The association between organised colorectal cancer screening strategies and reduction of its related mortality: a systematic review and meta-analysis

BACKGROUND

To assess the long-term association between organised colorectal cancer (CRC) screening strategies and CRC-relate mortality.

METHODS

We systematically reviewed studies on organised CRC screening through PubMed, Ovid Medline, Embase and Cochrane from the inception. We retrieved characteristics of organised CRC screening from included literature and matched mortality (over 50 years) of those areas from the International Agency for Research on Cancer in May 2023. The variations of mortality were reported via the age-standardised mortality ratio. A random-effects model was used to synthesis results.

RESULTS

We summarised 58 organised CRC screening programmes and recorded > 2.7 million CRC-related deaths from 22 countries where rollout screening programmes were performed. The CRC screening strategy with faecal tests (guaiac faecal occult blood test (gFOBT) or faecal immunochemical tests (FIT)) or colonoscopy as the primary screening offer was associated with a 41.8% reduction in mortality, which was higher than those offered gFOBT (4.4%), FIT (16.7%), gFOBT or FIT (16.2%), and faecal tests (gFOBT or FIT) or flexible sigmoidoscopy (16.7%) as primary screening test. The longer duration of screening was associated with a higher reduction in the pooled age-standardised mortality ratio. In particular, the pooled age-standardised mortality ratio became non-significant when the screening of FIT was implemented for less than 5 years.

CONCLUSIONS

A CRC screening programme running for > 5 years was associated with a reduction of CRC-related mortality. Countries with a heavy burden of CRC should implement sustainable, organised screening providing a choice between faecal tests and colonoscopy as a preferred primary test.

Interval cancers in a national colorectal screening programme based on faecal immunochemical testing: Implications for faecal haemoglobin concentration threshold and sex inequality

OBJECTIVE

To compare interval cancer proportions (ICP) in the faecal immunochemical test (FIT)-based Scottish Bowel Screening Programme (SBoSP) with the former guaiac faecal occult blood test (gFOBT)-based SBoSP and investigate associations between interval cancer (IC) and faecal haemoglobin concentration (f-Hb) threshold, sex, age, deprivation, site, and stage.

METHODS

The ICP data from first year of the FIT-based SBoSP and the penultimate year of the gFOBT-based SBoSP were compared in a prospective cohort design.

RESULTS

With FIT, 801 colorectal cancers (CRCs) were screen detected (SDC), 802 were in non-participants, 548 were ICs, 39 were colonoscopy missed and 72 were diagnosed after incomplete screening; with gFOBT: 540, 904, 556, 45, and 13, respectively. FIT had a significantly higher proportion of SDC compared to IC than gFOBT. For FIT and gFOBT, ICP was significantly higher in women than men. As f-Hb threshold increased, ICP increased and, for any f-Hb threshold for men, a lower threshold was required for comparable ICP in women. In Scotland, the current threshold of ≥80 µg Hb/g faeces would have to be lowered to ≥40 µg Hb/g faeces for women to achieve sex equality for ICP. In the FIT-based SBoSP, there were four times as many stage I SDC than IC. This was reversed in advanced stages, with twice as many stage IV CRC diagnosed as IC versus SDC.

CONCLUSIONS

Reducing the numbers of IC requires lowering the f-Hb threshold. Using different f-Hb thresholds for women and men could eliminate the sex disparity, but with additional colonoscopy.

Post-colonoscopy colorectal cancer: A population-based cohort study of fecal occult blood test-positive colonoscopies

BACKGROUND

Data on post-colonoscopy colorectal cancers (PCCRCs) after fecal occult blood test (FOBT)-positive colonoscopies is scarce (guaiac-based (gFOBT) or fecal immunochemical test (FIT)).

AIMS

Evaluate the prevalence and characteristics of PCCRCs in the French gFOBT CRC screening program.

METHODS

Retrospective population-based cohort study of all gFOBT-positive colonoscopies performed among individuals aged 50-74 between 2003 and 2014 within the CRC screening program organized in the Haut-Rhin (Alsace, France). The main outcome was PCCRC-3y rate. Adenoma detection rates (ADRs) calculated on gFOBT-positive colonoscopies were compared to those calculated on FIT-positive colonoscopies performed by the same gastroenterologists.

RESULTS

Overall, 9106 gFOBT-positive colonoscopies performed by 36 gastroenterologists were included. Sixteen PCCRC-3y and 31 PCCRC-5y were diagnosed (68.8 % and 58.1 % were true interval PCCRCs respectively). The unadjusted PCCRC-3y rate was 2.4 % [95 % confidence interval (CI) 1.4 %-3.9 %]. The risk for PCCRC-5y was significantly higher when the gastroenterologist's ADR was <35 % compared to ≥35 % (HR 2.17 [95 %CI 1.19-3.93]). The mean absolute difference for ADR between gFOBT- and FIT-positive colonoscopies was 16.3 % in favor of FIT-positive colonoscopies.

CONCLUSION

PCCRC-3y prevalence was low, estimated at 2.4 %. We suggest that the minimum standard for ADR in gFOBT- and FIT-positive colonoscopies should be set at 35 % and 50 % to 55 % respectively, in the French screening program.

The Non-Invasive Prediction of Colorectal Neoplasia (NIPCON) Study 1995-2022: A Comparison of Guaiac-Based Fecal Occult Blood Test (FOBT) and an Anti-Adenoma Antibody, Adnab-9

Given the need to improve the sensitivity of non-invasive methods to detect colorectal neoplasia, particularly adenomas, we compared a fecal test using a monoclonal antibody (Mab) raised against constituents of colonic adenomas designated Adnab-9 (Adenoma Antibody 9), recognizing an N-linked 87 kDa glycoprotein, to gFOBT, which is shown to reduce CRC mortality. p87 immunohistochemistry testing is significantly more sensitive (OR 3.64[CI 2.37-5.58]) than gFOBT (guaiac-based fecal occult blood test) for adenomas (<3 in number), advanced adenomas (OR 4.21[CI 2.47-7.15]), or a combination of the two (OR 3.35[CI 2.47-4.53]). p87 immunohistochemistry shows regional Paneth cell (PC) expression mainly in the right-sided colon and is significantly reduced in the ceca of African Americans (p < 0.0001). In a subset of patients, we obtained other body fluids such as urine, colonic effluent, and saliva. Urine tests (organ-specific neoantigen) showed a significant difference for advanced adenomas (p < 0.047). We conclude that fecal p87 testing is more sensitive than gFOBT and Adnab-9 and could be used to better direct the colonoscopy screening effort.

Healthcare costs, resource utilization, and productivity loss associated with colorectal cancer screening

OBJECTIVES

To evaluate healthcare costs, resource utilization, associated costs, and lost productivity for colorectal cancer (CRC) screening in an average-risk population.

METHODS

This retrospective cohort study identified average-risk individuals (50-75 years) with claims in the Optum Research Database for CRC screening test between 1 January 2014 to 31 December 2018. Index date was defined as the first date of a claim for colonoscopy, fecal immunochemical test (FIT), guaiac-based fecal occult blood test (FOBT) or multi-target stool DNA test (mt-sDNA). Screening costs were evaluated with descriptive statistics and multivariable analyses, adjusting for patient characteristics and index screening costs.

RESULTS

In total, 903,831 individuals were identified by test groups: mt-sDNA (n = 29,614), FIT (n = 254,002), guaiac-based FOBT (n = 112,757) and colonoscopy (n = 507,458). Adjusted costs for index screening were, colonoscopy ($3,029), mt-sDNA ($752), FIT ($45), and (FOBT ($153). Adjusted costs across the six months following the index screening were $146 for colonoscopy, $329 for mt-sDNA, $306 for FIT, and $412 for FOBT. Colonoscopy had the highest costs for lost productivity.

CONCLUSIONS

Screening colonoscopy had the highest productivity loss and healthcare costs up-front, suggesting potential cost benefits for noninvasive screening modalities. The more frequent screening interval required for FIT and FOBT resulted in a higher yearly cost than colonoscopy or mt-sDNA.

Supply and quality of colonoscopy according to the characteristics of gastroenterologists in the French population-based colorectal-cancer screening program

BACKGROUND

Since its complete roll-out in 2009, the French colorectal cancer screening program (CRCSP) experienced 3 major constraints [use of a less efficient Guaiac-test (gFOBT), stopping the supply of Fecal-Immunochemical-Test kits (FIT), and suspension of the program due to the coronavirus disease 2019 (COVID-19)] affecting its effectiveness.

