The impact of sample type and procedural attributes on relative acceptability of different colorectal cancer screening regimens

Diagnostic Accuracy of an Add-On, Blood-Based Screening Test for Colorectal Cancer in Two Established Screening Programmes

BACKGROUND

CELTiC is a blood-based test consisting of a panel of four mRNAs (CEACAM6, LGALS4, TSPAN8 and COL1A2) associated with colorectal cancer (CRC). CELTiC has a high sensitivity (90%) for detecting advanced neoplasia (AN) when compared to faecal immunochemical test (FIT)-negative subjects.

AIMS

To evaluate the diagnostic accuracy of CELTiC as an add-on test following a positive FIT in two existing CRC screening programmes.

METHODS

We designed a prospective study in FIT-positive screenees. Analyses were performed in two (partially overlapping) groups: participants with FIT ≥ 47 μg Hb/g faeces (group I) and FIT ≥ 20 μg Hb/g faeces (group II). We estimated CELTIC sensitivity and specificity in detecting AN at a pre-defined and a post hoc threshold (targeted sensitivity: 90%).

RESULTS

We included 809 participants (n = 567 in group I and n = 486 in group II). CELTiC did not reach a sensitivity of 90% at the pre-defined threshold (Group I 41%, group II 27%). At the post hoc thresholds for 90% sensitivity in detecting AN, CELTiC had a specificity of 14% (53/388; 95% CI: 10% to 17%) in group I and 12% (44/354; 95% CI: 9% to 16%) in group II.

CONCLUSIONS

In a FIT-positive population, CELTiC did not reach 90% sensitivity at the pre-defined threshold. At post hoc thresholds corresponding to 90% sensitivity, specificity was low. CELTiC cannot currently be recommended as an add-on test to detect AN in FIT-positive screenees in a CRC screening programme.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04980443, NCT05205967, NCT04369053.

Annual Blood Tests Are an Acceptable form of Surveillance to Supplement Colonoscopies for Colorectal Cancer

BACKGROUND

Individuals at increased risk of colorectal cancer (CRC) are recommended surveillance colonoscopies as a preventative measure, but timely provision of colonoscopies remains a significant hurdle. Biomarker testing has emerged as a potential strategy to mitigate excessive colonoscopy use by prioritizing procedures for those most at risk of CRC. However, the acceptability of supplementing surveillance colonoscopies with regular blood tests is unknown.

AIM

To evaluate patient acceptance of a hypothetical surveillance protocol providing annual blood tests between 5-yearly colonoscopies.

METHODS

Eight hundred individuals enrolled in an Australian surveillance colonoscopy program were invited to complete a survey on surveillance preferences. Ordinal logistic regression analysis was performed to assess the influence of sociodemographic, clinical, and psychological variables on participants' comfort with the surveillance protocol.

RESULTS

A total of 409 (51%) individuals participated, with 346 (51% male, mean age 63 years) providing complete outcome data. Most participants (n = 250/346, 72%) reported being comfortable with the surveillance protocol. Significantly higher levels of comfort were reported by individuals with greater confidence in their ability to undergo blood testing (OR 1.26, 95% CI 1.08-1.47, p = 0.003) and those having less frequent surveillance colonoscopies (OR 1.26, 95% CI 1.01-1.58, p = 0.043). Significant associations were not observed between other variables and comfort with the surveillance protocol (p > 0.05).

CONCLUSIONS

Annual blood testing between surveillance colonoscopies was highly accepted by individuals at increased risk of CRC. Offering new blood-based modalities to specific subpopulations, particularly individuals who are more comfortable with blood testing, or those having less frequent surveillance colonoscopies, could enhance overall acceptance.

A multi-gene blood-based methylation assay for early diagnosis of colorectal cancer

Background

Early detection for colorectal cancer (CRC) can enhance the patient prognosis. We aimed to validate the combined multi-gene detection in plasma of Septin9, SDC2, KCNQ5, and IKZF1 for early diagnosing of CRC in this prospective study.

