by individuals between October 2019 and December 2020. Survey responses were collected electronically, and the data analysed using online surveys statistical tools.

Results

A total of 3178 women completed the questionnaire (65.9% Caucasian, 27.7% Asian/British Asian, 0.6% black and 5.0% other). Of these, 2650 women (83.4%) had no prior knowledge of NAF and 89.4% were unaware that NAF can be expressed in up to 90% of all women. Concerning their risk of breast cancer, 89.8% of women were keen to know their future risk of breast cancer, 8.5% were unsure whether they wanted to know their risk and a further, 1.6% did not want to know. Regarding screening, 944 women (29.8%) were unaware of the lack of routine National Health Service Breast Screening for those under the age of 47 years. Furthermore, 53.0% of women were unaware that mammographic screening is affected by breast density. In terms of the acceptability of home testing for breast health, 92.0% were keen to undergo a home test. Both 79.7% and 70.9% stated they would consider hand massage and a breast pump to acquire nipple fluid samples, respectively. A further 48.6% of women would consider the use of a hormonal nasal spray for the same purpose. However, with regards to acquiring results from NAF testing, 42.6% of women would prefer to receive results at home and 34.2% in a medical facility. Finally, 91.6% of women believed that breast health should be incorporated as part of school education curriculum.

Conclusion

Public awareness regarding breast screening protocols and limitations of mammography could be improved. Many women were unaware that NAF might be a useful biofluid for future risk prediction, and yet the concept of self-testing of nipple fluid, with either hand massage or a breast pump was well received. Efforts should be made to increase awareness of the benefits of alternative and supplementary tests, especially in the context of high-risk individuals and younger patients.

GP access to FIT increases the proportion of colorectal cancers detected on urgent pathways in symptomatic patients in Nottingham

OBJECTIVE

Service evaluation of GP access to Faecal Immunochemical Test (FIT) for colorectal cancer (CRC) detection in Nottinghamshire and use of FIT for "rule out", "rule in" and "first test selection".

DESIGN

Retrospective audit of FIT results, CRC outcomes and resource utilisation before and after introduction of FIT in Primary Care in November 2017. Data from the new pathway up to December 2018 was compared with previous experience.

RESULTS

Between November 2017 and December 2018, 6747 GP FIT test requests yielded 5733 FIT results, of which 4082 (71.2%) were <4.0 μg Hb/g faeces, 579 (10.1%) were 4.0-9.9 μg Hb/g faeces, 836 (14.6%) were 10.0-149.9 μg Hb/g faeces, and 236 (4.1%) were ≥150.0 μg Hb/g faeces. The proportion of "rule out" results <4.0 μg Hb/g faeces was significantly higher than in the Getting FIT cohort (71.2% vs 60.4%, Chi squared 42.8, p < 0.0001) and the proportion of "rule in" results ≥150.0 μg Hb/g faeces was significantly lower (4.1% vs 8.1%, Chi squared 27.3,P < 0.0001). There was a 33% rise in urgent referrals across Nottingham overall during the evaluation period. 2 CRC diagnoses were made in 4082 patients who had FIT<4.0 μg Hb/g faeces. 58.4% of new CRC diagnoses associated with a positive FIT were early stage cancers (Stage I and II). The proportion of all CRC diagnoses that follow an urgent referral s rose after introduction of FIT.

CONCLUSIONS

FIT allows GP's to select a more appropriate cohort for urgent investigation without a large number of missed diagnoses. FIT appears to promise a "stage migration" effect which may ultimately improve CRC outcomes.

Faecal immunochemical testing in symptomatic patients to prioritize investigation: diagnostic accuracy from NICE FIT Study

BACKGROUND

This study investigated whether a quantitative faecal immunochemical test (FIT) could be used to select patients with either high- or low-risk symptoms of colorectal cancer for urgent investigation.

METHODS

A double-blinded diagnostic accuracy study was conducted in 50 hospitals in England between October 2017 and December 2019. Patients were eligible for inclusion if they had been referred to secondary care with suspected colorectal cancer symptoms meeting national criteria for urgent referral and triaged to investigation with colonoscopy.

RESULTS

The study included 9822 patients, of whom 7194 (73.2 per cent) had high-risk symptoms, 1994 (20.3 per cent) low-risk symptoms, and 634 (6.5 per cent) had other symptoms warranting urgent referral. In patients with high-risk symptoms, the sensitivity of FIT for colorectal cancer at cut-off values of 2 and 10 μg haemoglobin per g faeces was 97.7 (95 per cent c.i. 95.0 to 99.1) and 92.2 (88.2 to 95.2) per cent respectively, compared with 94.3 (84.3 to 98.8) and 86.8 (74.7 to 94.5) per cent in patients with low-risk symptoms at the same cut-off points. At cut-off values of 2, 10, and 150 μg/g, the positive predictive value for colorectal cancer was 8.9, 16.2, and 30.5 per cent respectively for those with high-risk symptoms, and 8.4, 16.9, and 35.5 per cent for those with low-risk symptoms.