AIM

To describe the impact of the constraints in terms of changes in the quality of screening-colonoscopy (Quali-Colo).

METHODS

This retrospective cohort study included screening-colonoscopies performed by gastroenterologists between Jan-2010 and Dec-2020 in people aged 50-74 living in Ile-de-France (France). The changes in Quali-colo (Proportion of colonoscopies performed beyond 7 mo (Colo_7 mo), Frequency of serious adverse events (SAE) and Colonoscopy detection rate) were described in a cohort of Gastroenterologists who performed at least one colonoscopy over each of the four periods defined according to the chronology of the constraints [gFOBT: Normal progress of the CRCSP using gFOBT (2010-2014); FIT: Normal progress of the CRCSP using FIT (2015-2018); STOP-FIT: Year (2019) during which the CRCSP experienced the cessation of the supply of test kits; COVID: Program suspension due to the COVID-19 health crisis (2020)]. The link between each dependent variable (Colo_7 mo; SAE occurrence, neoplasm detection rate) and the predictive factors was analyzed in a two-level multivariate hierarchical model.

RESULTS

The 533 gastroenterologists (cohort) achieved 21509 screening colonoscopies over gFOBT period, 38352 over FIT, 7342 over STOP-FIT and 7995 over COVID period. The frequency of SAE did not change between periods (gFOBT: 0.3%; FIT: 0.3%; STOP-FIT: 0.3%; and COVID: 0.2%; P = 0.10). The risk of Colo_7 mo doubled between FIT [adjusted odds ratio (aOR): 1.2 (1.1; 1.2)] and STOP-FIT [aOR: 2.4 (2.1; 2.6)]; then, decreased by 40% between STOP-FIT and COVID [aOR: 2.0 (1.8; 2.2)]. Regardless of the period, this Colo_7 mo’s risk was twice as high for screening colonoscopy performed in a public hospital [aOR: 2.1 (1.3; 3.6)] compared to screening-colonoscopy performed in a private clinic. The neoplasm detection, which increased by 60% between gFOBT and FIT [aOR: 1.6 (1.5; 1.7)], decreased by 40% between FIT and COVID [aOR: 1.1 (1.0; 1.3)].

CONCLUSION

The constraints likely affected the time-to-colonoscopy as well as the colonoscopy detection rate without impacting the SAE’s occurrence, highlighting the need for a respectable reference time-to-colonoscopy in CRCSP.

Benefit of Biennial Fecal Occult Blood Screening on Colorectal Cancer in England: A Population-Based Case-Control Study

BACKGROUND

The English national bowel cancer screening program offering a guaiac fecal occult blood test began in July 2006. In randomized controlled trials of guaiac fecal occult blood test screening, reductions in mortality were accompanied by reductions in advanced stage colorectal cancer (CRC). We aimed to evaluate the effect of participation in the national bowel cancer screening program on stage-specific CRC incidence as a likely precursor of a mortality effect.

METHODS

In this population-based case-control study, cases were individuals diagnosed with CRC aged 60-79 years between January 1, 2012, and December 31, 2013. Two controls per case were matched on geographic region, gender, date of birth, and year of first screening invitation. Screening histories were extracted from the screening database. Conditional logistic regression with correction for self-selection bias was used to estimate odds ratios (odds ratios corrected for self-selection bias [cOR]) and 95% confidence intervals (CIs) by Duke stage, sex, and age.

RESULTS

14 636 individuals with CRC and 29 036 without were eligible for analysis. The odds of CRC (any stage) were increased within 30 days of a screening test and decreased thereafter. No reduction in CRC (any stage) among screened individuals compared with those not screened was observed (cOR = 1.00, 95% CI = 0.89 to 1.15). However, screened individuals had lower odds of Duke stage D CRC (cOR = 0.68, 95% CI = 0.50 to 0.93). We estimate 435 fewer Duke D CRC by age 80 years in 100 000 people screened biennially between ages 60 and 74 years compared with an unscreened cohort.

CONCLUSION

The impact of colorectal screening on advanced CRC incidence suggests that the program will meet its aim of reducing mortality.

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.

Optimizing the Design of a Repeated Fecal Immunochemical Test Bowel Cancer Screening Programme With a Limited Endoscopy Capacity From a Health Economic Perspective

OBJECTIVES

In 2016, it was announced that the fecal immunochemical test (FIT) would replace the guaiac fecal occult blood test in the UK Bowel Cancer Screening Programme. England has limited endoscopy capacity. This study informed decision making by determining the most cost-effective FIT screening strategy (age range, frequency, and FIT threshold) under a constrained endoscopy capacity.

METHODS

An economic model with a colorectal cancer natural history component was used to model 60 221 screening strategies with first screening at age 50 to 60 years, screening interval of 1 to 6 years, 3+ screening episodes, and FIT integer threshold of 20 to 180 μg hemoglobin/g feces. Screening strategies requiring the same endoscopy capacity were compared to determine the characteristics of the most cost-effective strategies.

RESULTS

With 50 000 annual screening referral colonoscopies, the 20 most cost-effective strategies had a starting age of 50 to 53 years, 2-yearly screening, 7 or 8 rounds of screening, and FIT threshold of 127 to 166. Compared with a 2-yearly screening interval, screening less frequently (3-, 4-, 5-, or 6-yearly) with a more sensitive FIT was less cost-effective.

CONCLUSIONS

The UK Bowel Cancer Screening Programme should use a 2-yearly FIT screening interval. When endoscopy capacity increases, the screening starting age should be reduced first followed by reducing the FIT threshold. These findings are relevant for other colorectal cancer screening programs with constrained endoscopy capacity.

The colorectal cancer-associated faecal microbiome of developing countries resembles that of developed countries

BACKGROUND

The incidence of colorectal cancer (CRC) is increasing in developing countries, yet limited research on the CRC- associated microbiota has been conducted in these areas, in part due to scarce resources, facilities, and the difficulty of fresh or frozen stool storage/transport. Here, we aimed (1) to establish a broad representation of diverse developing countries (Argentina, Chile, India, and Vietnam); (2) to validate a 'resource-light' sample-collection protocol translatable in these settings using guaiac faecal occult blood test (gFOBT) cards stored and, importantly, shipped internationally at room temperature; (3) to perform initial profiling of the collective CRC-associated microbiome of these developing countries; and (4) to compare this quantitatively with established CRC biomarkers from developed countries.

METHODS

We assessed the effect of international storage and transport at room temperature by replicating gFOBT from five UK volunteers, storing two in the UK, and sending replicates to institutes in the four countries. Next, to determine the effect of prolonged UK storage, DNA extraction replicates for a subset of samples were performed up to 252 days apart. To profile the CRC-associated microbiome of developing countries, gFOBT were collected from 41 treatment-naïve CRC patients and 40 non-CRC controls from across the four institutes, and V4 16S rRNA gene sequencing was performed. Finally, we constructed a random forest (RF) model that was trained and tested against existing datasets from developed countries.

RESULTS

The microbiome was stably assayed when samples were stored/transported at room temperature and after prolonged UK storage. Large-scale microbiome structure was separated by country and continent, with a smaller effect from CRC. Importantly, the RF model performed similarly to models trained using external datasets and identified similar taxa of importance (Parvimonas, Peptostreptococcus, Fusobacterium, Alistipes, and Escherichia).

CONCLUSIONS

This study demonstrates that gFOBT, stored and transported at room temperature, represents a suitable method of faecal sample collection for amplicon-based microbiome biomarkers in developing countries and suggests a CRC-faecal microbiome association that is consistent between developed and developing countries.

Effect of once-only flexible sigmoidoscopy screening on the outcomes of subsequent faecal occult blood test screening

OBJECTIVE

To investigate the outcomes of biennial guaiac faecal occult blood test (gFOBT) screening after once-only flexible sigmoidoscopy (FS) screening.

METHODS

Between 1994 and 1999, as part of the UK FS Screening Trial (UKFSST), adults aged 55-64 were randomly allocated to an intervention group (offered FS screening) or a control group (not contacted). From 2006, a subset of UKFSST participants (20,895/44,041 intervention group; 41,497/87,149 control group) were invited to biennial gFOBT screening by the English Bowel Cancer Screening Programme. We analysed gFOBT uptake, test positivity, yield of colorectal cancer (CRC), and positive predictive value (PPV) for CRC, advanced adenomas (AAs), and advanced colorectal neoplasia (ACN: AA/CRC).

