Impact of a new sampling buffer on faecal haemoglobin stability in a colorectal cancer screening programme by the faecal immunochemical test

PPV and Detection Rate of mt-sDNA Testing, FIT, and CT Colonography for Advanced Neoplasia: A Hierarchic Bayesian Meta-Analysis of the Noninvasive Colorectal Screening Tests

BACKGROUND. Noninvasive tests for colorectal cancer (CRC) screening and prevention limit the need for invasive colonoscopy to follow up positive test results. However, the relative performance characteristics of available noninvasive tests have not yet been adequately compared. OBJECTIVE. We performed a systematic review and meta-analysis to compare the diagnostic performance of the available noninvasive CRC screening tests, including multitarget stool DNA (mt-sDNA) testing, fecal immunochemical testing (FIT), and CT colonography (CTC), with an emphasis on comparison of PPV and detection rate (DR) for advanced neoplasia (AN; encompassing cases of advanced adenomas and CRC). EVIDENCE ACQUISITION. After systematic searches of MEDLINE and Google Scholar databases, 10 mt-sDNA, 27 CTC, and 88 FIT published screening studies involving 25,132, 33,493, and 2,355,958 asymptomatic adults, respectively, were included. Meta-analysis with hierarchic Bayesian modeling was conducted in accordance with Cochrane Collaboration and PRISMA guidelines to determine test positivity rates (TPRs) leading to optical colonoscopy, as well as PPVs and DRs for both AN and CRC. Different positivity thresholds were considered for FIT and CTC. EVIDENCE SYNTHESIS. Point estimates (with 95% credible intervals) from pooled Bayesian meta-analysis combining all thresholds for FIT and stratifying CTC results by a polyp size threshold of 6 mm or larger (CTC6) and 10 mm or larger (CTC10) were calculated. TPR was 13.5% (10.9-16.6%) for mt-sDNA testing, 6.4% (5.8-7.2%) for FIT, 13.4% (11.4-15.6%) for CTC6, and 6.6% (5.2-7.7%) for CTC10. AN PPV was 26.9% (95% credible interval, 21.8-33.2%) for mt-sDNA testing, 31.8% (29.3-34.5%) for FIT, 34.4% (27.2-41.0%) for CTC6, and 61.0% (54.0-70.0%) for CTC10. CRC PPV was 2.4% (1.5-3.9%) for mt-sDNA testing, 4.9% (4.3-5.3%) for FIT, 3.5% (2.5-4.8%) for CTC6, and 6.0% (4.3-8.0%) for CTC10. The DR for AN was 3.4% (95% credible interval, 2.5-4.8%) for mt-SDNA, 2.0% (1.8-2.3%) for FIT, 4.8% (4.0-6.5%) for CTC6, and 4.0% (3.0-4.6%) for CTC10. When FIT is restricted to a lower threshold (< 10 μg Hb/g feces), its performance profile is similar to that of mt-sDNA testing, although available data are limited. AN PPV odds ratios (relative to CTC10 as the reference) were 0.24 (95% credible interval, 0.17-0.33) for mt-sDNA testing, 0.30 (0.24-0.45) for FIT, and 0.33 (0.25-0.47) for CTC6. CONCLUSION. Among noninvasive CRC screening tests, CTC with a polyp size threshold of 10 mm or larger most effectively targets AN, preserving detection while also decreasing unnecessary colonoscopies compared with mt-sDNA testing and FIT. CLINICAL IMPACT. CTC performed with a polyp size threshold for colonoscopy referral set at 10 mm or larger represents the most effective and efficient noninvasive screening test for CRC prevention and detection.

Faecal immunochemical tests for haemoglobin: Analytical challenges and potential solutions

Quantitative faecal immunochemical tests for haemoglobin (FIT) are being used increasingly around the world in colorectal cancer screening programmes, and in patients presenting with lower bowel symptoms to determine who should proceed to further bowel visualisation investigations, usually colonoscopy. The clinical utility of FIT is well reported. There are a number of analytical challenges including pre-analytical variation, difficulty setting up external quality assessment schemes, access to third party internal quality control material and a lack of standardisation or harmonisation of FIT methods. Here we report the work of the International Federation of Clinical Chemistry FIT Working Group. We provide an overview of the main pre-analytical variables; discuss different approaches to external quality assurance of FIT; propose a solution to third party internal quality assurance materials and summarise the challenges of standardisation and harmonisation of FIT.

