Population-based colorectal cancer screening: comparison of two fecal occult blood test

Current trends in digital camera-based bioassays for point-of-care tests

Point-of-care and bedside tests are analytical devices suitable for a growing role in the current healthcare system and provide the opportunity to achieve an exact diagnosis by an untrained person and in various conditions and sites where it is necessary. Using a digital camera integrated into a well-accessible device like a smartphone brings a new way in which a colorimetric point-of-care diagnostic test can provide unbiased data. This review summarizes basic facts about the colorimetric point-of-care tests, principles of how to use a portable device with a camera in the assay, applications of digital cameras for the current tests, and new devices described in the recent papers. An overview of the recent literature and a discussion of recent developments and future trends are provided.

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.

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.

The effect of educational intervention based on theory of planned behavior on the improvement of colorectal cancer screening intention among average-risk individuals referring to Asadabad city clinics

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer in men and the fourth most common cancer in women in Iran. Therefore, the aim of this study was to determine the effect of educational intervention based on the theory of planned behavior (TPB) on the improvement of CRC screening intention among average-risk individuals.

MATERIALS AND METHODS

This quasi-experimental study was performed on the 50-69-year-old individuals referred to Asadabad city clinics in 2020. The individuals were randomly assigned to multistage cluster sampling in each intervention and control group. The instrument used in this research was a researcher-made questionnaire based on TPB. Educational intervention was conducted for the intervention group, one of their family members, and staff of clinic under intervention. Finally, the data were entered into SPSS and analyzed utilizing descriptive and analytical statistics. Results were considered significantly <0.05.

RESULTS

There were no significant differences between two intervention and control groups in the preintervention phase in terms of the mean scores of attitude (P = 0.58), subjective norms (P = 0.59), and behavioral intention (P = 0.66). However, in the postintervention phase, these differences were significant. Furthermore, regarding the mean score of perceived behavioral control, there was a significant difference between the two groups in the preintervention phase (P < 0.02), while in the postintervention phase, this difference was not significant (P = 0.29).

CONCLUSION

Educational intervention based on the TPB has been effective in improving the CRC screening intention among average-risk individuals. Therefore, using the results of this research and developing appropriate educational programs at the community level can be increased the participation of community members in CRC screening programs.

Mailed fecal immunochemical test outreach for colorectal cancer screening: Summary of a Centers for Disease Control and Prevention-sponsored Summit

Uptake of colorectal cancer screening remains suboptimal. Mailed fecal immunochemical testing (FIT) offers promise for increasing screening rates, but optimal strategies for implementation have not been well synthesized. In June 2019, the Centers for Disease Control and Prevention convened a meeting of subject matter experts and stakeholders to answer key questions regarding mailed FIT implementation in the United States. Points of agreement included: 1) primers, such as texts, telephone calls, and printed mailings before mailed FIT, appear to contribute to effectiveness; 2) invitation letters should be brief and easy to read, and the signatory should be tailored based on setting; 3) instructions for FIT completion should be simple and address challenges that may lead to failed laboratory processing, such as notation of collection date; 4) reminders delivered to initial noncompleters should be used to increase the FIT return rate; 5) data infrastructure should identify eligible patients and track each step in the outreach process, from primer delivery through abnormal FIT follow-up; 6) protocols and procedures such as navigation should be in place to promote colonoscopy after abnormal FIT; 7) a high-quality, 1-sample FIT should be used; 8) sustainability requires a program champion and organizational support for the work, including sufficient funding and external policies (such as quality reporting requirements) to drive commitment to program investment; and 9) the cost effectiveness of mailed FIT has been established. Participants concluded that mailed FIT is an effective and efficient strategy with great potential for increasing colorectal cancer screening in diverse health care settings if more widely implemented.

