Diagnostic yield improves with collection of 2 samples in fecal immunochemical test screening without affecting attendance

Risk prediction for advanced neoplasia using longitudinal adherence measures to fecal immunochemical test-based colorectal cancer screening programs

BACKGROUND

Patterns of longitudinal adherence may predict advanced neoplasia (AN) detection in subsequent rounds of colorectal cancer (CRC) screening. However, after more than five rounds, it is important to obtain a simplified measure. The aim was to determine the best simplified measure of longitudinal adherence to predict AN detection in CRC screening.

METHODS

Individuals with four invitations from a Dutch Fecal immunochemical testing (FIT-)based pilot study and two Italian FIT-based CRC screening programs were included. We calculated AN detection in the fourth round, stratified by prior adherence. Five simplified measures were compared to full information (permutations) using chi-squared goodness-of-fit: adherence previous invitation, consistency, frequency, frequency + adherence previous invitation, and proportion of invitations covered.

RESULTS

AN detection in the fourth round was highly dependent on prior adherence behavior. For inconsistent adherence, detection in the fourth round was strongly dependent on frequency and time since last participation. The performance of the simplified measures to capture this variation differed considerably. 'Adherence previous invitation' scored worst in predicting AN detection. 'Frequency+adherence previous invitation' had lowest chi-squared goodness-of-fit.

DISCUSSION

The simplified measure 'frequency+adherence previous invitation' is the best measure to reflect patterns of longitudinal adherence and could be used to emphasize to individuals the importance of CRC screening.

Impact of changes to the interscreening interval and faecal immunochemical test threshold in the national bowel cancer screening programme in England: results from the FIT pilot study

INTRODUCTION

The NHS Bowel Cancer Screening Programme (BCSP) faces endoscopy capacity challenges from the COVID-19 pandemic and plans to lower the screening starting age. This may necessitate modifying the interscreening interval or threshold.

METHODS

We analysed data from the English Faecal Immunochemical Testing (FIT) pilot, comprising 27,238 individuals aged 59-75, screened for colorectal cancer (CRC) using FIT. We estimated screening sensitivity to CRC, adenomas, advanced adenomas (AA) and mean sojourn time of each pathology by faecal haemoglobin (f-Hb) thresholds, then predicted the detection of these abnormalities by interscreening interval and f-Hb threshold.

RESULTS

Current 2-yearly screening with a f-Hb threshold of 120 μg/g was estimated to generate 16,092 colonoscopies, prevent 186 CRCs, detect 1142 CRCs, 7086 adenomas and 4259 AAs per 100,000 screened over 15 years. A higher threshold at 180 μg/g would reduce required colonoscopies to 11,500, prevent 131 CRCs, detect 1077 CRCs, 4961 adenomas and 3184 AAs. A longer interscreening interval of 3 years would reduce required colonoscopies to 10,283, prevent 126 and detect 909 CRCs, 4796 adenomas and 2986 AAs.

CONCLUSION

Increasing the f-Hb threshold was estimated to be more efficient than increasing the interscreening interval regarding overall colonoscopies per screen-benefited cancer. Increasing the interval was more efficient regarding colonoscopies per cancer prevented.

Cost-effectiveness analysis of colorectal cancer screening in Shanghai, China: a modelling study

•

The current Shanghai CRC screening program is cost-effective.

•

Changing to a validated FIT would make the program more efficient.

•

The results were sensitive to an increase in the cost of the validated FIT.

•

The results were sensitive to more participation in screening and colonoscopy.

Background

The current community-based colorectal cancer (CRC) screening program in Shanghai, launched in 2013, invited individuals aged 50–74 years to triennial screening with a qualitative faecal immunochemical test (FIT) and questionnaire-based risk assessment (RA). We aimed to evaluate the effectiveness and cost-effectiveness of the existing Shanghai screening program and compare it to using a validated two-sample quantitative FIT.

Methods

We simulated four strategies (no screening, Shanghai FIT, Shanghai FIT + RA and validated FIT) for the Shanghai screening program and evaluated CRC incidence, CRC mortality, the number of life years gained (LYG), the number of FITs, and colonoscopies required for each. An incremental cost-effectiveness analysis was performed to assess the cost- effectiveness of each strategy.

Results

All screening modalities reduced CRC incidence and CRC mortality, gained extra number of LYG compared to no screening. Screening using the Shanghai FIT and validated FIT reduced CRC incidence from 45 cases to 43 per 1,000 simulated individuals (4.4%). Incidence was reduced to 42 cases (6.7%) using the Shanghai FIT + RA. All screening strategies reduced CRC mortality by 10.0% (from 10 to 9 deaths) and resulted in 6 to 7 LYG. The validated FIT was the most cost-effective among the evaluated strategies (ICER ¥26,461 per LYG).

Conclusions

Our findings show that the current Shanghai screening program is (cost-) effective compared to no screening, but changing to a validated FIT would make the program more efficient.

Guaiac-based faecal occult blood tests versus faecal immunochemical tests for colorectal cancer screening in average-risk individuals

BACKGROUND

Worldwide, many countries have adopted colorectal cancer (CRC) screening programmes, often based on faecal occult blood tests (FOBTs). CRC screening aims to detect advanced neoplasia (AN), which is defined as CRC or advanced adenomas. FOBTs fall into two categories based on detection technique and the detected blood component: qualitative guaiac-based FOBTs (gFOBTs) and faecal immunochemical tests (FITs), which can be qualitative and quantitative. Screening with gFOBTs reduces CRC-related mortality.

OBJECTIVES

To compare the diagnostic test accuracy of gFOBT and FIT screening for detecting advanced colorectal neoplasia in average-risk individuals.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, BIOSIS Citation Index, Science Citation Index Expanded, and Google Scholar. We searched the reference lists and PubMed-related articles of included studies to identify additional studies.

SELECTION CRITERIA

We included prospective and retrospective studies that provided the number of true positives, false positives, false negatives, and true negatives for gFOBTs, FITs, or both, with colonoscopy as reference standard. We excluded case-control studies. We included studies in which all participants underwent both index test and reference standard ("reference standard: all"), and studies in which only participants with a positive index test underwent the reference standard while participants with a negative test were followed for at least one year for development of interval carcinomas ("reference standard: positive"). The target population consisted of asymptomatic, average-risk individuals undergoing CRC screening. The target conditions were CRC and advanced neoplasia (advanced adenomas and CRC combined).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected studies for inclusion. In case of disagreement, a third review author made the final decision. We used the Rutter and Gatsonis hierarchical summary receiver operating characteristic model to explore differences between tests and identify potential sources of heterogeneity, and the bivariate hierarchical model to estimate sensitivity and specificity at common thresholds: 10 µg haemoglobin (Hb)/g faeces and 20 µg Hb/g faeces. We performed indirect comparisons of the accuracy of the two tests and direct comparisons when both index tests were evaluated in the same population.

MAIN RESULTS

We ran the initial search on 25 June 2019, which yielded 63 studies for inclusion. We ran a top-up search on 14 September 2021, which yielded one potentially eligible study, currently awaiting classification. We included a total of 33 "reference standard: all" published articles involving 104,640 participants. Six studies evaluated only gFOBTs, 23 studies evaluated only FITs, and four studies included both gFOBTs and FITs. The cut-off for positivity of FITs varied between 2.4 μg and 50 µg Hb/g faeces. For each Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability than gFOBTs for AN (P < 0.001) and CRC (P = 0.004). For the detection of AN, the summary sensitivity of gFOBTs was 15% (95% confidence interval (CI) 12% to 20%), which was significantly lower than FITs at both 10 μg and 20 μg Hb/g cut-offs with summary sensitivities of 33% (95% CI 27% to 40%; P < 0.001) and 26% (95% CI 21% to 31%, P = 0.002), respectively. Results were simulated in a hypothetical cohort of 10,000 screening participants with 1% CRC prevalence and 10% AN prevalence. Out of 1000 participants with AN, gFOBTs missed 850, while FITs missed 670 (10 μg Hb/g cut-off) and 740 (20 μg Hb/g cut-off). No significant differences in summary specificity for AN detection were found between gFOBTs (94%; 95% CI 92% to 96%), and FITs at 10 μg Hb/g cut-off (93%; 95% CI 90% to 95%) and at 20 μg Hb/g cut-off (97%; 95% CI 95% to 98%). So, among 9000 participants without AN, 540 were offered (unnecessary) colonoscopy with gFOBTs compared to 630 (10 μg Hb/g) and 270 (20 μg Hb/g) with FITs. Similarly, for the detection of CRC, the summary sensitivity of gFOBTs, 39% (95% CI 25% to 55%), was significantly lower than FITs at 10 μg and 20 μg Hb/g cut-offs: 76% (95% CI 57% to 88%: P = 0.001) and 65% (95% CI 46% to 80%; P = 0.035), respectively. So, out of 100 participants with CRC, gFOBTs missed 61, and FITs missed 24 (10 μg Hb/g) and 35 (20 μg Hb/g). No significant differences in summary specificity for CRC were found between gFOBTs (94%; 95% CI 91% to 96%), and FITs at the 10 μg Hb/g cut-off (94%; 95% CI 87% to 97%) and 20 μg Hb/g cut-off (96%; 95% CI 91% to 98%). So, out of 9900 participants without CRC, 594 were offered (unnecessary) colonoscopy with gFOBTs versus 594 (10 μg Hb/g) and 396 (20 μg Hb/g) with FITs. In five studies that compared FITs and gFOBTs in the same population, FITs showed a higher discriminative ability for AN than gFOBTs (P = 0.003). We included a total of 30 "reference standard: positive" studies involving 3,664,934 participants. Of these, eight were gFOBT-only studies, 18 were FIT-only studies, and four studies combined both gFOBTs and FITs. The cut-off for positivity of FITs varied between 5 µg to 250 µg Hb/g faeces. For each QUADAS-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability for detecting CRC than gFOBTs (P < 0.001). The summary sensitivity for CRC of gFOBTs, 59% (95% CI 55% to 64%), was significantly lower than FITs at the 10 μg Hb/g cut-off, 89% (95% CI 80% to 95%; P < 0.001) and the 20 μg Hb/g cut-off, 89% (95% CI 85% to 92%; P < 0.001). So, in the hypothetical cohort with 100 participants with CRC, gFOBTs missed 41, while FITs missed 11 (10 μg Hb/g) and 11 (20 μg Hb/g). The summary specificity of gFOBTs was 98% (95% CI 98% to 99%), which was higher than FITs at both 10 μg and 20 μg Hb/g cut-offs: 94% (95% CI 92% to 95%; P < 0.001) and 95% (95% CI 94% to 96%; P < 0.001), respectively. So, out of 9900 participants without CRC, 198 were offered (unnecessary) colonoscopy with gFOBTs compared to 594 (10 μg Hb/g) and 495 (20 μg Hb/g) with FITs. At a specificity of 90% and 95%, FITs had a higher sensitivity than gFOBTs.