Methods

Overall, 124 participants including 45 CRC patients, 8 advanced adenoma patients, 34 small polyp patients, and 37 normal controls who underwent colonoscopy were enrolled. The carcinoembryonic antigen (CEA) test and methylation tests for Septin9, SDC2, KCNQ5, and IKZF1 were performed. Sensitivity, specificity, and the area under the curve (AUC) of the receiver operating characteristic (ROC) curve were utilized to evaluate the diagnostic value of each biomarker. Additionally, the association between the positive rates of methylated Septin9, SDC2, KCNQ5, and IKZF1 and the clinicopathological characteristics of CRC was also analyzed.

Results

The positive detection rate of multi-gene methylation in CRC patients was 86.67%, for stage I and stage II patients, the positive rates were 90.91% and 87.50%, both of which were significantly higher than CEA, which had rates of 55.56%, 18.18% and 56.25% for the corresponding stages. In patients with advanced adenomas and small polyps, the positive rates for the four-gene combined test were 62.50% and 52.94%, respectively, which were markedly higher than the CEA rates of 12.50% and 14.71%. AUC of the ROC curve indicated that the diagnostic value of the multi-gene test for CRC was superior to that of any single gene. Correlation analysis revealed that the positive rate of the test was not affected by patients' clinicopathological characteristics.

Conclusions

A combination of methylated Septin9, SDC2, KCNQ5, and IKZF1 test has the potential for early diagnosis of CRC patients, advanced adenoma patients, and small polyp patients.

Diagnosis of Helicobacter pylori infection: serology vs. urea breath test

The objective of the study was to ascertain an optimal Helicobacter pylori diagnostic strategy using population-level laboratory data comparing the performance of serology against urea breath test (UBT). H. pylori diagnostic test results for serology and UBT from two laboratories over a 12-year period (2006-20017) were extracted, linked, and analyzed. A subset of this population underwent both methods of testing within days of each other, enabling a direct comparison of the two methods. The average prevalence of H. pylori positivity was 21.3% by serology and 17.5% by UBT. There were 2,612 individuals who had serology performed first, followed by UBT within 14 days. For this subset, the sensitivity of serology compared with UBT was 96.5% with a specificity of 79.2%. The negative predictive value for serology was 98.4%. Contrary to various recent clinical guidelines, the data show that serology still has utility as a sensitive enough test to be used as an initial H. pylori screening test in a lower prevalence population. Negative serology can be used with confidence to rule out active infection, whereas a positive serology could be followed up with a UBT or a similar performing test such as stool antigen to differentiate active from past infection. For population-based diagnostic recommendations, such a strategy may be ideal since serology generally costs less than UBT and may be combined with a blood draw being done for other diagnostic tests. Continuing to offer serology increases options for patients and may provide economic benefits for single-payer health care systems or health maintenance organizations.

IMPORTANCE

This study compares the performance of serology with urea breath test in the diagnosis of Helicobacter pylori in a population-level data set and mimics a head-to-head direct comparison as the study population had both tests performed within 2 weeks of each other. This provides new information supporting the use of serology in a diagnostic algorithm. There are several instances where serology could be preferable to patients to rule out disease, despite some guidelines suggesting serology should not be used.

Where do we stand with screening for colorectal cancer and advanced adenoma based on serum protein biomarkers? A systematic review

Colorectal cancer (CRC) screening has been proven to reduce both mortality and the incidence of this disease. Most CRC screening programs are based on fecal immunochemical tests (FITs), which have a low participation rate. Searching for blood protein biomarkers can lead to the development of a more accepted screening test. The aim of this systematic review was to compare the diagnostic potential of the most promising serum protein biomarkers. A systematic review based on PRISMA guidelines was conducted in the PubMed and Web of Science databases between January 2010 and December 2023. Studies assessing blood protein biomarkers for CRC screening were included. The sensitivity, specificity, and area under the ROC curve of each biomarker were collected. Among 4685 screened studies, 94 were considered for analysis. Most of them were case-control studies, leading to an overestimation of the performance of candidate biomarkers. The performance of no protein biomarker or combination of biomarkers appears to match that of the FIT. Studies with a suitable design and population, testing new assay techniques, or based on algorithms combining FIT with serum tests are needed.

