The Global Paradigm Shift in Screening for Colorectal Cancer

Colon cancer screening: What to choose?

Colorectal cancer is one of the predominant tumors in the world, primarily generated by a progression from polyp to cancer which can last several years, giving a great opportunity to the scientific community for its prevention by screening programs that can be done with invasive and non-invasive tests. In this issue, Lopes et al show us an excellent review of screening, its options, its advantages and disadvantages.

Identification and validation of the surface proteins FIBG, PDGF-β, and TGF-β on serum extracellular vesicles for non-invasive detection of colorectal cancer: experimental study

OBJECTIVES

The absence of non-invasive biomarkers for the early diagnosis of colorectal cancer (CRC) has contributed to poor prognosis. Extracellular vesicles (EVs) have emerged as promising candidates for cancer monitoring using liquid biopsy. However, the complexity of EVs isolation procedures and the absence of clear targets for detecting serum-derived EVs have hindered the clinical application of EVs in early CRC diagnosis.

METHODS

In the discovery phase, we conducted a comprehensive 4D-DIA proteomic analysis of serum-derived EVs samples from 37 individuals, performing an initial screening of EVs surface proteins. In the technical validation phase, we developed an extraction-free CRC-EVArray microarray to assess the expression of these potential EVs surface proteins in a multi-centre study comprising 404 individuals. In the application phase, the authors evaluated the diagnostic efficacy of the CRC-EVArray model based on machine-learning algorithms.

RESULTS

Through 4D-DIA proteomic analysis, the authors identified seven potential EVs surface proteins showing significantly differential expression in CRC patients compared to healthy controls. Utilizing our developed high-throughput CRC-EVArray microarray, we further confirmed the differential expression of three EVs surface proteins, FIBG, PDGF-β and TGF-β, in a large sample population. Moreover, we established an optimal CRC-EVArray model using the NNET algorithm, demonstrating superior diagnostic efficacy with an area under the curve (AUC) of 0.882 in the train set and 0.937 in the test set. Additionally, we predicted the functions and potential origins of these EVs-derived proteins through a series of multi-omics approaches.

CONCLUSIONS

Our systematic exploration of surface protein expression profiles on serum-derived EVs has identified FIBG, PDGF-β, and TGF-β as novel diagnostic biomarkers for CRC. The development of CRC-EVArray diagnostic model based on these findings provided an effective tool for the large-scale CRC screening, thus facilitating its translation into clinical practice.

Screening for liver fibrosis: lessons from colorectal and lung cancer screening

Many countries have incorporated population screening programmes for cancer, such as colorectal and lung cancer, into their health-care systems. Cirrhosis is more prevalent than colorectal cancer and has a comparable age-standardized mortality rate to lung cancer. Despite this fact, there are no screening programmes in place for early detection of liver fibrosis, the precursor of cirrhosis. In this Perspective, we use insights from colorectal and lung cancer screening to explore the benefits, challenges, implementation strategies and pathways for future liver fibrosis screening initiatives. Several non-invasive methods and referral pathways for early identification of liver fibrosis exist, but in addition to accurate detection, screening programmes must also be cost-effective and demonstrate benefit through a reduction in liver-related mortality. Randomized controlled trials are needed to confirm this. Future randomized screening trials should evaluate not only the screening tests, but also interventions used to halt disease progression in individuals identified through screening.

Colonoscopy vs the Fecal Immunochemical Test: Which is Best?

Although there is no debate around the effectiveness of colorectal cancer screening in reducing disease burden, there remains a question regarding the most effective and cost-effective screening modality. Current United States guidelines present a panel of options that include the 2 most commonly used modalities, colonoscopy and stool testing with the fecal immunochemical test (FIT). Large-scale comparative effectiveness trials comparing colonoscopy and FIT for colorectal cancer outcomes are underway, but results are not yet available. This review will separately state the "best case" for FIT and colonoscopy as the screening tool of first choice. In addition, the review will examine these modalities from a health economics perspective to provide the reader further context about the relative advantages of these commonly used tests.

Systematic scoping review: Use of the faecal immunochemical test residual buffer to enhance colorectal cancer screening

BACKGROUND

The faecal immunochemical test (FIT) is an inexpensive and convenient modality to screen for colorectal cancer. However, its one-time sensitivity for detecting colorectal cancer and cancer precursors is limited. There is growing interest in using the non-haemoglobin contents of FIT residual buffer to enhance colonic neoplasia detection.

AIM

To establish from the literature a framework to catalogue candidate biomarkers within FIT residual buffer for non-invasive colorectal cancer screening.

METHODS

The search strategy evaluated PubMed, Scopus, Web of Science, Embase, and Google Scholar for publications through 25 October 2023, with search terms including FIT, buffer, OC-sensor, biomarkers, microbiome, microRNA (miR), colon, rectum, screening, neoplasm, and early detection. Studies employing home-based collection samples using quantitative FIT first processed for haemoglobin were included. One author reviewed all articles; a second author completed a 20% full-text audit to ensure adherence to eligibility criteria.

RESULTS

A broad search yielded 1669 studies and application of eligibility criteria identified 18 relevant studies. Multiple protein, DNA/RNA, and microbiome biomarkers (notably haptoglobin, miR-16, miR-27a-3p, miR-92a, miR-148a-3p, miR-223, miR-421, let-7b-5p, and Tyzzerella 4) were associated with colorectal neoplasia. Furthermore, studies highlighted the short-term stability of biomarkers for clinical use and long-term stability for research purposes.

CONCLUSIONS

This scoping review summarises the framework and progress of research on stability of biomarkers in FIT residual buffer and their associations with colorectal neoplasia to guide opportunities for further confirmatory studies to enhance colorectal cancer screening.

Stool Glycoproteomics Signatures of Pre-Cancerous Lesions and Colorectal Cancer

Colorectal cancer (CRC) screening relies primarily on stool analysis to identify occult blood. However, its sensitivity for detecting precancerous lesions is limited, requiring the development of new tools to improve CRC screening. Carcinogenesis involves significant alterations in mucosal epithelium glycocalyx that decisively contribute to disease progression. Building on this knowledge, we examined patient series comprehending premalignant lesions, colorectal tumors, and healthy controls for the T-antigen-a short-chain O-glycosylation of proteins considered a surrogate marker of malignancy in multiple solid cancers. We found the T-antigen in the secretions of dysplastic lesions as well as in cancer. In CRC, T-antigen expression was associated with the presence of distant metastases. In parallel, we analyzed a broad number of stools from individuals who underwent colonoscopy, which showed high T expressions in high-grade dysplasia and carcinomas. Employing mass spectrometry-based lectin-affinity enrichment, we identified a total of 262 proteins, 67% of which potentially exhibited altered glycosylation patterns associated with cancer and advanced pre-cancerous lesions. Also, we found that the stool (glyco)proteome of pre-cancerous lesions is enriched for protein species involved in key biological processes linked to humoral and innate immune responses. This study offers a thorough analysis of the stool glycoproteome, laying the groundwork for harnessing glycosylation alterations to improve non-invasive cancer detection.

Cumulative Incidence, Risk Factors, and Overall Survival of Disease Recurrence after Curative Resection of Stage II-III Colorectal Cancer: A Population-based Study

Real-world data are necessitated to counsel patients about the risk for recurrent disease after curative treatment of colorectal cancer. This study provided a population-based overview of the epidemiology of recurrent disease in patients with surgically resected stage II/III colorectal cancer.Patients diagnosed with stage II/III primary colorectal cancer between July and December 2015 were selected from the Netherlands Cancer Registry (N = 3,762). Cumulative incidence of recurrent disease was estimated, and multivariable competing risk regression was used to identify risk factors for recurrent disease in patients with primary colon and rectal cancer. Moreover, overall survival (OS) after diagnosis of recurrent colorectal cancer was estimated.Median clinical follow-up was 58 months (Q1-Q3: 22-62). Five-year cumulative incidence of recurrent disease was 21.6% [95% confidence interval (CI): 20.0-23.2] and 30.0% (95% CI: 28.3-33.5) for patients with primary colon and rectal cancer, respectively. Stage III disease and incomplete resection margin in patients with primary colon cancer and extramural vascular invasion in patients with primary rectal cancer were strongly (HR ≥ 2) associated with recurrent disease. Median OS of patients with distant, locoregional, or the synchronous combination of distant and locoregional recurrent disease was 29, 27, and 13 months, respectively (P < 0.001). Patients with distant recurrences limited to liver or lung showed a median OS of 46 and 48 months, respectively. The incidence of recurrent disease was higher in patients with rectal cancer than in patients with colon cancer, predominantly due to higher rates of distant recurrences. OS after recurrent disease was impaired, but subgroups of patients diagnosed with recurrent disease limited to one site showed statistically significantly longer OS.