CONCLUSION

FIT safely selects patients with high or low risk symptoms of colorectal cancer for investigation.

Faecal immunochemical testing and blood tests for prioritization of urgent colorectal cancer referrals in symptomatic patients: a 2-year evaluation

BACKGROUND

A novel pathway incorporating faecal immunochemical testing (FIT) for rapid colorectal cancer diagnosis (RCCD) was introduced in 2017. This paper reports on the service evaluation after 2 years of pathway implementation.

METHODS

The RCCD protocol was based on FIT, blood results and symptoms to stratify adult patients in primary care. Two-week-wait (2WW) investigation was indicated for patients with rectal bleeding, rectal mass and faecal haemoglobin (fHb) level of 10 µg Hb/g faeces or above or 4 µg Hb/g faeces or more in the presence of anaemia, low ferritin or thrombocytosis, in all other symptom groups. Patients with 100 µg Hb/g faeces or above had expedited investigation . A retrospective audit of colorectal cancer detected between 2017 and 2019 was conducted, fHb thresholds were reviewed and critically assessed for cancer diagnoses.

RESULTS

In 2 years, 14788 FIT tests were dispatched with 13361 (90.4 per cent) completed returns. Overall, fHb was less than 4 µg Hb/g faeces in 9208 results (68.9 per cent), 4-9.9 µg Hb/g in 1583 (11.8 per cent), 10-99.9 µg Hb/g in 1850 (13.8 per cent) and 100 µg Hb/g faeces or above in 720 (5.4 per cent). During follow-up (median 10.4 months), 227 colorectal cancers were diagnosed. The cancer detection rate was 0.1 per cent in patients with fHb below 4 µg Hb/g faeces, 0.6 per cent in those with fHb 4-9.9 µg Hb/g faeces, 3.3 per cent for fHb 10-99.9 µg Hb/g faeces and 20.7 per cent for fHb 100 µg Hb/g faeces or above. The detection rate in the cohort with 10-19.9 µg Hb/g faeces was 1.4 per cent, below the National Institute for Health and Care Excellence threshold for urgent referral. The colorectal cancer rate in patients with fHb below 20 µg Hb/g faeces was less than 0.3 per cent.

CONCLUSION

Use of FIT to "rule out" urgent referral from primary care misses a small number of cases. The threshold for referral may be adjusted with blood results to improve stratification .

The Multiomics Analyses of Fecal Matrix and Its Significance to Coeliac Disease Gut Profiling

Gastrointestinal (GIT) diseases have risen globally in recent years, and early detection of the host’s gut microbiota, typically through fecal material, has become a crucial component for rapid diagnosis of such diseases. Human fecal material is a complex substance composed of undigested macromolecules and particles, and the processing of such matter is a challenge due to the unstable nature of its products and the complexity of the matrix. The identification of these products can be used as an indication for present and future diseases; however, many researchers focus on one variable or marker looking for specific biomarkers of disease. Therefore, the combination of genomics, transcriptomics, proteomics and metabonomics can give a detailed and complete insight into the gut environment. The proper sample collection, sample preparation and accurate analytical methods play a crucial role in generating precise microbial data and hypotheses in gut microbiome research, as well as multivariate data analysis in determining the gut microbiome functionality in regard to diseases. This review summarizes fecal sample protocols involved in profiling coeliac disease.

Faecal haemoglobin concentration thresholds for reassurance and urgent investigation for colorectal cancer based on a faecal immunochemical test in symptomatic patients in primary care

Background

Faecal haemoglobin concentration (f-Hb), estimated using a faecal immunochemical test, can be safely implemented in primary care to assess risk of colorectal cancer (CRC). Clinical outcomes of patients presenting with symptoms of lower gastrointestinal disease were examined using an extensive range of f-Hb thresholds to decide on reassurance or referral for further investigation.

Methods

All patients who attended primary care and submitted a single faecal specimen faecal immunochemical test in the first year of the routine service had f-Hb estimated using HM-JACKarc: f-Hb thresholds from <2 to ≥ 400 µg Hb/g faeces (µg/g) were examined.

Results

Low f-Hb thresholds of <2, <7, <10 and <20 µg/g gave respective CRC risks of 0.1, 0.3, 0.3 and 0.4%, numbers needed to scope for one CRC of 871, 335, 300 and 249, and ‘false negative’ rates of 2.9, 11.4, 13.3 and 17.1%. With thresholds of <2, <7, <10 and <20 µg/g, 48.6, 74.6, 78.1 and 83.2% respectively of symptomatic patients could be managed without further investigation. With reassurance thresholds of <2 µg/g, <7 µg/g and <10 µg/g, the thresholds for referral for urgent investigation would be >400 µg/g, ≥200 µg/g and ≥100 µg/g. However, patients with a f-Hb concentration of <10 or <20 µg/g with iron deficiency anaemia, or with severe or persistent symptoms, should not be denied further investigation.