Making FIT Count: Maximizing Appropriate Use of the Fecal Immunochemical Test for Colorectal Cancer Screening Programs

Colorectal cancer (CRC) remains one of the most common and deadly malignancies despite advancements in screening, diagnostic capabilities, and treatment. The ability to detect and remove precancerous and cancerous lesions via screening has altered the epidemiology of the disease, decreasing incidence, mortality, and late-stage disease presentation. The fecal immunochemical test (FIT) is a screening test that aims to detect human hemoglobin in the stool. FIT is the most common CRC screening modality worldwide and second most common in the United States. Its use in screening programs has been shown to increase screening uptake and improve CRC outcomes. However, FIT-based screening programs vary widely in quality and effectiveness. In health systems with high-quality FIT screening programs, only superior FIT formats are used, providers order FIT appropriately, annual patient participation is high, and diagnostic follow-up after an abnormal result is achieved in a timely manner. Proper utilization of FIT involves multiple steps beyond provider recommendation of the test. In this commentary, we aim to highlight ongoing challenges in FIT screening and suggest interventions to maximize FIT effectiveness. Through active engagement of patients and providers, health systems can use FIT to help optimize CRC screening rates and improve CRC outcomes.

Strategies for increasing participation in mail-out colorectal cancer screening programs: a systematic review and meta-analysis

BACKGROUND

Population mail-out bowel screening programs are a convenient, cost-effective and sensitive method of detecting colorectal cancer (CRC). Despite the increased survival rates associated with early detection of CRC, in many countries, 50% or more of eligible individuals do not participate in such programs. The current study systematically reviews interventions applied to increase fecal occult blood test (FOBT) kit return, specifically in population mail-out programs.

METHODS

Five electronic databases (PubMed, PsycINFO, Scopus, CINAHL, and ProQuest Dissertations and Theses) were searched for articles published before the 10th of March 2018. Studies were included if they reported the results of an intervention designed to increase the return rate of FOBT kits that had been mailed to individuals' homes. PRISMA systematic review reporting methods were applied and each study was assessed using Cochrane's Risk of Bias tool. Pooled effect sizes were calculated for each intervention type and the risk of bias was tested as a moderator for sensitivity analysis.

RESULTS

The review identified 53 interventions from 30 published studies from which nine distinct intervention strategy types emerged. Sensitivity analysis showed that the risk of bias marginally moderated the overall effect size. Pooled risk ratios and confidence intervals for each intervention type revealed that telephone contact RR = 1.23, 95% CI (1.08-1.40), GP endorsement RR = 1.19, 95% CI (1.10-1.29), simplified test procedures RR = 1.17, 95% CI (1.09-1.25), and advance notifications RR = 1.09, 95% CI (1.07-1.11) were effective intervention strategies with small to moderate effect sizes. Studies with a high risk of bias were removed and pooled effects remained relatively unchanged.

CONCLUSIONS

Interventions that combine program-level changes incorporating the issue of advance notification and alternative screening tools with the involvement of primary health professionals through endorsement letters and telephone contact should lead to increases in kit return in mail-out CRC screening programs.

SYSTEMATIC REVIEW REGISTRATION

This review is registered with PROSPERO; registration number CRD42017064652.

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.

Urinary Metabolomics to Identify a Unique Biomarker Panel for Detecting Colorectal Cancer: A Multicenter Study

BACKGROUND

Population-based screening programs are credited with earlier colorectal cancer diagnoses and treatment initiation, which reduce mortality rates and improve patient health outcomes. However, recommended screening methods are unsatisfactory as they are invasive, are resource intensive, suffer from low uptake, or have poor diagnostic performance. Our goal was to identify a urine metabolomic-based biomarker panel for the detection of colorectal cancer that has the potential for global population-based screening.

METHODS

Prospective urine samples were collected from study participants. Based upon colonoscopy and histopathology results, 342 participants (colorectal cancer, 171; healthy controls, 171) from two study sites (Canada, United States) were included in the analyses. Targeted liquid chromatography-mass spectrometry (LC-MS) was performed to quantify 140 highly valuable metabolites in each urine sample. Potential biomarkers for colorectal cancer were identified by comparing the metabolomic profiles from colorectal cancer versus controls. Multiple models were constructed leading to a good separation of colorectal cancer from controls.

RESULTS

A panel of 17 metabolites was identified as possible biomarkers for colorectal cancer. Using only two of the selected metabolites, namely diacetylspermine and kynurenine, a predictor for detecting colorectal cancer was developed with an AUC of 0.864, a specificity of 80.0%, and a sensitivity of 80.0%.