SIGNIFICANCE

Population-based data on recurrent colorectal cancer are rare, but crucial for counseling patients and their physicians. This large nationwide, population-based study provides an up-to-date overview of the epidemiology of recurrent disease in patients with stage II and III primary colon and rectal cancer treated with surgical resection.

Comparison and commutability study among four faecal immunochemical tests (FIT) systems

OBJECTIVES

Faecal immunochemical tests for haemoglobin (FIT) are used in colorectal cancer screening programs around the world and increasingly for triage of symptomatic patients. FIT results are currently not traceable to a common reference standard and results obtained on various FIT systems may not be equivalent. The size of the bias between the systems is difficult to quantify due to the complex pre-analytical aspects of FIT.

METHODS

This study aimed to quantify the bias and the correlation between four FIT systems by measuring a panel of 38 faecal samples while limiting the effect of the pre-analytical aspects. In addition, the commutability of seven candidate reference materials (RM) was assessed.

RESULTS

Pairwise method comparisons based on faecal samples demonstrated Pearson correlation coefficients ranging between 0.944 and 0.970 and an average proportional bias of -30 to -35 % for one FIT system compared to the other three. The relative standard deviation among biases of the individual samples was around 20 %. Due to these sample specific differences, no decisive conclusions could be drawn in the commutability study. However, two candidate RMs, prepared in the FIT system-specific storage/extraction buffers, had a better commutable profile than the other five.

CONCLUSIONS

The use of a common threshold for all FIT systems is currently not possible due to the presence of a proportional bias. We have identified potential commutable RMs to take to further studies on the production of a common calibrator, with the aim being to reduce the analytical bias observed on different FIT systems.

A review on model-based and model-free approaches to control soft actuators and their potentials in colonoscopy

Colorectal cancer (CRC) is the third most common cancer worldwide and responsible for approximately 1 million deaths annually. Early screening is essential to increase the chances of survival, and it can also reduce the cost of treatments for healthcare centres. Colonoscopy is the gold standard for CRC screening and treatment, but it has several drawbacks, including difficulty in manoeuvring the device, patient discomfort, and high cost. Soft endorobots, small and compliant devices thatcan reduce the force exerted on the colonic wall, offer a potential solution to these issues. However, controlling these soft robots is challenging due to their deformable materials and the limitations of mathematical models. In this Review, we discuss model-free and model-based approaches for controlling soft robots that can potentially be applied to endorobots for colonoscopy. We highlight the importance of selecting appropriate control methods based on various parameters, such as sensor and actuator solutions. This review aims to contribute to the development of smart control strategies for soft endorobots that can enhance the effectiveness and safety of robotics in colonoscopy. These strategies can be defined based on the available information about the robot and surrounding environment, control demands, mechanical design impact and characterization data based on calibration.

An efficient strategy for evaluating new non-invasive screening tests for colorectal cancer: the guiding principles

OBJECTIVE

New screening tests for colorectal cancer (CRC) are rapidly emerging. Conducting trials with mortality reduction as the end point supporting their adoption is challenging. We re-examined the principles underlying evaluation of new non-invasive tests in view of technological developments and identification of new biomarkers.

DESIGN

A formal consensus approach involving a multidisciplinary expert panel revised eight previously established principles.

RESULTS

Twelve newly stated principles emerged. Effectiveness of a new test can be evaluated by comparison with a proven comparator non-invasive test. The faecal immunochemical test is now considered the appropriate comparator, while colonoscopy remains the diagnostic standard. For a new test to be able to meet differing screening goals and regulatory requirements, flexibility to adjust its positivity threshold is desirable. A rigorous and efficient four-phased approach is proposed, commencing with small studies assessing the test's ability to discriminate between CRC and non-cancer states (phase I), followed by prospective estimation of accuracy across the continuum of neoplastic lesions in neoplasia-enriched populations (phase II). If these show promise, a provisional test positivity threshold is set before evaluation in typical screening populations. Phase III prospective studies determine single round intention-to-screen programme outcomes and confirm the test positivity threshold. Phase IV studies involve evaluation over repeated screening rounds with monitoring for missed lesions. Phases III and IV findings will provide the real-world data required to model test impact on CRC mortality and incidence.

CONCLUSION

New non-invasive tests can be efficiently evaluated by a rigorous phased comparative approach, generating data from unbiased populations that inform predictions of their health impact.

Rationale for organized Colorectal cancer screening programs

Colorectal cancer (CRC) is a major health problem and it is expected that the number of persons diagnosed with CRC and CRC-related deaths will continue to increase. However, recent years have shown reductions in CRC incidence and mortality particularly among individuals aged 50 years and older which can be attributed to screening, improvements in patients' management, closer adherence to treatment guideline recommendations and a higher utilization of curative surgery, chemotherapy and radiotherapy. The International Agency for Research on Cancer has concluded that there has been sufficient evidence that biennially screening using a stool-test or once-only endoscopy screening reduces CRC-related mortality. In Europe, between 2008 and 2018, nine countries have successfully implemented a population-based organized program and another six are in the roll-out phase. Population-based organized programs show higher screening participation rates and lower lack of compliance to follow-up testing after a positive screen test compared to opportunistic screening. Moreover, organized programs aim to provide high quality screening thereby reducing the risk of the harms of screening, including over-screening, and complications of screening, and poor follow-up of those who test positive. We describe how population-based organized CRC screening programs are preferred, since they reflect a more appropriate utilization of available resources, reduce inequities in access, and can integrate interventions addressing barriers to screening at the individual and health system levels.

Comprehensive Cost Implications of Commercially Available Noninvasive Colorectal Cancer Screening Modalities

BACKGROUND

There is an increasing usage of noninvasive screening modalities for colorectal cancer (CRC), primarily the fecal immunochemical test (FIT) and multi-target stool DNA test (Cologuard [CG]). The aim of this study was to determine the comprehensive, long-term cost implications of these noninvasive screening modalities.

STUDY DESIGN

Using a national insurer-based administrative dataset, patients screened for CRC from January 1, 2019 to December 31, 2019 were analyzed. A hierarchical logic system was used to determine the primary screening modality for each patient. The total annual costs in US dollars ($) were extrapolated using number of patients screened, costs per test, screening intervals, and costs incurred from false results. Patients within our tumor registry diagnosed with CRC were matched to their claims data, and cancer stage distribution was compared.

RESULTS

Of 119,334 members who underwent noninvasive screening, 38.1% underwent screening with FIT and 40.0% with CG. The combined annual cost for these 2 screening modalities was $13.7 million. By transitioning to FIT alone for all noninvasive screening, the total annual cost would decrease to $7.9 million, resulting in a savings of approximately $5.8 million per year. Additionally, by combining data from the network cancer registry and insurer-based claims dataset, we were able to match 533 individuals who underwent screening and were later diagnosed with CRC. The rate of early-stage (stage 0 to II) disease was found to be similar between those screened with FIT and CG (59.5% FIT vs 63.2% CG; p = 0.77).

CONCLUSIONS

The adoption of FIT as the primary noninvasive CRC screening method has the potential to generate significant cost savings, and therefore, carries significant value implications for a large population health system.

Baseline Features and Reasons for Nonparticipation in the Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) Study, a Colorectal Cancer Screening Trial

Importance

The Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) randomized clinical trial sought to recruit 50 000 adults into a study comparing colorectal cancer (CRC) mortality outcomes after randomization to either an annual fecal immunochemical test (FIT) or colonoscopy.

Objective

To (1) describe study participant characteristics and (2) examine who declined participation because of a preference for colonoscopy or stool testing (ie, fecal occult blood test [FOBT]/FIT) and assess that preference's association with geographic and temporal factors.