Conclusions

In primary care, f-Hb, in conjunction with clinical assessment, can safely and objectively determine individual risk of CRC and decide on simple reassurance or urgent, or routine referral.

Correlation of Fecal Immunochemical Testing Levels With Pathology Results in a National Colorectal Cancer Screening Program

INTRODUCTION

Fecal immunochemical testing (FIT) positivity is determined by a threshold decided by individual screening programs. Data are limited on correlation between FIT levels and pathology identified at colonoscopy. Our aim was to examine the correlation between FIT levels and pathology identified in a national colorectal cancer screening program.

METHODS

FIT levels (n = 9,271) were analyzed and correlated with patient demographics and pathology identified, including adenomas, sessile serrated lesions, number/size of adenomas, and presence of dysplasia. Levels were divided into 2 categories: FIT levels were defined as "high" or "low" based on whether they were above or below the median (479 ngHb/mL). Multivariate analysis was performed.

RESULTS

A total of 8,084 patients (87%) underwent colonoscopy. Those younger than 65 years (odds ratio [OR] 1.267, 95% confidence interval [CI] 1.107-1.45, P = 0.001), those with an adenoma >10 mm (OR 1.736, 95% CI 01.512-1.991, P < 0.001), and those with left-sided adenomas (OR 1.484, 95% CI 1.266-1.74, P < 0.001) had higher FIT levels. Cancers (OR 2.8, 95% CI 2.09-3.75, P < 0.001) and high-grade dysplasia (OR 1.356, 95% CI 1.08-1.7, P = 0.008) had higher FIT levels, but varied greatly. The number of adenomas was not significant.

DISCUSSION

In this study, FIT levels were high for left-sided and large adenomas, suggesting that FIT has poor sensitivity for detection of diminutive and right-sided neoplasia. FIT levels had no association with gender and declined with age. Adenoma burden did not correlate with FIT levels; this is a novel finding. FIT levels vary greatly even in those with advanced neoplasia; therefore, FIT is unlikely to be useful as a risk stratification tool.

Diagnosing colorectal cancer in primary care: cohort study in Sweden of qualitative faecal immunochemical tests, haemoglobin levels, and platelet counts

BACKGROUND

Colorectal cancer (CRC) diagnostics are challenging in primary care and reliable diagnostic aids are desired. Qualitative faecal immunochemical tests (FITs) have been used for suspected CRC in Sweden since the mid-2000s, but evidence regarding their effectiveness is scarce. Anaemia and thrombocytosis are both associated with CRC.

AIM

To evaluate the usefulness of qualitative FITs requested for symptomatic patients in primary care, alone and combined with findings of anaemia and thrombocytosis, in the diagnosis of CRC.

DESIGN AND SETTING

A population-based cohort study using electronic health records and data from the Swedish Cancer Register, covering five Swedish regions.

METHOD

Patients aged ≥18 years in the five regions who had provided FITs requested by primary care practitioners from 1 January 2015 to 31 December 2015 were identified. FIT and blood-count data were registered and all CRC diagnoses made within 2 years were retrieved. Diagnostic measurements were calculated.

RESULTS

In total, 15 789 patients provided FITs (four different brands); of these patients, 304 were later diagnosed with CRC. Haemoglobin levels were available for 13 863 patients, and platelet counts for 10 973 patients. Calculated for the different FIT brands only, the sensitivities for CRC were 81.6%-100%; specificities 65.7%-79.5%; positive predictive values 4.7%-8.1%; and negative predictive values 99.5%-100%. Calculated for the finding of either a positive FIT or anaemia, the sensitivities increased to 88.9-100%. Adding thrombocytosis did not further increase the diagnostic performance.

CONCLUSION

Qualitative FITs requested in primary care seem to be useful as rule-in tests for referral when CRC is suspected. A negative FIT and no anaemia indicate a low risk of CRC.

Accuracy of faecal immunochemical testing in patients with symptomatic colorectal cancer

BACKGROUND

The aim of this study was to determine the diagnostic accuracy of the faecal immunochemical test (FIT) for detecting colorectal cancer in symptomatic patients.

METHODS

This was a prospective study of patients with bowel symptoms. Stool samples were collected during rectal examination. The HM-JACKarc assay (Kyowa Medex, Tokyo, Japan) was used to quantify faecal haemoglobin (Hb); positive results were those with at least 10 μg Hb/g faeces. Two-by-two tables and receiver operating characteristic (ROC) curve analysis were used to determine diagnostic accuracy; χ2 and Mann-Whitney U tests were used to compare other parameters.