CONCLUSIONS

We present a potentially "universal" metabolomic biomarker panel for colorectal cancer independent of cohort clinical features based on a North American population. Further research is needed to confirm the utility of the profile in a prospective, population-based colorectal cancer screening trial.

IMPACT

A urinary metabolomic biomarker panel was identified for colorectal cancer with the potential of clinical application.

Participation and Ease of Use in Colorectal Cancer Screening: A Comparison of 2 Fecal Immunochemical Tests

INTRODUCTION

The impact of fecal immunochemical test (FIT)-based colorectal cancer (CRC) screening on disease incidence and mortality is affected by participation, which might be influenced by ease of use of the FIT. We compared the participation rates and ease of use of 2 different FITs in a CRC screening program.

METHODS

There were two study designs within the Dutch CRC screening program. In a paired cohort study, all invitees received 2 FITs (OC-Sensor, Eiken, Japan, and FOB-Gold, Sentinel, Italy) and were asked to sample both from the same stool. Ease of use of both FITs was evaluated by a questionnaire. In a randomized controlled trial, invitees were randomly allocated to receive one of the 2 FITs to compare participation and analyzability.

RESULTS

Of 42,179 invitees in the paired cohort study, 21,078 (50%) completed 2 tests and 20,727 (98%) returned the questionnaire. FOB-Gold was reported significantly easier to use. More participants preferred FOB-Gold (36%) than OC-Sensor (5%), yet most had no preference (59%; P < 0.001). In the randomized trial, 936 of 1,923 invitees (48.7%) returned the FOB-Gold and 940 of 1,923 invitees (48.9%) returned the OC-Sensor, a difference of -0.2% (confidence interval, -3.4% to 3.0%), well within the pre-specified 5% noninferiority margin (P = 0.001). Only one FOB-Gold (0.1%) and 4 OC-Sensors (0.4%) were not analyzable (P = 0.18).

CONCLUSIONS

Although FOB-Gold was significantly but marginally considered easier to use than OC-Sensor, the number of analyzable tests and the participation rates in organized CRC screening are not affected when either of the FITs is implemented as a primary screening test.

Equivalent Accuracy of 2 Quantitative Fecal Immunochemical Tests in Detecting Advanced Neoplasia in an Organized Colorectal Cancer Screening Program

BACKGROUND & AIMS

Although different brands of fecal immunochemical tests (FITs) are used for colorectal cancer (CRC) screening, few studies have compared their accuracy in detecting advanced neoplasia.

METHODS

We performed a large prospective cohort study within the Dutch national CRC screening program to evaluate 2 quantitative FITs: FOB-Gold (Sentinel, Milan, Italy) and OC-Sensor (Eiken Chemical, Tokyo Japan), from May 2016 through March 2017. We randomly selected 42,179 screening-naïve individuals (55-75 years old), who were asked to perform both FITs themselves using the same bowel movement. Participants with positive results from 1 or both FITs (≥15 μg hemoglobin/gram feces) were invited for colonoscopy examination (reference standard). Equivalence in detection of advanced neoplasia was evaluated with a predefined margin of 0.15%.

RESULTS

Of 42,179 invitees, 22,064 (52%) participated and FITs were completed for 21,078 participants. Of 2112 participants (9.6%) with 1 or 2 positive results from FITs, 1778 (84%) underwent a colonoscopy. Of all invitees, the FOB-Gold test detected advanced neoplasia (confirmed by colonoscopy) in 610 participants (1.45%) and the OC-Sensor detected advanced neoplasia (confirmed by colonoscopy) in 606 participants (1.44%)-an absolute difference of 0.01% (95% confidence interval [CI], -0.06% to 0.08%). Of the 21,078 participants who completed both FITs, 1582 (7.5%) had a positive result from the FOB-Gold test and 1627 (7.7%) a positive result from the OC-Sensor test (P = .140). The relative true-positive rate of FOB-Gold vs OC-Sensor in detecting advanced neoplasia was 0.97 (95% CI, 0.92-1.01) and 0.95 (95% CI, 0.87-1.03) for CRC. The relative false-positive rate of the FOB-Gold test vs the OC-Sensor test in detecting advanced neoplasia was 0.99 (95% CI, 0.93-1.05).