Design, Setting, and Participants

This cross-sectional study within CONFIRM, which completed enrollment through 46 Department of Veterans Affairs medical centers between May 22, 2012, and December 1, 2017, with follow-up planned through 2028, comprised veterans aged 50 to 75 years with an average CRC risk and due for screening. Data were analyzed between March 7 and December 5, 2022.

Exposure

Case report forms were used to capture enrolled participant data and reasons for declining participation among otherwise eligible individuals.

Main Outcomes and Measures

Descriptive statistics were used to characterize the cohort overall and by intervention. Among individuals declining participation, logistic regression was used to compare preference for FOBT/FIT or colonoscopy by recruitment region and year.

Results

A total of 50 126 participants were recruited (mean [SD] age, 59.1 [6.9] years; 46 618 [93.0%] male and 3508 [7.0%] female). The cohort was racially and ethnically diverse, with 748 (1.5%) identifying as Asian, 12 021 (24.0%) as Black, 415 (0.8%) as Native American or Alaska Native, 34 629 (69.1%) as White, and 1877 (3.7%) as other race, including multiracial; and 5734 (11.4%) as having Hispanic ethnicity. Of the 11 109 eligible individuals who declined participation (18.0%), 4824 (43.4%) declined due to a stated preference for a specific screening test, with FOBT/FIT being the most preferred method (2820 [58.5%]) vs colonoscopy (1958 [40.6%]; P < .001) or other screening tests (46 [1.0%] P < .001). Preference for FOBT/FIT was strongest in the West (963 of 1472 [65.4%]) and modest elsewhere, ranging from 199 of 371 (53.6%) in the Northeast to 884 of 1543 (57.3%) in the Midwest (P = .001). Adjusting for region, the preference for FOBT/FIT increased by 19% per recruitment year (odds ratio, 1.19; 95% CI, 1.14-1.25).

Conclusions and Relevance

In this cross-sectional analysis of veterans choosing nonenrollment in the CONFIRM study, those who declined participation more often preferred FOBT or FIT over colonoscopy. This preference increased over time and was strongest in the western US and may provide insight into trends in CRC screening preferences.

Perspective on oral cancer screening: Time for implementation research and beyond

Screening aims to detect cancer in asymptomatic populations. In oral cancer, clinical oral examination is the current standard method for screening. Oral cancer screening may be performed by a physician or a healthcare workers and is an affordable and feasible method. There is some evidence that this low-cost method is effective in decreasing mortality from oral cancer in high risk population. The cluster-randomised trial in India that had 15 years of follow-up reported an 81 % mortality reduction in high-risk populations of tobacco and/or alcohol users who adhered to four screening rounds. The observational studies similarly reported 21-22 % reduction in advanced oral cancer and 24-26 % reduction in oral cancer mortality among high risk population. Implementation and evaluation of oral cancer screening programmes in high risk population will support the goals of the World Health Organisation on global oral health.

The role of disgust as an emotional barrier to colorectal cancer screening participation: a systematic review and meta-analysis

OBJECTIVE

Worldwide colorectal cancer (CRC) screening rates are suboptimal. This systematic review and meta-analysis examine the role of disgust in CRC screening avoidance.

DESIGN

A systematic literature search was conducted. In all, 46 studies were included in the review. Among these, 16 studies were compared with a meta-analytical approach in order to 1) estimate the effect size of state disgust on screening intention and attendance; 2) examine whether methodological characteristics moderate the effect of state disgust on screening behaviour; 3) estimate the effect sizes of trait disgust and type of exam kit on state disgust.

RESULTS

In the reviewed studies, state disgust was often associated with CRC screening and especially with CRC screening avoidance. The meta-analysis confirmed low-to-moderate negative effects of state disgust on screening intention and attendance. Population sampling strategy was the only significant moderator of the effect of state disgust on screening attendance, i.e. studies that used convenience (versus random/representative) samples found a significantly lower effect size. Trait disgust and type of exam kit exerted a large and a moderate-to-large positive effect, respectively, on state disgust.

CONCLUSIONS

Disgust can boost CRC screening avoidance. Further studies and interventions must be designed to help patients in overcoming this emotional barrier.

Machine Learning in Colorectal Cancer Risk Prediction from Routinely Collected Data: A Review

The inclusion of machine-learning-derived models in systematic reviews of risk prediction models for colorectal cancer is rare. Whilst such reviews have highlighted methodological issues and limited performance of the models included, it is unclear why machine-learning-derived models are absent and whether such models suffer similar methodological problems. This scoping review aims to identify machine-learning models, assess their methodology, and compare their performance with that found in previous reviews. A literature search of four databases was performed for colorectal cancer prediction and prognosis model publications that included at least one machine-learning model. A total of 14 publications were identified for inclusion in the scoping review. Data was extracted using an adapted CHARM checklist against which the models were benchmarked. The review found similar methodological problems with machine-learning models to that observed in systematic reviews for non-machine-learning models, although model performance was better. The inclusion of machine-learning models in systematic reviews is required, as they offer improved performance despite similar methodological omissions; however, to achieve this the methodological issues that affect many prediction models need to be addressed.

Multiple Negative Fecal Immunochemical Tests Reduce Risk of Advanced Neoplasia in a Colonoscopy Surveillance Program

BACKGROUND & AIMS

In above-average-risk individuals undergoing colonoscopy-based surveillance for colorectal cancer (CRC), screening with fecal immunochemical tests (FIT) between colonoscopies might facilitate personalization of surveillance intervals. Because a negative FIT is associated with a reduced risk for CRC, we examined the relationship between number of rounds of negative FIT and risk for advanced neoplasia in individuals undergoing surveillance colonoscopy.

METHODS

We conducted a retrospective cohort study on 4021 surveillance intervals in 3369 individuals (50-74 years), who had completed a 2-sample FIT between colonoscopies, from 1 to 4 rounds at 1-2 yearly intervals, each with a negative result (<20 μg hemoglobin/g feces). Incidence of advanced neoplasia (CRC or advanced adenoma) was determined at the follow-up colonoscopy. Competing-risk regression was used to assess the association between multiple negative FIT results and the risk of advanced neoplasia within 2 years.

RESULTS

The incidence of advanced neoplasia in the cohort was 9.9% and decreased with increasing numbers of rounds of negative FIT results: 11.1% after 1 negative FIT to 5.7% after 4 negative FIT. The risk of advanced neoplasia was significantly lower in participants with 3 (subdistribution hazard ratio, 0.50; 95% confidence interval, 0.24-0.97) and 4 (subdistribution hazard ratio, 0.33; 95% confidence interval, 0.15-0.73) rounds of negative FIT compared with only 1 negative FIT.

CONCLUSIONS

There was a low risk of advanced neoplasia after multiple rounds of negative FIT in above-average-risk people undergoing surveillance with no neoplasia or nonadvanced adenoma at prior colonoscopy. This supports the use of interval FIT to personalize surveillance by lengthening colonoscopy intervals following multiple negative FIT results.

Microbiome Profiling from Fecal Immunochemical Test Reveals Microbial Signatures with Potential for Colorectal Cancer Screening

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer deaths worldwide. Early diagnosis of CRC, which saves lives and enables better outcomes, is generally implemented through a two-step population screening approach based on the use of Fecal Immunochemical Test (FIT) followed by colonoscopy if the test is positive. However, the FIT step has a high false positive rate, and there is a need for new predictive biomarkers to better prioritize cases for colonoscopy. Here we used 16S rRNA metabarcoding from FIT positive samples to uncover microbial taxa, taxon co-occurrence and metabolic features significantly associated with different colonoscopy outcomes, underscoring a predictive potential and revealing changes along the path from healthy tissue to carcinoma. Finally, we used machine learning to develop a two-phase classifier which reduces the current false positive rate while maximizing the inclusion of CRC and clinically relevant samples.