Evaluation of Multigene Methylation for Blood-Based Detection of Colorectal Cancer

Background: Early screening for colorectal cancer (CRC) has the potential to improve patient prognosis, but current screening methods are limited. In this prospective study, we aimed to evaluate the multigene (Septin9, SDC2, KCNQ5, and IKZF1) detection in patient plasma for CRC diagnosis. Methods: Overall, 67 participants were enrolled, including 31 patients with CRC, 17 patients with colorectal polyp, and 19 normal controls who underwent colonoscopy. Carcinoembryonic antigen (CEA) and Septin9, SDC2, KCNQ5, and IKZF1 methylation tests were performed. Sensitivity, specificity, and the area under the receiver operating characteristic (ROC) curve were used to evaluate the diagnostic value of each biomarker. The association between positive rates of methylated Septin9, SDC2, KCNQ5, and IKZF1 and the clinicopathological characteristics of CRC was also analyzed. Results: The positive rate of multigene methylation detection was 87.1% (27/31) in patients with CRC, which was higher than single indicators: CEA (51.61%, 16/31), Septin9 (41.94%, 13/31), SDC2 (41.94%, 13/31), KCNQ5 (58.06%, 18/31), and IKZF1 (32.26%, 10/31). In the colorectal polyp group, the rate of multigene methylation detection is 88.24% (15/17), which was also higher than single indicator: CEA (17.65%, 3/17), Septin9 (11.76%, 2/17), SDC2 (64.71%, 11/17), KCNQ5 (58.82%, 10/17), and IKZF1 (35.29%, 6/17). The ROC curves further showed better diagnostic value of the multigene test for CRC than any single gene. Correlation analysis found that the positive rate of the test was not affected by patients' clinicopathologic characteristics. Conclusion: The combination of methylated Septin9, SDC2, KCNQ5, and IKZF1 tests is preferable to individual gene tests for patients with CRC and polyp.

Facing the Emotional Barriers to Colorectal Cancer Screening. The Roles of Reappraisal and Situation Selection

BACKGROUND

Disgust, embarrassment, and fear can hinder the attendance of colorectal cancer (CRC) screening. However, individuals can respond to these emotions differently. The present study tested whether reappraising a negative stimulus versus avoiding a negative stimulus is associated with age; whether these two emotion regulation strategies (reappraisal and situation selection) moderate the effects of disgust, embarrassment and fear on CRC screening intention; and the efficacy of a message based on participants' preferred emotion regulation strategy.

METHODS

We recruited 483 Italian participants (aged 40-84 years) through snowball sampling. Participants were randomly assigned to one of four conditions differing for a message promoting CRC screening with an affective lever, a cognitive lever, both levers or none. Key variables included emotion regulation strategies, emotional barriers and intention to get screened.

RESULTS

The preference for reappraisal over situation selection increased with age. Reappraisal neutralized the effect of disgust on CRC screening intention. The combined message with both affective and cognitive levers increased CRC screening intention (b = 0.27, β = 0.11, SE = 0.13 p = .049), whereas reading the message based only on the affective (b = 0.16, β = 0.06, SE = 0.14 p = .258) or the cognitive (b = 0.22, β = 0.09, SE = 0.14 p = .107) lever was not effective.

CONCLUSIONS

Communication campaigns should support the activation of a reappraisal strategy of emotion control, and messages promoting CRC screening should highlight both the instrumental (i.e., early detection) and affective (i.e., peace of mind) benefits of attendance.

Machine learning-based identification of colorectal advanced adenoma using clinical and laboratory data: a phase I exploratory study in accordance with updated World Endoscopy Organization guidelines for noninvasive colorectal cancer screening tests

Objective

The recent World Endoscopy Organization (WEO) guidelines now recognize precursor lesions of colorectal cancer (CRC) as legitimate screening targets. However, an optimal screening method for detecting advanced adenoma (AA), a significant precursor lesion, remains elusive.