RESULTS

A total of 928 patients were included (M : F ratio 1 : 1·5; median age 72 (i.q.r. 64-80) years). The overall prevalence of colorectal cancer was 5·1 per cent. The FIT had sensitivity of 85·1 per cent, specificity of 83·5 per cent, positive predictive value of 22·6 per cent and negative predictive value of 99·0 per cent. ROC analysis of FIT for diagnosing colorectal cancer gave an area under the curve value of 0·89 (95 per cent c.i. 0·84 to 0·94). Significant bowel pathology was detected more frequently in FIT-positive patients (35·1 per cent versus 7·1 per cent in FIT-negative patients; P < 0·001). There were sex differences in FIT positivity (23·7 per cent in men versus 17·4 per cent in women; P = 0·019); the sensitivity of FIT for colorectal cancer in women was also low. False-negative FIT results were found mainly in women referred with iron-deficiency anaemia, who were found to have caecal cancer.

CONCLUSION

FIT effectively excluded colorectal cancer in symptomatic patients. Integration of FIT into the diagnostic pathway for colorectal cancer would direct resources appropriately to patients with a greater likelihood of having the disease.

Reducing the Cut-Off Value of the Fecal Immunochemical Test for Symptomatic Patients Does Not Improve Diagnostic Performance

Introduction: The fecal immunochemical test (FIT) has been established as a cost-effective test in colon cancer screening programmes. This test could also be helpful in symptomatic patients prior to colonoscopy, but data about diagnostic performance, and accurate cut-off values for these patients are still scarce.

Materials and Methods: Prospective study that included consecutive unselected patients with gastrointestinal symptoms referred for colonoscopy between November 2016 and June 2018. We performed a FIT (FOB Gold^® test, cut-off 20 micrograms of Hb/gram of feces) prior to colonoscopy and determined the accuracy of FIT in terms of sensitivity, specificity, positive and negative predictive value for clinically significant pathology, advanced neoplasia, and colorectal cancer in symptomatic patients, using two different cut-off values.

Results: A total of 727 patients (44.3% men, aged 58.5 ± 14.9 years) was included in the study. The main symptom was history of previous (non-active) rectal bleeding (34.7%), followed by diarrhea (15.0%). Over one quarter of the patients (25.9%) had a positive FIT result. The caecal intubation rate was 95.5%. Clinically significant pathology was identified in 142 colonoscopies (19.5%), advanced neoplasia in 115 (15.8%) and colorectal cancer in 36 colonoscopies (5.0%). FIT performed very well for clinically significant pathology, advanced neoplasia and cancer, with a high negative predictive value (NPV). Reducing the cut-off value to 10 μg/g yielded similar NPV results, with a decrease in specificity. Using a combination of symptoms with a positive FIT result did not improve FIT performance. Only specificity was slightly higher compared to FIT alone, but this was paralleled by a decrease in sensitivity and NPV for cancer and clinically significant pathology. The odds of presenting clinically significant pathology, advanced neoplasia, or cancer increased with FIT concentration.

Conclusions: The specificity and NPV of FIT for clinically significant pathology, advanced neoplasia, and cancer are high in symptomatic patients. FIT is a helpful test for determining the need to perform further studies. It may not be necessary to reduce the cut-off value for symptomatic patients, since FIT performance with the current standard cut-off value used in colorectal cancer screening was accurate. FIT can be used to avoid or prioritize colonoscopy procedures.

Faecal immunochemical testing for adults with symptoms of colorectal cancer attending English primary care: a retrospective cohort study of 14 487 consecutive test requests

BACKGROUND

Faecal immunochemical testing (FIT) is recommended by the National Institute for Health and Care Excellence (NICE) to triage symptomatic primary care patients for further investigation of colorectal cancer.

AIM

To ascertain the diagnostic performance of FIT in symptomatic adult primary care patients.

METHODS

Faecal samples from routine primary care practice in Oxfordshire, UK were analysed using the HM-JACKarc FIT method between March 2017 and March 2020. Clinical details were recorded. Patients were followed for up to 36 months in linked hospital records for evidence of benign and serious (colorectal cancer, high-risk adenomas and bowel inflammation) colorectal disease. The diagnostic accuracy of FIT is reported by gender, age group and FIT threshold.

RESULTS

In 9896 adult patients with at least 6-month follow-up, a FIT result ≥10 µg Hb/g faeces had a sensitivity for colorectal cancer of 90.5% (95% CI 84.9%-96.1%), specificity 91.3% (90.8%-91.9%), positive predictive value (PPV) 10.1% (8.15%-12.0%) and negative predictive value (NPV) 99.9% (99.8%-100.0%). The PPV and specificity for serious colorectal disease were higher and the sensitivity and NPV lower than for colorectal cancer alone. The area under the curve for all adults did not change substantially by gender or by increasing the minimum age of testing. Using ≥10 µg Hb/g faeces, 10% of adults would be investigated to detect 91% of cancers, a number needed to scope of ten to detect one cancer. Using ≥7, ≥50 and ≥150 µg Hb/g faeces, 11%, 4% and 3% of adults would be investigated, and 91%, 74% and 54% cancers detected, respectively.