RESULTS

Uptake of gFOBT at first invitation was 1.9% lower (65.7% vs. 67.6%, p < 0.01) among intervention versus control group participants. Positivity was 0.4% lower (2.0% vs. 2.4%, p < 0.01) and CRC yield was 0.08% lower (0.19% vs. 0.27%, p = 0.14). PPVs were also lower in the intervention versus control group, at 10.3% vs. 12.3% ( p = 0.44) for CRC, 22.7% vs. 31.4% ( p < 0.01) for AA, and 33.0% vs. 43.7% ( p < 0.01) for ACN. Among those who refused FS ( n = 5532), gFOBT uptake at first invitation was 47.7%, CRC yield was 0.25%, and PPV for ACN was 46.2%. Among FS attenders ( n = 15,363), uptake was 72.2%, CRC yield was 0.18%, and PPV for ACN was 27.9%.

CONCLUSIONS

Uptake, positivity and PPV of gFOBT screening were reduced following prior offer of FS screening. However, a quarter of FS screened participants receiving a diagnostic examination after positive gFOBT were diagnosed with ACN.

High test positivity and low positive predictive value for colorectal cancer of continued faecal occult blood test screening after negative colonoscopy

Objectives The English Bowel Cancer Screening Programme offers biennial guaiac faecal occult blood test (gFOBT) screening to 60-74-year-olds. Participants with positive results are referred for follow-up, but many do not have significant findings. If they remain age eligible, these individuals are reinvited for gFOBT screening. We evaluated the performance of repeat screening in this group. Methods We analysed data on programme participants reinvited to gFOBT screening after either previous negative gFOBT ( n = 327,542), or positive gFOBT followed by a diagnostic investigation negative for colorectal cancer (CRC) or adenomas requiring surveillance ( n = 42,280). Outcomes calculated were uptake, test positivity, yield of CRC, and positive predictive value (PPV) of gFOBT for CRC. Results For participants with a previous negative gFOBT, uptake in the subsequent screening round was 87.5%, positivity was 1.3%, yield of CRC was 0.112% of those adequately screened, and the PPV of gFOBT for CRC was 9.1%. After a positive gFOBT and a negative diagnostic investigation, uptake in the repeat screening round was 82.6%, positivity was 11.3%, CRC yield was 0.172% of participants adequately screened, and the PPV of gFOBT for CRC was 1.7%. Conclusion With high positivity and low PPV for CRC, the suitability of routine repeat gFOBT screening in two years among individuals with a previous positive test and a negative diagnostic examination needs to be carefully considered.

Cost-effectiveness of the faecal immunochemical test at a range of positivity thresholds compared with the guaiac faecal occult blood test in the NHS Bowel Cancer Screening Programme in England

OBJECTIVES

Through the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP), men and women in England aged between 60 and 74 years are invited for colorectal cancer (CRC) screening every 2 years using the guaiac faecal occult blood test (gFOBT). The aim of this analysis was to estimate the cost-utility of the faecal immunochemical test for haemoglobin (FIT) compared with gFOBT for a cohort beginning screening aged 60 years at a range of FIT positivity thresholds.

DESIGN

We constructed a cohort-based Markov state transition model of CRC disease progression and screening. Screening uptake, detection, adverse event, mortality and cost data were taken from BCSP data and national sources, including a recent large pilot study of FIT screening in the BCSP.

RESULTS

Our results suggest that FIT is cost-effective compared with gFOBT at all thresholds, resulting in cost savings and quality-adjusted life years (QALYs) gained over a lifetime time horizon. FIT was cost-saving (p<0.001) and resulted in QALY gains of 0.014 (95% CI 0.012 to 0.017) at the base case threshold of 180 µg Hb/g faeces. Greater health gains and cost savings were achieved as the FIT threshold was decreased due to savings in cancer management costs. However, at lower thresholds, FIT was also associated with more colonoscopies (increasing from 32 additional colonoscopies per 1000 people invited for screening for FIT 180 µg Hb/g faeces to 421 additional colonoscopies per 1000 people invited for screening for FIT 20 µg Hb/g faeces over a 40-year time horizon). Parameter uncertainty had limited impact on the conclusions.

CONCLUSIONS

This is the first published economic analysis of FIT screening in England using data directly comparing FIT with gFOBT in the NHS BSCP. These results for a cohort starting screening aged 60 years suggest that FIT is highly cost-effective at all thresholds considered. Further modelling is needed to estimate economic outcomes for screening across all age cohorts simultaneously.

Harms, benefits and costs of fecal immunochemical testing versus guaiac fecal occult blood testing for colorectal cancer screening

BACKGROUND

The ColonCancerCheck screening program for colorectal cancer (CRC) in Ontario, Canada, is considering switching from biennial guaiac fecal occult blood test (gFOBT) screening between age 50-74 years to the more sensitive, but also less specific fecal immunochemical test (FIT). The aim of this study is to estimate whether the additional benefits of FIT screening compared to gFOBT outweigh the additional costs and harms.

METHODS

We used microsimulation modeling to estimate quality adjusted life years (QALYs) gained and costs of gFOBT and FIT, compared to no screening, in a cohort of screening participants. We compared strategies with various age ranges, screening intervals, and cut-off levels for FIT. Cost-efficient strategies were determined for various levels of available colonoscopy capacity.

RESULTS

Compared to no screening, biennial gFOBT screening between age 50-74 years provided 20 QALYs at a cost of CAN$200,900 per 1,000 participants, and required 17 colonoscopies per 1,000 participants per year. FIT screening was more effective and less costly. For the same level of colonoscopy requirement, biennial FIT (with a high cut-off level of 200 ng Hb/ml) between age 50-74 years provided 11 extra QALYs gained while saving CAN$333,300 per 1000 participants, compared to gFOBT. Without restrictions in colonoscopy capacity, FIT (with a low cut-off level of 50 ng Hb/ml) every year between age 45-80 years was the most cost-effective strategy providing 27 extra QALYs gained per 1000 participants, while saving CAN$448,300.

INTERPRETATION

Compared to gFOBT screening, switching to FIT at a high cut-off level could increase the health benefits of a CRC screening program without considerably increasing colonoscopy demand.

Interval Colorectal Cancers following Guaiac Fecal Occult Blood Testing in the Ontario ColonCancerCheck Program

Background. This work examines the occurrence of interval colorectal cancers (CRCs) in the Ontario ColonCancerCheck (CCC) program. We define interval CRC as CRC diagnosed within 2 years following normal guaiac fecal occult blood testing (gFOBT). Methods. Persons aged 50-74 who completed a baseline CCC gFOBT kit in 2008 and 2009, without a prior history of CRC, or recent colonoscopy, flexible sigmoidoscopy, or gFOBT, were identified. Rates of CRC following positive and normal results at baseline and subsequent gFOBT screens were computed and overall survival was compared between those following positive and normal results. Results. Interval CRC was diagnosed within 24 months following the baseline screen among 0.16% of normals and following the subsequent screen among 0.18% of normals. Interval cancers comprised 38.70% of CRC following the baseline screen and 50.86% following the subsequent screen. Adjusting for age and sex, the hazard ratio (HR) for death following interval cancer compared to CRC following positive result was 1.65 (1.32, 2.05) following the first screen and 1.71 (1.00, 2.91) following the second screen. Conclusion. Interval CRCs following gFOBT screening comprise a significant proportion of CRC diagnosed within 2 years after gFOBT testing and are associated with a higher risk of death.

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.

Prevalence of colorectal diseases in immunological fecal occult blood test (I-FOBT) positive patients in a tertiary care hospital in Bangladesh

Bleeding lesion anywhere in the GI tract can cause positive reaction to Immunological Fecal Occult Blood Test (FOBT). Although any colonic lesion can cause occult lower GI bleeding, relative frequency of this lesion not known. Guaic based tests require prior preparation and dietary restriction and less sensitive and specific than IFOBT for detection of occult bleeding .IFOBT is specific for human hemoglobin and is more sensitive and specific for detection of occult bleeding from any colonic lesion. Aim of this study was to diagnose occult gastrointestinal bleeding with positive IFOBT and the prevalence of colorectal disease in IFOBT positive patients in a tertiary care hospital in Bangladesh. This was a prospective cross sectional study conducted in Department of gastroenterology in collaboration with clinical pathology, BSMMU, Dhaka during the period of January 2009 to December 2009. In this study 200 patients meeting the inclusion criteria were included. Detailed clinical history and physical findings were recorded; FOBT was done on single stool specimen. Positive occult bleeding was confirmed in 90 patients of whom 80 patients underwent colonoscopy. The mean age of study population was 36.73±13.64 (range 16 to 72) years. At colonoscopy lesion were identified in 46(57.50%) patients, of which colonic polyp in12 (15%), colorectal cancer in 11(13.7%), inflammatory bowel disease in 3(3.75%), hemorrhoids and anal fissure in 7(8.75%), tuberculosis in 5(6.25%), and proctitis in 1(1.25%) cases. A positive IFOBT is more sensitive and specific test than other FOBT for detection of occult lower GI bleeding of colonic origin. In this study colorectal diseases were detected in 57.50% of the IFOBT positive patients, so IOBT can be used as an important diagnostic tool for detection of occult lower GI bleeding.