Fecal Immunochemical Test: The World's Colorectal Cancer Screening Test

The fecal immunochemical test (FIT) is a tool used for colorectal cancer screening and its use is growing rapidly. FIT, applied as a qualitative or quantitative test, has far better sensitivity for hemoglobin than older, guaiac fecal occult blood tests. This translates into several advantages of FIT, including ability to screen using only 1 stool sample per cycle. This article reviews current understanding of FIT performance as a 1-time test and when applied programmatically. It outlines how to apply the test at the patient level and track performance at the program level. Future prospects for FIT application are highlighted.

Non-Invasive Colorectal Cancer Screening: An Overview

Background

Colorectal cancer (CRC) follows a protracted stepwise progression, from benign adenomas to malignant adenocarcinomas. If detected early, 90% of deaths are preventable. However, CRC is asymptomatic in its early-stage and arises sporadically within the population. Therefore, CRC screening is a public health priority.

Summary

Faecal immunochemical test (FIT) is gradually replacing guaiac faecal occult blood test and is now the most commonly used screening tool for CRC screening program globally. However, FIT is still limited by the haemoglobin degradation and the intermittent bleeding patterns, so that one in four CRC cases are still diagnosed in a late stage, leading to poor prognosis. A multi-target stool DNA test (Cologuard, a combination of NDRG4 and BMP3 DNA methylation, KRAS mutations, and haemoglobin) and a plasma SEPT9 DNA methylation test (Epi proColon) are non-invasive tools also approved by the US FDA, but those screening approaches are not cost-effective, and the detection accuracies remain unsatisfactory. In addition to the approved tests, faecal-/blood-based microRNA and CRC-related gut microbiome screening markers are under development, with work ongoing to find the best combination of molecular biomarkers which maximise the screening sensitivity and specificity.

Key Message

Maximising the detection accuracy with a cost-effective approach for non-invasive CRC screening is urgently needed to further reduce the incidence of CRC and associated mortality rates.

Faecal haemoglobin concentration among subjects with negative FIT results is associated with the detection rate of neoplasia at subsequent rounds: a prospective study in the context of population based screening programmes in Italy

OBJECTIVE

To estimate the predictive role of faecal haemoglobin (f-Hb) concentration among subjects with faecal immunochemical test (FIT) results below the positivity cut-off for the subsequent risk of advanced neoplasia (AN: colorectal cancer-CRC-or advanced adenoma).

DESIGN

Prospective cohort of subjects aged 50-69 years, undergoing their first FIT between 1 January 2004 and 31 December 2010 in four population-based programmes in Italy.

METHODS

All programmes adopted the same analytical procedure (OC Sensor, Eiken Japan), performed every 2 years, on a single sample, with the same positivity cut-off (20 µg Hb/g faeces). We assessed the AN risk at subsequent exams, the cumulative AN detection rate (DR) over the 4-year period following the second FIT and the interval CRC (IC) risk following two negative FITs by cumulative amount of f-Hb concentration over two consecutive negative FITs, using multivariable logistic regression models and the Kaplan-Meier method.

RESULTS

The cumulative probability of a positive FIT result over the subsequent two rounds ranged between 7.8% (95% CI 7.5 to 8.2) for subjects with undetectable f-Hb at the initial two tests (50% of the screenees) and 48.4% (95% CI 44.0 to 53.0) among those (0.7% of the screenees) with a cumulative f-Hb concentration ≥20 µg/g faeces. The corresponding figures for cumulative DR were: 1.4% (95% CI 1.3 to 1.6) and 25.5% (95% CI 21.4 to 30.2) for AN; 0.17% (95% CI 0.12 to 0.23) and 4.5% (95% CI 2.8 to 7.1) for CRC. IC risk was also associated with cumulative f-Hb levels.