AUTHORS' CONCLUSIONS

FITs are superior to gFOBTs in detecting AN and CRC in average-risk individuals. Specificity of both tests was similar in "reference standard: all" studies, whereas specificity was significantly higher for gFOBTs than FITs in "reference standard: positive" studies. However, at pre-specified specificities, the sensitivity of FITs was significantly higher than gFOBTs.

Optimising colorectal cancer screening in Shanghai, China: a modelling study

INTRODUCTION

To reduce the burden of colorectal cancer (CRC) in Shanghai, China, a CRC screening programme was commenced in 2013 inviting those aged 50-74 years to triennial screening with a faecal immunochemical test (FIT) and risk assessment. However, it is unknown whether this is the optimal screening strategy for this population. We aimed to determine the optimal CRC screening programme for Shanghai in terms of benefits, burden, harms and cost-effectiveness.

METHODS

Using Microsimulation Screening Analysis-Colon (MISCAN-Colon), we estimated the costs and effects of the current screening programme compared with a situation without screening. Subsequently, we estimated the benefits (life years gained (LYG)), burden (number of screening events, colonoscopies and false-positive tests), harms (number of colonoscopy complications) and costs (Renminb (¥)) of screening for 324 alternative screening strategies. We compared several different age ranges, screening modalities, intervals and FIT cut-off levels. An incremental cost-effectiveness analysis determined the optimal strategy assuming a willingness-to-pay of ¥193 931 per LYG.

RESULTS

Compared with no screening, the current screening programme reduced CRC incidence by 40% (19 cases per 1000 screened individuals) and CRC mortality by 67% (7 deaths). This strategy gained 32 additional life years, increased colonoscopy demand to 1434 per 1000 individuals and cost an additional ¥199 652. The optimal screening strategy was annual testing using a validated one-sample FIT, with a cut-off of 10 µg haemoglobin per gram from ages 45 to 80 years (incremental cost-effectiveness ratio, ¥62 107). This strategy increased LY by 0.18% and costs by 27%. Several alternative cost-effective strategies using a validated FIT offered comparable benefits to the current programme but lower burden and costs.

CONCLUSIONS

Although the current screening programme in Shanghai is effective at reducing CRC incidence and mortality, the programme could be optimised using a validated FIT. When implementing CRC screening, jurisdictions with limited health resources should use a validated test.

One or two faecal immunochemical tests in an organised population-based colorectal cancer screening programme in Murcia (Spain)

OBJECTIVE

Roll-out of population-based colorectal cancer (CRC) screening with faecal immunochemical test (FIT) is limited by availability of further investigations, particularly colonoscopy and examination of excised lesions. Our objective was to assess whether variation in number of faecal samples and threshold adjustment can optimise resource utilisation and CRC detection rate.

METHODS

Three different screening strategies were compared for the same FIT threshold using a quantitative FIT system: one FIT, positive when >20 µg Hb/g faeces; two FIT, positive when either was >20 µg Hb/g faeces; and two FIT, positive when the mean was >20 µg Hb/g faeces. We calculated changes in the size of population the provider could invite to screening for an equal number of screening positive results, and CRC and adenoma detected.

RESULTS

In our setting, Region of Murcia, south of Spain (not fully rolled out screening programme), changing the usual strategy of two FIT, positive when either to positive when the mean was >20 µg Hb/g faeces, would increase population invited by 37.81% with the same number of positive results (which would generate a CRC detection rate of 19.2%). In a fully rolled out programme, changing the strategy from one to two FIT (positive when the mean is >20 µg Hb/g faeces), would increase CRC detection rate by 4.64% with an increase of only 13.34% in positive FIT.

CONCLUSIONS

In a population-based CRC screening programme, smart use of number of FITs and positivity threshold can increase population invited and CRC detection without increasing the number of colonoscopies and pathological examinations needed.

Brand interchangeability of pepsinogen tests in the real-world setting after eradication of Helicobacter pylori: a community-based study

Background

Serum pepsinogen (PG) is recommended as a screening test for premalignant gastric lesions. However, real-world evidence demonstrating its applicability and equivalence between different test brands is limited.

Methods

Mass screening began in 2018 in a high-risk Taiwanese population after eradication of Helicobacter pylori, with the first stage of two PG tests (GastroPanel^®, Helsinki, Finland and LZ-Test^®, Tokyo, Japan) and the second stage of endoscopy. A positive test was defined as PG-I < 30 ng/mL or PG-I/II ratio < 3 for GastroPanel^® and PG-I ≤ 70 ng/mL and PG-I/II ratio ≤ 3 for LZ-Test^®. Index lesions included atrophic gastritis and intestinal metaplasia. Test performance was evaluated based on the participation rate, positivity rate, referral rate, positive predictive value (PPV), and the detection rate.

Results

Among 7616 eligible participants, 5117 (67.2%) received PG tests and 284 (5.6%) tested positive. Of those who tested positive, 105 (37.0%) underwent endoscopy. Overall PPVs for atrophic gastritis and intestinal metaplasia were 12.4% and 18.9%, respectively, with detection rates of 2.5 and 3.9 per 1000, respectively. Correlations of numerical measures between tests were high and the agreements of test results were substantial. The PPVs (16.3% vs. 16.3% and 23.8% vs. 21.3%, P = 1.00 and 0.71, respectively), detection rates (2.5 vs. 2.5 and 3.7 vs. 3.3 per 1000, P = 1.00 and 0.27, respectively), and the stage distributions of gastritis were all comparable, which were confirmed by multiple regression analyses.

Conclusions

PG testing is effective for mass screening after eradication of H. pylori. Tests from different manufacturers, even using different analytical methods and cutoff criteria, can perform equivalently.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02155-7.

Faecal immunochemical testing in bowel cancer screening: Estimating outcomes for different diagnostic policies

OBJECTIVES

The National Health Service Bowel Cancer Screening Programme (NHS BCSP) in England has replaced guaiac faecal occult blood testing by faecal immunochemical testing (FIT). There is interest in fully exploiting FIT measures to improve bowel cancer (CRC) screening strategies. In this paper, we estimate the relationship of the quantitative haemoglobin concentration provided by FIT in faecal samples with underlying pathology. From this we estimate thresholds required for given levels of sensitivity to CRC and high-risk adenomas (HRA).

METHODS

Data were collected from a pilot study of FIT in England in 2014, in which 27,238 participants completed a FIT. Those with a faecal haemoglobin concentration (f-Hb) of at least 20 µg/g were referred for further investigation, usually colonoscopy. Truncated regression models were used to explore the relationship between bowel pathology and FIT results. Regression results were applied to estimate sensitivity to different abnormalities for a number of thresholds.

RESULTS

Participants with CRC and HRA had significantly higher f-Hb, and this remained unchanged after adjusting for age and sex. While a threshold of 20 μg/g was estimated to capture 82.2% of CRC and 64.0% of HRA, this would refer 7.8% of participants for colonoscopy. The current programme threshold used in England of 120 μg/g was estimated to identify 47.8% of CRC and 25.0% of HRA.

CONCLUSIONS

Under the current diagnostic policy of dichotomising FIT results, a very low threshold would be required to achieve high sensitivity to CRC and HRA, which would place further strain on colonoscopy resources. The NHS BCSP in England might benefit from a diagnostic policy that makes greater use of the quantitative nature of FIT.

Evaluating key characteristics of ideal colorectal cancer screening modalities: the microsimulation approach

BACKGROUND AND AIMS

Screening for colorectal cancer (CRC) can effectively reduce CRC incidence and mortality. Besides colonoscopy, tests for the detection of biomarkers in stool, blood, or serum, including the fecal immunochemical test (FIT), ColoGuard, Epi proColon, and PolypDx, have recently been advanced. We aimed to identify the characteristics of theoretic, highly efficient screening tests and calculated the effectiveness and cost effectiveness of available screening tests.