Urine NMR Metabolomics for Precision Oncology in Colorectal Cancer

Metabolomics is a fundamental approach to discovering novel biomarkers and their potential use for precision medicine. When applied for population screening, NMR-based metabolomics can become a powerful clinical tool in precision oncology. Urine tests can be more widely accepted due to their intrinsic non-invasiveness. Our review provides the first exhaustive evaluation of NMR metabolomics for the determination of colorectal cancer (CRC) in urine. A specific search in PubMed, Web of Science, and Scopus was performed, and 10 studies met the required criteria. There were no restrictions on the query for study type, leading to not only colorectal cancer samples versus control comparisons, but also prospective studies of surgical effects. With this review, all compounds in the included studies were merged into a database. In doing so, we identified up to 100 compounds in urine samples, and 11 were found in at least three articles. Results were analyzed in three groups: case (CRC and adenomas)/control, pre-/post-surgery, and combining both groups. When combining the case-control and the pre-/post-surgery groups, up to twelve compounds were found to be relevant. Seven down-regulated metabolites in CRC were identified, creatinine, 4-hydroxybenzoic acid, acetone, carnitine, d-glucose, hippuric acid, l-lysine, l-threonine, and pyruvic acid, and three up-regulated compounds in CRC were identified, acetic acid, phenylacetylglutamine, and urea. The pathways and enrichment analysis returned only two pathways significantly expressed: the pyruvate metabolism and the glycolysis/gluconeogenesis pathway. In both cases, only the pyruvic acid (down-regulated in urine of CRC patients, with cancer cell proliferation effect in the tissue) and acetic acid (up-regulated in urine of CRC patients, with chemoprotective effect) were present.

Colon and Rectal Cancer Management in Low-Resource Settings

Colorectal cancer (CRC) incidence is rising in low- and middle-income countries, which also face disproportionate mortality from CRC, mainly due to diagnosis at late stages. Various challenges to CRC care exist at multiple societal levels in underserved populations. In this article, barriers to CRC care, strategies for screening, and treatment in resource-limited settings, and future directions are discussed within a global context.

Evaluating the Potential of Polygenic Risk Score to Improve Colorectal Cancer Screening

BACKGROUND

Colorectal cancer has high incidence and associated mortality worldwide. Screening programs are recommended for men and women over 50. Intermediate screens such as fecal immunochemical testing (FIT) select patients for colonoscopy with suboptimal sensitivity. Additional biomarkers could improve the current scenario.

METHODS

We included 2,893 individuals with a positive FIT test. They were classified as cases when a high-risk lesion for colorectal cancer was detected after colonoscopy, whereas the control group comprised individuals with low-risk or no lesions. 65 colorectal cancer risk genetic variants were genotyped. Polygenic risk score (PRS) and additive models for risk prediction incorporating sex, age, FIT value, and PRS were generated.

RESULTS

Risk score was higher in cases compared with controls [per allele OR = 1.04; 95% confidence interval (CI), 1.02-1.06; P < 0.0001]. A 2-fold increase in colorectal cancer risk was observed for subjects in the highest decile of risk alleles (≥65), compared with those in the first decile (≤54; OR = 2.22; 95% CI, 1.59-3.12; P < 0.0001). The model combining sex, age, FIT value, and PRS reached the highest accuracy for identifying patients with a high-risk lesion [cross-validated area under the ROC curve (AUROC): 0.64; 95% CI, 0.62-0.66].

CONCLUSIONS

This is the first investigation analyzing PRS in a two-step colorectal cancer screening program. PRS could improve current colorectal cancer screening, most likely for higher at-risk subgroups. However, its capacity is limited to predict colorectal cancer risk status and should be complemented by additional biomarkers.

IMPACT

PRS has capacity for risk stratification of colorectal cancer suggesting its potential for optimizing screening strategies alongside with other biomarkers.

Examining the Factors That Affect the Diagnosis of Patients with Positive Fecal Occult Blood Test Results

Due to the threat of colorectal cancer (CRC) to health, Taiwan included the fecal occult blood test (FOBT) under preventive health services in 2010. We examined the factors that affect the diagnosis of people with positive FOBT results. Data were retrospectively collected from the CRC screening database. In the model predicting factors that affect the diagnosis of 89,046 people with positive FOBT results, the risks of disease in the CRC group were lower in medical institutions that conducted follow-up examinations in regions such as Northern Taiwan compared to that in Eastern Taiwan (p = 0.013); they were lower in the age group of 50 to 65 years than those in the age group of 71 to 75 years (p < 0.001, p = 0.016), and lower in the outpatient medical units that conducted follow-up examinations than those in the inpatient medical units by 0.565 times (p < 0.001, 95% CI: 0.493−0.647). Factors affecting the diagnosis of patients with positive FOBT results were gender, the region of the medical institution, medical unit for follow-up examinations, age, screening site, family history, type of follow-up examinations, and follow-up time. Therefore, the identification of characteristics of patients with positive FOBT results and the promotion of follow-up examination are important prevention strategies for CRC.

The present and future of gastroenterology and hepatology: an international SWOT analysis (the GASTROSWOT project)

GASTROSWOT is a strategic analysis of the current and projected states of the different subspecialties in gastroenterology that aims to provide guidance for research, clinical, and financial planning in gastroenterology. We executed a consensus-based international strengths, weaknesses, opportunities, and threats (SWOT) analysis. Four general coordinators, six field coordinators, and 12 experts participated in the study. SWOTs were provided for the following fields: neurogastroenterology, functional gastrointestinal disorders, and upper gastrointestinal diseases; inflammatory bowel disease; pancreatology and biliary diseases; endoscopy; gastrointestinal oncology; and hepatology. The GASTROSWOT analysis highlights the following in the current state of the field of gastroenterology: the incidence and complexity of several gastrointestinal diseases, including malignancies, are increasing; the COVID-19 pandemic has affected patient care on several levels; and with the advent of technical innovations in gastroenterology, a well trained workforce and strategic planning are required to optimise health-care utilisation. The analysis calls attention to the following in the future of gastroenterology: artificial intelligence and the use of big data will speed up discovery and smarter health-care provision in the field; the growth and diversification of gastroenterological specialties will improve specialised care for patients, but could promote fragmentation of care and health system inefficiencies; and furthermore, thoughtful planning is needed to reach an effective balance between the need for subspecialists and the value of general gastroenterology services.

MiR-130b-3p promotes colorectal cancer progression by targeting CHD9

Colorectal cancer (CRC) is the third most common cancer worldwide. Previous research revealed that microRNA 130b-3p (miR-130b-3p) significantly upregulated in CRC patients can be detected in feces from patients with such a neoplasm. In this study, the biological role and molecular mechanism of miR-130b-3p in CRC were explored. The miR-130b-3p level in CRC tissues, feces and cell lines was measured using RT-qPCR analysis. CCK-8, EdU, TUNEL, flow cytometry, Western blotting, and in vivo experiments were performed to explore the biological function of miR-130b-3p in CRC progression. For this purpose, 16 BALB/c nude mice were assigned to two groups. The experiment lasted for four months. Bioinformatics analysis and luciferase reporter assay were used to investigate the regulatory mechanism related to miR-130b-3p. In our research, miR-130b-3p was upregulated in CRC tissues and cells and it was detected in feces from CRC patients. Moreover, miR-130b-3p inhibition suppressed CRC cell proliferation and promoted cell apoptosis in vitro as well as repressed CRC tumor growth in vivo. Mechanistically, miR-130b-3p directly targeted the 3'untranslated region (UTR) of chromodomain helicase DNA binding protein 9 (CHD9) and negatively regulated CHD9 expression. Furthermore, CHD9 played an anti-oncogenic role in CRC. Inhibition of CHD9 expression was likely to be a key mechanism by which miR-130b-3p increased CRC cell growth, with a target protector experiment revealing miR-130b-3p influenced proliferation via direct inhibition of CHD9. MiR-130b-3p promotes the progression and tumorigenesis of CRC at least partially by targeting CHD9.Abbreviations: CRC: Colorectal cancer; miR-130b-3p: microRNA 130b-3p; CHD9: chromodomain helicase DNA binding protein 9; UTR: untranslated region; FIT: fecal immunochemical test; AAs: advanced adenomas.

Hypotension during propofol sedation for colonoscopy: an exploratory analysis

BACKGROUND

Intraoperative and postoperative hypotension occur commonly and are associated with organ injury and poor outcomes. Changes in arterial blood pressure (BP) during procedural sedation are not well described.