CONCLUSION

A FIT threshold of ≥10 µg Hb/g faeces would be appropriate to triage adult patients presenting to primary care with symptoms of serious colorectal disease. FIT may be used to reprioritise patients referred with colorectal cancer symptoms whose investigations have been delayed by the COVID-19 pandemic.

Pre-analytical and analytical variables that influence urinary volatile organic compound measurements

There has been rapidly accelerating interest in the utilization of volatile organic compounds (VOCs) as non-invasive methods for rapid point-of-care medical diagnostics. There is widespread variation in analytical methods and protocols, with little understanding of the effects of sample storage on VOC profiles. This study aimed to determine the effects on VOC profiles of different storage times, at room temperature, prior to freezing, of sealed urine samples from healthy individuals. Analysis using Field Asymmetric Ion Motility Spectrometry (FAIMS) determined the alterations in VOC and total ion count profiles as a result of increasing room temperature storage times. Results indicated that increasing exposure time to room temperature prior to freezing had a threefold effect. Firstly, increased urinary VOC profile variability, with a plateau phase between 12 and 48 hours, before further degradation. Secondly, an increase in total ion count with time exposed to room temperature. Finally, a deterioration in VOCs with each sample run during the analysis process. This provides new insight into the effect of storage of urine samples for VOC analysis using FAIMS technology. Results of this study provide a recommendation for a 12-hour maximum duration at room temperature prior to storage.

Patient-reported and doctor-reported symptoms when faecal immunochemical tests are requested in primary care in the diagnosis of colorectal cancer and inflammatory bowel disease: a prospective study

BACKGROUND

Rectal bleeding and a change in bowel habits are considered to be alarm symptoms for colorectal cancer and they are also common symptoms for inflammatory bowel disease. However, most patients with these symptoms do not have any of these diseases. Faecal immunochemical tests (FITs) for haemoglobin are used as triage tests in Sweden and other countries but little is known about the symptoms patients have when FITs are requested.

OBJECTIVE

Firstly, to determine patients' symptoms when FITs are used as triage tests in primary care and whether doctors record the symptoms that patients report, and secondly to evaluate the association between symptoms, FIT results and possible prediction of colorectal cancer or inflammatory bowel disease.

METHODS AND MATERIALS

This prospective study included 364 consecutive patients for whom primary care doctors requested a FIT. Questionnaires including gastrointestinal symptoms were completed by patients and doctors.

RESULTS

Concordance between symptoms reported from patients and doctors was low. Rectal bleeding was recorded by 43.5% of patients versus 25.6% of doctors, FITs were negative in 58.3 and 52.7% of these cases respectively. The positive predictive value (PPV) of rectal bleeding recorded by patients for colorectal cancer or inflammatory bowel disease was 9.9% (95% confidence interval [CI] 5.2-14.7); for rectal bleeding combined with a FIT the PPV was 22.6% (95% CI 12.2-33.0) and the negative predictive value (NPV) was 98.9% (95% CI 96.7-100). For patient-recorded change in bowel habits the PPV was 6.1% (95% CI 2.4-9.8); for change in bowel habits combined with a FIT the PPV was 18.2% (95% CI 9.1-30.9) and the NPV 100% (95% CI 90.3-100).

CONCLUSIONS

Doctors should be aware that, during consultations, they do not record all symptoms experienced by patients. FITs requested in primary care, when found positive, may potentially be of help in prioritising referrals, also when patients present with rectal bleeding or change in bowel habits.

Early clinical outcomes of a rapid colorectal cancer diagnosis pathway using faecal immunochemical testing in Nottingham

AIM

We introduced primary care access to faecal immunochemical testing (FIT) as a stratification tool for symptomatic patients considered to be at risk of colorectal cancer (CRC) prior to urgent referral. We aimed to evaluate clinical and pathway outcomes during the first 6 months of this novel approach.

METHOD

FIT was recommended for all patients who consulted their general practitioner with lower gastrointestinal symptoms other than rectal bleeding and rectal mass. We undertook a retrospective audit of the results of FIT, related clinical outcomes and resource utilization on prospectively logged cases between November 2017 and May 2018.

RESULTS

Of the 1862 FIT kits dispatched by post 91.4% were returned, with a median return time of 7 days (range 2-110 days); however, 1.3% of returned kits could not be analysed. FIT results ≥ 150.0 μg haemoglobin (Hb)/g faeces identified patients with a significantly higher risk of CRC (30.9% vs 1.4%, chi-square 167.1, P < 0.0001). FIT results ≥ 10.0 μg Hb/g faeces identified patients with significantly higher risk of significant noncancer bowel pathology (24.1% vs 4.9%, chi-square 73.6, P < 0.0001) and FIT results < 4.0 μg Hb/g faeces identified a group more likely to have non-CRC pathology (5.1% vs 2.4%, chi-square 3.9, P < 0.05). The CRC detection rate in 531 patients investigated after a FIT result of < 4.0 μg Hb/g faeces was 0.2%. In 899 investigated patients, a FIT result with a threshold of 4.0 μg Hb/g faeces had sensitivity 97.2% (85.5-99.9% CI), specificity 61.4% (58.1-64.7% CI), negative predictive value 99.8% (98.7-100.0% CI) and positive predictive value 9.5% (8.7-10.4% CI).