Reasons for non-uptake and subsequent participation in the NHS Bowel Cancer Screening Programme: a qualitative study

BACKGROUND

Screening for bowel cancer using the guaiac faecal occult blood test offered by the NHS Bowel Cancer Screening Programme (BCSP) is taken up by 54% of the eligible population. Uptake ranges from 35% in the most to 61% in the least deprived areas. This study explores reasons for non-uptake of bowel cancer screening, and examines reasons for subsequent uptake among participants who had initially not taken part in screening.

METHODS

Focus groups with a socio-economically diverse sample of participants were used to explore participants' experience of invitation to and non-uptake of bowel cancer screening.

RESULTS

Participants described sampling faeces and storing faecal samples as broaching a cultural taboo, and causing shame. Completion of the test kit within the home rather than a formal health setting was considered unsettling and reduced perceived importance. Not knowing screening results was reported to be preferable to the implications of a positive screening result. Feeling well was associated with low perceived relevance of screening. Talking about bowel cancer screening with family and peers emerged as the key to subsequent participation in screening.

CONCLUSIONS

Initiatives to normalise discussion about bowel cancer screening, to link the BCSP to general practice, and to simplify the test itself may lead to increased uptake across all social groups.

Nursing assessment of guaiac-positive and occult blood in preterm infant stools

Guaiac testing the stool of very low birth weight (VLBW; <1,500 g) preterm infants has been a standard of care for many neonatal intensive care units (NICUs) and considered a diagnostic tool that could potentially provide early warning of gastrointestinal disturbances, feeding intolerance (FI), or necrotizing enterocolitis (NEC). Evidence to either support or eliminate testing stool for occult blood from standard care practices is lacking. Support to eliminate testing is often based on the knowledge that neonatal treatment interventions-such as gastric tube placement, intubation, and/or suctioning- may often result in occult blood in stools. However, there is also reasonable concern that occult blood may indicate a cascade of pathophysiological events, which may lead to FI and NEC, is in progress.Feeding intolerance remains one of the most consistent reasons VLBW preterm infants experience poor weight gain and extended hospital stays. Every nursing assessment is strategic to the early identification of contributing factors to either the development of FI or NEC. Including low-cost, noninvasive diagnostic tools to augment the findings of the nursing assessment can only help guide health care providers in appropriate decision making related to the feeding plan.

FIT testing: an overview

Colorectal cancer (CRC) is a common, but preventable, disease and is the second most common cause of cancer-related deaths in the U.S. CRC screening has proven effective at reducing both the incidence and mortality of this disease, using any of a number of screening tests available. The test options range from the least invasive and least expensive to more invasive and costly options. Fecal occult blood testing is the oldest, least expensive, and least invasive of these options and has evolved from the poorly sensitive standard guaiac test to the newer and diagnostically superior fecal immunochemical test (FIT) for hemoglobin. This article explores the evolutionary history of fecal occult blood testing, examines test performance characteristics among different FOBTs, and evaluates the role of the FIT in programmatic CRC screening.

Flexible sigmoidoscopy versus faecal occult blood testing for colorectal cancer screening in asymptomatic individuals

BACKGROUND

Colorectal cancer is the third most frequent cancer in the world. As the sojourn time for this cancer is several years and a good prognosis is associated with early stage diagnosis, screening has been implemented in a number of countries. Both screening with faecal occult blood test and flexible sigmoidoscopy have been shown to reduce mortality from colorectal cancer in randomised controlled trials. The comparative effectiveness of these tests on colorectal cancer mortality has, however, never been evaluated, and controversies exist over which test to choose.

OBJECTIVES

To compare the effectiveness of screening for colorectal cancer with flexible sigmoidoscopy to faecal occult blood testing.

SEARCH METHODS

We searched MEDLINE and EMBASE (November 16, 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 11) and reference lists for eligible studies.

SELECTION CRITERIA

Randomised controlled trials comparing screening with flexible sigmoidoscopy or faecal occult blood testing to each other or to no screening. Only studies reporting mortality from colorectal cancer were included. Faecal occult blood testing had to be repeated (annually or biennially).

DATA COLLECTION AND ANALYSIS

Data retrieval and assessment of risk of bias were performed independently by two review authors. Standard meta-analyses using a random-effects model were conducted for flexible sigmoidoscopy and faecal occult blood testing (FOBT) separately and we calculated relative risks with 95% confidence intervals (CI). We used a Bayesian approach (a contrast-based network meta-analysis method) for indirect analyses and presented the results as posterior median relative risk with 95% credibility intervals. We assessed the quality of evidence using GRADE.

MAIN RESULTS

We identified nine studies comprising 338,467 individuals randomised to screening and 405,919 individuals to the control groups. Five studies compared flexible sigmoidoscopy to no screening and four studies compared repetitive guaiac-based FOBT (annually and biennially) to no screening. We did not consider that study risk of bias reduced our confidence in our results. We did not identify any studies comparing the two screening methods directly. When compared with no screening, colorectal cancer mortality was lower with flexible sigmoidoscopy (relative risk 0.72; 95% CI 0.65 to 0.79, high quality evidence) and FOBT (relative risk 0.86; 95% CI 0.80 to 0.92, high quality evidence). In the analyses based on indirect comparison of the two screening methods, the relative risk of dying from colorectal cancer was 0.85 (95% credibility interval 0.72 to 1.01, low quality evidence) for flexible sigmoidoscopy screening compared to FOBT. No complications occurred after the FOBT test itself, but 0.03% of participants suffered a major complication after follow-up. Among more than 60,000 flexible sigmoidoscopy screening procedures and almost 6000 work-up colonoscopies, a major complication was recorded in 0.08% of participants. Adverse event data should be interpreted with caution as the reporting of adverse effects was incomplete.

AUTHORS' CONCLUSIONS

There is high quality evidence that both flexible sigmoidoscopy and faecal occult blood testing reduce colorectal cancer mortality when applied as screening tools. There is low quality indirect evidence that screening with either approach reduces colorectal cancer deaths more than the other. Major complications associated with screening require validation from studies with more complete reporting of harms

Immunoassay-based screening for colorectal cancer. More colonoscopies performed and more cancers detected than with Haemoccult

In adults with no specific risk factors, colorectal cancer screening based on detection of occult blood in stools with a guaiac test (Haemoccult) has several technical limitations. Sensitivity is low, only about 50% for colorectal cancer. Immunochemical tests for faecal occult blood are now also available. Do they improve the performance of colorectal cancer screening? To answer this question, we reviewed the available literature using the standard Prescrire methodology. These immunochemical tests are specific for human haemoglobin, are read automatically, and provide quantitative results. Their sensitivity in detecting lesions, and the proportion of patients who subsequently require colonoscopy, depends on the chosen cutoff. In 9 screening studies including a total of about 86 000 participants, immunochemical tests had a sensitivity of between 61% and 89% for colorectal cancer, depending on the test modalities and positivity cutoffs. In France, immunochemical tests have been compared with Haemoccult for mass screening in a total of 85 149 persons. They detected nearly twice as many colorectal cancers as Haemoccult, but led to twice as many colonoscopies. Both methods detected about 1 cancer per 14 colonoscopies. The main risks of screening are those associated with colonoscopy, which results in about 3 serious complications (including perforation and bleeding) per 1000 procedures. We found no studies of screening-related complications in France. In practice, immunoassay-based tests appear to increase the number of colorectal cancers detected but are associated with a proportionate increase in the number of patients who undergo colonoscopy. In France, better assessment and supervision of colonoscopies resulting from mass screening are needed.

Guaiac interpretation by non-certified clinicians

OBJECTIVE

To assess the ability of non-certified clinicians to interpret guaiac test results.

