A higher detection rate for colorectal cancer and advanced adenomatous polyp for screening with immunochemical fecal occult blood test than guaiac fecal occult blood test, despite lower compliance rate. A prospective, controlled, feasibility study

Repeat Faecal Immunochemical Testing for Colorectal Cancer Detection in Symptomatic and Screening Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Faecal immunochemical testing (FIT) is widely used in bowel screening programmes and assessing symptomatic patients for suspected colorectal cancer (CRC). The evidence for single test performance of FIT in both settings is considerable; however, the use of a repeat test to increase sensitivity remains uncertain. We aimed to review what increase in test positivity would be generated by additional FITs, whether a repeated FIT detects previously missed CRC and advanced colorectal neoplasia (ACRN), and to estimate the sensitivity of double-FIT strategies to diagnose CRC and ACRN.

METHODS

A systematic search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) was performed using key search terms. Studies reporting the use of more than one FIT in the same screening round or planned assessment of a single symptomatic patient episode were included. Studies were categorised by the reported study population into asymptomatic, mixed (cohorts of combined asymptomatic, symptomatic, or high-risk surveillance), or symptomatic cohorts.

RESULTS

A total of 68 studies were included for analysis (39 asymptomatic, 21 mixed, 7 symptomatic, and 1 study with discrete asymptomatic and symptomatic data). At a threshold of 10 µg Hb/g, the two-test positivity ranged between 8.1 and 34.5%, with an increase from the second test of 3-9.2 percentage points. Four out of five studies comparing one versus two tests for diagnosing CRC at 10 µg Hb/g identified additional cases with the second test, with a minimum of 50% reduction in missed CRC. At a threshold of 20 µg Hb/g, the second test increased the positivity by 1.3-6.7 percentage points, with a two-test positivity of between 5.1 and 25.0%. Using a threshold of 20 µg Hb/g, five out of seven studies had a 25% reduction in missed CRC. A meta-analysis estimated the double-FIT sensitivity at 10 µg Hb/g for CRC in mixed-risk and symptomatic cohorts to be 94% and 98%, respectively.

CONCLUSIONS

Repeated use of FIT helps to diagnose more cases of CRC with a moderate increase in positivity. A double-FIT strategy at 10 µg Hb/g in mixed and symptomatic cohorts has a very high sensitivity for CRC.

Effect of fecal immunochemical test cut-off levels on adenoma detection rate: a systematic review and meta-analysis

BACKGROUND

Adenoma detection rate (ADR) is higher after a positive fecal immunochemical test (FIT) compared to direct screening colonoscopy.

OBJECTIVE

This meta-analysis evaluated how ADR, the rates of advanced adenoma detection (AADR), colorectal cancer detection (CDR), and sessile serrated lesion detection (SSLDR) are affected by different FIT positivity thresholds.

METHODS

We searched MEDLINE, EMBASE, CINAHL, and EBM Reviews databases for studies reporting ADR, AADR, CDR, and SSLDR according to different FIT cut-off values in asymptomatic average-risk individuals aged 50-74 years old. Data were stratified according to sex, age, time to colonoscopy, publication year, continent, and FIT kit type. Study quality, heterogeneity, and publication bias were assessed.

RESULTS

Overall, 4280 articles were retrieved and fifty-eight studies were included (277,661 FIT-positive colonoscopies; mean cecal intubation 96.3%; mean age 60.8 years; male 52.1%). Mean ADR was 56.1% (95% CI 53.4 - 58.7%), while mean AADR, CDR, and SSLDR were 27.2% (95% CI 24.4 - 30.1%), 5.3% (95% CI 4.7 - 6.0%), and 3.0% (95% CI 1.7 - 4.6%), respectively. For each 20 μg Hb/g increase in FIT cut-off level, ADR increased by 1.54% (95% CI 0.52 - 2.56%, p < 0.01), AADR by 3.90% (95% CI 2.76 - 5.05%, p < 0.01) and CDR by 1.46% (95% CI 0.66 - 2.24%, p < 0.01). Many detection rates were greater amongst males and Europeans.

CONCLUSIONS

ADRs in FIT-positive colonoscopies are influenced by the adopted FIT positivity threshold, and identified targets, importantly, proved to be higher than most current societal recommendations.

Novel DNA methylation biomarkers in stool and blood for early detection of colorectal cancer and precancerous lesions

BACKGROUND

Early detection and prevention of precancerous lesions can significantly reduce the morbidity and mortality of colorectal cancer (CRC). Here, we developed new candidate CpG site biomarkers for CRC and evaluated the diagnostic value of their expression in blood and stool samples of CRC and precancerous lesions.

METHODS

We analyzed 76 pairs of CRC and adjacent normal tissue samples, 348 stool samples, and 136 blood samples. Candidate biomarkers for CRC were screened using a bioinformatics database and identified using a quantitative methylation-specific PCR method. The methylation levels of the candidate biomarkers were validated using blood and stool samples. The divided stool samples were used to construct and validate a combined diagnostic model and to analyze the independent or combined diagnostic value of candidate biomarkers in stool samples of CRC and precancerous lesions.

RESULTS

Two candidate CpG site biomarkers for CRC, cg13096260 and cg12993163, were identified. Although both biomarkers demonstrated diagnostic performance to a certain extent when using blood samples, they showed better diagnostic value for different stages of CRC and AA with stool samples.

CONCLUSIONS

cg13096260 and cg12993163 detection in stool samples could be a promising approach for screening and early diagnosis of CRC and precancerous lesions.

Colorectal Cancer: A Systematic Review of the Current Situation and Screening in North and Central Asian Countries

The prevalence of colorectal cancer (CRC) is increasing in the past few decades. A significant proportion of this increase is from low to middle income countries (LMIC). CRC prevalence is also increasing in North and Central Asian Countries (NCAC). Screening for colorectal cancer has decreased CRC mortality but data regarding screening practices in NCAC is limited.  A literature search was conducted in PubMed/Medline, Embase and Cochrane for current colorectal cancer screening practices in NCAC. Incidence and mortality rates were derived from public health agency websites to calculate age-standardized CRC mortality-to-incidence ratios. Web-based online break-point testing defined as statistical major changes in CRC mortality trends was completed. Among the 677 screened studies, 37 studies met the criteria for inclusion for review. CRC screening in NCAC is not organized, although most countries have cancer registries. The data availability is scarce, and most data is prior to 2017. Most studies are observational. There is minimal data about colonoscopy preparations, adenoma detection and complications rates. The polyp detection rates (PDRs) and adenoma detection rates (ADRs) seem low to optimal in this region. Commonly measured outcomes include participation rate, fecal immunochemical tests (FIT) positivity rate and cost-benefit measures. Lower mortality-to-incidence ratios is seen in countries with screening programs. Kazakhstan and Lithuania with screening programs have achieved breakpoint suggesting major changes in CRC mortality trends. Data about CRC screening varies widely within NCAC. High human developmental index (HDI) countries like Lithuania and Estonia have higher incidence of CRC and mortality. Seven NCAC have CRC screening programs with most utilizing non-invasive methods for screening. Data collection is regional and not organized. The ADR and PDR are low to optimal in this region and cancer detection rates are comparable to other high-income countries (HIC). CRC detection rate is 0.05% for screening in Kazakhstan and 0.2% for screening in Lithuania. Very limited information is available on the actual cost and logistics of implementing a CRC screening program. All NCAC have a cancer registry, with some having a high-quality registry showing national coverage with good validity and completeness. Establishing guideline-based registries and increasing screening efficacy could improve CRC outcomes in NCAC.

Pooled rates of adenoma detection by colonoscopy in asymptomatic average-risk individuals with positive fecal immunochemical test: a systematic review and meta-analysis

BACKGROUND AND AIMS

Current adenoma detection rate (ADR) benchmarks for colonoscopy in individuals positive for a fecal immunochemical test (FIT) are ≥45% in men and ≥35% in women. These are based on weak, low-quality evidence. We performed a meta-analysis to ascertain the pooled ADR in FIT-positive colonoscopy.