CONCLUSION

A symptomatic pathway incorporating FIT is feasible and appears more clinically effective than pathways based on age and symptoms alone.

The combination of quantitative faecal occult blood test and faecal calprotectin is a cost-effective strategy to avoid colonoscopies in symptomatic patients without relevant pathology

BACKGROUND

Faecal occult blood test (FOBT) has demonstrated effectiveness in colorectal cancer (CRC) screening. Faecal calprotectin (FC) has proven efficient for evaluating activity in inflammatory bowel disease (IBD), but its value in CRC detection is less established. Most symptomatic patients have benign pathologies, but still undergo colonoscopy in many settings.

AIMS

To evaluate the diagnostic accuracy and cost-effectiveness of the combination of FOBT plus FC in symptomatic patients.

METHODS

Patients who completed colonic investigations and returned stool samples, on which FOBT and FC were performed, were recruited prospectively. CRC, advanced adenoma, IBD and angiodysplasia were considered as relevant pathologies.

RESULTS

A total of 404 patients were included, of whom 87 (21.5%) had relevant pathologies. Sensitivity and specificity were 50.6% and 69.6% for FOBT, 78.2% and 54.4% for FC. Negative predictive value (NPV) was 90.1% for FC and 86.9% for FOBT. NPV for the combination of FOBT and FC was 94.1%, with a sensitivity and specificity of 88.5% and 50.3%. The area under ROC (receiver operator curve) (AUC) was 0.741 for FOBT, 0.736 for FC and 0.816 for the combination. The total cost for visits and procedures was €233,016 (€577/patient). Using a combination of FOBT and FC as pre-endoscopic tool allows colonoscopies to be reduced by 39.4%, reducing total costs by 20.5%.

CONCLUSION

The combination of FOBT and FC has a better diagnostic accuracy compared with each test alone. Performing both tests before colonoscopy is a less costly and more effective strategy, reducing unnecessary procedures and complications.

Public preferences for using quantitative faecal immunochemical test versus colonoscopy as diagnostic test for colorectal cancer: evidence from an online survey

BACKGROUND

There has been interest in using the non-invasive, home-based quantitative faecal immunochemical test (FIT) to rule out colorectal cancer (CRC) in high-risk symptomatic patients.

AIM

To elicit public preferences for FIT versus colonoscopy (CC) and its delivery in primary care.

DESIGN & SETTING

A cross-sectional online survey in England.

METHOD

A total of 1057 adults (without CRC symptoms and diagnosis) aged 40-59 years were invited from an English online survey panel. Responders were asked to imagine they had been experiencing CRC symptoms that would qualify them for a diagnostic test. Participants were presented with choices between CC and FIT in ascending order of number of CRCs missed by FIT (from 1-10%). It was measured at what number of missed CRCs responders preferred CC over FIT.

RESULTS

While 150 participants did not want either of the tests when both missed 1% CRCs, the majority (n = 741, 70.0%) preferred FIT to CC at that level of accuracy. However, this preference reduced to 427 (40.4%) when FIT missed one additional cancer. Women were more likely to tolerate missing CRC when using FIT. Having lower numeracy and perceiving a higher level of risk meant participants were less likely to tolerate a false negative test. Most of those who chose FIT preferred to return it by mail (62.2%), to be informed about normal test results by letter (42.1%), and about abnormal test results face to face (32.5%).

CONCLUSION

While the majority of participants preferred FIT over CC when both tests had the same sensitivity, tolerance for missed CRCs was low.

Diagnostic accuracy of a quantitative faecal immunochemical test vs. symptoms suspected for colorectal cancer in patients referred for colonoscopy

Objective: Determine diagnostic accuracy of a quantitative faecal immunochemical haemoglobin test (QuikRead go^® FIT, Orion Diagnostica Oy) in symptomatic patients referred for colonoscopy, at various cut-offs and for one or two tests.Methods: Patients referred to four endoscopy units in mid-Sweden between 2013 and 2017 provided information on lower abdominal symptoms and faecal samples from two separate days prior to colonoscopy.Results: In all, 5.4% (13/242) patients had colorectal cancer (CRC). For one FIT at cut-off 10 µg Hb/g faeces, sensitivity for CRC was 92% (95% CI 78-100%) and specificity 77% (95% CI 72-83%); equal to 74%; 95% CI 68-80 (178/242) colonoscopies potentially avoidable and one CRC missed. Based on the maximal outcome of two FITs, sensitivity was 100%, specificity 71% (66-77%) and 68%; 95% CI 62-74 (160/237) colonoscopies potentially avoidable. Among 17% (42/242) patients with one FIT of >200 µg Hb/g faeces, 85% (11/13) had CRC. Positive predictive values of FIT varied 16.9-26.2% depending on cut-off and one or two FITs, whereas NPVs were 99% and above in all scenarios.In 60 patients reporting rectal bleeding, one FIT at cut-off 10 µg Hb/g discriminated well between CRC and other conditions (p = .001). In regression models, FIT was more important than age, sex and all symptoms.Conclusion: One or two FITs in symptomatic patients referred for colonoscopy imply powerful risk stratification abilities for CRC, even among patients reporting rectal bleeding. Larger studies in various settings will clarify how to make the best use of this opportunity. Trial registration: Clinicaltrails.gov NCT02491593.