METHODS

Individual patient data from five trials of propofol sedation for colonoscopy and a clinical database were pooled and explored with logistic and linear regression. A literature search and focused meta-analysis compared the incidence of hypotension with propofol and alternative forms of procedural sedation. Hypotensive episodes were characterised by the original authors' definitions (typically systolic BP <90 mm Hg).

RESULTS

In pooled individual patient data (n=939), 36% of procedures were associated with episodes of hypotension. Longer periods of propofol sedation and larger propofol doses were associated with longer-lasting and more-profound hypotension. Amongst 380 patients for whom individual BP measurements were available, 107 (28%) experienced systolic BP <90 mm Hg for >5 min, and in 89 (23%) the episodes exceeded 10 min. Meta-analysis of 18 RCTs identified an increased risk ratio for the development of hypotension in procedures where propofol was used compared with the use of etomidate (two studies; n=260; risk ratio [RR] 2.0 [95% confidence interval: 1.37-2.92]; P=0.0003), remimazolam (one study; n=384; RR 2.15 [1.61-2.87]; P=0.0001), midazolam (14 studies; n=2218; RR 1.46 [1.18-1.79]; P=0.0004), or all benzodiazepines (15 studies; n=2602; 1.67 [1.41-1.98]; P<0.00001). Hypotension was less likely with propofol than with dexmedetomidine (one study; n=60; RR 0.24 [0.09-0.62]; P=0.003).

CONCLUSIONS

Hypotension is common during propofol sedation for colonoscopy and of a magnitude and duration associated with harm in surgical patients.

Intraprocedural Artificial Intelligence for Colorectal Cancer Detection and Characterisation in Endoscopy and Laparoscopy

In this article, we provide an evidence-based primer of current tools and evolving concepts in the area of intraprocedural artificial intelligence (AI) methods in colonoscopy and laparoscopy as a 'procedure companion', with specific focus on colorectal cancer recognition and characterisation. These interventions are both likely beneficiaries from an impending rapid phase in technical and technological evolution. The domains where AI is most likely to impact are explored as well as the methodological pitfalls pertaining to AI methods. Such issues include the need for large volumes of data to train AI systems, questions surrounding false positive rates, explainability and interpretability as well as recent concerns surrounding instabilities in current deep learning (DL) models. The area of biophysics-inspired models, a potential remedy to some of these pitfalls, is explored as it could allow our understanding of the fundamental physiological differences between tissue types to be exploited in real time with the help of computer-assisted interpretation. Right now, such models can include data collected from dynamic fluorescence imaging in surgery to characterise lesions by their biology reducing the number of cases needed to build a reliable and interpretable classification system. Furthermore, instead of focussing on image-by-image analysis, such systems could analyse in a continuous fashion, more akin to how we view procedures in real life and make decisions in a manner more comparable to human decision-making. Synergistical approaches can ensure AI methods usefully embed within practice thus safeguarding against collapse of this exciting field of investigation as another 'boom and bust' cycle of AI endeavour.

Faecal haemoglobin concentrations in women and men diagnosed with colorectal cancer in a national screening programme

Objective

There is evidence that colorectal cancer screening using faecal haemoglobin is less effective in women than men. The faecal haemoglobin concentrations were therefore examined in women and men with screen-detected colorectal cancer.

Setting

Scottish Bowel Screening Programme, following the introduction of a faecal immunochemical test from November 2017, to March 2020.

Methods

Data were collated on faecal haemoglobin concentrations, pathological stage and anatomical site of the main lesion in participants who had colorectal cancer detected. The data in women and men were compared.

Results

For the faecal haemoglobin concentrations studied (>80 µg Hb/g faeces), the distributions indicated lower concentrations in women. Marked differences were found between women and men diagnosed with colorectal cancer. The median faecal haemoglobin concentration for women (n = 720) was 408 µg Hb/g faeces compared to 473 µg Hb/g faeces for men (n = 959) (p = 0.004) and 50.6% of the results were >400 µg Hb/g faeces in women; in men, this was 57.8%. The difference in faecal haemoglobin concentrations in women and men became less statistically significant as stage advanced from stages I–IV. For right-sided, left-sided and rectal colorectal cancer, a similar gender difference persisted in all sites. Differences in faecal haemoglobin between the genders were significant for left-sided cancers and stage I and approached significance for rectal cancers and stage II, but all sites and stages showed lower median faecal haemoglobin concentrations for women.

Conclusions

To minimise gender inequalities, faecal immunochemical test-based colorectal cancer screening programmes should evaluate a strategy of using different faecal haemoglobin concentration thresholds in women and men.

Noninvasive fecal testing for colorectal cancer

INTRODUCTION

Colorectal cancer (CRC) is the third most common malignancy worldwide, with the second highest mortality rate among all malignancies. In this review, we describe the current utility of stool diagnostic biomarkers for CRC.

METHODS

We reviewed stool-related tests and biomarker candidates for the diagnosis of CRC. The guaiac-based fecal occult blood test (gFOBT), fecal immunochemical test (FIT), and multitarget stool DNA test (MT-sDNA) have been used as clinical CRC screening tools. Although microRNAs, protein biomarkers, and microbiota have not yet been used in clinical CRC screening, there is growing evidence that they have the potential to function as CRC screening tools.

RESULTS

According to the literature, the sensitivity of MT-sDNA for detecting CRC was 87.0-100%, 32.7-82.0% for advanced adenomas, and the specificity was 86.1-95.2%. The sensitivity of individual biomarkers of fecal microRNAs for detecting CRC was 34.2-88.2%, 73.0% for advanced adenomas, and the specificity was 68-100%. The sensitivity of fecal protein markers for detecting CRC was 63.6-93.0%, 47.7-69.4% for advanced adenomas, and the specificity was 38.3-97.5%. The sensitivity of fecal microbiota for detecting CRC was 54.0-100.0%, 32.0-48.3% for advanced adenomas, and the specificity was 61.3-90.0%.

CONCLUSION

MT-sDNA is the most sensitive CRC screening test, and its sensitivity is the highest for advanced adenomas; however, its detection cost is high. MT-sDNA was more sensitive to CRC and advanced precancerous lesions than FIT, but compared to three years of MT-sDNA, annual FIT as the first non-invasive screening test for CRC seemed to be more effective.

A fecal-based test for the detection of advanced adenoma and colorectal cancer: a case-control and screening cohort study

BACKGROUND

Colorectal cancer (CRC) is the leading cause of cancer death worldwide. Screening is a confirmed way to reduce the incidence and mortality rates of CRC. This study aimed to identify a fecal-based, noninvasive, and accurate method for detection of colorectal cancer (CRC) and advanced adenoma (AA).

METHODS

Through detection in tissue (n = 96) and fecal samples (n = 88) and tested in an independent group of fecal samples (n = 294), the methylated DNA marker ITGA4 and bacterial markers Fusobacterium nucleatum (Fn) and Pepetostreptococcusanaerobius (Pa) were identified from the candidate biomarkers for CRC and AA detection. A prediction score (pd-score) was constructed using the selected markers and fecal immunochemical test (FIT) for distinguishing AA and CRC from healthy subjects by logistic regression method. The diagnostic performance of the pd-score was compared with FIT and validated in the external validation cohort (n = 117) and in a large CRC screening cohort.

RESULTS

The pd-score accurately identified AA and CRC from healthy subjects with an area under the curve (AUC) of 0.958, at a specificity of 91.37%; the pd-score showed sensitivities of 95.38% for CRC and 70.83% for AA, respectively. In the external validation cohort, the sensitivities of the pd-score for CRC and AA detection were 94.03% and 80.00%, respectively. When applied in screening, the pd-score identified 100% (11/11) of CRC and 70.83% (17/24) of AA in participants with both colonoscopy results and qualified fecal samples, showing an improvement by 41.19% compared to FIT.

CONCLUSIONS

The current study developed a noninvasive and well-validated approach for AA and CRC detection, which could be applied widely as a diagnostic and screening test.