METHODS

50 clinicians were shown photographs of 20 guaiac test cards. They were asked to classify these as positive, negative, or uncertain.

RESULTS

31 nurses, 4 clinical assistants, 7 emergency attending MDs, 2 resident MDs, and 6 medical students comprised the study group. Mean correct percentages for 15 clearly positive or negative guaiac test cards ranged from 87% to 96% in each of the above groups. Correct results were lower for five of the borderline positive guaiac cards.

CONCLUSION

This study demonstrates that all clinician groups correctly interpreted the guaiac result most of the time, but there was a moderate error rate. This data supports the Joint Commission standard for this particular point of care test; clinicians interpreting guaiac testing should be trained with demonstrated competency.

Are medication restrictions before FOBT necessary?: practical advice based on a systematic review of the literature

OBJECTIVE

To determine whether medication interventions enhance the sensitivity and specificity of guaiac-based fecal occult blood testing (FOBT) when screening for colorectal cancer (CRC).

DATA SOURCES

We searched PubMed-MEDLINE, CINAHL, and the Cochrane databases using the MeSH headings occult blood, feces/analysis, and guaiac/analysis, linking them to variations of anticoagulants, heparin, warfarin, iron, aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), clopidogrel, cyclooxygenase-2 inhibitors, and ascorbic acid (vitamin C). Study selections were limited to English studies involving humans.

STUDY SELECTION

All resulting titles and abstracts were reviewed for studies that included manipulation of medications associated with guaiac-based FOBT. If the study's relevance was unclear from the abstract, the full article was reviewed. The search resulted in 31 pertinent studies.

SYNTHESIS

No studies addressed the effects of medication interventions on the sensitivity or specificity of FOBT screening. Randomized controlled trials, however, showed no increase in the rate of positive results among those taking NSAIDs. The literature is mixed regarding the effect of NSAIDs on the positive predictive value of a positive FOBT result, although no change in positive predictive value has been shown for warfarin. Iron will not affect FOBT results in vivo. Ascorbic acid might inhibit positive FOBT results both in vitro and in vivo, but it has not been studied in screening populations.

CONCLUSION

Studies evaluating the effects of medication intervention on FOBT screening for CRC are limited by their lower quality and because they do not address sensitivity and specificity. Available evidence, however, does not suggest a benefit from withholding NSAIDs, anticoagulant medications, or iron during the screening period. These recommendations should be abandoned in order to maximize adherence to screening. Positive FOBT results obtained among patients taking these medications deserve full evaluation for CRC. Until further studies clarify the effect of ascorbic acid on FOBT screening, withholding this medication before testing seems prudent.

Comparison between a guaiac and three immunochemical faecal occult blood tests in screening for colorectal cancer

BACKGROUND

The aim of this study was to compare the performance of the guaiac-based faecal occult blood test (G-FOBT), with that of three immunochemical faecal occult blood tests (I-FOBT) which allow automatic interpretation.

PATIENTS AND METHODS

Under the French organised screening programme, 85,149 average-risk individuals aged 50-74 participating in the third screening round, performed both the G-FOBT (Hemoccult-II test) and one of the I-FOBTs: FOB-Gold, Magstream and OC-Sensor.

RESULTS

Given the chosen threshold, the positivity ratio between the different I-FOBTs and the G-FOBT was 2.4 for FOB-Gold, 2.0 for Magstream and 2.2 for OC-Sensor (P=0.17). The three I-FOBTs were superior to the G-FOBT for colorectal cancer (CRC) detection. The ratios for detection rates were 1.6 (FOB-Gold), 1.7 (Magstream) and 2.1 (OC-Sensor) (P=0.74). For non-invasive CRC they were, respectively, 2.5, 3.0 and 4.0 (P=0.83) and for advanced adenomas 3.6, 3.1 and 4.0 (P=0.39).

CONCLUSIONS

This study provides further evidence that I-FOBT is superior to G-FOBT. None of the three I-FOBTs studied appeared to be significantly better than the others.

A proposal to standardize reporting units for fecal immunochemical tests for hemoglobin

Fecal immunochemical tests for hemoglobin are replacing traditional guaiac fecal occult blood tests in population screening programs for many reasons. However, the many available fecal immunochemical test devices use a range of sampling methods, differ with regard to hemoglobin stability, and report hemoglobin concentrations in different ways. The methods for sampling, the mass of feces collected, and the volume and characteristics of the buffer used in the sampling device also vary among fecal immunochemical tests, making comparisons of test performance characteristics difficult. Fecal immunochemical test results may be expressed as the hemoglobin concentration in the sampling device buffer and, sometimes, albeit rarely, as the hemoglobin concentration per mass of feces. The current lack of consistency in units for reporting hemoglobin concentration is particularly problematic because apparently similar hemoglobin concentrations obtained with different devices can lead to very different clinical interpretations. Consistent adoption of an internationally accepted method for reporting results would facilitate comparisons of outcomes from these tests. We propose a simple strategy for reporting fecal hemoglobin concentration that will facilitate the comparison of results between fecal immunochemical test devices and across clinical studies. Such reporting is readily achieved by defining the mass of feces sampled and the volume of sample buffer (with confidence intervals) and expressing results as micrograms of hemoglobin per gram of feces. We propose that manufacturers of fecal immunochemical tests provide this information and that the authors of research articles, guidelines, and policy articles, as well as pathology services and regulatory bodies, adopt this metric when reporting fecal immunochemical test results.

Fecal immunochemical tests compared with guaiac fecal occult blood tests for population-based colorectal cancer screening

Colorectal cancer (CRC) is the second most common cause of cancer deaths in Canadian men and women - accounting for almost 12% of all cancer deaths. In Ontario, it is estimated that 8100 persons were diagnosed with CRC in 2011, and 3250 died from the disease. CRC incidence and mortality rates in Ontario are among the highest in the world. Screening offers the best opportunity to reduce this burden of disease. The present report describes the findings and recommendations of Cancer Care Ontario's Fecal Immunochemical Tests (FIT) Guidelines Expert Panel, which was convened in September 2010 by the Program in Evidence-Based Care. The purpose of the present guideline is to evaluate the existing evidence concerning FIT to inform the decision on how to replace the current guaiac fecal occult blood test with FIT in the Ontario ColonCancerCheck Program. Eleven articles were included in the present guideline, comprising two systematic reviews, five articles reporting on three randomized controlled trials, and reports of four other studies. Additionally, one laboratory study was obtained that reported on several parameters of FIT tests that helped to inform the present recommendation. The performance of FIT is superior to the standard guaiac fecal occult blood test in terms of screening participation rates and the detection of CRC and advanced adenoma. Given greater specimen instability with the use of FIT, a pilot study should be undertaken to determine how to implement the FIT in Ontario.

Cost-effectiveness of population-based screening for colorectal cancer: a comparison of guaiac-based faecal occult blood testing, faecal immunochemical testing and flexible sigmoidoscopy

BACKGROUND

Several colorectal cancer-screening tests are available, but it is uncertain which provides the best balance of risks and benefits within a screening programme. We evaluated cost-effectiveness of a population-based screening programme in Ireland based on (i) biennial guaiac-based faecal occult blood testing (gFOBT) at ages 55-74, with reflex faecal immunochemical testing (FIT); (ii) biennial FIT at ages 55-74; and (iii) once-only flexible sigmoidoscopy (FSIG) at age 60.

METHODS

A state-transition model was used to estimate costs and outcomes for each screening scenario vs no screening. A third party payer perspective was adopted. Probabilistic sensitivity analyses were undertaken.

RESULTS

All scenarios would be considered highly cost-effective compared with no screening. The lowest incremental cost-effectiveness ratio (ICER vs no screening euro 589 per quality-adjusted life-year (QALY) gained) was found for FSIG, followed by FIT euro 1696) and gFOBT (euro 4428); gFOBT was dominated. Compared with FSIG, FIT was associated with greater gains in QALYs and reductions in lifetime cancer incidence and mortality, but was more costly, required considerably more colonoscopies and resulted in more complications. Results were robust to variations in parameter estimates.

CONCLUSION

Population-based screening based on FIT is expected to result in greater health gains than a policy of gFOBT (with reflex FIT) or once-only FSIG, but would require significantly more colonoscopy resources and result in more individuals experiencing adverse effects. Weighing these advantages and disadvantages presents a considerable challenge to policy makers.