METHODS

Major databases like PubMed, EMBASE, and Web of Science were searched in October 2021 for studies reporting on ADR of colonoscopy in a FIT-positive population. Meta-analysis was performed by standard methodology using the random-effects model. Heterogeneity was assessed by I² and 95% prediction interval statistics.

RESULTS

Thirty-four high-quality studies that included more than 6 million asymptomatic average-risk individuals were analyzed; 2,655,345 individuals completed a screening FIT test. The pooled FIT screening rate was 69.8% (95% CI, 62.8-76.1), the pooled FIT positivity rate was 5.4% (95% CI, 4.3-6.9), and the colonoscopy completion rate was 85% (95% CI, 82.8-86.9). The pooled ADR was 47.8% (95% CI, 44.1-51.6), pooled advanced ADR was 25.3% (95% CI, 22-29), and the pooled colorectal cancer detection rate was 5.1% (95% CI, 4.4-5.9). The pooled ADR in men was 58.3% (95% CI, 52.8-63.6) and in women was 41.9% (95% CI, 36.4-47.6). The pooled ADR with qualitative FIT assessment was 67.7% (95% CI, 50.7-81), with 1-stool sample FIT was 52.8% (95% CI, 48.8-56.8), and at a cutoff threshold of 100 ng hemoglobin/mL was 52.1% (95% CI, 47-57.1). Based on time-period cumulative analysis, the ADR improved over time from 30.5% (95% CI, 24.6-37.2) to 47.8% (95% CI, 44.1-51.6).

CONCLUSIONS

This meta-analysis supports the current ADR benchmarks for colonoscopy in FIT-positive individuals. Excellent pooled ADR parameters were demonstrated with qualitative assessment of 1 stool sample at a test cutoff value of 100 ng hemoglobin/mL, and ADR per endoscopist improved over time.

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.

Screening and prevention of colorectal cancer

Mortality from colorectal cancer is reduced through screening and early detection; moreover, removal of neoplastic lesions can reduce cancer incidence. While understanding of the risk factors, pathogenesis, and precursor lesions of colorectal cancer has advanced, the cause of the recent increase in cancer among young adults is largely unknown. Multiple invasive, semi- and non-invasive screening modalities have emerged over the past decade. The current emphasis on quality of colonoscopy has improved the effectiveness of screening and prevention, and the role of new technologies in detection of neoplasia, such as artificial intelligence, is rapidly emerging. The overall screening rates in the US, however, are suboptimal, and few interventions have been shown to increase screening uptake. This review provides an overview of colorectal cancer, the current status of screening efforts, and the tools available to reduce mortality from colorectal cancer.

Colorectal Cancer Screening Outcomes of 2412 Prostate Cancer Patients Considered for Carbon Ion Radiotherapy

Colorectal cancer (CRC) screening is effective for detecting cancer in average-risk adults. For prostate cancer (PCa) patients considered for carbon ion radiotherapy (CIRT), pre-treatment CRC screening is performed empirically to avoid post-treatment colonoscopic manipulation. However, the outcomes of screening this population remain unclear. Here, we compared the outcomes of routine pre-CIRT CRC screening of 2412 PCa patients at average risk for CRC with data from two published datasets: the Japan National Cancer Registry (JNCR) and a series of 17 large-scale screening studies analyzing average-risk adults. The estimated prevalence rate was calculated using the pooled sensitivity elucidated by a previous meta-analysis. Consequently, 28 patients (1.16%) were diagnosed with CRC. CRC morbidity was significantly associated with high pre-treatment levels of prostate-specific antigen (p = 0.023). The screening positivity rate in this study cohort exceeded the annual incidence reported in the JNCR for most age brackets. Furthermore, the estimated prevalence rate in this study cohort (1.46%) exceeded that reported in all 17 large-scale studies, making the result an outlier (p = 0.005). These data indicate the possibility that the prevalence of CRC in PCa patients is greater than that in general average-risk adults, warranting further research in a prospective setting.

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.

What Factors Influence Non-Participation Most in Colorectal Cancer Screening? A Discrete Choice Experiment

Background and Objective

Non-participation in colorectal cancer (CRC) screening needs to be decreased to achieve its full potential as a public health strategy. To facilitate successful implementation of CRC screening towards unscreened individuals, this study aimed to quantify the impact of screening and individual characteristics on non-participation in CRC screening.

Methods

An online discrete choice experiment partly based on qualitative research was used among 406 representatives of the Dutch general population aged 55–75 years. In the discrete choice experiment, respondents were offered a series of choices between CRC screening scenarios that differed on five characteristics: effectiveness of the faecal immunochemical screening test, risk of a false-negative outcome, test frequency, waiting time for faecal immunochemical screening test results and waiting time for a colonoscopy follow-up test. The discrete choice experiment data were analysed in a systematic manner using random-utility-maximisation choice processes with scale and/or preference heterogeneity (based on 15 individual characteristics) and/or random intercepts.

Results

Screening characteristics proved to influence non-participation in CRC screening (21.7–28.0% non-participation rate), but an individual’s characteristics had an even higher impact on CRC screening non-participation (8.4–75.5% non-participation rate); particularly the individual’s attitude towards CRC screening followed by whether the individual had participated in a cancer screening programme before, the decision style of the individual and the educational level of the individual. Our findings provided a high degree of confidence in the internal–external validity.

Conclusions

This study showed that although screening characteristics proved to influence non-participation in CRC screening, a respondent’s characteristics had a much higher impact on CRC screening non-participation. Policy makers and physicians can use our study insights to improve and tailor their communication plans regarding (CRC) screening for unscreened individuals.

Novel Toilet Paper-Based Point-Of-Care Test for the Rapid Detection of Fecal Occult Blood: Instrument Validation Study

BACKGROUND

Colorectal cancer screening by fecal occult blood testing has been an important public health test and shown to reduce colorectal cancer-related mortality. However, the low participation rate in colorectal cancer screening by the general public remains a problematic public health issue. This fact could be attributed to the complex and unpleasant operation of the screening tool.

OBJECTIVE

This study aimed to validate a novel toilet paper-based point-of-care test (ie, JustWipe) as a public health instrument to detect fecal occult blood and provide detailed results from the evaluation of the analytic characteristics in the clinical validation.

METHODS

The mechanism of fecal specimen collection by the toilet-paper device was verified with repeatability and reproducibility tests. We also evaluated the analytical characteristics of the test reagents. For clinical validation, we conducted comparisons between JustWipe and other fecal occult blood tests. The first comparison was between JustWipe and typical fecal occult blood testing in a central laboratory setting with 70 fecal specimens from the hospital. For the second comparison, a total of 58 volunteers were recruited, and JustWipe was compared with the commercially available Hemoccult SENSA in a point-of-care setting.

RESULTS

Adequate amounts of fecal specimens were collected using the toilet-paper device with small day-to-day and person-to-person variations. The limit of detection of the test reagent was evaluated to be 3.75 µg of hemoglobin per milliliter of reagent. Moreover, the test reagent also showed high repeatability (100%) on different days and high reproducibility (>96%) among different users. The overall agreement between JustWipe and a typical fecal occult blood test in a central laboratory setting was 82.9%. In the setting of point-of-care tests, the overall agreement between JustWipe and Hemoccult SENSA was 89.7%. Moreover, the usability questionnaire showed that the novel test tool had high scores in operation friendliness (87.3/100), ease of reading results (97.4/100), and information usefulness (96.1/100).

CONCLUSIONS

We developed and validated a toilet paper-based fecal occult blood test for use as a point-of-care test for the rapid (in 60 seconds) and easy testing of fecal occult blood. These favorable characteristics render it a promising tool for colorectal cancer screening as a public health instrument.

Effect of Sex, Age, and Positivity Threshold on Fecal Immunochemical Test Accuracy: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Quantitative fecal immunochemical tests (FITs) for hemoglobin are commonly used for colorectal cancer (CRC) screening. We aimed to quantify the change in CRC and advanced adenoma detection and number of positive test results at different positivity thresholds and by sex and age.

METHODS

We searched MEDLINE and EMBASE, selecting articles of FIT for CRC detection in asymptomatic adults undergoing screening. We calculated sensitivity and specificity, as well as detected number of cancers, advanced adenomas, and positive test results at positivity thresholds ≤10 μg hemoglobin/g feces, 10 to ≤20 μg/g, 20 to ≤30 μg/g, and >30 μg/g. We also analyzed results from stratified by patient sex, age, and reference standard.