Factors affecting the follow-up time after a positive result in the fecal occult blood test

In 2010, Taiwan included the fecal occult blood test (FOBT) under preventive health insurance services. For patients whose test positive, receiving follow-ups is paramount. This study investigated factors affecting the follow-up time of these patients. This retrospective study used data from the colorectal cancer screening archives. The study period was from 2010 to 2013, and the subjects were 50-75-year-old persons who tested positive for FOBT. The t test, one-way ANOVA, and multiple regression were performed to address the differences in the mean tracking period between variables such as the population's demographic characteristics. The mean follow-up time for the 98,482 participants whose screening results were positive exhibited significant differences (p < 0.001) according to medical unit region and classification, age, screening location, family history, examination method, and diagnosis. The model predicting the mean follow-up time predicted a period of 10.079 days longer for those whose hospital was on an offshore island than that of those whose hospital was in the eastern regions. The follow-up time was 1.257 days shorter for people who were inpatients than those who were outpatients and was 8.902 days longer for people who underwent double contrast barium enema plus flexible sigmoidoscopy than those who underwent other examination methods. Patients with a family history of colorectal cancer and those whose examination results indicated cancer had a follow-up time of 2.562 and 2.476 days shorter than those who did not know their family history and those with other results, respectively. Factors affecting the follow-up time of people whose FOBT results were positive consisted of the location and classification of the follow-up institution, age, screening location, family history, examination method, and diagnosis. This provides valuable references for improving the cancer screening program.

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

Endorobots for Colonoscopy: Design Challenges and Available Technologies

Colorectal cancer (CRC) is the second most common cause of cancer death worldwide, after lung cancer (Sung et al., 2021). Early stage detection is key to increase the survival rate. Colonoscopy remains to be the gold standard procedure due to its dual capability to optically inspect the entire colonic mucosa and to perform interventional procedures at the same time. However, this causes pain and discomfort, whereby it requires sedation or anaesthesia of the patient. It is a difficult procedure to perform that can cause damage to the colonic wall in some cases. Development of new technologies aims to overcome the current limitations on colonoscopy by using advancements in endorobotics research. The design of these advanced medical devices is challenging because of the limited space of the lumen, the contorted shape, and the long tract of the large bowel. The force applied to the colonic wall needs to be controlled to avoid collateral effects such as injuries to the colonic mucosa and pain during the procedure. This article discusses the current challenges in the colonoscopy procedure, the available locomotion technologies for endorobots used in colonoscopy at a prototype level and the commercial products available.

Faecal immunochemical test after negative colonoscopy may reduce the risk of incident colorectal cancer in a population-based screening programme

OBJECTIVE

Subjects with a positive faecal immunochemical test (FIT) have a much higher likelihood of advanced neoplasms than the general population. Whether FIT-positive subjects with negative colonoscopy should receive subsequent FIT screening remain unclear.

DESIGN

Subjects with a negative colonoscopy after positive FIT in the first screening in the Taiwanese Colorectal Cancer (CRC) Screening Program 2004-2009 were followed until the end of 2014. CRC incidence was compared between those who did and did not receive subsequent FIT screening. Cox regression analysis was conducted, adjusting for major confounders to investigate whether subsequent FIT was associated with lower risk of incident CRC.

RESULTS

The study cohort was comprised of 9179 subjects who had negative diagnostic colonoscopy after positive FIT in 2004-2009, of whom 6195 received subsequent FIT during the study period. The CRC incidence (per 1000 person years) was 1.34 in those who received subsequent FIT and 2.69 in those who did not, with corresponding adjusted HR (aHR) of 0.47 (95% CI 0.31 to 0.71). Lower adenoma detection rate of diagnostic colonoscopy was associated with higher risk of incident CRC but became non-significant in multivariable analysis after adjustment for subsequent FIT. Higher baseline faecal haemoglobin concentration (FHbC, μg haemoglobin/g faeces) was associated with increased risk of incident CRC (reference: FHbC=20-39; aHR=1.93 (1.04-3.56), 0.95 (0.45-2.00), 2.26 (1.16-4.43) and 2.44 (1.44-4.12) for FHbC=40-59, 60-99, 100-149 and ≥150, respectively).

CONCLUSION

Subsequent FIT should be scheduled after negative colonoscopy to detect missed neoplasms and reduce the risk of incident CRC in a national FIT screening programme.

"Rescue" of Nonparticipants in Colorectal Cancer Screening: A Randomized Controlled Trial of Three Noninvasive Test Options

Few studies have directly targeted nonparticipants in colorectal cancer screening to identify effective engagement strategies. We undertook a randomized controlled trial that targeted nonparticipants in a previous trial of average-risk subjects which compared participation rates for mailed invitations offering a fecal test, a blood test or a choice of either. Nonparticipants (n = 899) were randomized to be offered a kit containing a fecal immunochemical test (FIT), directions on how to arrange a blood DNA test, or the option of doing either. Screening participation was assessed 12 weeks after the offer. To assess the cognitive and attitudinal variables related to participation and invitee choice, invitees were surveyed after 12 weeks, and associations were investigated using multinomial logistic regression. Participation rates were similar between groups (P = 0.88): 12.0% for FIT (35/292), 13.3% for the blood test (39/293), and 13.4% for choice (39/290). Within the choice group, participation was significantly higher with FIT (9.7%, 28/290) compared with the blood test (3.8%, 11/290, P = 0.005). The only variable significantly associated with participation was socioeconomic status when offered FIT, and age when offered choice but there was none when offered the blood test. Survey respondents indicated that convenience, time-saving, comfort, and familiarity were major influences on participation. There was no clear advantage between a fecal test, blood test, or choice of test although, when given a choice, the fecal test was preferred. Differences in variables associated with participation according to invitation strategy warrant consideration when deciding upon an invitation strategy for screening nonparticipants. PREVENTION RELEVANCE: This trial of screening for those at average risk for colorectal cancer targeted past fecal-test nonparticipants and compared participation rates for mailed invitations offering a fecal test, blood test, or choice of either. Although there was no clear advantage between strategies, factors associated with participation differed between each strategy.

Identification of Novel Mutations in Colorectal Cancer Patients Using AmpliSeq Comprehensive Cancer Panel

Biomarker discovery would be an important tool in advancing and utilizing the concept of precision and personalized medicine in the clinic. Discovery of novel variants in local population provides confident targets for developing biomarkers for personalized medicine. We identified the need to generate high-quality sequencing data from local colorectal cancer patients and understand the pattern of occurrence of variants. In this report, we used archived samples from Saudi Arabia and used the AmpliSeq comprehensive cancer panel to identify novel somatic variants. We report a comprehensive analysis of next-generation sequencing results with a coverage of >300X. We identified 466 novel variants which were previously unreported in COSMIC and ICGC databases. We analyzed the genes associated with these variants in terms of their frequency of occurrence, probable pathogenicity, and clinicopathological features. Among pathogenic somatic variants, 174 were identified for the first time in the large intestine. APC, RET, and EGFR genes were most frequently mutated. A higher number of variants were identified in the left colon. Occurrence of variants in ERBB2 was significantly correlated with those of EGFR and ATR genes. Network analyses of the identified genes provide functional perspective of the identified genes and suggest affected pathways and probable biomarker candidates. This report lays the ground work for biomarker discovery and identification of driver gene mutations in local population.

Comprehensive Volatilome and Metabolome Signatures of Colorectal Cancer in Urine: A Systematic Review and Meta-Analysis

To increase compliance with colorectal cancer screening programs and to reduce the recommended screening age, cheaper and easy non-invasiveness alternatives to the fecal immunochemical test should be provided. Following the PRISMA procedure of studies that evaluated the metabolome and volatilome signatures of colorectal cancer in human urine samples, an exhaustive search in PubMed, Web of Science, and Scopus found 28 studies that met the required criteria. There were no restrictions on the query for the type of study, leading to not only colorectal cancer samples versus control comparison but also polyps versus control and prospective studies of surgical effects, CRC staging and comparisons of CRC with other cancers. With this systematic review, we identified up to 244 compounds in urine samples (3 shared compounds between the volatilome and metabolome), and 10 of them were relevant in more than three articles. In the meta-analysis, nine studies met the criteria for inclusion, and the results combining the case-control and the pre-/post-surgery groups, eleven compounds were found to be relevant. Four upregulated metabolites were identified, 3-hydroxybutyric acid, L-dopa, L-histidinol, and N1, N12-diacetylspermine and seven downregulated compounds were identified, pyruvic acid, hydroquinone, tartaric acid, and hippuric acid as metabolites and butyraldehyde, ether, and 1,1,6-trimethyl-1,2-dihydronaphthalene as volatiles.