Detection of methylated SEPT9 in plasma is a reliable screening method for both left- and right-sided colon cancers

BACKGROUND

Methylated Septin 9 (SEPT9) is a sensitive biomarker for colorectal cancer (CRC) from peripheral blood. However, its relationship to cancer localization, guaiac-based fecal occult blood test (gFOBT) and carcinoembryonic antigen (CEA) have not been described.

METHODOLOGY/PRINCIPAL FINDINGS

Plasma samples were collected for SEPT9 analysis from patients with no evidence of disease (NED) (n=92) before colonoscopy and CRC (n=92) before surgical treatment. DNA was isolated and bisulfite-converted using Epi proColon kit 2.0. Qualitative determination was performed using Epi proColon 2.0 RT-PCR assay. Samples for gFOBT and CEA analysis were collected from NED (n=17 and 27, respectively) and CRC (n=22 and 27, respectively). SEPT9 test was positive in 15.2% (14/92) of NED and 95.6% (88/92) of CRC, including 100% (67/67) from stage II to stage IV CRC and 84% (21/25) of stage I CRC when a sample was called positive if 1 out of 3 PCR replicates was positive. In a second analysis (2 out of 3 PCR replicates) specificity improved to 99% (91/92) of NEDs, at a sensitivity of 79.3% (73/92) of SEPT9 positives in CRC. gFOBT was positive in 29.4% (5/17) of NED and 68.2% (15/22) of CRC and elevated CEA levels were detected in 14.8% (4/27) of NED and 51.8% (14/27) of CRC. Both SEPT9 (84.8%) and CEA (85.2%) showed higher specificity than gFOBT (70.6%). SEPT9 was positive in 96.4% (54/56) of left-sided colon cancer (LSCC) cases and 94.4% (34/36) of right-sided colon cancer (RSCC) cases. gFOBT was positive in 83.3% (10/12) of cases with LSCC and 50% (5/10) of cases with RSCC, elevated CEA was detected 60% (9/15) of LSCC and 41.7% (5/12) of RSCC.

CONCLUSIONS/SIGNIFICANCE

The high degree of sensitivity and specificity of SEPT9 in plasma makes it a better method to detect CRC than gFOBT and CEA, even for the more difficult to detect RSCC.

Case study: aphthous ulcers in a 14-year-old girl

Recurrent aphthous ulcers (RAUs), also known as canker sores, aphthous stomatitis, or aphthae, are a very common and often painful condition presenting in primary care. The majority of aphthous ulcers are benign, time-limited (7 to 14 days), and in some cases, require pain management until healed. However, RAUs can be a manifestation of a serious health condition, such as an autoimmune disorder, human immunodeficiency virus, infection, and hematologic or oncologic conditions. Initially, the most important priority in caring for these patients is to obtain a complete history and physical examination to rule out systemic disease and lead to an accurate diagnosis and plan of care.

Screening and diagnosis for colorectal cancer: present and future

AIMS AND BACKGROUND

Colon cancer is the third most common cause of cancer diagnosed in the United States, and the second leading cause of cancer death. Although rates of the disease have been going down in recent years, results can be further improved. About 90% of people whose colon cancer is caught before it has spread to nearby lymph nodes or organs survive more than 5 years after diagnosis. However, only 10% of patients whose cancer has spread to distant parts of the body survive 5 years. Diagnosis at an early stage aims to reduce the incidence of tumors in an advanced stage and hence mortality.

METHODS AND STUDY DESIGN

We analyzed the literature to understand what new tests to use and new directions to take.

RESULTS

There is evidence to support the screening of average-risk individuals over the age of 50 years to detect and prevent colon cancer. Screening of these people can only reduce mortality rates, not incidence, identifying cancer at an early stage and through the removal of clinically significant adenomas. Patient preferences and availability of resources play an important role in the selection of screening tests, because each test presents specific risks and specific benefits.

CONCLUSIONS

The American Cancer Society has added two new screening methods, CT colonography, also known as virtual colonoscopy, and stool DNA tests to the list of options. A small revolution in screening for colon cancer is in the making. The availability of these less invasive tests should increase the number of people who undergo regular screening.

Colon cancer screening in 2010: an up-date

Colorectal cancer is among the most common cancers worldwide. The prognosis for limited disease is excellent; however, it becomes poor for more advanced disease. The majority of colorectal cancers arise from premalignant adenomatous polyps. This makes the detection of polyps and early carcinoma an attractive screening strategy. This article will review the current tests available for screening for colorectal cancer. These include stool based tests (guaiac-based fecal occult blood tests, immunochemical fecal tests, stool DNA panel), radiologic tests (double contrast barium enema and computed tomography colonography), and endoscopy (flexible sigmoidoscopy and colonoscopy). The current use of these tests in population-based screening programs and the most recent screening guidelines from the largest advisory groups in North America and Europe will be discussed.

Dietary interventions for fecal occult blood test screening: systematic review of the literature

OBJECTIVE

To determine whether dietary restrictions enhance the specificity of guaiac-based fecal occult blood tests (FOBTs) when screening for colorectal cancer.

DATA SOURCES

PubMed-MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, and Cochrane databases were searched.

STUDY SELECTION

English-language case series, cohort studies, randomized controlled trials (RCTs), and meta-analyses were selected. Studies that did not include dietary manipulation or the use of guaiac-based FOBTs available in North America were excluded.

SYNTHESIS

Ten case series, 5 cohort studies, 4 RCTs, and 1 meta-analysis were critically appraised. All studies used Hemoccult, Hemoccult II, or Hemoccult SENSA tests. Data from case series involving challenge diets showed no increase in positive FOBT results from high-peroxidase vegetables, but results varied with red-meat challenges depending on the amount of meat consumed and the test used. Case series, cohort studies, and RCTs comparing FOBT results during restricted versus unrestricted diets consistently showed no differences in positive FOBT results.

CONCLUSION

Most of the evidence evaluating the effect of dietary restrictions on FOBT results is dated and of suboptimal quality. However, 4 RCTs and a meta-analysis of these data do not support dietary restrictions when screening for colorectal cancer. Because patient adherence can be an issue with FOBTs, and dietary restrictions can affect adherence in some populations, it is reasonable to abandon these recommendations without fear of substantially affecting specificity.

[Improvement in screening for colorectal cancer associated with the use of immunochemical faecal occult blood test]

Faecal occult blood tests (FOBT) have been established as the most relevant procedure for colorectal cancer screening in the general average risk population. Immunochemical FOBT consists in monoclonal antibodies reacting with the globin of the haemoglobin. These tests provide higher performances than traditional guaiac tests. They do not need any diet restriction and their analytic sensitivity is higher. An increasing number of papers suggest that their acceptance and clinical performances in the general population are more satisfactory than the guaiac test. The use of automated reading allowed to cut the process price making it similar to the guaiac test. The providing of quantitative measure of haemoglobin allows to choose the positivity threshold associated with the best balance between sensitivity, specificity and positivity rate. Comparative studies conducted in France suggest the use of a positivity threshold allowing an increase in both sensitivity and specificity compared to the guaiac tests.

Earlier stages of colorectal cancer detected with immunochemical faecal occult blood tests

BACKGROUND

The aim of colorectal cancer screening is to improve prognosis by the detection of early cancer and precursor stages. We compared the stage distribution of asymptomatic colorectal cancer patients detected by a positive immunochemical or guaiac-based faecal occult blood test (FOBT) with symptomatic colorectal cancer patients.

METHODS

In a longitudinal cohort study tumour stages were assessed in 144 symptomatic (mean age 69.3 years, 56% male) and 41 asymptomatic colorectal cancer patients (mean age 64.9 years, 56% male) of which 11 were detected with guaiac FOBT s (G-FOBT, Hemoccult-II) and 30 with immunochemical FOBTs (I-FOBT, OCSensor). Stage distributions were used to calculate average stage specific predicted five-year survival rates and to analyse group differences with Wilcoxon log-rank test.

RESULTS

Colorectal cancer was detected in significantly earlier stages in symptomatic compared with asymptomatic patients patients (p<0.0001). Average stage specific predicted five-year survival was 59.1% in symptomatic and 76.6% in asymptomatic patients. Compared with the symptomatic patients the stage distribution for colorectal cancer patients detected with Hemoccult-II was not significantly different(p=0.29), whereas colorectal cancer was detected at significantly earlier stages with the OCSensor (p<0.0001).Treatment could be confined to colonoscopy in 27% of the asymptomatic patients compared with 3% of the symptomatic patients (p<0.0001). Cancer distribution over the colon was comparable between symptomatic and asymptomatic patients (p=0.3).