RESULTS

Our meta-analysis comprised 46 studies with 2.4 million participants and 6478 detected cancers. Sensitivity for detection of CRC increased from 69% (95% confidence interval [CI], 63%-75%) at thresholds >10 μg/g and ≤20 μg/g to 80% (95% CI, 76%-83%) at thresholds ≤10 μg/g. At these threshold values, sensitivity for detection of advanced adenomas increased from 21% (95% CI, 18%-25%) to 31% (95% CI, 27%-35%), whereas specificity decreased from 94% (95% CI, 93%-96%) to 91% (95% CI, 89%-93%). In 3 studies stratified by sex, sensitivity of CRC detection was 77% in men (95% CI, 75%-79%) and 81% in women (95% CI, 60%-100%) (P = .68). In 3 studies stratified by age groups, sensitivity of CRC detection was 85% for ages 50-59 years (95% CI, 71%-99%) and 73% for ages 60-69 years (95% CI, 71%-75%) (P = .10). All studies with colonoscopy follow-up had similar sensitivity levels for detection of CRC to studies that analyzed 2-year registry follow-up data (74%; 95% CI, 68%-78% vs 75%; 95% CI, 73%-77%).

CONCLUSIONS

In a meta-analysis of studies that analyzed detection of CRC and advanced adenomas at different FIT positivity thresholds, we found the sensitivity and specificity of detection to vary with positive cutoff value. It might be possible to decrease positive threshold values for centers with sufficient follow-up colonoscopy resources. More research is needed to precisely establish FIT thresholds for each sex and age subgroup.

PROTOCOL

PROSPERO CRD42017068760.

Overestimated Sensitivity of Fecal Immunochemical Tests in Screening Cohorts With Registry-Based Follow-up

OBJECTIVES

Several recent studies have reported very high estimates of sensitivity and specificity of fecal immunochemical tests (FITs) at seemingly high levels of precision using registry-based follow-up of participants in very large FIT-based screening programs. We aimed to assess the validity of estimates of diagnostic performance parameters derived by this indirect approach.

METHODS

We modeled expected values of sensitivity and specificity of colorectal cancer detection in studies using the indirect approach and their deviation from true values under a broad range of plausible assumptions, and we compared these expected values with recently reported estimates of FIT sensitivity and specificity from such studies.

RESULTS

Using a sensitivity of 75% and specificity of 93.6% (from studies using a direct approach, i.e., colonoscopy follow-up of all participants), the indirect approach would be expected to yield sensitivities between 84.5% and 91.1% and specificities between 93.4% and 93.6% under a range of realistic assumptions regarding colonoscopic follow-up rates of positive FITs and clinical manifestation rates of preclinical colorectal cancer.

DISCUSSION

Very high sensitivities of FITs recently reported with seemingly very high levels of precision by several large-scale registry-based studies, which are in line with expected results based on our model calculations, are likely to be strongly overestimated and need to be interpreted with due caution.

Cost-effectiveness of a multitarget stool DNA test for colorectal cancer screening of Medicare beneficiaries

BACKGROUND

In 2014, the Centers for Medicare and Medicaid Services (CMS) began covering a multitarget stool DNA (mtSDNA) test for colorectal cancer (CRC) screening of Medicare beneficiaries. In this study, we evaluated whether mtSDNA testing is a cost-effective alternative to other CRC screening strategies reimbursed by CMS, and if not, under what conditions it could be.

METHODS

We use three independently-developed microsimulation models to simulate a cohort of previously unscreened US 65-year-olds who are screened with triennial mtSDNA testing, or one of six other reimbursed screening strategies. Main outcome measures are discounted life-years gained (LYG) and lifetime costs (CMS perspective), threshold reimbursement rates, and threshold adherence rates. Outcomes are expressed as the median and range across models.

RESULTS

Compared to no screening, triennial mtSDNA screening resulted in 82 (range: 79-88) LYG per 1,000 simulated individuals. This was more than for five-yearly sigmoidoscopy (80 (range: 71-89) LYG), but fewer than for every other simulated strategy. At its 2017 reimbursement rate of $512, mtSDNA was the most costly strategy, and even if adherence were 30% higher than with other strategies, it would not be a cost-effective alternative. At a substantially reduced reimbursement rate ($6-18), two models found that triennial mtSDNA testing was an efficient and potentially cost-effective screening option.

CONCLUSIONS

Compared to no screening, triennial mtSDNA screening reduces CRC incidence and mortality at acceptable costs. However, compared to nearly all other CRC screening strategies reimbursed by CMS it is less effective and considerably more costly, making it an inefficient screening option.

Current state and future direction of screening tool for colorectal cancer

As the second-most-common cause of cancer death, colorectal cancer (CRC) has been recognized as one of the biggest health concerns in advanced countries. The 5-year survival rate for patients with early-stage CRC is significantly better than that for patients with CRC detected at a late stage. The primary target for CRC screening and prevention is advanced neoplasia, which includes both CRC itself, as well as benign but histologically advanced adenomas that are at increased risk for progression to malignancy. Prevention of CRC through detection of advanced adenomas is important. It is, therefore, necessary to develop more efficient detection methods to enable earlier detection and therefore better prognosis. Although a number of CRC diagnostic methods are currently used for early detection, including stool-based tests, traditional colonoscopy, etc., they have not shown optimal results due to several limitations. Hence, development of more reliable screening methods is required in order to detect the disease at an early stage. New screening tools also need to be able to accurately diagnose CRC and advanced adenoma, help guide treatment, and predict the prognosis along with being relatively simple and non-invasive. As part of such efforts, many proposals for the early detection of colorectal neoplasms have been introduced. For example, metabolomics, referring to the scientific study of the metabolism of living organisms, has been shown to be a possible approach for discovering CRC-related biomarkers. In addition, a growing number of high-performance screening methodologies could facilitate biomarker identification. In the present, evidence-based review, the authors summarize the current state as recognized by the recent guideline recommendation from the American Cancer Society, US Preventive Services Task Force and the United States Multi-Society Task Force and discuss future direction of screening tools for colorectal cancer. Further, we highlight the most interesting publications on new screening tools, like molecular biomarkers and metabolomics, and discuss these in detail.

Incidence of faecal occult blood test interval cancers in population-based colorectal cancer screening: a systematic review and meta-analysis

OBJECTIVE

Faecal immunochemical tests (FITs) are replacing guaiac faecal occult blood tests (gFOBTs) for colorectal cancer (CRC) screening. Incidence of interval colorectal cancer (iCRC) following a negative stool test result is not yet known. We aimed to compare incidence of iCRC following a negative FIT or gFOBT.

DESIGN

We searched Ovid Medline, Embase, Cochrane Library, Science Citation Index, PubMed and Google Scholar from inception to 12 December 2017 for citations related to CRC screening based on stool tests. We included studies on FIT or gFOBT iCRC in average-risk screening populations. Main outcome was pooled incidence rate of iCRCs per 100 000 person-years (p-y). Pooled incidence rates were obtained by fitting random-effect Poisson regression models.

RESULTS

We identified 7 426 records and included 29 studies. Meta-analyses comprised data of 6 987 825 subjects with a negative test result, in whom 11 932 screen-detected CRCs and 5 548 gFOBT or FIT iCRCs were documented. Median faecal haemoglobin (Hb) positivity cut-off used was 20 (range 10-200) µg Hb/g faeces in the 17 studies that provided FIT results. Pooled incidence rates of iCRC following FIT and gFOBT were 20 (95% CI 14 to 29; I²=99%) and 34 (95% CI 20 to 57; I²=99%) per 100 000 p-y, respectively. Pooled incidence rate ratio of FIT versus gFOBT iCRC was 0.58 (95% CI 0.32 to 1.07; I²=99%) and 0.36 (95% CI 0.17 to 0.75; I²=10%) in sensitivity analysis. For every FIT iCRC, 2.6 screen-detected CRCs were found (ratio 1:2.6); for gFOBT, the ratio between iCRC and screen-detected CRC was 1:1.2. Age below 60 years and the third screening round were significantly associated with a lower iCRC rate.