METHODS

Using the microsimulation-based colon modeling open-source tool (CMOST), we simulated 142,501 theoretic screening tests with variable assumptions for adenoma and carcinoma sensitivity, specificity, test frequency, and adherence, and we identified highly efficient tests outperforming colonoscopy. For available screening tests, we simulated 10 replicates of a virtual population of 2 million individuals, using epidemiologic characteristics and costs assumptions of the United States.

RESULTS

Highly efficient theoretic screening tests were characterized by high sensitivity for advanced adenoma and carcinoma and high patient adherence. All simulated available screening tests were effective at 100% adherence to screening and at expected real-world adherence rates. All tests were cost effective below the threshold of 100,000 U.S. dollars per life year gained. With perfect adherence, FIT was the most effective and cost-efficient intervention, whereas Epi proColon was the most effective at expected real-world adherence rates. In our sensitivity analysis, assumptions for patient adherence had the strongest impact on effectiveness of screening.

CONCLUSIONS

Our microsimulation study identified characteristics of highly efficient theoretic screening tests and confirmed the effectiveness and cost-effectiveness of colonoscopy and available urine-, blood-, and stool-based tests. Better patient adherence results in superior effectiveness for CRC prevention in the whole population.

Detection of advanced colorectal neoplasia and relative colonoscopy workloads using quantitative faecal immunochemical tests: an observational study exploring the effects of simultaneous adjustment of both sample number and test positivity threshold

OBJECTIVE

When screening for colorectal cancer (CRC) using quantitative faecal immunochemical tests (FIT), test parameters requiring consideration are the faecal haemoglobin concentration (f-Hb) positivity cut-off and the number of stools sampled. This observational study explored variation in f-Hb between samples and the relationship between sensitivity for advanced neoplasia (AN, cancer or advanced adenoma) and colonoscopy workload across a range of independently-adjusted parameter combinations.

DESIGN

Quantitative FIT data (OC-Sensor) were accessed from individuals undergoing personalised colonoscopic screening with an offer of 2-sample FIT in the intervening years. We estimated variation in f-Hb between samples in 12 710 completing 2-sample FIT, plus test positivity rates (colonoscopy workload) and sensitivity for AN according to parameter combinations in 4037 instances where FIT was done in the year preceding colonoscopy.

RESULTS

There was large within-subject variability between samples, with the ratio for the second to the first sample f-Hb ranging up to 18-fold for all cases, and up to 56-fold for AN cases. Sensitivity for AN was greatest at lower f-Hb cut-offs and/or using 2-sample FIT. Colonoscopy workload varied according to how parameters were combined. Using different cut-offs for 1-sample FIT and 2-sample FIT to return similar sensitivity, workload was less with 2-sample FIT when the sensitivity goal exceeded 35%.

CONCLUSION

Variation in f-Hb between samples is such that both parameters are crucial determinants of sensitivity and workload; independent adjustment of each should be considered. The 2-sample FIT approach is best for detecting advanced adenomas as well as CRC provided that the colonoscopy workload is feasible.

The impact of 6 years of the National Colorectal Cancer Screening Program on colorectal cancer incidence and 5-year survival

We aimed to assess the impact of the first three rounds of the National Colorectal Cancer Screening Program (NCCSP) on CRC incidence and mortality in Slovenia. In NCCSP, we use two fecal immune tests (FITs) and if test is positive patient is referred to colonoscopy. From 2009, we invite Slovenian residents aged 50-69 years, one screening round takes 2 years. The response rate was from 56.9 to 59.9%. FIT was positive in 6.0-6.2% (more in older patients and in men; P < 0.05). The adenoma detection rate was >51.3% (more in men; P < 0.01). In NCCSP, 70.3% of all cancers diagnosed were in stages I and II, while 20.7% of all CRC were found in polyps resected during colonoscopies. Patients with positive first FIT have odds ratio 2.19 [95% confidence interval (CI), 2.06-2.32] for advanced neoplasia and cancer compared to patients with two negative FITs. The incidence rate for CRC has dropped significantly after 6 years in population and in men (P < 0.01) but not in women. Five-year CRC survival was 31.3% higher if cancer was diagnosed in NCCSP (P < 0.05). After 6 years of NCCSP, the incidence rate for CRC has dropped significantly (P < 0.01). Hazard ratio for death from CRC was 3.84 higher (95% CI, 3.36-4.40; P < 0.001) in patients with cancer detected outside the program.

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.

Priority stratification for colonoscopy based on two-sample faecal immunochemical test screening: results from a cross-sectional study at an endoscopy clinic in Japan

OBJECTIVES

Little has been reported on the yield and characteristics of colorectal neoplasia detected by the two-sample faecal immunochemical test (FIT), particularly the difference between subjects with two-positive results on the two-sample FIT and those with one-positive results. We aimed to assess risk stratification among patients with positive two-sample FIT to prioritise colonoscopy.

DESIGN

A retrospective cross-sectional study.

SETTING

A single-centre, representative endoscopy clinic in Japan.

PARTICIPANTS

Consecutive patients who underwent colonoscopy were enrolled. Indications for colonoscopy included two-positive results on the two-sample FIT (FIT (+/+)), one-positive results on the two-sample FIT (FIT (+/-)), and other reasons (non-FIT group, including presence of symptoms, screening or surveillance).

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes were detection rates of colorectal cancers, including in situ (all cancers) and invasive cancers, based on the indications for colonoscopy. Secondary outcomes were cancer features, such as location, size, T stage and histological subtype.

RESULTS

Of the 8724 patients, 264 underwent colonoscopy following FIT (+/+), 1018 following FIT (+/-) and 7442 for reasons other than positive FIT. Detection rates of all (and invasive) cancers in the FIT (+/+), FIT (+/-) and non-FIT groups were 12.1% (8.3%), 1.9% (0.3%) and 0.4% (0.2%), respectively. The cancer detection rates were much higher in the FIT (+/+) group than in the FIT (+/-) group, which in turn had higher rates than the non-FIT group. Moreover, the FIT (+/+) group showed more advanced T stages on tumour, node, metastasis (TNM) classification (Tis/T1/T2/T3/T4: 10/7/4/10/1) than the FIT (+/-) group (16/1/2/0/0, p<0.001).

CONCLUSIONS

Two-positive results for two-sample FIT showed a much higher yield for more advanced colorectal cancers than the one-positive result. High priority for diagnostic colonoscopy should be assigned to patients with two-positive-FIT results.

Screening for Colorectal Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Colorectal cancer (CRC) remains a significant cause of morbidity and mortality in the US.

OBJECTIVE

To systematically review the effectiveness, test accuracy, and harms of screening for CRC to inform the US Preventive Services Task Force.

DATA SOURCES

MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials for relevant studies published from January 1, 2015, to December 4, 2019; surveillance through March 26, 2021.

STUDY SELECTION

English-language studies conducted in asymptomatic populations at general risk of CRC.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently appraised the articles and extracted relevant study data from fair- or good-quality studies. Random-effects meta-analyses were conducted.

MAIN OUTCOMES AND MEASURES

Colorectal cancer incidence and mortality, test accuracy in detecting cancers or adenomas, and serious adverse events.

RESULTS

The review included 33 studies (n = 10 776 276) on the effectiveness of screening, 59 (n = 3 491 045) on the test performance of screening tests, and 131 (n = 26 987 366) on the harms of screening. In randomized clinical trials (4 trials, n = 458 002), intention to screen with 1- or 2-time flexible sigmoidoscopy vs no screening was associated with a decrease in CRC-specific mortality (incidence rate ratio, 0.74 [95% CI, 0.68-0.80]). Annual or biennial guaiac fecal occult blood test (gFOBT) vs no screening (5 trials, n = 419 966) was associated with a reduction of CRC-specific mortality after 2 to 9 rounds of screening (relative risk at 19.5 years, 0.91 [95% CI, 0.84-0.98]; relative risk at 30 years, 0.78 [95% CI, 0.65-0.93]). In observational studies, receipt of screening colonoscopy (2 studies, n = 436 927) or fecal immunochemical test (FIT) (1 study, n = 5.4 million) vs no screening was associated with lower risk of CRC incidence or mortality. Nine studies (n = 6497) evaluated the test accuracy of screening computed tomography (CT) colonography, 4 of which also reported the test accuracy of colonoscopy; pooled sensitivity to detect adenomas 6 mm or larger was similar between CT colonography with bowel prep (0.86) and colonoscopy (0.89). In pooled values, commonly evaluated FITs (14 studies, n = 45 403) (sensitivity, 0.74; specificity, 0.94) and stool DNA with FIT (4 studies, n = 12 424) (sensitivity, 0.93; specificity, 0.85) performed better than high-sensitivity gFOBT (2 studies, n = 3503) (sensitivity, 0.50-0.75; specificity, 0.96-0.98) to detect cancers. Serious harms of screening colonoscopy included perforations (3.1/10 000 procedures) and major bleeding (14.6/10 000 procedures). CT colonography may have harms resulting from low-dose ionizing radiation. It is unclear if detection of extracolonic findings on CT colonography is a net benefit or harm.

CONCLUSIONS AND RELEVANCE

There are several options to screen for colorectal cancer, each with a different level of evidence demonstrating its ability to reduce cancer mortality, its ability to detect cancer or precursor lesions, and its risk of harms.

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.