CONCLUSIONS

In a large prospective study of individuals invited for CRC screening in The Netherlands, we found equivalent accuracy of the FOB-Gold FIT vs the OC-Sensor FIT in detecting advanced neoplasia. These results are relevant for selecting FITs for CRC screening programs worldwide. Dutch National Trial Registry: NTR5874.

Population-based colorectal cancer screening programmes using a faecal immunochemical test: should faecal haemoglobin cut-offs differ by age and sex?

BACKGROUND

The Basque Colorectal Cancer Screening Programme has both high participation rate and high compliance rate of colonoscopy after a positive faecal occult blood test (FIT). Although, colorectal cancer (CRC) screening with biannual (FIT) has shown to reduce CRC mortality, the ultimate effectiveness of the screening programmes depends on the accuracy of FIT and post-FIT colonoscopy, and thus, harms related to false results might not be underestimated. Current CRC screening programmes use a single faecal haemoglobin concentration (f-Hb) cut-off for colonoscopy referral for both sexes and all ages. We aimed to determine optimum f-Hb cut-offs by sex and age without compromising neoplasia detection and interval cancer proportion.

METHODS

Prospective cohort study using a single-sample faecal immunochemical test (FIT) on 444,582 invited average-risk subjects aged 50-69 years. A result was considered positive at ≥20 μg Hb/g faeces. Outcome measures were analysed by sex and age for a wide range of f-Hb cut-offs.

RESULTS

We analysed 17,387 positive participants in the programme who underwent colonoscopy. Participation rate was 66.5%. Men had a positivity rate for f-Hb of 8.3% and women 4.8% (p < 0.0001). The detection rate for advanced neoplasia (cancer plus advanced adenoma) was 44.0‰ for men and 15.9‰ for women (p < 0.0001). The number of colonoscopies required decreased in both sexes and all age groups through increasing the f-Hb cut-off. However, the loss in CRC detection increased by up to 28.1% in men and 22.9% in women. CRC missed were generally at early stages (Stage I-II: from 70.2% in men to 66.3% in women).

CONCLUSIONS

This study provides detailed outcomes in men and women of different ages at a range of f-Hb cut-offs. We found differences in positivity rates, neoplasia detection rate, number needed to screen, and interval cancers in men and women and in younger and older groups. However, there are factors other than sex and age to consider when consideration is given to setting the f-Hb cut-off.

Selecting a Cut-off for Colorectal Cancer Screening With a Fecal Immunochemical Test

OBJECTIVES

Fecal immunochemical tests (FITs) for hemoglobin (Hb) are increasingly used for colorectal cancer (CRC) screening. However, cut-offs for defining test positivity are varying widely. We aimed to evaluate the impact of cut-off selection on key indicators of diagnostic performance in a true screening setting.

METHODS

We evaluated diagnostic performance of FOB Gold, a widely used quantitative FIT, for detecting advanced neoplasms (AN) across a wide range of possible cut-offs among 1822 participants of screening colonoscopy aged 50-79 years in Germany.

RESULTS

The positive predictive value (PPV) for detecting AN showed a very steep increase with increasing cut-off up to 35.2% (95% CI 29.9-40.9%) at a cut-off of 9 μg Hb/g feces at which sensitivity and specificity were 48.8% (95% CI 42.1-55.6%) and 88.5% (95% CI 86.8-89.9%), respectively. A further moderate increase of PPV up to 56.9% (95% CI 47.8-65.5%), along with a major decrease in sensitivity was observed when gradually increasing the cut-off to 25 μg Hb/g feces at which sensitivity and specificity were 31.9% (95% CI 25.9-38.5%) and 96.9% (95% CI 95.9-97.6%), respectively. Further increases of the cut-off hardly affected PPV and specificity, but went along with further relevant decline in sensitivity.

CONCLUSIONS

Our study illustrates delineation of a range of meaningful cut-offs (here: 9-25 μg Hb/g feces) according to expected diagnostic yield in a true screening setting. Selecting a cut-off within or beyond this range should consider characteristics of the specific target population, such as AN prevalence or available colonoscopy capacity.