Qualitative faecal immunochemical tests (FITs) for diagnosing colorectal cancer in patients with histories of rectal bleeding in primary care: a cohort study

BACKGROUND

Rectal bleeding is considered an alarm symptom for colorectal cancer (CRC) but it is common and mostly caused by benign conditions. Qualitative faecal immunochemical tests (FITs) for occult blood have been used as diagnostic aids for many years in Sweden when CRC is suspected. The study aimed to evaluate the usefulness of FITs requested by primary care physicians for patients with and without histories of rectal bleeding, in the diagnosis of CRC.

METHODS

Results of all FITs requested in primary care for symptomatic patients in the Örebro region during 2015 were retrieved. Data on each patient's history of rectal bleeding was gathered from electronic health records. Patients diagnosed with CRC within 2 years were identified from the Swedish Cancer Register. The analysis focused on three-sample FITs, the customary FIT in Sweden.

RESULTS

A total of 4232 patients provided three-sample FITs. Information about the presence/absence of rectal bleeding was available for 2027 patients, of which 59 were diagnosed with CRC. For 606 patients with the presence of rectal bleeding, the FIT showed sensitivity 96.2%, specificity 60.2%, positive predictive value 9.8% (95% CI 6.1-13.4) and negative predictive value 99.7% (95% CI 99.2-100) for CRC. For 1421 patients without rectal bleeding, the corresponding figures were 100%, 73.6%, 8.3% (95% CI 5.6-10.9) and 100% (95% CI 99.6-100).

CONCLUSION

The diagnostic performance of a qualitative three-sample FIT provided by symptomatic patients in primary care was similar for those with and without a history of rectal bleeding. FITs seem useful for prioritising patients also with rectal bleeding for further investigation.

A risk-stratified approach to colorectal cancer prevention and diagnosis

Population screening and endoscopic surveillance are used widely to prevent the development of and death from colorectal cancer (CRC). However, CRC remains a major cause of cancer mortality and the increasing burden of endoscopic investigations threatens to overwhelm some health services. This Perspective describes the rationale for and approach to improved risk stratification and decision-making for CRC prevention and diagnosis. Limitations of current approaches will be discussed using the UK as an example of the challenges faced by a particular health-care system, followed by discussion of novel risk biomarker utilization. We explore how risk stratification will be advantageous to current health-care providers and users, enabling more efficient use of limited colonoscopy resources. We discuss risk stratification in the setting of population screening as well as the surveillance of high-risk groups and investigation of symptomatic patients. We also address challenges in the development and validation of risk stratification tools and identify key research priorities.

The faecal immunochemical test in low risk patients with suspected bowel cancer

The National Institute for Health and Care Excellence produced guidance recommending use of the faecal immunochemical test in patients with low risk symptoms for colorectal cancer. At a cut off of 10 μg haemoglobin per gram of faeces, the National Institute for Health and Care Excellence estimated that the sensitivity of the faecal immunochemical test to detect colorectal cancer ranged from 89% to 100%. The authors evaluated the evidence and noted that the data for the use of the faecal immunochemical test were extrapolated from all comers including high risk patients. Data on low risk patients were scarce and weak. Furthermore, faecal immunochemical test results vary by age, sex, deprivation, ethnicity and symptoms. Large national cohort studies are currently underway investigating the role of the faecal immunochemical test in the English population. Clear clinical pathways and rigorous safety netting are essential and should be part of implementing these guidelines to avoid missed cancers.

Fecal calprotectin and colorectal cancer

Fecal calprotectin (FC) is a bioactive protein secreted by inflammatory cells in the intestine, having anti-microbial and anti-infection activities. The content of FC reflects the inflammatory state of the intestine, and its role in inflammatory bowel disease has been translated into clinical practice. In recent years, the application of FC in colorectal cancer (CRC) has been increasing. Previous research results show that FC can be used to screen colorectal cancer and differentiate it from other intestinal diseases, and the concentration of FC may be related to the stage, location, and resectability of CRC. However, its role still needs to be further clarified through high-quality, large-sample research. This paper reviews the application of FC in colorectal cancer.