DIAGNOSTIC ACCURACY OF ONE SAMPLE OR TWO SAMPLES QUANTITATIVE FECAL IMMUNOCHEMICAL TESTS FOR INTESTINAL NEOPLASIA DETECTION

BACKGROUND

Rectal bleeding is the most important symptom of intestinal neoplasia; thus, tests of occult blood detection in stools are widely used for pre neoplastic lesions and colorectal cancer (CRC) screening.

OBJECTIVE

Evaluate the accuracy of OC-Sensor quantitative test (Eiken Chemical, Tokyo, Japan) at cut-off 10 µg Hb/g feces (50 ng/mL) in a cohort of subjects that had to undergo diagnostic colonoscopy, and if more than one sample collected in consecutive days would improve the diagnostic accuracy of the test.

METHODS

Patients (mean age 56.3±9.7 years) that underwent colonoscopy prospectively randomly received one (1-sample FIT, FIT 1) or two (2-sample FIT, FIT 2) collection tubes. They collected the stool sample before starting colonoscopy preparation. Samples were analyzed by the OC-Auto Micro 80 (Eiken Chemical, Tokyo, Japan). The performance of FIT 1 and FIT 2 were compared to the colonoscopy findings.

RESULTS

Among 289 patients, CRC was diagnosed in 14 (4.8%), advanced adenoma in 37 (12.8%), early adenoma in 71 (24.6%) and no abnormalities in 141 (48.8%). For FIT 1, the sensitivity for CRC was 83.3% (95%CI 36.5-99.1%), for advanced adenoma was 24% (95%CI 10.1-45.5%), with specificity of 86.9% (95%CI 77.3-92.9%). For FIT 2, the sensitivity for CRC was 75% (95%CI 35.6-95.5%), for advanced adenoma was 50% (95%CI 22.3-77.7%), with specificity of 92.9% (95%CI 82.2-97.7%). The positive likelihood ratios were 1.8 (95%CI 0.7-4.4 for FIT 1) and 7.1 (95%CI 2.4-21.4 for FIT 2) for advanced adenoma, and 6.4 (95%CI 3.3-12.3, for FIT 1) and 10.7 (95%CI 3.8-29.8, for FIT 2) for CRC. The negative likelihood ratio were 0.9 (95%CI 0.7-1, for FIT 1) and 0.5 (95%CI 0.3-0.9, for FIT 2) for advanced adenoma, and 0.2 (0.03-1.1, for FIT 1) and 0.3 (0.08-0.9, for FIT 2) for CRC. The differences between FIT 1 and FIT 2 performances were not significant. However, the comparison of the levels of hemoglobin in feces of patients of FIT 1 and FIT 2 showed that the differences between no polyp group and advanced adenoma and CRC were significant.

CONCLUSION

The accuracy of OCR Sensor with 10 µg Hb/g feces cut-off was comparable to other reports and two-sample collection improved the detection rate of advanced adenoma, a pre neoplastic condition to prevent CRC incidence.

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.

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.

Comparative effectiveness and cost-effectiveness analysis of a urine metabolomics test vs. alternative colorectal cancer screening strategies

PURPOSE

Despite the success of provincial screening programs, colorectal cancer (CRC) is still the third most common cancer in Canada and the second most common cause of cancer-related death. Fecal-based tests, such as fecal occult blood test (FOBT) and fecal immunochemical test (FIT), form the foundation of the provincial CRC screening programs in Canada. However, those tests have low sensitivity for CRC precursors, adenomatous polyps and have low adherence. This study evaluated the effectiveness and cost-effectiveness of a new urine metabolomic-based test (UMT) that detects adenomatous polyps and CRC.

METHODS

A Markov model was designed using data from the literature and provincial healthcare databases for Canadian at average risk for CRC; calibration was performed against statistics data. Screening strategies included the following: FOBT every year, FIT every year, colonoscopy every 10 years, and UMT every year. The costs, quality adjusted life years (QALY) gained, and incremental cost-effectiveness ratios (ICERs) for each strategy were estimated and compared.

RESULTS

Compared with no screening, a UMT strategy reduced CRC mortality by 49.9% and gained 0.15 life years per person at $42,325/life year gained in the base case analysis. FOBT reduced CRC mortality by 14.9% and gained 0.04 life years per person at $25,011/life year gained. FIT reduced CRC mortality by 35.8% and gained 0.11 life years per person at $25,500/life year while colonoscopy reduced CRC mortality by 24.7% and gained 0.08 life years per person at $50,875/life year.

CONCLUSIONS

A UMT strategy might be a cost-effective strategy when used in programmatic CRC screening programs.

Diagnostic Accuracy Of Fecal Occult Blood Tests For Detecting Proximal Versus Distal Colorectal Neoplasia: A Systematic Review And Meta-Analysis

Objective

We conducted a systematic review and meta-analysis aimed at evaluating the differences of diagnostic performance of fecal occult blood tests (FOBTs) in detecting advanced colorectal neoplasms located in the proximal versus distal colorectum.

Methods

PubMed, Embase, Cochrane Library, and Web of Science were searched for eligible articles published before August 17, 2018. Two independent reviewers conducted study assessment and data extraction. Diagnosis-related indicators of FOBT for detecting proximal and distal colorectal neoplasms were summarized, and further stratified by the type of FOBT (guaiac-based FOBT (gFOBT) and immunochemical FOBT (iFOBT)). Pooled sensitivities and specificities were calculated using a random effect model. Summary receiver operating characteristic curves were plotted and area under the curves were calculated.

Results

Overall, 31 studies meeting the inclusion criteria were included in this review. For gFOBT, we found no site-specific difference (proximally vs distally located) of pooled sensitivities observed in the colorectal cancer (CRC), advanced adenomas, and advanced neoplasms groups. As for iFOBT, pooled sensitivities for detecting CRC located in the distal colon/rectum were comparable with that in the proximal colon (proximal vs distal, 0.67, 95% CI 0.62-0.72 vs 0.72, 95% CI 0.68-0.75), while higher pooled sensitivities for detecting advanced adenomas and advanced neoplasms located in the distal colon/rectum than for detecting those in the proximal colon were observed for iFOBT with the values of 0.24 (95% CI 0.22-0.25) vs 0.32 (95% CI 0.30-0.34) and 0.25 (95% CI 0.23-0.28) vs 0.38 (95% CI 0.36-0.40), respectively. Summary receiver operating characteristic curve analyses showed similar patterns for both types of FOBT regarding the diagnostic accuracy for detecting colorectal neoplasms according to the anatomical sites of the colorectum.

Conclusion

iFOBT had higher sensitivity for detecting advanced adenomas and advanced neoplasia located in the distal colon/rectum than that for those in the proximal colon.

Low Sensitivity of Fecal Immunochemical Tests and Blood-Based Markers of DNA Hypermethylation for Detection of Sessile Serrated Adenomas/Polyps

BACKGROUND

Early detection and removal of precursor lesions reduce colorectal cancer morbidity and mortality. Sessile serrated adenomas/polyps (SSP) are a recognized precursor of cancer, but there are limited studies on whether current screening techniques detect this pathology.

AIMS

To investigate the sensitivity of fecal immunochemical tests (FIT) and epigenetic biomarkers in blood for detection of SSP.

METHODS

A prospective study offered FIT and a blood test (Colvera for methylated BCAT1 and IKZF1) to adults referred for colonoscopy. Sensitivity of FIT and the blood test were determined for four types of pathology: low-risk conventional adenoma, high-risk adenoma, SSP, and absence of neoplasia. Comparisons were made for FIT positivity at 10 and 20 μg hemoglobin (Hb)/g feces.

RESULTS

One thousand eight hundred and eighty-two subjects completed FIT and underwent colonoscopy. One thousand four hundred and three were also tested for methylated BCAT1/IKZF1. The sensitivity of FIT (20 μg Hb/g feces) for SSP was 16.3%. This was lower than the sensitivity for high-risk adenomas (28.7%, p < 0.05), but no different to that for low-risk adenomas (13.1%) or no neoplasia (8.4%). A positive FIT result for SSP was not associated with demographics, morphology, concurrent pathology or intake of medications that increase bleeding risk. FIT sensitivity for SSP did not significantly increase through lowering the positivity threshold to 10 μg Hb/g feces (20.4%, p > 0.05). Sensitivity of the blood test for SSP was 8.8%, and 26.5% when combined with FIT.

CONCLUSIONS

Both FIT and blood-based markers of DNA hypermethylation have low sensitivity for detection of SSP. Further development of sensitive screening tests is warranted.

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.

Effect of anticoagulants and NSAIDs on accuracy of faecal immunochemical tests (FITs) in colorectal cancer screening: a systematic review and meta-analysis

OBJECTIVE

Most colorectal cancer (CRC) screening programmes are nowadays based on faecal immunochemical testing (FIT). Eligible subjects often use oral anticoagulants (OACs) or non-steroidal anti-inflammatory drugs (NSAIDs), which could possibly stimulate bleeding from both benign and premalignant lesions in the colon. The aim of this meta-analysis was to study the effect of OACs and NSAIDs use on FIT performance.

DESIGN

A systematic search was conducted until June 2017 to retrieve studies from PubMed, Embase, MEDLINE, Web of science, Cochrane Central and Google Scholar. Studies were included when reporting on FIT results in users versus non-users of OACs and/or NSAIDs in average risk CRC screening populations. Primary outcome was positive predictive value for advanced neoplasia (PPV_AN) of FIT in relation to OACs/NSAIDs use. Values were obtained by conducting random-effect forest plots.