Association Between Colorectal Cancer Mortality and Gradient Fecal Hemoglobin Concentration in Colonoscopy Noncompliers

Background: To what extent the risk for colorectal cancer (CRC) death among noncompliers of colonoscopy is elevated following positive fecal immunological testing and whether the elevated risk varies with the fecal hemoglobin concentration (f-Hb) and location of CRC have not been researched.

Methods: We used data on 59 389 individuals (4.0%) among 1 489 937 Taiwanese screenees age 50 to 69 years with f-Hb 20 μg hemoglobin or more per gram of feces from 2004 to 2009. They were classified into 41 995 who received colonoscopy and 10 778 who received no confirmatory examination; the latter was categorized into three risk groups according to f-Hb (20–49, 50–99, and 100+). Mortality from CRC as the primary end point was monitored until December 31, 2012.

Results: A 1.64-fold (95% confidence interval [CI] = 1.32 to 2.04) increased risk for CRC death for the noncolonoscopy group as opposed to the colonoscopy group adjusting for differences in baseline characteristics. A gradient relationship was noted between cumulative mortality and age- and sex-adjusted f-Hb categories with 1.31-fold (95% CI = 1.04 to 1.71), 2.21-fold (95% CI = 1.55 to 3.34), and 2.53-fold (95% CI = 1.95 to 3.43) increased risk, respectively, for the 20–49, 50–99, and 100+ risk groups in the noncolonoscopy group compared with the colonoscopy group. The noncolonoscopy group led to a statistically significant 1.75-fold increased risk (95% CI = 1.35 to 2.33) for CRC of the distal colon but a statistically nonsignificant 1.11-fold increased risk (95% CI = 0.70 to 1.75) for the proximal colon, compared with the colonoscopy group. When the comparator was limited to subjects whose colonoscopy was completed to the cecum, the statistically significantly elevated risk for CRC mortality was seen for both distal and proximal colon in the noncolonoscopy group.

Conclusions: After a positive fecal immunochemical test, colonoscopy can reduce by about half the number of deaths from CRC. Among colonoscopy noncompliers, higher f-Hb is associated with an increased risk of mortality from CRC in a dose-response manner.

Fecal occult blood versus DNA testing: indirect comparison in a colorectal cancer screening population

Background

A multitarget stool DNA test (MSDT) that showed higher sensitivity but lower specificity than a fecal immunochemical test (FIT) for hemoglobin in one recent study from the US and Canada, is increasingly used for colorectal cancer (CRC) screening, despite its ~20-fold higher costs compared to FITs. We aimed to assess diagnostic performance of a quantitative FIT in an independent study among participants of screening colonoscopy and to compare it with the previously reported performance of MSDT.

Methods

A total of 3494 participants, aged 50–84 years, who underwent screening colonoscopy in private gastroenterological practices in Germany, and who provided a stool sample before colonoscopy to be evaluated by a commercially available quantitative FIT (FOB Gold^®) were included. Diagnostic performance (sensitivity, specificity) for detecting CRC or advanced precancerous lesions (APCLs) was evaluated by comparison of test results with findings at screening colonoscopy. In addition to the original cutoff, we used an adjusted cutoff yielding the same specificity as reported for the MSDT to enhance comparability.

Results

The most advanced finding at colonoscopy was CRC and APCL in 30 (0.86%) and 359 (10.3%) cases, respectively. At a cutoff yielding the same specificity as reported for MSDT (86.6%), the sensitivities (95% CI) of the FIT for detecting CRC and APCL >1 cm were 96.7% (82.8–99.9%) and 54.3% (48.3–60.3%), respectively. These sensitivities are higher than those reported for MSDT (92.3% and 43.6%, p=0.66 and 0.003, respectively).

Conclusion

In this large screening population, FIT showed equivalent or better diagnostic performance in comparison to reported performance of MSDT.

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.