CONCLUSION

A negative gFOBT result is associated with a higher iCRC incidence than a negative FIT. This supports the use of FIT over gFOBT as CRC screening tool.

The compliance rate for the second diagnostic evaluation after a positive fecal occult blood test: A systematic review and meta-analysis

Introduction

Only a minority of patients with a positive fecal occult blood test (FOBT) undergo a follow-up second diagnostic procedure, thus minimizing its contribution for colorectal cancer (CRC) prevention. We aimed to obtain a precise estimation of this problem and also assess the diagnostic yield of CRC and adenomas by colonoscopy in these patients.

Methods

Literature searches were conducted for "compliance" OR "adherence" AND "fecal occult blood test" OR "fecal immunohistochemical test" AND "colonoscopy." Comprehensive meta-analysis software was used.

Results

The search resulted in 42 studies (512,496 patients with positive FOBT), published through December 31, 2017. A funnel plot demonstrates a moderate publication bias. Compliance with any second procedure, colonoscopy, or combination of double-contrast barium enema with or without sigmoidoscopy in patients with a positive FOBT was 0.725 with 95% confidence interval (CI) 0.649-0.790 (p = 0.000), 0.804 with 95% CI 0.740-0.856 (p = 0.000) and 0.197 with 95% CI 0.096-0.361 (p = 0.000), respectively. The diagnostic yield for CRC, advanced adenoma and simple adenoma was 0.058 with 95% CI 0.050-0.068 (p = 0.000), 0.242 with 95% CI 0.188-0.306 (p = 0.000) and 0.147 with 95% CI 0.116-0.184 (p < 0.001), respectively.

Discussion

Compliance with diagnostic evaluation after a positive FOBT is still suboptimal. Therefore, measures to increase compliance need to be taken given the increased risk of CRC in these patients.

Colorectal Cancer Screening: Is Colonoscopy the Best Option?

Colorectal cancer is the second leading cause of cancer death in the United States. Prospective studies demonstrate that colorectal cancer screening reduces incidence and mortality, but uptake remains suboptimal. More than a third of age-eligible Americans are not up to date on screening. There are several available screening tests, which may cause primary care providers to ponder which is the best test. This article provides an overview of the available test options and the evidence for each; a summary of major guidelines; and a comparison of the two most widely used tests, colonoscopy and fecal immunochemical testing.

Contribution of the OC Sensor® immunoassay in comparison to the Hemoccult II® guaiac-test in organized colorectal cancer screening

Colorectal cancer (CRC) is a major cause of cancer-related death of worldwide with high incidence and mortality rate, accessible to a screening program in France, first with guaiac- based fecal occult blood test (g-FOBT) then with fecal immunochemical tests (FIT), since 2015, because of better accuracy. The aim of our study was to compare the characteristics of screen-detected lesions in two successive CRC screening campaigns, using two different tests (Hemoccult II^® and OC Sensor^®) in the department of Maine-et-Loire, and to precise the performance of these tests [participation rate, detection rates (DR), positive predictive value (PPV)]. Participants, invited by CAP SANTE 49, with polyps or cancer at the colonoscopy after a positive screening test between 01/01/2013 and 31/12/2016 were included. A guaiac-based fecal occult blood test (g-FOBT) was used from January 2013 to December 2014 and a FIT was used from June 2015 to December 2016). 2575 participants, 642 in g-FOBT group and 1933 in FIT group had lesions. Participation rate was not different between tests (p = 0.104), whereas DR and PPV were statistically higher in FIT for all lesions (2.61, 95% CI [2.50-2.70] vs 0.93, 95% CI [0.90-1.00], p < 0.0001 and 64.84, 95% CI [63.10-66.60], 50.00, 95% CI [47.30-52.70], p < 0.0001 respectively). FIT detects more precancerous lesions (adenomas, p < 0.001, and advanced adenomas, p < 0.001) than g-FOBT but g-FOBT detects more serrated polyps (p = 0.025). AAs were more in right colon in FIT than g-FOBT (p = 0.035). No different participation rate was detected between FIT and g-FOBT but DR and PPV of all lesions was higher with FIT.

Circulating tumor DNA in patients with colorectal adenomas: assessment of detectability and genetic heterogeneity

Improving early detection of colorectal cancer (CRC) is a key public health priority as adenomas and stage I cancer can be treated with minimally invasive procedures. Population screening strategies based on detection of occult blood in the feces have contributed to enhance detection rates of localized disease, but new approaches based on genetic analyses able to increase specificity and sensitivity could provide additional advantages compared to current screening methodologies. Recently, circulating cell-free DNA (cfDNA) has received much attention as a cancer biomarker for its ability to monitor the progression of advanced disease, predict tumor recurrence and reflect the complex genetic heterogeneity of cancers. Here, we tested whether analysis of cfDNA is a viable tool to enhance detection of colon adenomas. To address this, we assessed a cohort of patients with adenomas and healthy controls using droplet digital PCR (ddPCR) and mutation-specific assays targeted to trunk mutations. Additionally, we performed multiregional, targeted next-generation sequencing (NGS) of adenomas and unmasked extensive heterogeneity, affecting known drivers such as APC, KRAS and mismatch repair (MMR) genes. However, tumor-related mutations were undetectable in patients' plasma. Finally, we employed a preclinical mouse model of Apc-driven intestinal adenomas and confirmed the inability to identify tumor-related alterations via cfDNA, despite the enhanced disease burden displayed by this experimental cancer model. Therefore, we conclude that benign colon lesions display extensive genetic heterogeneity, that they are not prone to release DNA into the circulation and are unlikely to be reliably detected with liquid biopsies, at least with the current technologies.

Colorectal cancer screening for average-risk adults: 2018 guideline update from the American Cancer Society

In the United States, colorectal cancer (CRC) is the fourth most common cancer diagnosed among adults and the second leading cause of death from cancer. For this guideline update, the American Cancer Society (ACS) used an existing systematic evidence review of the CRC screening literature and microsimulation modeling analyses, including a new evaluation of the age to begin screening by race and sex and additional modeling that incorporates changes in US CRC incidence. Screening with any one of multiple options is associated with a significant reduction in CRC incidence through the detection and removal of adenomatous polyps and other precancerous lesions and with a reduction in mortality through incidence reduction and early detection of CRC. Results from modeling analyses identified efficient and model-recommendable strategies that started screening at age 45 years. The ACS Guideline Development Group applied the Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria in developing and rating the recommendations. The ACS recommends that adults aged 45 years and older with an average risk of CRC undergo regular screening with either a high-sensitivity stool-based test or a structural (visual) examination, depending on patient preference and test availability. As a part of the screening process, all positive results on noncolonoscopy screening tests should be followed up with timely colonoscopy. The recommendation to begin screening at age 45 years is a qualified recommendation. The recommendation for regular screening in adults aged 50 years and older is a strong recommendation. The ACS recommends (qualified recommendations) that: 1) average-risk adults in good health with a life expectancy of more than 10 years continue CRC screening through the age of 75 years; 2) clinicians individualize CRC screening decisions for individuals aged 76 through 85 years based on patient preferences, life expectancy, health status, and prior screening history; and 3) clinicians discourage individuals older than 85 years from continuing CRC screening. The options for CRC screening are: fecal immunochemical test annually; high-sensitivity, guaiac-based fecal occult blood test annually; multitarget stool DNA test every 3 years; colonoscopy every 10 years; computed tomography colonography every 5 years; and flexible sigmoidoscopy every 5 years. CA Cancer J Clin 2018;68:250-281. © 2018 American Cancer Society.

Malignant Melanoma Metastasizes to Colonic Polyp

Malignant tumors metastasizing to the colon has been observed rarely. Gastrointestinal metastasis can present as benign, unpigmented polyps endoscopically. Most patients do not display any symptoms, and if symptomatic, they usually present with gastrointestinal bleeding. For patients with the history of melanoma, histopathology of polyp can change or alter the course of management. This is a case of a 74-year-old male diagnosed with recurrent melanoma of left ear. Colon cancer screening found blood in his stool. Colonoscopy displayed to have three polyps, one polyp was found to be malignant melanoma. The patient was started on Pembrolizumab, and was tolerating immunotherapy well with no new complaints three months later.