RESULTS

Our literature search identified 2022 records, of which 8 studies were included. A total of 3563 participants with a positive FIT were included. Use of OACs was associated with a PPV_AN of 37.6% (95% CI 33.9 to 41.4) compared with 40.3% (95% CI 38.5 to 42.1) for non-users (p=0.75). Pooled PPV_AN in aspirin/NSAID users was 38.2% (95% CI 33.8 to 42.9) compared with 39.4% (95% CI 37.5 to 41.3) for non-users (p=0.59).

CONCLUSION

FIT accuracy is not affected by OACs and aspirin/NSAIDs use. Based on the current literature, withdrawal of OACs or NSAIDs before FIT screening is not recommended. Future studies should focus on duration of use, dosage and classes of drugs in association with accuracy of FIT to conduct more specific guideline recommendations.

Fecal immunochemical test in cancer screening - colonoscopy outcome in FIT positives and negatives

Objectives: Fecal immunochemical test (FIT) is used in colorectal cancer (CRC) screening, but evaluations of multiple sample strategies in colonoscopy screening cohorts are rare. The aim of this study was to assess accuracy of FIT for advanced neoplasia (AN) with two fecal samples in a colonoscopy screening cohort. Materials and methods: The study comprised 1155 participants of the colonoscopy arm in SCREESCO (Screening of Swedish Colons, NCT02078804), a randomized controlled study on CRC screening of 60-year-olds from the Swedish average-risk population. Participants provided two FIT samples prior to colonoscopy. First sample, mean of two, and any of the two samples above cut off level were assessed. Colonoscopy findings (CRC, advanced adenoma (AA), AN (CRC + AA) and adenoma characteristics) were evaluated in uni- and multivariable analysis in relation to FIT positivity (at ≥10 µg hemoglobin (Hb)/g). Results: Of 1155 invited, 806 (416 women, 390 men) participated. CRC, AA and non-AA were found in one (0.1%), 80 (9.9%) and 145 (18%), respectively. Sensitivity and specificity for AN were 20%/93%, 25%/92% and 26%/89% for first, mean of two and any of the two samples respectively at cut off level 10 µg/g, corresponding to 60 (74%)-65 (80%) participants with missed AN. The difference in sensitivity between screening strategies was non-significant. The specificity for first sample was significantly higher than for any of the two samples at cut off 10 µg/g (p = .02) and 20 µg/g (p = .04). FIT positivity in participants with adenoma was associated with pedunculated shape (p = .007) and high-risk dysplasia (p = .009). Conclusions: In an average-risk colonoscopy screening cohort of 60-year-olds, sensitivity for AN was modest and did not increase when using two samples instead of one. FIT predominantly detected adenomas with pedunculated shape and high-risk dysplasia, and participants with flat or broad based adenomas may thus be missed in screening.

Fecal immunochemical test in colorectal cancer screening: Colonoscopy findings by different cut-off levels

BACKGROUND AND AIM

Fecal immunochemical test (FIT) is used in colorectal cancer (CRC) screening, but number of tests and cut-off level differ by program. The aim was to evaluate CRC screening with two FIT samples in average-risk 60-year-old men and women and to investigate hemoglobin (Hb) level in correlation to adenoma characteristics.

METHODS

We analyzed a cohort from Screening of Swedish Colons trial where participants with at least one of two FIT samples ≥10 μg Hb/g are offered colonoscopy. FIT levels and colonoscopy findings were assessed in multivariable analyses. Cut-off levels 10-80 μg Hb/g for one and two samples were assessed. FIT levels and advanced neoplasia (AN) were investigated by gender.

RESULTS

A total of 12 383 participated and 1182 positives (551 women) completed colonoscopy diagnosing 27 (2.3%) CRC and 269 (23%) advanced adenomas (AA). Median FIT level was 241.0 and 23.8 for CRC and AA compared with 13.4-15.8 in other subgroups (P = 0.002) correlating with adenoma size (P = 0.038). CRC was detected in 22 and 19 subjects for the first sample at cut-off 20 and 40 μg Hb/g, compared with 20 and 17 for the mean of two samples at cut-off 40 and 80 μg Hb/g (P < 0.05). Men had more AN (CRC + AA), (P = 0.003). In women, similar number of AN would be detected with cut-off lowered from 40 to 20 or from 80 to 40 μg Hb/g, requiring additional 26-34% colonoscopies.

CONCLUSION

In average-risk 60-year-olds, FIT was higher in participants with AN and correlated with adenoma size. FIT screening with one sample at low cut-off detected more CRC than two samples at higher cut-off. Applying lower cut-off in women to equalize gender differences in AN would result in considerable increase in colonoscopy workload.

Performance of the Fecal Immunochemical Test for Colorectal Cancer Screening Using Different Stool-Collection Devices: Preliminary Results from a Randomized Controlled Trial

Background/Aims

We are in the process of conducting a randomized trial to determine whether compliance with the fecal immunochemical test (FIT) for colorectal cancer screening differs according to the stool-collection method. This study was an interim analysis of the performance of two stool-collection devices (sampling bottle vs conventional container).

Methods

In total, 1,701 individuals (age range, 50 to 74 years) were randomized into the sampling bottle group (intervention arm) or the conventional container group (control arm). In both groups, we evaluated the FIT positivity rate, the positive predictive value for advanced neoplasia, and the detection rate for advanced neoplasia.

Results

The FIT positivity rates were 4.1% for the sampling bottles and 2.0% for the conventional containers; these values were significantly different. The positive predictive values for advanced neoplasia in the sampling bottles and conventional containers were 11.1% (95% confidence interval [CI], −3.4 to 25.6) and 12.0% (95% CI, −0.7 to 24.7), respectively. The detection rates for advanced neoplasia in the sampling bottles and conventional containers were 4.5 per 1,000 persons (95% CI, 2.0 to 11.0) and 2.4 per 1,000 persons (95% CI, 0.0 to 5.0), respectively.

Conclusions

The impact of these findings on FIT screening performance was unclear in this interim analysis. This impact should therefore be evaluated in the final analysis following the final enrollment period.

Fecal Immunochemical Test Detects Sessile Serrated Adenomas and Polyps With a Low Level of Sensitivity

BACKGROUND & AIMS

The serrated pathway is a distinct pathway of colorectal carcinogenesis that has been implicated in development of a substantial proportion of interval colorectal cancers. The fecal immunochemical test (FIT) detects early neoplasms with a higher level of sensitivity than the guaiac test. We investigated the sensitivity of the FIT in detection of sessile serrated adenomas/polyps (SSA/Ps).

METHODS

We performed a prospective study of 6198 asymptomatic subjects (mean age, 59.0 ± 7.0 years) who received concurrent screening colonoscopies and FITs at the Health Management Center of National Taiwan University Hospital from August 2010 through November 2014. The sensitivity of FIT for conventional adenoma, advanced adenoma, and SSA/P at different cutoffs was calculated, and results were compared by using multivariate analysis adjusted for potential confounders.

RESULTS

Prevalence values of SSA/P, adenoma, and advanced adenoma were 1.4%, 20.2%, and 5.5%, respectively. At cutoffs of 10, 15, and 20 μg hemoglobin/g feces, the FIT detected all SSA/Ps with 12.3%, 6.2%, and 6.2% sensitivity, large SSA/Ps with 18.4%, 10.5%, and 10.5% sensitivity, and advanced adenomas with 32.4%, 24.5%, and 20.9% sensitivity, respectively. Multivariate analysis revealed that positive results from the FIT did not differ significantly between individuals with SSA/P and those with non-advanced adenoma or those with negative findings from colonoscopy. Patients with large SSA/Ps were less likely to have positive results from the FIT than patients with advanced adenoma, with odds ratios of 0.44 (95% confidence interval [CI], 0.18-1.05), 0.30 (95% CI, 0.10-0.90), and 0.37 (95% CI, 0.12-1.12) at cutoffs of 10, 15, and 20 μg hemoglobin/g feces, respectively, after adjusting for lesion size, even with synchronous conventional adenoma.

CONCLUSIONS

In a prospective study of 6198 subjects receiving the FIT and colonoscopy, we found that the FIT detected SSA/Ps with significantly lower levels of sensitivity than conventional adenoma. Further studies are needed to determine the effects of these findings on the effectiveness of FIT-based colorectal cancer screening program.

Recommendations on Fecal Immunochemical Testing to Screen for Colorectal Neoplasia: A Consensus Statement by the US Multi-Society Task Force on Colorectal Cancer

The use of the fecal occult blood test (FOBT) for colorectal cancer (CRC) screening is supported by randomized trials demonstrating effectiveness in cancer prevention and widely recommended by guidelines for this purpose. The fecal immunochemical test (FIT), as a direct measure of human hemoglobin in stool has a number of advantages relative to conventional FOBT and is increasingly used relative to that test. This review summarizes current evidence for FIT in colorectal neoplasia detection and the comparative effectiveness of FIT relative to other commonly used CRC screening modalities. Based on evidence, guidance statements on FIT application were developed and quality metrics for program implementation proposed.

Recommendations on Fecal Immunochemical Testing to Screen for Colorectal Neoplasia: A Consensus Statement by the US Multi-Society Task Force on Colorectal Cancer

The use of the fecal occult blood test (FOBT) for colorectal cancer (CRC) screening is supported by randomized trials demonstrating effectiveness in cancer prevention and widely recommended by guidelines for this purpose. The fecal immunochemical test (FIT), as a direct measure of human hemoglobin in stool has a number of advantages relative to conventional FOBT and is increasingly used relative to that test. This review summarizes current evidence for FIT in colorectal neoplasia detection and the comparative effectiveness of FIT relative to other commonly used CRC screening modalities. Based on evidence, guidance statements on FIT application were developed and quality metrics for program implementation proposed.