CONCLUSION

The association of cumulative f-Hb concentration with subsequent AN and IC risk may allow to design tailored strategies to optimise the utilisation of endoscopy resources: subjects with cumulative f-Hb concentration ≥20 µg/g faeces over two negative tests could be referred immediately for total colonoscopy (TC), while screening interval might be extended for those with undetectable f-Hb.

Multiple rounds of one sample versus two sample faecal immunochemical test-based colorectal cancer screening: a population-based study

BACKGROUND

Faecal immunochemical test (FIT)-based colorectal cancer screening requires successive rounds for maximum preventive effect. Advanced neoplasia can bleed intermittently and thus might be missed by single faecal sampling. Few studies have been done on two sample FIT (2-FIT) screening over multiple rounds. Therefore, we compared multiple rounds of one sample FIT (1-FIT) with 2-FIT screening with respect to participation, positive predictive value (PPV), diagnostic yield, and interval colorectal cancer.

METHODS

In this population-based study, a random selection of asymptomatic individuals aged 50-74 years in the Rotterdam-Rijnmond region, Netherlands, were invited by post for four rounds (every 2 years) of 1-FIT or 2-FIT screening. Key exclusion criteria were a history or colorectal cancer or inflammatory bowel disease, colon imaging in the previous 2 years, and life expectancy of less than 5 years. Per round, invitees received one or two FITs to sample either one or two consecutive bowel movements. OC-Sensor Micro (Eiken Chemical Co., Ltd, Japan) FITs were used by all participants, except the fourth round of screening for the 1-FIT cohort, for which participants used either an OC-Sensor or a FOB-Gold (Sentinel Diagnostics, Milan, Italy). A faecal haemoglobin cutoff concentration of 10 μg/g of faeces in at least one test was used for referral for colonoscopy.

FINDINGS

Between 2006 and 2015, of 10 008 invited individuals for the 1-FIT cohort, 9787 were eligible for inclusion, of whom 7310 participated at least once in four successive rounds. Of 3197 invited individuals for the 2-FIT cohort, 3131 were eligible for inclusion, and 2269 participated at least once in four successive rounds. In the 1-FIT screening cohort, 74·7% (7310 of 9787) of invitees participated at least once versus 72·5% (2269 of 3131) of invitees in the 2-FIT cohort (p=0·013). Among participants who participated at least once, the cumulative positivity rate over four rounds was 19·2% (1407 of 7310) for the 1-FIT cohort versus 28·5% (647 of 2269) for the 2-FIT cohort (p<0·0001). The cumulative PPV for advanced neoplasia was 33·0% (432 of 1308 colonoscopies) for the 1-FIT cohort versus 24·2% (147 of 607 colonoscopies) for the 2-FIT cohort (p<0·0001). The cumulative diagnostic yield of advanced neoplasia among invited individuals was 4·4% (432 of 9787) for 1-FIT versus 4·7% (147 of 3131) for 2-FIT screening (p=0·46)). FIT interval colorectal cancers were detected in eight (0·1%) of 7310 participants in the 1-FIT cohort and two (0·1%) of 2269 with 2-FIT screening (p=1·00).

INTERPRETATION

Four rounds of 2-FIT screening with a low faecal haemoglobin cutoff level did not result in a significant increase in diagnostic yield or a decrease in interval colorectal cancers compared with 1-FIT, despite higher colonoscopy demand. Therefore, 1-FIT colorectal cancer screening programmes should be preferred.

FUNDING

None.

Quality Monitoring of a FIT-Based Colorectal Cancer Screening Program

BACKGROUND

Quality assessment is crucial for consistent program performance of colorectal cancer (CRC) screening programs using fecal immunochemical test for hemoglobin (FIT). However, literature on the consistency of FIT performance in laboratory medicine was lacking. This study examined the consistency of FIT in testing positive or detecting advanced neoplasia (AN) for different specimen collection devices, lot reagents, and laboratories.