Stool Based Testing for Colorectal Cancer: an Overview of Available Evidence

PURPOSE OF REVIEW

The goal of this review is to summarize stool-based testing for colorectal cancer (CRC). The key questions answered in this review were the advantages and limitations of each available stool-based test for CRC and to examine their comparative efficacy.

RECENT FINDINGS

Guaiac-based fecal occult blood testing (gFOBT) is no longer a relevant test for CRC screening. fecal immunochemical testing (FIT) tests, especially quantitative assays, are clearly a reliable stool-based test. Multitarget DNA (mtsDNA) stool testing may represent a viable option as well, although cost and test characteristics are yet fully defined. FIT and mtsDNA represent the options for stool-based CRC screening. In larger screening centers, quantitative FIT assays represent an attractive option for stool-based testing. Qualitative FIT has applicability in smaller centers. Although a large validation trial showed promising results for mtsDNA, further head-to-head trials with FIT will help define the ultimate role of mtsDNA. Ultimately, however, the best test for CRC screening is the one performed stool-based CRC screening as an initial or alternative option can increase participation in CRC screening.

Screening of colorectal cancer: present and future

INTRODUCTION

Colorectal cancer (CRC) is the third most common cancer in males and second in females, and the fourth most common cause of cancer death worldwide. Currently, about 60-70% of diagnosed cases in symptomatic patients are detected at an advanced stage of disease. Earlier stage detection through the use of screening strategies would allow for better outcomes in terms of reducing the disease burden. Areas covered: The aim of this paper is to review the current published evidence from literature which assesses the performance and effectiveness of different screening tests for the early detection of CRC. Expert commentary: Adequate screening strategies can reduce CRC incidence and mortality. In the last few decades, several tests have been proposed for CRC screening. To date, there is still insufficient evidence to identify which approach is definitively superior, and no screening strategy for CRC can therefore be defined as universally ideal. The best strategy would be the one that can be economically viable and to which the patient can adhere best to over time. The latest guidelines suggest colonoscopy every 10 years or annual fecal immuno-chemical test (FIT) for people with normal risk, while for individuals with high risk or hereditary syndromes specific recommendations are provided.

Effect of Physician Notification Regarding Nonadherence to Colorectal Cancer Screening on Patient Participation in Fecal Immunochemical Test Cancer Screening: A Randomized Clinical Trial

IMPORTANCE

Increasing participation in fecal screening tests is a major challenge in countries that have implemented colorectal cancer (CRC) screening programs.

OBJECTIVE

To determine whether providing general practitioners (GPs) a list of patients who are nonadherent to CRC screening enhances patient participation in fecal immunochemical testing (FIT).

DESIGN, SETTING, AND PARTICIPANTS

A 3-group, cluster-randomized study was conducted from July 14, 2015, to July 14, 2016, on the west coast of France, with GPs in 801 practices participating and involving adult patients (50-74 years) who were at average risk of CRC and not up-to-date with CRC screening. The final follow-up date was July 14, 2016.

INTERVENTIONS

General practitioners were randomly assigned to 1 of 3 groups: 496 received a list of patients who had not undergone CRC screening (patient-specific reminders group, 10 476 patients), 495 received a letter describing region-specific CRC screening adherence rates (generic reminders group, 10 606 patients), and 455 did not receive any reminders (usual care group, 10 147 patients).

MAIN OUTCOMES AND MEASURES

The primary end point was patient participation in CRC screening 1 year after the intervention.

RESULTS

Among 1482 randomized GPs (mean age, 53.4 years; 576 women [38.9%]), 1446 participated; of the 33 044 patients of these GPs (mean age, 59.7 years; 17 949 women [54.3%]), follow-up at 1 year was available for 31 229 (94.5%). At 1 year, 24.8% (95% CI, 23.4%-26.2%) of patients in the specific reminders group, 21.7% (95% CI, 20.5%-22.8%) in the generic reminders group, and 20.6% (95% CI, 19.3%-21.8%) in the usual care group participated in the FIT screening. The between-group differences were 3.1% (95% CI, 1.3%-5.0%) for the patient-specific reminders group vs the generic reminders group, 4.2% (95% CI, 2.3%-6.2%) for the patient-specific reminders group vs the usual care group, and 1.1% (95% CI, -0.6% to 2.8%) for generic reminders group vs the usual care group.

CONCLUSIONS AND RELEVANCE

Providing French GPs caring for adults at average risk of CRC with a list of their patients who were not up-to-date with their CRC screening resulted in a small but significant increase in patient participation in FIT screening at 1 year compared with patients who received usual care. Providing GPs with generic reminders about regional rates of CRC screening did not increase screening rates compared with usual care.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02515344.

Comparative Evaluation of Preliminary Screening Methods for Colorectal Cancer in a Mass Program

BACKGROUND

The fecal immunochemical test (FIT) has been widely used in preliminary screening for colorectal cancer (CRC). The high-risk factor questionnaire (HRFQ) and quantitative risk-assessment method (QRAM) are recommended for estimating the risk of CRC qualitatively and quantitatively in China.

AIM

We aimed to prospectively compare the diagnostic values of CRC preliminary screening methods to identify which method is preferable as a screening strategy.

METHODS

Individuals aged 40-74 years old were enrolled in a mass CRC screening program from January 1, 2007 to December 31, 2014, in Jiashan County, Zhejiang Province, China. FIT of two stool specimens at 1-week intervals was performed by laboratory personnel and face-to-face interviews were conducted by trained investigators. Screening data in the program were linked to a CRC surveillance and registry system, and CRC cases reported in the system were regarded as true patients.

RESULTS

A total of 96,043 subjects were included. The sensitivity and specificity of FIT for detecting CRC cases were 75.49% (95% CI 69.84-80.39) and 90.36% (95% CI 90.17-90.54), respectively. QRAM was more sensitive (p < 0.001) and less specific (p < 0.001) than HRFQ. The sensitivity and specificity of FIT along with HRFQ were 86.56% (95% CI 81.81-90.22) and 81.37% (95% CI 81.12-81.62), and those of FIT along with QRAM were 88.93% (95% CI 84.47-92.23) and 73.95% (95% CI 73.67-74.23).

CONCLUSIONS

Our findings suggest that CRC preliminary screening with FIT and QRAM in parallel has high sensitivity and satisfactory specificity, and is a useful strategy in mass screening programs.

Lifestyle predictors for non-participation and outcome in the second round of faecal immunochemical test in colorectal cancer screening

BACKGROUND

To reduce colorectal cancer (CRC) mortality through population-based screening programmes using faecal tests, it is important that individuals continue to participate in the repeated rounds of screening. We aimed to identify lifestyle predictors for discontinuation of faecal immunochemical test (FIT) screening after the first round, as well as lifestyle predictors for colorectal neoplasia detected in the second-round FIT screening.

METHODS

In this longitudinal study, we invited 6959 individuals aged 50-74 years from south-east Norway for a first round of FIT screening and to complete a self-reported lifestyle questionnaire on demographic factors, body mass index (BMI, kg m-2), smoking habits, physical activity, consumption of alcohol and dietary items. Two years later, we estimated the associations between these factors, non-participation and screening results in the second round of FIT screening using adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Of the 3114 responders to the questionnaire who completed the first-round FIT and who were invited to participate in second-round FIT screening, 540 (17%) did not participate. The OR and (95% CI) for discontinuation of FIT screening after the first round was 1.61 (1.24-2.10) for current smoking compared with non-smoking; 2.01 (1.25-3.24) for BMI⩾35 kg m-2 compared with BMI 16.9-24.9 kg m-2 and 0.70 (0.52-0.94) for physical activity in the third quartile vs the first. Among participants, smoking, high BMI and high alcohol consumption were associated with an increased odds of detecting colorectal neoplasia (n=107).

CONCLUSIONS

These results may indicate that Norwegian FIT screening participants who discontinue after the first round have lifestyle behaviours associated with increased risk of CRC.