CONCLUSIONS

Compared with symptomatic patients,patients detected by FOBT and especially immunochemical FOBT , presented significantly more often at earlier stages suggesting increased survival. Additionally treatment could more often be confined to colonoscopy.

[Colorectal cancer in a population with a guaiac-based screening programme]

BACKGROUND AND OBJECTIVE

Colorectal cancer (CRC) screening effectiveness depends on the degree of implementation and population adherence. The goals of this study were to determine the number of CRC cases diagnosed in L'Hospitalet of Llobregat (Spain) and to identify the features of those cases detected by the population-based screening programme initiated in 2000 in this city.

PATIENTS AND METHOD

Patients aged 50-69 year-old with a CRC diagnosis identified by cancer registries from the hospitals of L'Hospitalet were included. Patients were classified in 4 groups according to participation in the screening programme: 1, no participants; 2 diagnosed by screening; 3 participants with a negative screening result; and 4, participants with an incomplete screening process.

RESULTS

We found 510 patients diagnosed of CRC, 88% of whom had been invited to the screening programme. The distribution by tumour stage was: 0, 50 (9.8%); I, 53 (10.4%); II, 135 (26.5%); III, 154 (30.2%); IV, 105 (20.6%); and unknown, 13 (2.5%). The number of patients in each group was: 1, 350 (78.0%); 2, 58 (12.9%); 3, 29 (6.5%); and 4, 12 (2.7%). CRC detected by screening and by clinical diagnosis differed in some characteristics: cancer of colon (89.7% vs 66.2%, P<.001), symptoms (32.8% vs 84.3%, P<.001) and stages (0-II 75.9% vs 42.9%, III-IV 24.1% vs 54.2%, P<.001).

DISCUSSION

These results show the benefit of a population-based screening programme. CRC detected by the screening programme is diagnosed in early stages and before disease symptoms appear.

Short term outcomes of the first round of a pilot colorectal cancer screening programme with guaiac based faecal occult blood test

OBJECTIVE

To assess both feasibility and short term outcomes of a population based colorectal cancer screening programme using a biennial guaiac based faecal occult blood test (gFOBT).

METHOD

All participants were invited by mail to take part in a screening programme using a non-rehydrated gFOBT. The gFOBTs were first provided by general practitioners (GPs) and then directly mailed to individuals who failed to comply after two invitations. The setting was a French administrative district: Haut-Rhin (710,000 inhabitants). 182,981 residents aged 50-74 years were invited to participate.

RESULTS

19,274 people (10.5%) were excluded from gFOBT screening and 90,706 completed a gFOBT, so that the participation rate was 55.4% of those eligible. 76.5% of the completed gFOBTs were provided by GPs and 15.5% by direct mailing. The gFOBT positivity rate was 3.4%. The positive predictive value was 42.7% for neoplasia (women 30.8%, men 52.5%), 23.6% for advanced adenoma, and 7.6% for cancer. The number of normal colonoscopic procedures (without neoplasia) needed to be performed for each colonoscopy detecting an advanced neoplasia was 1.8, lower in men (1.2) than in women (3.4), and decreasing with age. Detection rates for neoplasia and cancer were 12.8 and 2.3 per 1000 people screened. 206 adenocarcinomas were detected: 47.6% were stage I and 23.8% stage II. The direct cost was estimated at euro 29.3 per screened person and euro 13,466 per cancer detected.

CONCLUSIONS

Participation and diagnostic yield of controlled trials of gFOBT screening are reproducible in the real world at an acceptable cost through an organised population based programme involving GPs.

Screening for Colorectal Neoplasms With New Fecal Occult Blood Tests: Update on Performance Characteristics

BACKGROUND

One type of fecal occult blood test (FOBT), the unrehydrated guaiac fecal occult blood test (GT), is recommended by the United States Preventive Services Task Force and the Institute of Medicine for use in screening programs, but it has relatively low sensitivity as a single test for detecting advanced colonic neoplasms (cancer and adenomatous polyps > or = 1 cm in diameter). Thus, improving the sensitivity of FOBT should make colon cancer screening programs that use these tests more effective.

METHODS

We assessed prospectively the performance characteristics of two newer FOBTs in 5841 subjects at average risk for colorectal cancer in a large group-model managed care organization. The tests evaluated included a sensitive GT, a fecal immunochemical test (FIT), and the combination of both tests. Patients with positive and negative test results were advised to have colonoscopy and sigmoidoscopy, respectively. Sensitivity and specificity for detecting advanced neoplasms in the left colon within 2 years after the FOBT screening were evaluated for the two tests administered separately and in combination.

RESULTS

A total of 139 patients were diagnosed with advanced colorectal neoplasms (n = 14 cancers, n = 128 adenomas) within the 2 years following their initial FOBT screening. Sensitivity for detecting cancer was 81.8% (95% confidence interval [CI] = 47.8% to 96.8%) for the FIT alone and 64.3% (95% CI = 35.6% to 86.0%) for the sensitive GT and the combination test. Sensitivity for detecting advanced colorectal adenomas was 41.3% (95% CI = 32.7% to 50.4%) for the sensitive GT, 29.5% (95% CI = 21.4% to 38.9%) for the FIT, and 22.8% (95% CI =16.1% to 31.3%) for the combination test. Specificity for detecting cancer and adenomas was 98.1% (95% CI = 97.7% to 98.4%) and 98.4% (95% CI = 98.0% to 98.7%), respectively, for the combination test; 96.9% (95% CI = 96.4% to 97.4%) and 97.3% (95% CI = 96.8% to 97.7%), respectively, for the FIT; and 90.1% (95% CI = 89.3% to 90.8%) and 90.6% (95% CI = 89.8% to 91.4%), respectively, for the sensitive GT.

CONCLUSIONS

The FIT has high sensitivity and specificity for detecting left-sided colorectal cancer, and it may be a useful replacement for the GT.

Guaiac versus immunochemical tests: faecal occult blood test screening for colorectal cancer in a rural community

OBJECTIVE

To describe patient participation and clinical performance in a colorectal cancer (CRC) screening program utilising faecal occult blood test (FOBT).

METHODS

A community-based intervention was conducted in a small, rural community in north Queensland, 2000/01. One of two FOBT kits--guaiac (Hemoccult-II) or immunochemical (!nform)--was assigned by general practice and mailed to participants (3,358 patients aged 50-74 years listed with the local practices).

RESULTS

Overall participation in FOBT screening was 36.3%. Participation was higher with the immunochemical kit than the guaiac kit (OR=1.9, 95% CI 1.6-2.2). Women were more likely to comply with testing than men (OR=1.4, 95% CI 1.2-1.7), and people in their 60s were less likely to participate than those 70-74 years (OR=0.8, 95% CI 0.6-0.9). The positivity rate was higher for the immunochemical (9.5%) than the guaiac (3.9%) test (chi2=9.2, p=0.002), with positive predictive values for cancer or adenoma of advanced pathology of 37.8% (95% CI 28.1-48.6) for !nform and 40.0% (95% CI 16.8-68.7) for Hemoccult-II. Colonoscopy follow-up was 94.8% with a medical complication rate of 2-3%.

CONCLUSIONS

An immunochemical FOBT enhanced participation. Higher positivity rates for this kit did not translate into higher false-positive rates, and both test types resulted in a high yield of neoplasia.

IMPLICATIONS

In addition to type of FOBT, the ultimate success of a population-based screening program for CRC using FOBT will depend on appropriate education of health professionals and the public as well as significant investment in medical infrastructure for colonoscopy follow-up.

A quantitative immunochemical fecal occult blood test for colorectal neoplasia

BACKGROUND

Guaiac-based fecal occult blood tests (FOBTs) for colorectal cancer screening are not specific for human hemoglobin and have low sensitivity. Automated-development, immunochemical FOBT is quality-controlled, is specific for human hemoglobin, and does not require diet restriction.

OBJECTIVES

To measure the sensitivity and specificity of quantitative immunochemical fecal hemoglobin measurements for detection of cancer and advanced adenoma in patients undergoing colonoscopy, to determine fecal hemoglobin thresholds that give the highest posttest probability for neoplasia, and to determine the number of immunochemical FOBTs needed.

DESIGN

Prospective, cross-sectional study.

SETTING

Ambulatory endoscopy services of the main health medical organization in Tel Aviv, Israel.