Recognising Colorectal Cancer in Primary Care

Colorectal cancer (CRC) is the third most common cancer worldwide. Primary care professionals can play an important role in both prevention and early detection of CRC. Most CRCs are attributed to modifiable lifestyle factors, which can be addressed within primary care, and promotion of population-based screening programmes can aid early cancer detection in asymptomatic patients. Primary care professionals have a vital role in clinically assessing patients presenting with symptoms that may indicate cancer, as most patients with CRC first present with symptoms. These assessments are often challenging—many of the symptoms of CRC are non-specific and commonly occur in patients presenting with non-malignant disease. The range of options for investigating symptomatic patients in primary care is rapidly growing. Simple tests, such as faecal immunochemical testing (FIT), are now being used to guide decisions around referral for more invasive tests, such as colonoscopy, while direct access to specialist investigations is also becoming more common. Clinical decision support tools (CDSTs) which calculate cancer risk based on symptomatology, patient characteristics and test results can provide an additional resource to guide decisions on further investigation. This article explores the challenges of CRC prevention and detection from the primary care perspective, discusses current evidence-based approaches for CRC detection used in primary care (with examples from UK guidelines), and highlights emerging research which may likely alter practice in the future.

Using Metamodeling to Identify the Optimal Strategy for Colorectal Cancer Screening

OBJECTIVES

Metamodeling can address computational challenges within decision-analytic modeling studies evaluating many strategies. This article illustrates the value of metamodeling for evaluating colorectal cancer screening strategies while accounting for colonoscopy capacity constraints.

METHODS

In a traditional approach, the best screening strategy was identified from a limited subset of strategies evaluated with the validated Adenoma and Serrated pathway to Colorectal CAncer model. In a metamodeling approach, metamodels were fitted to this limited subset to evaluate all potentially plausible strategies and determine the best overall screening strategy. Approaches were compared based on the best screening strategy in life-years gained compared with no screening. Metamodel runtime and accuracy was assessed.

RESULTS

The metamodeling approach evaluated >40 000 strategies in <1 minute with high accuracy after 1 adaptive sampling step (mean absolute error: 0.0002 life-years) using 300 samples in total (generation time: 8 days). Findings indicated that health outcomes could be improved without requiring additional colonoscopy capacity. Obtaining similar insights using the traditional approach could require at least 1000 samples (generation time: 28 days). Suggested benefits from screening at ages <40 years require adequate validation of the underlying Adenoma and Serrated pathway to Colorectal CAncer model before making policy recommendations.

CONCLUSIONS

Metamodeling allows rapid assessment of a vast set of strategies, which may lead to identification of more favorable strategies compared to a traditional approach. Nevertheless, metamodel validation and identifying extrapolation beyond the support of the original decision-analytic model are critical to the interpretation of results. The screening strategies identified with metamodeling support ongoing discussions on decreasing the starting age of colorectal cancer screening.

Fecal MicroRNA-Based Algorithm Increases Effectiveness of Fecal Immunochemical Test-Based Screening for Colorectal Cancer

BACKGROUND & AIMS

An algorithm based on fecal levels of 2 microRNAs (miR-421 and miR-27a-3p), fecal hemoglobin concentration, and patient age and sex can identify patients with advanced colorectal neoplasia. We investigated whether this algorithm, called miRFec, could increase effectiveness and efficiency of fecal immunochemical test (FIT)-based colorectal cancer (CRC) screening programs.

METHODS

We obtained data and fecal samples from 767 persons with a positive result from the FIT who then underwent colonoscopy examination while participating a population-based CRC screening program, from March 2011 through May 2017 in Barcelona, Spain. Fecal miRNAs were isolated from the buffer contained in the original FIT collection device and analyzed by quantitative reverse transcription PCR. Aims were to evaluate the usefulness of the miRFec algorithm in identifying persons at greatest risk for CRC who should be prioritized for colonoscopy examination and individuals at low risk for whom colonoscopy could be avoided.

RESULTS

Of the 767 study subjects, 414 (54.0%) were found by colonoscopy to have advanced colorectal neoplasia (67 with CRC and 347 with advanced adenomas) and 353 (46.0%) were found to have either non-advanced adenomas (n = 136) or a normal examination (n = 217). MiRFec algorithm scores (1-4) were independently associated with the presence of advanced colorectal neoplasia (P < .001). The miRFec algorithm differentiated patients with CRC from those with non-advanced adenomas or normal colonoscopy with an area under the receiver operating characteristic curve of 90% (95% CI, 86-94). Subjects with miRFec scores in the 4th quartile (above 3.09, high-risk group) were 8-fold more likely to have advanced colorectal neoplasia than subjects with miRFec scores in the 1st quartile (below 2.14, low-risk group). Subjects in the low-risk group had a positive predictive value below 30% for detection of advanced colorectal neoplasia. When we used a 50% specificity cut-off value, the miRFec algorithm identified 97% of patients with CRC and would allow 264 subjects (34.4%) to avoid colonoscopy examination.

CONCLUSIONS

An algorithm based on fecal levels of 2 miRNAs and hemoglobin, patient age and sex (miRFec) differentiated patients with CRC from those with non-advanced adenomas or normal colonoscopy with an area under the receiver operating characteristic curve value of 90% and avoided 34% of colonoscopies. Inclusion of this algorithm in FIT-based CRC screening programs could increase their effectiveness and efficiency.

Evaluation of a panel of tumor-specific differentially-methylated DNA regions in IRF4, IKZF1 and BCAT1 for blood-based detection of colorectal cancer

BACKGROUND

Differentially-methylated regions (DMRs) are characteristic of colorectal cancer (CRC) and some occur more frequently than common mutations. This study aimed to evaluate the clinical utility of assaying circulating cell-free DNA for methylation in BCAT1, IKZF1 and IRF4 for detection of CRC.

METHODS

A multiplexed real-time PCR assay targeting DMRs in each of the three genes was developed. Assay accuracy was explored in plasma specimens banked from observational cross-sectional trials or from volunteers scheduled for colonoscopy or prior to CRC surgery.

RESULTS

1620 specimens were suitable for study inclusion including 184 and 616 cases with CRC and adenomas, respectively, and 820 cases without neoplasia (overall median age, 63.0 years; 56% males). Combining the PCR signals for all targeted DMRs returned the best sensitivity for CRC (136/184, 73.9%, 95% CI 67.1-79.7), advanced adenomas (53/337, 15.7%, 95% CI 12.0-20.1) and high-grade dysplastic (HGD) adenomas (9/35, 25.7%, 95% CI 14.0-42.3) with a 90.1%, specificity for neoplasia (739/820, 95% CI 87.9-92.0, p < 0.01). Detection of methylation in all three genes were more likely in CRC cases than those without it (OR 28.5, 95% CI 7.3-121.2, p < 0.0001). Of the 81 positive cases without neoplasia, 62 (76.5%) were positive by a single PCR replicate only and predominantly due to detection of methylated BCAT1 (53.2%). Single replicate positivity was significantly higher than that in CRC (26/136, 19.1%, p < 0.0001), and single BCAT1 replicate positivity was more likely in cases without neoplasia than in CRC (OR 17.7, 95% CI 6.6-43.3, p < 0.0001). When a positive result was limited to those with ≥ 1 PCR replicate positive for either IKZF1 or IRF4, or at least two replicates positive for BCAT1, the multi-panel test maintained a high sensitivity for CRC (131/184, 71.2%, 95% CI 64.3-77.3) and HGD adenomas (8/35, 22.9%, 95% CI 11.8-39.3, p = 0.029) but improved specificity significantly (772/820, 94.1%, 95% CI 92.3-95.6, p < 0.0001 vs. any PCR replicate positive).

CONCLUSION

The multi-panel methylation assay differentiates cases with CRC from those without it and does so with high specificity when criteria for BCAT1 detection are applied. The marker panel is flexible and studies in those at average risk for CRC are now warranted to determine which panel configuration best suits screening goals.