Evaluation of the colorectal cancer screening Programme in the Basque Country (Spain) and its effectiveness based on the Miscan-colon model

Abstract

The population-based Basque Colorectal Cancer (CRC) Screening Programme started in 2009 with a biennial immunochemical quantitative test (FIT) biennial and colonoscopy under sedation in positive cases. The population target of 586,700 residents was from 50 to 69 years old and the total coverage was reached at the beginning of 2014. The aim of our study was to determine possible scenarios in terms of incidence, mortality and reduction of Life-years-Lost (L-y-L) in the medium and long term of CRC.

Methods

Invitations were sent out by the Programme from 2009 to 2014, with combined organizational strategies. Simulation was done by MISCAN-colon (Microsimulation Screening Analysis) over 30 years comparing the results of screening vs no-screening, taking the population-based Cancer Registry into account. Lifetime population and real data from the Programme were used from 2008 to 2012. The model was run differentially for men and women.

Results

924,416 invitations were sent out from 2009 to 2014. The average participation rate was 68.4%, CRC detection rate was 3.4% and the Advanced Adenoma detection rate was 24.0‰, with differences observed in sex and age. Future scenarios showed a higher decrease of incidence (17.2% vs 14.7%), mortality (28.1% vs 22.4%) and L-y-L (22.6% vs 18.4%) in men than women in 2030.

Conclusions

The Basque Country CRC Programme results are aligned to its strategy and comparable to other programmes. MISCAN model was found to be a useful tool to predict the benefits of the programme in the future. The effectiveness of the Programme has not been formally established as case control studies are required to determine long term benefits from the screening strategy.

Diagnostic Accuracy of Fecal Immunochemical Test in Patients at Increased Risk for Colorectal Cancer: A Meta-analysis

IMPORTANCE

The potential role of the fecal immunochemical test (FIT) for screening patients at increased risk for colorectal cancer (CRC) has not yet been elucidated.

OBJECTIVE

To assess the diagnostic accuracy of FIT for CRC or advanced neoplasia (AN) in asymptomatic patients at above-average risk.

DATA SOURCES

MEDLINE, EMBASE, Cochrane Library, and gray literature sources through August 2016.

STUDY SELECTION

Diagnostic studies evaluating the accuracy of FIT for CRC or AN in patients with a personal or familial history of CRC using colonoscopy as the reference standard.

DATA EXTRACTION AND SYNTHESIS

Two authors (A.K. and P.P.) independently extracted data and evaluated study quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, and evaluated the quality of the body of evidence by means of GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Hierarchical models were used to synthesize available evidence.

MAIN OUTCOMES AND MEASURES

The primary outcome was the diagnostic performance of FIT for detecting CRC or AN.

RESULTS

We included 12 studies (6204 participants). Seven studies were deemed at high or unclear risk of bias. The average sensitivity of FIT for CRC was 93% (95% CI, 53%-99%), and the average specificity was 91% (95% CI, 89%-92%), yielding a positive likelihood ratio (LR+) of 10.30 (CI 7.7-13.9) and a negative likelihood ratio (LR-) of 0.08 (95% CI, 0.01-0.75) (GRADE: very low). The average sensitivity of FIT for AN was 48% (95% CI, 39%-57%); and the average specificity was 93% (95% CI, 91%-94%), yielding an LR+ of 6.55 (95% CI, 5.0-8.5) and an LR- of 0.57 (95% CI, 0.48-0.67) (GRADE: very low). Subgroup analyses indicated that FIT cutoff values between 15- and 25-μg/g feces provided the best combination of sensitivity and specificity for the diagnosis of CRC (93% and 94%, respectively). Quantitative and 1-sample FIT showed adequate test performance, but data on other FIT brands and multiple samples were insufficient.

CONCLUSIONS AND RELEVANCE

The FIT has high overall diagnostic accuracy for CRC but moderate accuracy for AN in patients at above-average personal or familial risk. Heterogeneity and wide confidence intervals limit the trustworthiness of our findings.

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.

Clinical impact of the immunochemical fecal occult blood test for colorectal cancer screening in Brazil

Background

Colorectal cancer (CRC) screening programs based on the fecal occult blood test (FOBT) reduce CRC mortality. We carried out an observational prospective study to determine the accuracy of immunochemical FOBTs for the detection of CRC in individuals at average risk for the disease.

Methods

This population-based study was performed between April 2015 and January 2016 in two gastroenterology referral centers in Southern Brazil. It included 1039 average-risk volunteers aged 50-75 years who were symptom-free for colonic disease. Participants underwent OC-Light immunochemical fecal occult blood test (i-FOBT, EIKEN chemical Co., Tokyo, Japan) as well as screening colonoscopy.

Results

Nine hundred forty-eight (91.2%) of the 1039 participants completed and returned the i-FOBT (95% confidence interval [CI] 89.4-92.9). Among the 73 participants with a positive i-FOBT who underwent colonoscopy, advanced CRC was detected in 9 (12.3%). Two (2.7%) early CRCs, 7 (9.5%) high-grade dysplasia adenomas and 25 (34.2%) low-grade dysplasia adenomas were also diagnosed. Among the 243 negative i-FOBT cases who underwent colonoscopy, one (0.4%) advanced CRC and 91 (37.6%) low-grade dysplasia adenomas were detected. The detection rate of CRC considering the whole screened population (n=1039) was 1.05% (11/1039).

Conclusions

The i-FOBT test in the CRC screening programs in Brazil showed a high compliance and high detection rates for cancers and high-risk adenomas. The i-FOBT test is feasible for CRC screening in an average-risk population.

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

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

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

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

Current noninvasive tests for colorectal cancer screening: An overview of colorectal cancer screening tests

Colorectal cancer (CRC) has become the third most common cancer in the world. Screening has been shown to be an effective way to identify early CRC and precancerous lesions, and to reduce its morbidity and mortality. Several types of noninvasive tests have been developed for CRC screening, including the fecal occult blood test (FOBT), the fecal immunochemical test (FIT), the fecal-based DNA test and the blood-based DNA test (the SEPT9 assay). FIT has replaced FOBT and become the major screening test due to high sensitivity, specificity and low costs. The fecal DNA test exhibited higher sensitivity than FIT but its current cost is high for a screening assay. The SEPT9 assay showed good compliance while its performance in screening needs further improvements. These tests exhibited distinct sensitivity and specificity in screening for CRC and adenoma. This article will focus on the performance of the current noninvasive in vitro diagnostic tests that have been used for CRC screening. The merits and drawbacks for these screening methods will also be compared regarding the techniques, usage and costs. We hope this review can provide suggestions for both the public and clinicians in choosing the appropriate method for CRC screening.

Fecal immunochemical test for colorectal cancer from a prospective cohort with 513,283 individuals: Providing detailed number needed to scope (NNS) before colonoscopy

The fecal immunochemical test (FIT) is underutilized, in part, because its benefits have not been fully understood. We assessed the relationship of FIT values with cancer incidence and mortality, and explored how repeated administrations of FIT could aid clinicians. A cohort with 513,283 adults in Taiwan participated in a screening program between 1994 and the end of 2007. Colorectal cancer was identified from National Cancer Registry and not from colonoscopy. Positive FIT was FIT ≥ 100 ng/mL. Number needed to scope (NNS) to identify 1 cancer by different FIT values was calculated for the study time. Only 4% of subjects had FIT ≥ 100 ng/mL but contributed 40% of cancer cases, leading to a NNS of 25 for finding 1 in this group. However, within the same FIT ≥ 100 ng/mL, NNS was different by age: 10 for age 60 to 69 years, 42 for age 40 to 49 years, and 156 for age 20 to 39 years. Furthermore, within the same age, NNS was different by FIT values, for instance, 66 for FIT 100 to 199 ng/mL and 12 for FIT 600 to 799 ng/mL, a difference of 5-fold for age 50 to 59 years. The dose-response relationship of FIT can facilitate consultation regarding the need for colonoscopy by providing a quantitative NNS for cancer risk, an index easily understood by patients. Our conclusion made use of (a) age-dependent and (b) quantitative interpretation of FIT values. This single cutpoint practice obliterates a large amount of valuable cancer risk information available to patients.