METHODS

All participants with a FIT sample with a cutoff concentration of 47 μg Hb/g feces in the Dutch CRC screening program in 2014 and 2015 were included in the analyses. Multivariable logistic regression analyses were performed to estimate the odds ratios of collection devices, reagents, and laboratories on testing positive or detecting AN and positive predictive value (PPV).

RESULTS

In total, 87519 (6.4%) of the 1371169 participants tested positive. Positivity rates and detection rates of AN differed between collection devices and reagents (all P &lt; 0.01). In contrast, PPVs were not found to vary between collection devices, reagents, or laboratories (all P &gt; 0.05). Positivity rates showed a small difference for laboratories (P = 0.004) but not for detection rates of AN. Size of the population affected by the deviating positivity rates was small (0.1% of the total tested population).

CONCLUSIONS

Variations were observed in positivity and detection rates between collection devices and reagents, but there was no detected variation in PPV. Although the overall population effect of these variations on the screened population is expected to be modest, there is room for improvement.

Faecal immunochemical tests for haemoglobin (FIT) in the assessment of patients with lower abdominal symptoms: current controversies

Faecal immunochemical tests for haemoglobin (FIT), as an adjunct to clinical information, assist in the triage of patients presenting in primary care with lower abdominal symptoms. Controversy remains regarding whether and which qualitative and quantitative FIT can be used, which groups of patients would benefit most from FIT, whether FIT should be done in primary and/or secondary care, and how FIT should be incorporated into diagnostic pathways. Controversy also exists as to the optimum cut-off used for referral for colonoscopy. A single sample of faeces may be sufficient. Reporting of results requires consideration. FIT provide a good rule in test for colorectal cancer and a good rule out test for significant bowel disease, but robust safety-netting is required for patients with negative results and ongoing symptoms. Risk scoring models have been developed, but their value is unclear as yet. Further evaluation of these topics is required to inform good practice.

A comparative effectiveness trial of two faecal immunochemical tests for haemoglobin (FIT). Assessment of test performance and adherence in a single round of a population-based screening programme for colorectal cancer

AIM

To compare acceptability and diagnostic accuracy of a recently available faecal immunochemical test (FIT) system (HM-JACKarc) with the FIT routinely used in an established screening programme (OC-Sensor).

DESIGN

Randomised controlled trial (ISRCTN20086618) within a population-based colorectal cancer (CRC) screening programme. Subjects eligible for invitation in the Umbria Region (Italy) programme were randomised (ratio 1:1) to be screened using one of the FIT systems.

RESULTS

Screening uptake among the 48 888 invitees was the same for both systems among subjects invited in the first round and higher with OC-Sensor than with HM-JACKarc (relative risk (RR): 1.03; 95% CI 1.02 to 1.04) among those invited in subsequent rounds. Positivity rate (PR) was similar with OC-Sensor (6.5%) as with HM-JACKarc (6.2%) among subjects performing their first FIT screening and higher with OC-Sensor (5.6%, RR: 1.25, 95% CI 1.12 to 1.40) than with HM-JACKarc (4.4%) among those screened in previous rounds. Positive predictive value (PPV) (OC-Sensor: 25.9%, HM-JACKarc: 25.6%) and detection rate (DR) (OC-Sensor: 1.40%; HM-JACKarc: 1.42%) for advanced neoplasia (AN: CRC + advanced adenoma) were similar among subjects performing their first FIT screening. The differences in the AN PPV (OC-Sensor: 20.3%, HM-JACKarc: 22.6%) and DR (OC-Sensor: 0.96%, HM-JACKarc: 0.83%) among those screened in previous rounds were not statistically significant. The number needed to scope to detect one AN was 3.9 (95% CI 5.8 to 2.9) and 3.9 (95% CI 5.5 to 2.9) at first and 4.9 (95% CI 5.8 to 4.2) and 4.4 (95% CI 5.3 to 3.7) at subsequent screening, with OC-Sensor and HM-JACKarc, respectively.

CONCLUSIONS

Our results suggest that acceptability and diagnostic performance of HM-JACKarc and of OC-Sensor systems are similar in a screening setting.

TRIAL REGISTRATION NUMBER

ISRCTN20086618; Results.