Real-Time Monitoring of Results During First Year of Dutch Colorectal Cancer Screening Program and Optimization by Altering Fecal Immunochemical Test Cut-Off Levels

BACKGROUND & AIMS

After careful pilot studies and planning, the national screening program for colorectal cancer (CRC), with biennial fecal immunochemical tests (FITs), was initiated in The Netherlands in 2014. A national information system for real-time monitoring was developed to allow for timely evaluation. Data were collected from the first year of this screening program to determine the importance of planning and monitoring for optimal screening program performance.

METHODS

The national information system of the CRC screening program kept track of the number of invitations sent in 2014, FIT kits returned, and colonoscopies performed. Age-adjusted rates of participation, the number of positive test results, and positive predictive values (PPVs) for advanced neoplasia were determined weekly, quarterly, and yearly.

RESULTS

In 2014, there were 741,914 persons invited for FIT; of these, 529,056 (71.3%; 95% CI, 71.2%-71.4%) participated. A few months into the program, real-time monitoring showed that rates of participation and positive test results (10.6%; 95% CI, 10.5%-10.8%) were higher than predicted and the PPV was lower (42.1%; 95% CI, 41.3%-42.9%) than predicted based on pilot studies. To reduce the burden of unnecessary colonoscopies and alleviate colonoscopy capacity, the cut-off level for a positive FIT result was increased from 15 to 47 μg Hb/g feces halfway through 2014. This adjustment decreased the percentage of positive test results to 6.7% (95% CI, 6.6%-6.8%) and increased the PPV to 49.1% (95% CI, 48.3%-49.9%). In total, the first year of the Dutch screening program resulted in the detection of 2483 cancers and 12,030 advanced adenomas.

CONCLUSIONS

Close monitoring of the implementation of the Dutch national CRC screening program allowed for instant adjustment of the FIT cut-off levels to optimize program performance.

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.

Comparison of the yield from two faecal immunochemical tests at identical cutoff concentrations - a randomized trial in Latvia

OBJECTIVE

We have compared the performance of two faecal immunochemical tests (FIT) in an average-risk population.

MATERIALS AND METHODS

Altogether, 10 000 individuals aged 50-74 were selected randomly from the population of Latvia in 2011 and assigned randomly either to OC-Sensor or to FOB Gold single-time testing. Positivity of the test, frequency of colonic lesions, number needed to screen (NNscreen) and scope for the detection of an advanced neoplasm (cancer and advanced adenoma) were compared between the tests using the same cutoff concentrations in µg/g faeces. Confidence intervals (CIs) at 95% were calculated.

RESULTS

Positivity with the cutoff set at 10 µg/g faeces was 12.8% (95% CI: 11.4-14.2) for FOB Gold and 8.3% (95% CI: 7.2-9.4) for OC-Sensor (P<0.001). Positivity was higher in men and the older age groups. Colonoscopy compliance was 55.5%. There was no significant difference between the two tests at comparable cutoff concentrations in µg/g, colonoscopy attendance rate or colonoscopy results. For advanced neoplasm detection, there was no significant difference in number needed to scope and NNscreen at a cutoff of 10 µg/g faeces; however, lower NNscreen was required to detect advanced neoplasms with the FOB Gold test at increased cutoff concentrations.

CONCLUSION

Different quantitative FIT systems may report different positivity rate at identical cutoff concentrations, which has to be considered when implementing the use of FIT in national screening programmes.

Colorectal cancer detection in an asymptomatic population: fecal immunochemical test for hemoglobin vs. fecal M2-type pyruvate kinase

Introduction

Screening programs for colorectal cancer (CRC) are mainly based on a first-line fecal immunochemical test for hemoglobin (FIT). Fecal M2-type pyruvate kinase (M2-PK) has been evaluated in clinical settings showing promising results for early CRC detection. However, the impact of fecal M2-PK assessment on the performance of first-round CRC screening programs is not known. We investigated whether fecal M2-PK alone or in combination with FIT may improve CRC screening efficacy in the general population.

Materials and methods

A total of 1027 asymptomatic subjects (median age 66 [59-74] years; females 504 [49.1%]), identified through the general practitioners’ rosters, were invited for the collection of 2 fecal samples for FIT and M2-PK evaluation. Participants with at least positive one fecal test were referred for colonoscopy. Quality indicators for screening performance were calculated and analyzed using Fisher’s exact test.