Methods

We employed five machine learning methods, using clinical and laboratory data, to develop and validate a diagnostic model for identifying patients with AA (569 AAs vs. 3228 controls with normal colonoscopy). The best-performing model was selected based on sensitivity and specificity assessments. Its performance in recognizing adenoma-carcinoma sequence was evaluated in line with guidelines, and adjustable thresholds were established. For comparison, the Fecal Occult Blood Test (FOBT) was also selected.

Results

The XGBoost model demonstrated superior performance in identifying AA, with a sensitivity of 70.8% and a specificity of 83.4%. It successfully detected 42.7% of non-advanced adenoma (NAA) and 80.1% of CRC. The model-transformed risk assessment scale provided diagnostic performance at different positivity thresholds. Compared to FOBT, the XGBoost model better identified AA and NAA, however, was less effective in CRC.

Conclusion

The XGBoost model, compared to FOBT, offers improved accuracy in identifying AA patients. While it may not meet the recommendations of some organizations, it provides value for individuals who are unable to use FOBT for various reasons.

Differential impact of test performance characteristics on burden-to-benefit tradeoffs for blood-based colorectal cancer screening: A microsimulation analysis

OBJECTIVES

To inform the development and evaluation of new blood-based colorectal cancer (CRC) screening tests satisfying minimum United States (US) coverage criteria, we estimated the impact of the different test performance characteristics on long-term testing benefits and burdens.

METHODS

A novel CRC-Microsimulation of Adenoma Progression and Screening (CRC-MAPS) model was developed, validated, then used to assess different screening tests for CRC. We compared multiple, hypothetical blood-based CRC screening tests satisfying minimum coverage criteria of 74% CRC sensitivity and 90% specificity, to measure how changes in a test's CRC sensitivity, specificity, and adenoma sensitivity (sizes 1-5 mm, 6-9 mm, ≥10 mm) affect total number of colonoscopies (COL), CRC incidence reduction (IR), CRC mortality reduction (MR), and burden-to-benefit ratios (incremental COLs per percentage-point increase in IR or MR).

RESULTS

A blood test meeting minimum US coverage criteria for performance characteristics resulted in 1576 lifetime COLs per 1000 individuals, 46.7% IR and 59.2% MR compared to no screening. Tests with increased CRC sensitivity of 99% ( + 25%) vs. increased ≥10 mm adenoma sensitivity of 13.6% ( + 3.6%) both yielded the same MR, 62.7%. Test benefits improved the most with increases in all-size adenoma sensitivity, then size-specific adenoma sensitivities, then specificity and CRC sensitivity, while increases in specificity or ≥10 mm adenoma sensitivity resulted in the most favorable burden-to-benefit tradeoffs (ratios <11.5).

CONCLUSIONS

Burden-to-benefit ratios for blood-based CRC screening tests differ by performance characteristic, with the most favorable tradeoffs resulting from improvements in specificity and ≥10 mm adenoma sensitivity.

Serum Activin A Is a Novel Biomarker of Endoscopic Activity in Ulcerative Colitis

Background

Endoscopic healing (EH) is the long-term therapeutic goal for ulcerative colitis (UC). Since repeated colonoscopies are inconvenient and invasive, a surrogate biomarker for endoscopic activity is needed. Activin A is one of the transforming growth factor-β superfamily of proteins and has been shown to be associated with intestinal inflammation.

Methods

This single-center observational study included 27 Japanese patients with UC in clinical remission who underwent colonoscopy and blood sampling. We investigated the correlations between laboratory parameters, including serum activin A levels, and endoscopic activity, classified by the Mayo endoscopic subscore (MES) in these patients.