Attendance and diagnostic yield of repeated two-sample faecal immunochemical test screening for colorectal cancer

OBJECTIVE

Limited data exist on attendance and additional yield of 2-sample faecal immunochemical testing (FIT) screening during multiple rounds. We therefore conducted a population-based colorectal cancer screening trial comparing attendance and yield of repeated 1-sample and 2-sample FIT screenings.

DESIGN

Two randomly selected groups of average-risk subjects aged 50-74 years were invited for two rounds of either 1-sample (n=5007) or 2-sample (n=3197) FIT (OC-sensor Micro) screening. The test was considered positive if at least one sample was positive (cut-off 50 ng/mL; 10 µg haemoglobin/g).

RESULTS

The cumulative attendance rate was similar for repeated 1-sample and 2-sample FIT screenings (1-sample FIT: 68.1%; 2-sample FIT: 67.1%, p=0.368). The positivity rate in the second round was lower for 1-sample FIT (6.2%, 95% CI 5.4% to 7.2%) than for 2-sample FIT (8.4%, 95% CI 7.1% to 9.8%, p=0.007), whereas the detection rate of advanced neoplasia (AN, 1-sample FIT: 1.9%, 95% CI 1.2% to 2.2%; 2-sample FIT: 1.7%, 95% CI 1.2% to 2.5%, p=0.861) and the positive predictive value (1-sample FIT: 32%, 95% CI 24% to 40%; 2-sample FIT: 21%, 95% CI 15% to 29%, p=0.075) did not differ. After two rounds of screening, the cumulative diagnostic yield of AN for 1-sample FIT was 29.3 per 1000 invitees, compared with 34.0 for 2-sample FIT (p=0.241).

CONCLUSIONS

Using 2-sample FIT instead of 1-sample FIT does not result in a higher detection rate of AN in the second round of repeated FIT screening. Furthermore, both strategies lead to a similar yield of AN over two rounds. These findings imply that 1-sample FIT screening is preferred over 2-sample FIT screening.

Does Low Threshold Value Use Improve Proximal Neoplasia Detection by Fecal Immunochemical Test?

BACKGROUND

Several studies have reported that the fecal immunochemical test (FIT) less sensitively detects proximal advanced neoplasia (AN) compared to distal AN. Low threshold value use may improve proximal AN detection.

AIM

To investigate whether FIT diagnostic accuracy for AN is different according to AN location and to compare FIT accuracy in proximal AN detection using different threshold values.

METHODS

This retrospective study was conducted in a university hospital in Korea from June 2013 to May 2015. Out of 34,547 participants who underwent FITs, 3990 subjects aged ≥50 years who also underwent colonoscopies were analyzed. The FIT diagnostic accuracy for AN with differing locations (proximal vs. distal) and threshold values (20, 15, and 10 mcg Hb/g feces) were assessed.

RESULTS

The sensitivity, specificity, positive predictive value, and negative predictive value of FIT in AN detection were 42.2, 84.3, 24.1, and 92.5 %, respectively. The FIT sensitivity for proximal AN detection was significantly lower than that for distal AN detection (32.7 and 49.0 %, respectively; P = 0.001). Lowering FIT threshold values tended to increase the sensitivity for proximal AN, whereas it significantly decreased the specificity for proximal AN. As a result, there was no significant difference in the accuracy for proximal AN detection (80.1, 79.3, and 78.1 % for 20, 15, and 10 mcg Hb/g feces, respectively; P = 0.107).

CONCLUSIONS

FIT was less sensitive in proximal AN detection than distal AN detection. Lowering the FIT cutoff threshold did not increase the accuracy for proximal AN detection. New biomarker development for colorectal cancer screening is required to improve proximal ACRN diagnostic accuracy.

Faecal calprotectin in patients with suspected colorectal cancer: a diagnostic accuracy study

BACKGROUND

NICE guidance exists for the use of faecal calprotectin (FC) when irritable bowel syndrome or inflammatory bowel disease are suspected. Often, however, colorectal cancer is considered within the differential. Should FC have a high diagnostic accuracy for colorectal cancer, it may be applicable as a primary care screening test for all patients with lower gastrointestinal symptoms.

AIM

To determine the negative and positive predictive value (NPV/PPV) of FC in patients referred from primary care with suspected colorectal cancer.

DESIGN AND SETTING

A diagnostic accuracy study conducted at a single secondary care site

METHOD

Consenting patients referred with suspected colorectal cancer within the '2-week wait' pathway provided a stool sample for FC prior to investigation. FC levels were reconciled with end diagnoses: cancer, adenomatous polyps ≥10 mm, and all enteric organic disease.

RESULTS

A total of 654 patients completed the evaluation; median age 69 years, female 56%. The NPV for colorectal cancer was 98.6% and 97.2% when including polyps ≥10 mm. The PPV for all organic enteric disease was 32.7%. The diagnostic yield for cancer based on clinical suspicion was 6.3%. By altering the FC cut-off to fix the NPV at 97.0%, the PPV for cancer increased from 8.7% to 13.3%.

CONCLUSION

FC has a high NPV for colorectal cancer and significant polyps in patients with suspected cancer. In total, 27.8% of patients had a normal FC and could safely have been spared a '2-week wait' referral. The addition of FC testing into the current symptom-based assessment has the potential to increase colorectal cancer detection rate yet be clinically and cost effective.

Nonbleeding adenomas: Evidence of systematic false-negative fecal immunochemical test results and their implications for screening effectiveness-A modeling study

BACKGROUND

If some adenomas do not bleed over several years, they will cause systematic false-negative fecal immunochemical test (FIT) results. The long-term effectiveness of FIT screening has been estimated without accounting for such systematic false-negativity. There are now data with which to evaluate this issue.

METHODS

The authors developed one microsimulation model (MISCAN [MIcrosimulation SCreening ANalysis]-Colon) without systematic false-negative FIT results and one model that allowed a percentage of adenomas to be systematically missed in successive FIT screening rounds. Both variants were adjusted to reproduce the first-round findings of the Dutch CORERO FIT screening trial. The authors then compared simulated detection rates in the second screening round with those observed, and adjusted the simulated percentage of systematically missed adenomas to those data. Finally, the authors calculated the impact of systematic false-negative FIT results on the effectiveness of repeated FIT screening.

RESULTS

The model without systematic false-negativity simulated higher detection rates in the second screening round than observed. These observed rates could be reproduced when assuming that FIT systematically missed 26% of advanced and 73% of nonadvanced adenomas. To reduce the false-positive rate in the second round to the observed level, the authors also had to assume that 30% of false-positive findings were systematically false-positive. Systematic false-negative FIT testing limits the long-term reduction of biennial FIT screening in the incidence of colorectal cancer (35.6% vs 40.9%) and its mortality (55.2% vs 59.0%) in participants.

CONCLUSIONS

The results of the current study provide convincing evidence based on the combination of real-life and modeling data that a percentage of adenomas are systematically missed by repeat FIT screening. This impairs the efficacy of FIT screening. Cancer 2016;122:1680-8. © 2016 American Cancer Society.

Different modalities for colorectal cancer screening: experiences in The Netherlands so far

In 2014, a nation-wide colorectal cancer (CRC) screening program was launched in The Netherlands. Every 2 years, men and women aged 55–75 years will be invited to participate in fecal immunochemical test screening. Participants with a positive test result will be scheduled for colonoscopy. Starting from 2006, screening pilots have been performed to ascertain the choice of an optimal screening modality, population acceptance, logistics and cost effectiveness, in order to ensure that a screening program with maximal benefits and the least amount of harms was offered to the Dutch population. In this overview, we will discuss the results of Dutch CRC screening pilots in which different screening modalities were studied, the preparations made before the launch of the nation-wide screening program, and finally the initial results and lessons learned so far from the Dutch CRC screening program.

Comparison of One versus Two Fecal Immunochemical Tests in the Detection of Colorectal Neoplasia in a Population-Based Colorectal Cancer Screening Program

Objective. To determine the positive predictive value (PPV) of two versus one abnormal FIT in the detection of colorectal neoplasia in a Canadian population. Methods. Three communities enrolled in a colorectal cancer (CRC) screening pilot program from 01/2009 to 04/2013 using 2 FITs. Data collected included demographics, colonoscopy, pathology, and FIT results. Participants completed both FITs and had one positive FIT and colonoscopy. PPV of one versus two abnormal FITs was calculated using a weighted-generalized score statistic. A two-sided 5% significance level was used. Results. 1576 of 17,031 average-risk participants, 50-75 years old, had a positive FIT. Colonoscopy revealed 58 (3.7%) cancers, 419 (31.6%) high-risk polyps, and 374 (23.7%) low-risk polyps as the most significant lesion. PPV of one versus two positive FITs for cancer, high-risk polyps, and any neoplasia were 1% versus 8%, 20% versus 40%, and 48% versus 67%, respectively (p value < 0.0001). When the first FIT was negative, the second positive FIT detected 7 CRCs and 98 high-risk polyps. Conclusions. PPV of two positive FITs is superior to one positive FIT for CRC and high-risk polyps. The added value of the second FIT was 12% of total CRCs and 23% of total high-risk polyps.