Colorectal Cancer Screening in Average Risk Populations: Evidence Summary

Introduction. The objectives of this systematic review were to evaluate the evidence for different CRC screening tests and to determine the most appropriate ages of initiation and cessation for CRC screening and the most appropriate screening intervals for selected CRC screening tests in people at average risk for CRC. Methods. Electronic databases were searched for studies that addressed the research objectives. Meta-analyses were conducted with clinically homogenous trials. A working group reviewed the evidence to develop conclusions. Results. Thirty RCTs and 29 observational studies were included. Flexible sigmoidoscopy (FS) prevented CRC and led to the largest reduction in CRC mortality with a smaller but significant reduction in CRC mortality with the use of guaiac fecal occult blood tests (gFOBTs). There was insufficient or low quality evidence to support the use of other screening tests, including colonoscopy, as well as changing the ages of initiation and cessation for CRC screening with gFOBTs in Ontario. Either annual or biennial screening using gFOBT reduces CRC-related mortality. Conclusion. The evidentiary base supports the use of FS or FOBT (either annual or biennial) to screen patients at average risk for CRC. This work will guide the development of the provincial CRC screening program.

Estimation of Benefits, Burden, and Harms of Colorectal Cancer Screening Strategies: Modeling Study for the US Preventive Services Task Force

IMPORTANCE

The US Preventive Services Task Force (USPSTF) is updating its 2008 colorectal cancer (CRC) screening recommendations.

OBJECTIVE

To inform the USPSTF by modeling the benefits, burden, and harms of CRC screening strategies; estimating the optimal ages to begin and end screening; and identifying a set of model-recommendable strategies that provide similar life-years gained (LYG) and a comparable balance between LYG and screening burden.

DESIGN, SETTING, AND PARTICIPANTS

Comparative modeling with 3 microsimulation models of a hypothetical cohort of previously unscreened US 40-year-olds with no prior CRC diagnosis.

EXPOSURES

Screening with sensitive guaiac-based fecal occult blood testing, fecal immunochemical testing (FIT), multitarget stool DNA testing, flexible sigmoidoscopy with or without stool testing, computed tomographic colonography (CTC), or colonoscopy starting at age 45, 50, or 55 years and ending at age 75, 80, or 85 years. Screening intervals varied by modality. Full adherence for all strategies was assumed.

MAIN OUTCOMES AND MEASURES

Life-years gained compared with no screening (benefit), lifetime number of colonoscopies required (burden), lifetime number of colonoscopy complications (harms), and ratios of incremental burden and benefit (efficiency ratios) per 1000 40-year-olds.

RESULTS

The screening strategies provided LYG in the range of 152 to 313 per 1000 40-year-olds. Lifetime colonoscopy burden per 1000 persons ranged from fewer than 900 (FIT every 3 years from ages 55-75 years) to more than 7500 (colonoscopy screening every 5 years from ages 45-85 years). Harm from screening was at most 23 complications per 1000 persons screened. Strategies with screening beginning at age 50 years generally provided more LYG as well as more additional LYG per additional colonoscopy than strategies with screening beginning at age 55 years. There were limited empirical data to support a start age of 45 years. For persons adequately screened up to age 75 years, additional screening yielded small increases in LYG relative to the increase in colonoscopy burden. With screening from ages 50 to 75 years, 4 strategies yielded a comparable balance of screening burden and similar LYG (median LYG per 1000 across the models): colonoscopy every 10 years (270 LYG); sigmoidoscopy every 10 years with annual FIT (256 LYG); CTC every 5 years (248 LYG); and annual FIT (244 LYG).

CONCLUSIONS AND RELEVANCE

In this microsimulation modeling study of a previously unscreened population undergoing CRC screening that assumed 100% adherence, the strategies of colonoscopy every 10 years, annual FIT, sigmoidoscopy every 10 years with annual FIT, and CTC every 5 years performed from ages 50 through 75 years provided similar LYG and a comparable balance of benefit and screening burden.

Stool Investigations for Colorectal Cancer Screening: From Occult Blood Test to DNA Analysis

PURPOSE

We report an update of current methods for colorectal cancer (CRC) screening based on fecal sample analysis.

METHODS

A systematic review of the literature was performed in MEDLINE, EMBASE, and Science Direct electronic databases.

RESULTS

Blood in the stools is the first and most used strategy. Fecal occult blood test (FOBT) and fecal immunochemical test (FIT) are the main methods. Both are economic, easy to perform with high specificity, and low sensitivity. Based on CRC multi-step process with genetic and epigenetic alterations in large bowel cell DNA, single mutations or panels of alterations have been detected. These tests have the advantage of a marked improvement of the sensitivity when compared to fecal blood. However, high costs, poor availability, and correct choice of marker panel represent the major limits. A specific sDNA panel including aberrantly methylated BMP3 and NDRG4 promoter regions, mutant k-ras and β-actin (a reference gene for human DNA quantity), and an immunochemical assay for human hemoglobin has been recently approved by Food and Drug Administration. Novel promising biomarkers for CRC screening are represented by microRNAs (miRNAs), a group of 18-25 nucleotide non-coding RNA molecules that regulate gene expression. Reports on these fecal biomarkers are case-control studies, and each of them evaluates single miRNAs or multi-target panels. On the other hand, some fecal proteins have been studied as possible CRC screening markers, even though they demonstrated poor results. Finally, alterations of estrogen receptor-beta (i.e., dramatic reduction in the early stage of CRC) have been demonstrated in tissue samples.

CONCLUSIONS

Specific investigations are warranted in order to add further noninvasive markers to the panel of CRC screening tools.

Screening for Colorectal Cancer: A Systematic Review and Meta-Analysis

To evaluate the effectiveness of colorectal cancer (CRC) screening in asymptomatic adults. A search was conducted of the Medline, Embase, and the Cochrane Library databases. A targeted search of PubMed was conducted for on-topic randomized controlled trials (RCTs). Meta-analysis across 4 RCTs for guaiac fecal occult blood testing (gFOBT) and flexible sigmoidoscopy (FS) screening showed a reduction of 18% (risk ratio [RR], 0.82; 95% CI [CI], 0.73-0.92) and 26% (RR, 0.74; 95% CI, 0.67-0.83) in CRC mortality for the screening group compared to controls, respectively. The number needed to screen (NNS) were 377 (95% CI, 249-887) and 864 (95% CI, 672-1266) for gFOBT and FS screening, respectively. A reduction of 8% and 27% in incidence of late-stage CRC was also observed for gFOBT and FS screening, respectively, but both had no significant effect on all-cause mortality. A single RCT found that screening with immunochemical fecal occult blood test (iFOBT) had no significant impact on CRC mortality (RR, 0.88; 95% CI, 0.72-1.07). Screening with FS has potential harms such as perforation, major and minor bleeding, and death from the procedure or from follow-up colonoscopy. gFOBT and FS screening reduce CRC mortality and incidence of late-stage disease. The absolute effect and NNS were much more favorable for older adults (≥ 60 years), suggesting that a targeted screening approach may avoid exposing younger adults to the harms of CRC screening, from which they are unlikely to derive any significant benefit. Although there is insufficient RCT evidence on the impact of iFOBT on mortality outcomes. compared to gFOBT, this test showed higher sensitivity and comparable specificity, indicating the need to update and reevaluate the evidence in light of future high-quality research. The protocol for this systematic review have been published with PROSPERO 2014: CRD42014009777.

Colorectal Cancer Screening Programme in Spain: Results of Key Performance Indicators After Five Rounds (2000-2012)

Effective quality assurance is essential in any screening programme. This article provides a unique insight into key quality indicators of five rounds of the first population-based colorectal cancer screening programme implemented in Spain (2000–2012), providing the results according to the type of screening (prevalent or first screen and incident or subsequent screen) and test (guaiac or immunochemical). The total crude participation rate increased from 17.2% (11,011) in the first round to 35.9% (22,988) in the last one. Rescreening rate was very high (88.6% in the fifth round). Positivity rate was superior with the faecal immunochemical test (6.2%) than with the guaiac-based test (0.7%) (p < 0.0001) and detection rates were also better with the immunochemical test. The most significant rise in detection rate was observed for high risk adenoma in men (45.5 per 1,000 screened). Most cancers were diagnosed at an early stage (61.4%) and there was a statistically significant difference between those detected in first or subsequent screening (52.6% and 70.0% respectively; p = 0.024). The availability of these results substantially improves data comparisons and the exchange of experience between screening programmes.