TRIAL REGISTRATION

ACTRN12611000318987. Registered 25 March 2011, https://www.anzctr.org.au/ ACTRN12611000318987.

Low Rate of Cancer Detection by Colonoscopy in Asymptomatic, Average-Risk Subjects with Negative Results From Fecal Immunochemical Tests

BACKGROUND & AIMS

Screening colonoscopies are of uncertain benefit for persons with negative results from a fecal immunochemical test (FIT). We investigated detection of CRC by colonoscopy in asymptomatic, average-risk, FIT-negative subjects.

METHODS

We conducted a retrospective, population-based cohort study of 96,804 subjects with an initial negative result from a FIT at ages 50-75 years, from 2008 through 2014, who then underwent colonoscopy, using the Kaiser Permanente California databases. We identified participants diagnosed with CRC from January 1, 2008 through December 31, 2015 from a cancer registry. Subjects were followed until initial colonoscopy, health plan disenrollment, death, or December 31, 2015. We reviewed records from 400 randomly selected persons without CRC (controls) for risk features to estimate the proportion who underwent screening colonoscopy. We performed logistic regression to identify variables associated with CRC detection.

RESULTS

Of 257 subjects with a diagnosis of CRC, 102 did not have a record of CRC risk factors; 86 of these patients (84.3%) had non-advanced-stage CRC (no regional node spread/distant metastases). Of the 400 controls, 299 (74.75%; 95% CI, 70.49%-79.01%) lacked CRC risk features, enabling estimation that 72,263 (mean age, 57.5 ± 7.0 y; 54.5% female) had undergone screening colonoscopy. CRC was detected in 1.4 per 1000 persons after 1 FIT, without association with increasing FITs (P = .97). CRC was detected in 1.3 per 1000 persons in 2 y or less after the last FIT and in 4.4 per 1000 persons more than 2 y after the last FIT (P < .001). When the last FIT was 2 y earlier or less, CRC increased from 0.7 per 1000 persons age 50-59 y to 3.1 per 1000 persons older than 70 y. Age and time from the last FIT were associated with CRC, with adjusted odds ratios of 1.08 (95% CI, 1.05-1.11) and 2.76 (95% CI, 1.28-5.95), respectively.

CONCLUSIONS

In asymptomatic, average-risk persons with a negative result from a FIT, CRC is infrequent within 2 y after the last FIT (especially for persons younger than 60 y), usually non-advanced, and unrelated to the number of FITs performed.

Googling on Colonoscopy: A Retrospective Analysis of Search Engine Statistics

PURPOSE

Colonoscopy is a gold standard for screening and diagnosis of colorectal cancer (CRC). The data from the search engine may reveal what information on coloscopy gains the attention of Internet users. We aimed to investigate Google searches trends and terms related to colonoscopy.

PATIENTS AND METHODS

We retrieved statistics searches related to colonoscopy using Google Trends (GT) and Google Ads (GA) for the period from April 2016 to March 2020. The GT data was used for the analysis of time and regional search patterns worldwide. GA data for Australia, Canada, Ireland, New Zealand (NZ), Poland, the United Kingdom (UK), and the United States (US) were used to calculate the search volume of categories of queries related to colonoscopy.

RESULTS

Globally, the relative search volume on colonoscopy has increased until the COVID-19 outbreak and revealed seasonal variation: the highest interest was observed in March (CRC awareness month), and the lowest during December (Christmas holidays). The highest number of searches per 1000 Google users-years was done in Poland (59.62) and the lowest in the UK (19.46). Most commonly, Google users searched for details on colonoscopy techniques (Australia, Canada, Ireland, NZ), anesthesia during the procedure (Poland), facility performing colonoscopy (UK, US). In all seven countries, less than 2% of queries concerned with bowel preparation before the procedure.

CONCLUSION

Before the COVID-19 pandemic, the interest in colonoscopy has increased among Google users. Google users may underestimate the importance of proper bowel preparation.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Tissue and Cell-Free DNA-Based Epigenomic Approaches for Cancer Detection

BACKGROUND

Over 9 million people die of cancer each year worldwide, reflecting the unmet need for effective biomarkers for both cancer diagnosis and prognosis. Cancer diagnosis is complex because the majority of malignant tumors present with long periods of latency and lack of clinical presentation at early stages. During carcinogenesis, premalignant cells experience changes in their epigenetic landscapes, such as differential DNA methylation, histone modifications, nucleosome positioning, and higher orders of chromatin changes that confer growth advantage and contribute to determining the biologic phenotype of human cancers.

CONTENT

Recent progress in microarray platforms and next-generation sequencing approaches has allowed the characterization of abnormal epigenetic patterns genome wide in a large number of cancer cases. The sizable amount of processed data also comes with challenges regarding data management and assessment for effective biomarker exploration to be further applied in prospective clinical trials. Epigenetics-based single or panel tests of genes are being explored for clinical management to fulfill unmet needs in oncology. The advance of these tests to the clinical routine will depend on rigorous, extensive, and independent validation in well-annotated cohort of patients and commercial development of clinical routine-friendly and adequate procedures.

SUMMARY

In this review we discuss the analytic validation of tissue and cell-free DNA-based epigenomic approaches for early cancer detection, diagnosis, and treatment monitoring and the clinical utility of candidate epigenetic alterations applied to colorectal, glioblastoma, breast, prostate, bladder, and lung cancer management.

Review of the epidemiology and burden of ulcerative colitis in Latin America

The incidence and prevalence of ulcerative colitis (UC) has been reported to be rising in newly industrialised regions, such as Latin America. Here, we review data from published studies reporting demographics and clinical aspects of UC in Latin America to further understand epidemiology and disease burden. The incidence and prevalence of UC in Latin America varied between regions and studies, ranging between 0.04 to 8.00/100,000 and 0.23 to 76.1/100,000, respectively, and generally increased over the period from 1986 to 2015. The majority of patients with UC were female (53.6-72.6%) and urban residents (77.8-97.4%). Extraintestinal manifestations were reported in approximately 26-89.4% of patients. Use of biologic therapies was generally low (0.8-16.2%), with the exception of Mato Grosso do Sul, Brazil, with a greater proportion of patients tending to receive 5-aminosalicylates, immunosuppressants or corticosteroids; colectomy rates varied between studies (1.5-22%). A high proportion of patients had moderate to severe UC (45.9-73.0%) and, in 11 of 19 studies, the greatest proportion of patients had extensive disease (pancolitis). Colorectal cancer (0-1.7%) and mortality rates (0-7.6%) were low. This evaluation of published studies may influence therapeutic approaches and the development of strategies to improve healthcare access and patient outcomes, although further high-quality studies are required in patients with UC in Latin America.

Colonoscopy Screening Behaviour and Associated Factors Amongst First-Degree Relatives of People with Colorectal Cancer in China: Testing the Health Belief Model Using a Cross-Sectional Design

Colonoscopy is the best screening choice for at-risk persons, because it offers prevention through the removal of preneoplastic lesions in addition to early detection. This study aims to report the participation rate of colonoscopy screening and examine its associated factors amongst Chinese first-degree relatives of people with colorectal cancer based on the health belief model (HBM). A cross-sectional study was conducted in Shenzhen, China from March to May 2019. Demographic characteristics, family history, variables derived from the HBM and colonoscopy screening behaviours were measured through online surveys as the independent variables of interest. A total of 186 online surveys were returned, with a final response rate of 57.0%. The participation rate of colonoscopy was 15.6%. Univariate analysis (independent t-test/chi-square test/Fisher test) was applied first to identify the candidate independent variables. Then, multivariate logistic regression was used to examine the association between independent variables and uptake of colonoscopy. Perceived barriers and cues to action were identified as factors associated with undergoing colonoscopy. The participation rate of colonoscopy in the study population was low. Health communication to promote colonoscopy screening for the Chinese at-risk population should include components in reducing barriers to colonoscopy tests, family history information and health professional recommendations on screening. Future studies with large sample size are suggested to examine perceived susceptibility, fatalism and other characteristics considering family history (treatment and outcome of patients) and their potential impacts on cancer screening behaviours for Chinese at-risk populations due to family history.