Non-invasive screening for colorectal cancer in Asia

There is an increasing trend of colorectal cancer incidence in Asia and nearly 45% of CRC cases worldwide occur in Asia therefore screening for CRC becomes an urgent task. Stool-based tests, including guaiac fecal occult blood test (gFOBT) and fecal immunochemical test (FIT), can select subjects at risk of significant colorectal neoplasms from the large target population thus are currently the most commonly used non-invasive screening tool in large population screening programs. FIT has the advantage over gFOBT in terms of higher sensitivity for early neoplasms, the ability to provide high-throughput automatic analysis, and better public acceptance thus greater effectiveness on reducing CRC mortality and incidence is expected. Owing to the large target population and constrained endoscopic capacity and manpower, FIT is nowadays the most popular CRC screening test in Asia. Some Asian countries have launched nationwide screening program in the past one or two decades but also encountered some challenges such as low screening participation rate, low verification rate after positive stool tests, low public awareness, and insufficient manpower. In addition, some controversial or potential future research issues are also addressed in this review.

Colorectal cancer

Colorectal cancer had a low incidence several decades ago. However, it has become a predominant cancer and now accounts for approximately 10% of cancer-related mortality in western countries. The 'rise' of colorectal cancer in developed countries can be attributed to the increasingly ageing population, unfavourable modern dietary habits and an increase in risk factors, such as smoking, low physical exercise and obesity. New treatments for primary and metastatic colorectal cancer have emerged, providing additional options for patients; these treatments include laparoscopic surgery for primary disease, more-aggressive resection of metastatic disease (such as liver and pulmonary metastases), radiotherapy for rectal cancer, and neoadjuvant and palliative chemotherapies. However, these new treatment options have had limited impact on cure rates and long-term survival. For these reasons, and the recognition that colorectal cancer is long preceded by a polypoid precursor, screening programmes have gained momentum. This Primer provides an overview of the current state of the art of knowledge on the epidemiology and mechanisms of colorectal cancer, as well as on diagnosis and treatment.

International collaboration between Japan and Chile to improve detection rates in colorectal cancer screening

BACKGROUND

In Chile, mortality from colorectal cancer (CRC) has increased rapidly. To help address this issue, the Prevention Project for Neoplasia of the Colon and Rectum (PRENEC) program was initiated in 2012 with intensive support from Tokyo Medical and Dental University (TMDU) in Tokyo, Japan, as part of an international collaboration.

METHODS

From June 2012 to July 2014, a total of 10,575 asymptomatic participants were enrolled in PRENEC. Participants with positive immunochemical fecal occult blood test (iFOBT) results or a family history of CRC underwent colonoscopy. The colonoscopy results from a similar, previous project in Chile (PREVICOLON) were compared with those from PRENEC. Furthermore, the initial colonoscopies of 1562 participants in PRENEC were analyzed according to whether the colonoscopists were from TMDU or Chile.

RESULTS

The complete colonoscopy, adenoma detection, and cancer detection rates were 88.0%, 26.7%, and 1.1%, respectively, in PREVICOLON, while the corresponding values were 94.4%, 41.8%, and 6.0%, respectively, in PRENEC. In PRENEC, 107 cases of CRC were detected, amounting for 1.0% of all participants. Considering initial colonoscopies in PRENEC, the complete colonoscopy, adenoma detection, and cancer detection rates were 97.4%, 45.3%, and 9.3%, respectively, for physicians at TMDU and 93.3%, 41.5%, and 5.1%, respectively for Chilean physicians. The detection rates of intramucosal cancer were 7.3% and 3.7%, respectively, for TMDU and Chilean physicians.

CONCLUSIONS

Quality indicators of colonoscopy substantially improved from PREVICOLON to PRENEC. The assessments made by Chilean physicians alone were improved in PRENEC, but remained better in the TMDU group. Moreover, physicians from TMDU detected more CRCs than Chilean physicians, especially at earlier stages.

Diagnostic Accuracy of a Qualitative Fecal Immunochemical Test Varies With Location of Neoplasia But Not Number of Specimens

BACKGROUND & AIMS

We compared the accuracy of a qualitative fecal immunochemical test (FIT) in identifying patients with proximal vs distal advanced neoplasia and evaluated whether analysis of 2 specimens performed better than analysis of 1 specimen. Distal advanced neoplasia was defined as colorectal cancer (CRC), any colorectal adenoma ≥10 mm in diameter, high-grade dysplasia, or a lesion with villous or tubulovillous histologic characteristics in a location distal to the splenic flexure, including the descending colon, the rectosigmoid, and the rectum.

METHODS

We collected data from 5343 subjects (50-70 years old) who received 2 FITs (Hemosure; cutoff value, 10 μg hemoglobin/g feces) before colonoscopy in an invitational CRC screening program in Hong Kong from 2008 through 2012. We calculated the FIT's sensitivity, specificity, positive predictive value (PPV), and negative predictive value in detecting colorectal neoplasia.

RESULTS

Of the participants, 13.6%, 12.2%, and 6.0% had distal, proximal, and synchronous distal or proximal neoplasia, respectively. Advanced neoplasia was detected in 291 subjects (5.4%); 22 (0.4%) had CRC. FIT detected distal advanced adenoma with 39.7% sensitivity (95% confidence interval [CI], 32.0%-48.0%) vs proximal advanced adenoma with 25.0% sensitivity (95% CI, 17.3%-34.6%; P = .014), distal advanced neoplasia with 40.0% sensitivity (95% CI, 32.5%-47.9%) vs proximal advanced neoplasia with 27.9% sensitivity (95% CI, 20.0%-37.4%; P = .039), and any distal adenoma ≥10 mm, irrespective of other lesion characteristics, with 39.5% sensitivity (95% CI, 31.0%-48.7%) vs. proximal adenoma with 25.3% sensitivity (95% CI, 16.5%-36.6%; P = .038). The specificity of FIT in detecting CRC was similar between the proximal and distal colon. FIT detected distal lesions with higher PPV than proximal lesions. One FIT detected advanced neoplasia with 31.8% sensitivity (95% CI, 25.9%-38.4%) and 92.4% specificity (95% CI, 91.6%-93.2%), whereas 2 FITs detected advanced neoplasia with 34.1% sensitivity (95% CI, 28.0%-40.8%; P = .617) and 91.9% specificity (95% CI, 91.0%-92.7%; P = .327). FIT detected distal advanced neoplasia with greater sensitivity and higher PPV than proximal advanced neoplasia.

CONCLUSIONS

In an analysis of data from subjects who underwent CRC screening in Hong Kong, FIT detected distal advanced neoplasia with higher sensitivity than proximal advanced neoplasia. Analysis of 1 vs 2 specimens by FIT identified advanced neoplasia with similar test characteristics.

Faecal immunochemical tests versus guaiac faecal occult blood tests: what clinicians and colorectal cancer screening programme organisers need to know

Although colorectal cancer (CRC) is a common cause of cancer-related death, it is fortunately amenable to screening with faecal tests for occult blood and endoscopic tests. Despite the evidence for the efficacy of guaiac-based faecal occult blood tests (gFOBT), they have not been popular with primary care providers in many jurisdictions, in part because of poor sensitivity for advanced colorectal neoplasms (advanced adenomas and CRC). In order to address this issue, high sensitivity gFOBT have been recommended, however, these tests are limited by a reduction in specificity compared with the traditional gFOBT. Where colonoscopy is available, some providers have opted to recommend screening colonoscopy to their patients instead of faecal testing, as they believe it to be a better test. Newer methods for detecting occult human blood in faeces have been developed. These tests, called faecal immunochemical tests (FIT), are immunoassays specific for human haemoglobin. FIT hold considerable promise over the traditional guaiac methods including improved analytical and clinical sensitivity for CRC, better detection of advanced adenomas, and greater screenee participation. In addition, the quantitative FIT are more flexible than gFOBT as a numerical result is reported, allowing customisation of the positivity threshold. When compared with endoscopy, FIT are less sensitive for the detection of advanced colorectal neoplasms when only one time testing is applied to a screening population; however, this is offset by improved participation in a programme of annual or biennial screens and a better safety profile. This review will describe how gFOBT and FIT work and will present the evidence that supports the use of FIT over gFOBT, including the cost-effectiveness of FIT relative to gFOBT. Finally, specific issues related to FIT implementation will be discussed, particularly with respect to organised CRC screening programmes.

Colorectal cancer in a second round after a negative faecal immunochemical test

OBJECTIVE

The faecal immunochemical test is one of the tests recommended by scientific societies for colorectal cancer (CRC) screening in average-risk populations. Our aim was to evaluate the characteristics of CRC detected in a second round of screening after negative results in a first round.

METHODS

We studied patients in whom CRC was detected in a screening programme. This programme included asymptomatic individuals between 50 and 69 years old and offered tests every 2 years. A total of 363,792 individuals were invited to participate in the first round of faecal immunochemical test screening and 100,135 individuals in the second round after a first negative result. The screening strategy consisted of faecal testing of a single sample using an automated semiquantitative kit, with a cut-off of 20 μg haemoglobin (Hb)/g faeces.