PARTICIPANTS

1000 consecutive ambulatory patients--some asymptomatic but at increased risk for colorectal neoplasia and some symptomatic--who were undergoing elective colonoscopy and volunteered to prepare immunochemical FOBTs.

INTERVENTION

The hemoglobin content of 3 bowel movements was measured, and the highest value was compared with colonoscopy findings.

MEASUREMENTS

Sensitivity, specificity, predictive values, likelihood ratios, and 95% CIs of fecal hemoglobin measurements for clinically significant neoplasia, their relationship to the amount of fecal hemoglobin measured, and the number of immunochemical FOBTs performed.

RESULTS

Colonoscopy identified clinically significant neoplasia in 91 patients (cancer in 17 patients and advanced adenomas in 74 patients). Using 3 immunochemical FOBTs and a hemoglobin threshold of 75 ng/mL of buffer, sensitivity and specificity were 94.1% (95% CI, 82.9% to 100.0%) and 87.5% (CI, 85.4% to 89.6%), respectively, for cancer and 67% (CI, 57.4% to 76.7%) and 91.4% (CI, 89.6% to 93.2%), respectively, for any clinically significant neoplasia.

LIMITATIONS

The fecal sampling method is standardized, but the sample size depends on fecal consistency. Some patients were tested while discontinuing aspirin and anticoagulant therapies. Study patients were at increased risk, and results might not apply to average-risk populations.

CONCLUSIONS

Quantitative immunochemical FOBT has good sensitivity and specificity for detection of clinically significant neoplasia. Test performance in screening average-risk populations is not known.

Comparison of a guaiac based and an immunochemical faecal occult blood test in screening for colorectal cancer in a general average risk population

BACKGROUND

The guaiac faecal occult blood test (G-FOBT) is recommended as a screening test for colorectal cancer but its low sensitivity has prevented its use throughout the world.

METHODS

We compared the performances of the reference G-FOBT (non-rehydrated Hemoccult II test) and the immunochemical faecal occult blood test (I-FOBT) using different positivity cut-off values in an average risk population sample of 10,673 patients who completed the two tests. Patients with at least one test positive were asked to undergo colonoscopy.

RESULTS

Using the usual cut-off point of 20 ng/ml haemoglobin, the gain in sensitivity associated with the use of I-FOBT (50% increase for cancer and 256% increase for high risk adenoma) was balanced by a decrease in specificity. The number of extra false positive results associated with the detection of one extra advanced neoplasia (cancer or high risk adenoma) was 2.17 (95% confidence interval 1.65-2.85). With a threshold of 50 ng/ml, I-FOBT detected more than twice as many advanced neoplasias as the G-FOBT (ratio of sensitivity = 2.33) without any loss in specificity (ratio of false positive rate = 0.99). With a threshold of 75 ng/ml, associated with a similar positivity rate to G-FOBT (2.4%), the use of I-FOBT allowed a gain in sensitivity of 90% and a decrease in the false positive rate of 33% for advanced neoplasia.

CONCLUSIONS

Evidence in favour of the substitution of G-FOBT by I-FOBT is increasing, the gain being more important for high risk adenomas than for cancers. The automated reading technology allows choice of the positivity rate associated with an ideal balance between sensitivity and specificity.

New stool screening tests for colorectal cancer

BACKGROUND/AIMS

The purpose of this review is to clarify the place of new-technology stool tests in screening for colorectal neoplasia.

FINDINGS

New technologies have been based on blood and cellular products of neoplasia. Fecal occult blood tests (FOBTs) based on guaiac (i.e. GFOBTs) have been proved to be effective, but their impact on mortality is modest. When GFOBTs are reconfigured to provide improved sensitivity for cancer, their specificity often becomes unacceptable. Fecal immunochemical tests (FITs) targeting the human hemoglobin molecule have been shown to have better sensitivity for neoplasia without an unacceptable deterioration in specificity. The new stool-sampling technologies for FITs also improve population participation rates in screening. Most recently, quantitative FITs have become available; these provide flexibility for the end-user as a desired sensitivity: specificity ratio can be selected that is feasible in the context of available colonoscopic resources. A multi-target fecal DNA test, comprising a test for undegraded DNA and certain common mutations, was found more sensitive for cancer, but not for adenoma, than the early GFOBTs. A more recent version including an epigenetic marker for the vimentin gene has further improved sensitivity for cancer, but performance relative to GFOBT or FIT is not clear. These 'fecal DNA tests' have not proved to be more specific for neoplasia than tests that detect blood.

CONCLUSIONS

FIT should replace GFOBT as the first test in two-step screening of large populations. It is not yet clear that tests targeting nonhemoglobin molecular events provide a clear advantage over FIT.

Comparison of a brush-sampling fecal immunochemical test for hemoglobin with a sensitive guaiac-based fecal occult blood test in detection of colorectal neoplasia

BACKGROUND

Fecal immunochemical tests (FIT) are an advanced fecal occult blood test (FOBT) technology that reduces barriers to population screening by simplifying the logistics of stool-sampling. The current study was conducted to undertake a paired comparison of a sensitive guaiac FOBT (GFOBT; Hemoccult II Sensa, Beckman Coulter, Fullerton, CA) with a brush-sampling FIT (InSure; Enterix, North Ryde, NSW, Australia), to determine whether this FIT improves detection of significant neoplasia.

METHODS

Individuals sampled consecutive stools, at home, with both FIT and GFOBT sampling devices while following dietary restrictions appropriate for GFOBT. Study populations included a screening cohort (n = 2351) and a symptomatic diagnostic group (n = 161). Paired comparison of positivity rates was undertaken in those found to have cancer and/or significant adenoma (high-grade dysplasia, villous change, > or =10 mm, serrated histology or > or =3 polyps), benign pathology, or no pathology.

RESULTS

Combined results for both cohorts showed that the FIT returned a true-positive result significantly more often in cancer (n = 24; 87.5% vs. 54.2%) and in significant adenomas (n = 61; 42.6% vs. 23.0%). Of all UICC Stage I cancers, the FIT was positive in 12 of 13 compared with 4 of 13 with the GFOBT (P = .002). In analyses of just the screening cohort, the FIT remained significantly better at detecting cancers and significant adenomas; the false-positive rate for any neoplasia was marginally higher with the FIT than the GFOBT (3.4% vs. 2.5%; 95% CI of difference, 0-1.8%), whereas positive predictive values were 41.9% and 40.4%, respectively.

CONCLUSIONS

This brush-sampling FIT is more sensitive for cancers and significant adenomas than a sensitive GFOBT. As such, it should deliver greater reductions in colorectal cancer mortality and incidence than the GFOBT.

Colorectal cancer screening

Colorectal cancer is a major public health burden worldwide. There is clear-cut evidence that screening will reduce colorectal cancer mortality and the only contentious issue is which screening tool to use. Most evidence points towards screening with fecal occult blood testing. The immunochemical fecal occult blood tests have a higher sensitivity than the guaiac-based tests. In addition, their automation and haemoglobin quantification allows a threshold for colonoscopy to be selected that can be accommodated within individual health care systems.

Prospective evaluation of the use and outcome of admission stool guaiac testing: the Digital Rectal Examination on Admission to the Medical Service (DREAMS) Study

BACKGROUND

Although physicians often perform fecal occult blood testing at the time of hospital admission, the practice of admission stool guaiac (ASG) testing has not been evaluated prospectively. The aim of this study was to determine the frequency and outcomes of digital rectal examination (DRE) and ASG testing in patients admitted to the hospital.

METHODS

We prospectively evaluated 2143 patients admitted to the medical service at our hospital over a 1-year period. A detailed clinical history was obtained, and the proportion of patients who had DRE and ASG testing, the frequency of positive tests, and the results of follow-up testing were determined.

RESULTS

A DRE was performed in 1539 of the 2143 subjects (71.8%), and 1.8% had abnormal findings, 21.8% had a normal examination, and the result of ASG testing was the only documented finding in the remaining 76.4% of patients. ASG testing was performed in 1342 of the 2143 subjects (62.6%), and the ASG test was positive in 237 persons (17.7%). However, only 161 (67.9%) of those with a positive ASG test had further diagnostic testing and a colonic source of occult gastrointestinal blood loss was detected in 68 (42.2%) of these 161 persons.

CONCLUSIONS

Although DRE and ASG testing are commonly performed on admission to the hospital, documentation of the findings and follow-up of positive tests are poor. These findings highlight the need to improve physician training on the appropriate use and documentation of the DRE and fecal occult blood testing.