The diagnostic accuracy of the faecal immunochemical test for colorectal cancer in risk-stratified symptomatic patients

INTRODUCTION

The faecal immunochemical test detects blood in the faeces, reporting faecal haemoglobin quantitatively in micrograms of haemoglobin per gram of faeces. The aim of this pilot study was to determine the feasibility of using the faecal immunochemical test as a rule-out test in symptomatic patients at low and high risk of colorectal cancer.

MATERIAL AND METHODS

Between November 2016 and October 2017, consecutive symptomatic patients within a multicultural part of London were recruited to perform a faecal immunochemical test prior to colonoscopy. Analysis was performed on the HM-JACKarc analyser.

RESULTS

Faecal immunochemical test samples were returned by 298 patients who underwent colonoscopy. There was no significant variation in faecal haemoglobin levels by age, sex, ethnicity or deprivation. The overall detection rate for colorectal cancer was 100% at 2 µg/g and 92% at 10 µg/g. If a faecal haemoglobin threshold for investigation of 2 µg/g (ie detectable) or 10 µg/g had been employed, the number of colonoscopies would have been reduced by 70% and 84%, respectively, in all symptomatic patients. For low-risk patients, the sensitivity of the faecal immunochemical test for colorectal cancer at both thresholds of 2 µg/g or 10 µg/g remained 100%, with the number of colonoscopies reduced by 80% and 91%, respectively.

CONCLUSION

This study shows that the faecal immunochemical test is a promising technology that detected colorectal cancer in all high- or low-risk symptomatic patients in our cohort at a threshold of detectable faecal haemoglobin. Data from adequately powered cohort studies will elucidate the true diagnostic accuracy of the test and the rate and patterns of undetected colorectal cancer.

Experience of adopting faecal immunochemical testing to meet the NICE colorectal cancer referral criteria for low-risk symptomatic primary care patients in Oxfordshire, UK

OBJECTIVE

To compare the diagnostic performance of guaiac faecal occult blood (gFOB) testing with faecal immunochemical test (FIT) in a low-risk symptomatic primary care population to provide objective data on which to base local referral guidelines.

DESIGN

Stool samples from routine primary care practice sent for faecal occult blood testing were analysed by a standard gFOB method and the HM-JACKarc FIT between January and March 2016. Symptoms described on the test request were recorded. Patients were followed up over 21 months for evidence of serious gastrointestinal pathology including colorectal adenocarcinoma.

RESULTS

In 238 patients, the sensitivity and specificity for colorectal adenocarcinoma detection using gFOB were 85.7% and 65.8%, respectively, compared with 85.7% and 89.2% for FIT. The positive predictive value (PPV) for gFOB was 7.1% and negative predictive value (NPV) was 99.3%. Comparatively, the PPV for FIT was 19.4% and NPV 99.5%. The improved performance of FIT over gFOB was due to a lower false positive rate (10.8 vs 34.2, p≤0.01) with no increase in the false negatives rate. For any significant colorectal disease, the PPV for FIT increased to 35.5% with a reduction in NPV to 95.7%.

CONCLUSION

In this low-risk symptomatic patient group, the proportion of samples considered positive by FIT was considerably lower than gFOB with the same rate of colorectal adenocarcinoma detection. One in three of those with positive FIT had a significant colorectal disease. This supports National Institute of Health and Care Excellence recommendation that FIT can be reliably used as a triage test in primary care without overburdening endoscopy resources.

Systematic review with meta-analysis of over 90 000 patients. Does fast-track review diagnose colorectal cancer earlier?

BACKGROUND

National UK data on colorectal cancer (CRC) stage at diagnosis is incomplete. Site-specific fast-track (2-week wait) cancer data are not collected directly by NHS England. Policy making based on these data alone can lead to inaccuracy.

AIMS

To review available data on key outcomes (cancer conversion rate and stage at diagnosis) for the UK's lower gastrointestinal 2-week wait pathway.

METHODS

A comprehensive literature search was conducted between 2000 and 2017. Primary outcomes were cancer conversion rate and cancer stage at diagnosis. Results were expressed as proportions with 95% CIs. A random effects model was used for meta-analysis; heterogeneity was assessed by I² .

RESULTS

Of 95 papers reviewed, 49 were included in analysis with a total study population of 93,655. Cancer conversion rate was 7.7% (95% CI: 6.9-8.5). The proportion presenting at Dukes A = 11.2% (95% CI 7.4-15.6), B = 36.7% (95% CI 30.8-42.8), C = 35.7% (95% CI: 30.8-40.8) and D = 11.1% (95% CI 7.3-15.5). No colonic pathology was diagnosed in 54.6% (95% CI: 46.2-62.8).

CONCLUSIONS

Only 7.7% of patients referred by the 2-week wait pathway were found to have CRC. No beneficial effect on stage at diagnosis was found compared to non-2-week wait referral pathways. Over half of patients had no colonic pathology and detection of adenomas was very low. These results should prompt a reconsideration of the benefits of the 2-week wait pathway in CRC diagnosis and outcomes, with more focus on strategies to improve patient selection.