RESULTS

The rate of positive results was 6.9% (16,467/238,647) in the first round and 4.8% (3359/69,193) in the second round (P < 0.0005). Overall, 860 (0.36%) cases of CRC were detected in the first round and 100 (0.14%) in the second round (P < 0.005). The location of the cancer was proximal in 12.5 and 24% of cases detected in the first and second rounds, respectively (P = 0.008). Hb concentrations were higher in the first round (211 vs. 109 μg Hb/g faeces in the second round; P = 0.002). Multivariate analysis confirmed that, in the second round, CRC diagnosed was more often proximal (hazard ratio vs. first round, 2.4; 95% confidence interval, 1.3-4.4; P = 0.003) and the concentration of Hb/g faeces was lower (hazard ratio vs. first round, 2.1; 95% confidence interval, 1.3-3.5; P = 0.003).

CONCLUSION

The CRC detection rate is lower in the second round of screening. Further, in the second round, CRC detected is more often in a proximal location and Hb concentrations are lower.

Controversies in colorectal cancer screening

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers worldwide and a good candidate for screening programmes. However, there is controversy concerning which of the available screening tests should be used.

SUMMARY

There is general agreement that screening for CRC in the asymptomatic population should begin at the age of 50. Several different screening methods are available which can be separated into those that mainly detect cancers: faecal occult blood tests [guaiac (FOBT) and immunochemical (FIT)], genetic stool tests, blood tests and the M2-pyruvate kinase (M2-PK) test. Methods that detect cancers and polyps are colonoscopy, sigmoidoscopy, CT-colonography (CT-C) and colon capsule endoscopy. The only tests for which a reduction in CRC mortality compared to no screening have been proven in randomized trials are FOBT and sigmoidoscopy. Several trials suggest that FIT are superior to FOBT in terms of detection rates of cancers and advanced adenomas and possibly compliance. There is indirect evidence suggesting efficacy of colonoscopy as a screening test. The role of CT-C is controversial. There is data suggesting a good sensitivity for neoplasia >9 mm with a lower sensitivity for smaller neoplasia. However, radiation exposure is considered a major limitation in some countries. Unresolved questions include the lesion cut-off for referral to colonoscopy and work-up of extracolonic findings. For other methods, like genetic stool testing using newer markers, blood tests, capsule endoscopy and M2-PK, there is currently insufficient data on screening of the asymptomatic population. Key Messages: Colorectal screening is recommended and should be performed in the form of an organized programme. If detection of early-stage cancers is the aim of a screening programme, FIT seem to be superior to FOBT. If detection and removal of adenomas is the aim of a screening programme, endoscopic methods seem to be good alternatives. Sigmoidoscopy is easier to perform but will likely only have an effect on distal cancers. Colonoscopy is more invasive but enables inspection of the whole colon. The role of CT-C, capsule endoscopy, genetic stool tests, blood tests and M2-PK is currently unknown.

Faecal occult blood testing for colorectal cancer screening: the past or the future

Screening for colorectal cancer (CRC) reduces CRC mortality; many countries have implemented population-based CRC screening programmes and many more are poised to do so. Whilst several different CRC screening modalities are available, choice will be influenced by cost, available resources (e.g. high-quality colonoscopy) and acceptability of the test by the invited population. For CRC screening, no screening test has so far surpassed the practicality, affordability and effectiveness of tests for the presence of blood in faeces (faecal occult blood tests, FOBt). The results of several large FOBt-based randomised controlled trials provide the best clinical evidence to support their use in population-based CRC screening. This review considers the current options for CRC screening and the future for FOBt.

Advances in Fecal Occult Blood Tests: the FIT revolution

There is a wide choice of fecal occult blood tests (FOBTs) for colorectal cancer screening.

GOAL

To highlight the issues applicable when choosing a FOBT, in particular which FOBT is best suited to the range of screening scenarios. Four scenarios characterize the constraints and expectations of screening programs: (1) limited colonoscopy resource with a need to constrain test positivity rate; (2) a priority for maximum colorectal neoplasia detection with little need to constrain colonoscopy workload; (3) an "adequate" endoscopy resource that allows balancing the benefits of detection with the burden of service provision; and (4) a need to maximize participation in screening. Guaiac-based FOBTs (gFOBTs) have significant deficiencies, and fecal immunochemical tests (FITs) for hemoglobin have emerged as better tests. gFOBTs are not sensitive to small bleeds, specificity can be affected by diet or drugs, participant acceptance can be low, laboratory quality control opportunities are limited, and they have a fixed hemoglobin concentration cutoff determining positivity. FITs are analytically more specific, capable of quantitation and hence provide flexibility to adjust cutoff concentration for positivity and the balance between sensitivity and specificity. FITs are clinically more sensitive for cancers and advanced adenomas, and because they are easier to use, acceptance rates are high.

CONCLUSIONS

FOBT must be chosen carefully to meet the needs of the applicable screening scenario. Quantitative FIT can be adjusted to suit Scenarios 1, 2 and 3, and for each, they are the test of choice. FITs are superior to gFOBT for Scenario 4 and gFOBT is only suitable for Scenario 1.

Diagnostic accuracy of fecal immunochemical test in average- and familial-risk colorectal cancer screening

BACKGROUND

There is little information about the fecal immunochemical test (FIT) in familial-risk colorectal cancer (CRC) screening.

OBJECTIVES

The objective of this article is to investigate whether FIT diagnostic accuracy for advanced neoplasia (AN) differs between average and familial-risk (first-degree relative) patients.

METHODS

A total of 1317 consecutive participants (595 familial) who collected one stool sample before performing a colonoscopy as a CRC screening test were included. FIT diagnostic accuracy for AN was evaluated with Chi-square test at a 20 µg hemoglobin/g of feces cut-off value. Finally, we determined which variables were independently related to AN.

RESULTS

An AN was found in 151 (11.5%) patients. The overall accuracy was not statistically different between both cohorts for AN (88.4%, 91.7%; p = 0.051). At the cut-off stablished, differences in FIT sensitivity (31.1%, 40.6%; p = 0.2) or specificity (96.5%, 97.3%; p = 0.1) were not statistically significant. Finally, independent variables such as sex (male) (odds ratio (OR) 2.1, 95% confidence interval (CI) 1.4-3.1), age (50-65, >65 years) (OR 2.1, 95% CI 1.1-4.3; OR 2.7, 95% CI 1.2-6.1), previous colonoscopy (OR 0.4, 95% CI 0.2-0.9) and FIT ≥20 µg/g feces (OR 17.7, 95% CI 10.8-29.1) were associated with AN diagnosis.

CONCLUSIONS

FIT accuracy for AN detection is equivalent in average and familial-risk CRC screening cohorts.

Sustained participation, colonoscopy uptake and adenoma detection rates over two rounds of the Tallaght-Trinity College colorectal cancer screening programme with the faecal immunological test

BACKGROUND

Studies to date support the use of the faecal immunological test (FIT) in colorectal cancer screening programmes, and it has been widely adopted across Europe, Canada, Australia, and the USA. Successive screening rounds are necessary to detect and prevent colorectal cancer. The overall success of FIT screening will depend on several factors, the most important probably being the acceptability of repeated screening rounds. Being a newer form of occult blood testing, there is little data available on its overall efficacy over time.

AIMS

The aim of this study was to assess key performance indices during a second round of FIT screening in an Irish cohort and to compare results between successive rounds.

METHODS

A biennial, two tests, two-step design with postal invites and colonoscopy offered to anyone with a single FIT greater than 100 ngHb/ml was used. Recommended key performance measures were assessed and compared, including participation, positivity, colonoscopy uptake and adenoma and cancer detection rates.

RESULTS

In round two, 9863 individuals (98.6%) of the round one cohort were contacted. The round two participation rate was 47.5% (n=4685), only slightly lower than the 51% registered in round one. Male sex and younger age were associated with lower uptake. Overall positivity decreased from 10 to 8% over time (P<0.0001). Although the number of cancers detected during round two decreased significantly, overall neoplasia detection rates remained stable; positive predictive values for cancer and adenoma were 4 versus 1% and 37 versus 35%, respectively.

CONCLUSION

Repeated rounds of FIT screening in the Tallaght-Trinity College cohort achieved stable participation and neoplasia detection rates, suggesting that this mode of screening is both effective and acceptable to patients in the long term.

Fecal-based colorectal cancer screening among the uninsured in northern Manhattan

BACKGROUND

Colorectal cancer (CRC) screening reduces CRC mortality; however, for many reasons, uninsured individuals are less likely to utilize CRC screening tests.

PURPOSE

To compare CRC screening behaviors and outcomes with guaiac fecal occult blood testing (gFOBT) from 1998 to 2006 and fecal immunochemical testing (FIT) from 2006 to 2010 in a community-based program serving uninsured patients in northern Manhattan.

METHODS

In 2013, we conducted a retrospective record review of individuals aged ≥50 years who received fecal-based CRC screening at the Northern Manhattan Cancer Screening Partnership between 1998 and 2010. Included were those with household income ≤250% of the federal poverty level, no medical insurance coverage, and who were not up to date with CRC screening. We assessed screening positivity rate, positive predictive value, differences in the use of diagnostic colonoscopy, colonoscopic findings, and adenoma detection rates for gFOBT versus FIT.

RESULTS

In total, 7,710 patients completed CRC screenings (4,951 gFOBT and 2,759 FIT). The majority were female, Hispanic, foreign born, and young at age of first screening. Compared to gFOBT, FIT detected twice as many positive tests (3.2% vs 1.5%, p≤0.001) and had a higher adenoma detection rate (18.2 vs 11.8, p=0.002).

CONCLUSIONS

The improved positivity and adenoma detection rates with greater number of screening tests over time favor the use of FIT over gFOBT for colorectal screening among uninsured populations in northern Manhattan.