A Blood Test for Methylated BCAT1 and IKZF1 vs. a Fecal Immunochemical Test for Detection of Colorectal Neoplasia

Objectives:

To compare the performance of a new blood test for colorectal cancer (CRC) to an established fecal immunochemical test (FIT) in a study population with the full range of neoplastic and non-neoplastic pathologies encountered in the colon and rectum.

Methods:

Volunteers were asked to complete a FIT prior to colonoscopy. Blood was collected after bowel preparation but prior to colonoscopy, and plasma was assayed for the presence of methylated BCAT1 and IKZF1 DNA using a multiplex real-time PCR assay. Sensitivity and specificity estimates for the blood test were calculated from true- and false-positive rates for neoplasia and compared with FIT at a range of fecal hemoglobin (Hb) concentration positivity thresholds.

Results:

In total, 1,381 volunteers (median age 64 years; 49% male) completed both tests prior to colonoscopy. Estimated sensitivity of the BCAT1/IKZF1 blood test for CRC was 62% (41/66; 95% confidence interval 49–74%) with a specificity of 92% (1207/1315; 90–93%). FIT returned the same specificity at a cutoff of 60 μg Hb/g, at which its corresponding sensitivity for cancer was 64% (42/66; 51–75%). In the range of commonly used FIT cutoffs, respective cancer sensitivity and specificity estimates with FIT were: 59% (46–71%) and 93% (92–95%) at 80 μg Hb/g, and 79% (67–88%) and 81% (78–83%) at 10 μg Hb/g. Although estimated sensitivities were not significantly different between the two tests for any stage of cancer, FIT showed a significantly higher sensitivity for advanced adenoma at the lower cutoffs. Specificity of FIT, but not of the BCAT1/IKZF1 blood test, deteriorated substantially in people with overt blood in the feces. When combining FIT (cutoff 10 μg Hb/g) with the BCAT1/IKZF1 blood test, sensitivity for cancer was 89% (79–96%) at 74% (72–77%) specificity.

Conclusions:

A test based on detection of methylated BCAT1/IKZF1 DNA in blood has comparable sensitivity but better specificity for CRC than FIT at the commonly used positivity threshold of 10 μg Hb/g. Further evaluation of the new test relative to FIT in the population screening context is now required to fully understand the potential advantages and disadvantages of these biomarkers in screening.

European Code against Cancer, 4th Edition: Cancer screening

In order to update the previous version of the European Code against Cancer and formulate evidence-based recommendations, a systematic search of the literature was performed according to the methodology agreed by the Code Working Groups. Based on the review, the 4th edition of the European Code against Cancer recommends: "Take part in organized cancer screening programmes for: Bowel cancer (men and women); Breast cancer (women); Cervical cancer (women)." Organized screening programs are preferable because they provide better conditions to ensure that the Guidelines for Quality Assurance in Screening are followed in order to achieve the greatest benefit with the least harm. Screening is recommended only for those cancers where a demonstrated life-saving effect substantially outweighs the potential harm of examining very large numbers of people who may otherwise never have, or suffer from, these cancers, and when an adequate quality of the screening is achieved. EU citizens are recommended to participate in cancer screening each time an invitation from the national or regional screening program is received and after having read the information materials provided and carefully considered the potential benefits and harms of screening. Screening programs in the European Union vary with respect to the age groups invited and to the interval between invitations, depending on each country's cancer burden, local resources, and the type of screening test used For colorectal cancer, most programs in the EU invite men and women starting at the age of 50-60 years, and from then on every 2 years if the screening test is the guaiac-based fecal occult blood test or fecal immunochemical test, or every 10 years or more if the screening test is flexible sigmoidoscopy or total colonoscopy. Most programs continue sending invitations to screening up to the age of 70-75 years. For breast cancer, most programs in the EU invite women starting at the age of 50 years, and not before the age of 40 years, and from then on every 2 years until the age of 70-75 years. For cervical cancer, if cytology (Pap) testing is used for screening, most programs in the EU invite women starting at the age of 25-30 years and from then on every 3 or 5 years. If human papillomavirus testing is used for screening, most women are invited starting at the age of 35 years (usually not before age 30 years) and from then on every 5 years or more. Irrespective of the test used, women continue participating in screening until the age of 60 or 65 years, and continue beyond this age unless the most recent test results are normal.

Comparative detection of aberrantly methylated DNA in preoperative and postoperative stool from patients with colorectal cancers

BACKGROUND

Early detection of colorectal cancer (CRC) is crucial to reducing tumor-related mortality. Evaluating aberrantly methylated DNA in stool is promising for CRC screening. However, DNA methylation in the colonic epithelium of background mucosa may compromise stool DNA (sDNA) test results. Thus, we compared aberrant methylation of cancer-related genes in preoperative and postoperative sDNA, with the aim of demonstrating that a cancer-specific methylated allele in sDNA originates from CRCs.

METHODS

Patients who were to undergo CRC resection in Kyushu University Hospital during 2003-2010 were prospectively enrolled. Preoperative (pre) stool samples from 54 patients, postoperative (post) samples from 52 of the patients and tumor samples were collected. Aberrant promoter methylation of CDH4 and GATA5 was assessed in the primary tumors by methylation-specific polymerase chain reaction (MSP) and in stool samples by real-time MSP.

REULTS

Aberrant methylation of CDH4 and/or GATA5 was detected in 45 of CRC tissue samples (83.3%) and identified in 23 pre sDNA samples (42.3%) from CRC patients. Aberrant methylation was not found in pre sDNA obtained from CRC patients without aberrant methylation of these genes or in post sDNA in any patient. The detection rate of methylated alleles did not correlate with depth of invasion or tumor stage.

CONCLUSION

Our findings demonstrate that aberrantly methylated alleles identified in sDNA originate from CRCs. Although tumor-specific aberrant methylation is found in sDNA from patients harboring early and advanced CRC throughout the colon and rectum, the sensitivity of this test needs to be improved for early detection of CRC.

Colorectal cancer screening: a global overview of existing programmes

Colorectal cancer (CRC) ranks third among the most commonly diagnosed cancers worldwide, with wide geographical variation in incidence and mortality across the world. Despite proof that screening can decrease CRC incidence and mortality, CRC screening is only offered to a small proportion of the target population worldwide. Throughout the world there are widespread differences in CRC screening implementation status and strategy. Differences can be attributed to geographical variation in CRC incidence, economic resources, healthcare structure and infrastructure to support screening such as the ability to identify the target population at risk and cancer registry availability. This review highlights issues to consider when implementing a CRC screening programme and gives a worldwide overview of CRC burden and the current status of screening programmes, with focus on international differences.

Definition and taxonomy of interval colorectal cancers: a proposal for standardising nomenclature

OBJECTIVE

Interval colorectal cancers (interval CRCs), that is, cancers occurring after a negative screening test or examination, are an important indicator of the quality and effectiveness of CRC screening and surveillance. In order to compare incidence rates of interval CRCs across screening programmes, a standardised definition is required. Our goal was to develop an internationally applicable definition and taxonomy for reporting on interval CRCs.

DESIGN

Using a modified Delphi process to achieve consensus, the Expert Working Group on interval CRC of the Colorectal Cancer Screening Committee of the World Endoscopy Organization developed a nomenclature for defining and characterising interval CRCs.

RESULTS

We define an interval CRC as a "colorectal cancer diagnosed after a screening or surveillance exam in which no cancer is detected, and before the date of the next recommended exam". Guidelines and principles for describing and reporting on interval CRCs are provided, and clinical scenarios to demonstrate the practical application of the nomenclature are presented.

CONCLUSIONS

The Working Group on interval CRC of the World Endoscopy Organization endorses adoption of this standardised nomenclature. A standardised nomenclature will facilitate benchmarking and comparison of interval CRC rates across programmes and regions.