Results

Overall, 572 subjects underwent both FIT and M2-PK assessment (participation rate 55.7%): 93 participants showed positive results for at least one test (positivity rate 16.3%). Only 10 patients were positive for both tests. Attendance rate to colonoscopy was 86.0% and a total of 65 adenomas and 7 cancers were detected. Combined use of FIT and fecal M2-PK permitted the identification of 18 more neoplasm (25%) without improving colonoscopy workload, as deduced by the comparable number needed to scope (P = 0.402).

Conclusion

The addition of M2-PK testing to FIT offers the potential to detect additional neoplasms that either do not bleed or only bleed intermittently without reducing participation rate and without increasing endoscopy workload.

Sensitivity and Specificity of Community Fecal Immunotesting Screening for Colorectal Carcinoma in a High-Risk Canadian Population

CONTEXT

Community-based programs are a common way of promoting colorectal cancer screening by primary care physicians. Fecal immunochemical testing (FIT) is a screening method commonly used in such programs. Fecal immunochemical testing has advantages to the patient as well as to clinical laboratories.

OBJECTIVE

To assess the operational test characteristics of a FIT pilot program in Calgary, Alberta, Canada, between April 2011 and May 2012.

DESIGN

Four hundred fifty-seven high-risk patients undergoing both FIT and colonoscopy were included. Areas under the curve and positive predictive values were derived for FIT values and biopsy-proven neoplasia. Subgroup analysis was also performed on men and women and for ages older and younger than the mean age of 62 years.

RESULTS

For colorectal carcinoma and colonic adenomas the areas under the curve were 0.79 (95% confidence interval 0.71-0.87) and 0.60 (95% confidence interval 0.54-0.65), respectively. The positive predictive value of a positive FIT result for any neoplasia was 53%. The overall performance of the test for all neoplasia was better for men and better for older individuals.

CONCLUSIONS

The performance of FIT in this clinical setting was very good for detecting carcinoma, but marginal for detection of colonic adenomas.

Difference in performance of fecal immunochemical tests with the same hemoglobin cutoff concentration in a nationwide colorectal cancer screening program

BACKGROUND & AIMS

We investigated whether 2 quantitative fecal immunochemical tests (FITs) with the same cutoff concentration of fecal hemoglobin perform equivalently in identifying patients with colorectal cancer (CRC).

METHODS

A total of 956,005 Taiwanese subjects, 50 to 69 years old, participated in a nationwide CRC screening program to compare results from 2 FITs; 78% were tested using the OC-Sensor (n = 747,076; Eiken Chemical Co, Tokyo, Japan) and 22% were tested using the HM-Jack (n = 208,929; Kyowa Medex Co Ltd, Tokyo, Japan), from 2004 through 2009. The cutoff concentration for a positive finding was 20 μg hemoglobin/g feces, based on a standardized reporting unit system. The tests were compared using short-term and long-term indicators of performance.

RESULTS

The OC-Sensor test detected CRC in 0.21% of patients, with a positive predictive value of 6.8%. The HM-Jack test detected CRC in 0.17% of patients, with a positive predictive value of 5.2%. The rate of interval cancer rate was 30.7/100,000 person-years among subjects receiving the OC-Sensor test and 40.6/100,000 person-years among those receiving the HM-Jack test; there was significant difference in test sensitivity (80% vs 68%, P = .005) that was related to the detectability of proximal CRC. After adjusting for differences in city/county, age, sex, ambient temperature, and colonoscopy quality, significant differences were observed between the tests in the positive predictive value for cancer detection (adjusted relative risk = 1.29; 95% confidence interval, 1.14-1.46) and the rates of interval cancer (0.75; 95% confidence interval, 0.62-0.92). Although each test was estimated to reduce CRC mortality by approximately 10%, no significant difference in mortality was observed when the 2 groups were compared.

CONCLUSIONS

Different brands of quantitative FITs, even with the same cutoff hemoglobin concentration, perform differently in mass screening. Population-level data should be gathered to verify the credibility of quantitative laboratory findings.