Results

This study included 15 males and 12 females. The median age was 44.0 years. In terms of endoscopic activity, five patients were diagnosed with MES 0, 14 patients with MES 1, seven patients with MES 2, and one patient with MES 3. The median serum activin level was 134.8 pg/mL (interquartile range (IQR), 105.3 - 188.1). Serum activin A levels were significantly correlated with the MES (Spearman's rank correlation coefficient r = 0.591, P = 0.001), which was better than that of C-reactive protein (CRP) (r = 0.487, P = 0.010). In the comparison between the EH group (MES 0) and non-EH group (MES 1-3), patients without EH had significantly higher serum activin A levels (Mann-Whitney U test, P = 0.047). A cutoff value of 133.6 pg/mL indicated non-EH with a sensitivity and specificity of 0.682 and 1.000, respectively. The area under the curve (AUC) of serum activin A for detecting non-EH was 0.791 (95% confidence interval (CI), 0.618 - 0.964), while that of CRP was 0.723 (95% CI, 0.504 - 0.941).

Conclusions

The serum activin A level is a potential novel biomarker of endoscopic activity in UC.

Psychosocial Predictors of Colorectal Cancer Screening Intention: An Experiment on the Invitation Letter

BACKGROUND

In Italy, attendance rates for colorectal cancer (CRC) screening are suboptimal. The present work analysed cognitive and emotional predictors of CRC screening intention and tested an intervention on a real invitation letter to improve CRC screening intention, both directly and in interaction with the predictors of our model.

METHODS

Our model included variables from the theory of planned behaviour and the emotional barriers to bowel screening scale. We applied six changes to an invitation letter used in Italy to avoid the repetition of words like 'faeces', 'blood', or 'occult' and reduce the prompting of disgust. The 228 participants were randomly assigned to a between-participants design (original letter vs. manipulated letter).

RESULTS

Disgust hindered CRC screening intention, while embarrassment, fear, and subjective norms (i.e., perception of the social pressures to attend CRC screening) were not associated with intention to screen. More positive attitudes towards CRC screening were associated with a higher intention to screen. The positive association between perceived behavioural control and CRC screening intention was stronger for participants who read the letter with fewer (vs. more) references to bodily waste. Letter manipulation did not affect intention to screen.

CONCLUSIONS

The disgust associated with faecal matter is a critical factor in determining CRC screening attendance, and it should be acknowledged as such in public policies. Until new screening tests avoiding the activation of this emotional reaction are concretely available, public campaigns should improve CRC screening participation by boosting both positive attitudes towards screening and patients' perceived behavioural control.

Serum methylation of GALNT9, UPF3A, WARS, and LDB2 as noninvasive biomarkers for the early detection of colorectal cancer and advanced adenomas

BACKGROUND

Early detection has proven to be the most effective strategy to reduce the incidence and mortality of colorectal cancer (CRC). Nevertheless, most current screening programs suffer from low participation rates. A blood test may improve both the adherence to screening and the selection to colonoscopy. In this study, we conducted a serum-based discovery and validation of cfDNA methylation biomarkers for CRC screening in a multicenter cohort of 433 serum samples including healthy controls, benign pathologies, advanced adenomas (AA), and CRC.

RESULTS

First, we performed an epigenome-wide methylation analysis with the MethylationEPIC array using a sample pooling approach, followed by a robust prioritization of candidate biomarkers for the detection of advanced neoplasia (AN: AA and CRC). Then, candidate biomarkers were validated by pyrosequencing in independent individual cfDNA samples. We report GALNT9, UPF3A, WARS, and LDB2 as new noninvasive biomarkers for the early detection of AN. The combination of GALNT9/UPF3A by logistic regression discriminated AN with 78.8% sensitivity and 100% specificity, outperforming the commonly used fecal immunochemical test and the methylated SEPT9 blood test.

CONCLUSIONS

Overall, this study highlights the utility of cfDNA methylation for CRC screening. Our results suggest that the combination methylated GALNT9/UPF3A has the potential to serve as a highly specific and sensitive blood-based test for screening and early detection of CRC.

Network approach in liquidomics landscape

Tissue-based biopsy is the present main tool to explore the molecular landscape of cancer, but it also has many limits to be frequently executed, being too invasive with the risk of side effects. These limits and the ability of cancer to constantly evolve its genomic profile, have recently led to the need of a less invasive and more accurate alternative, such as liquid biopsy. By searching Circulating Tumor Cells and residues of their nucleic acids or other tumor products in body fluids, especially in blood, but also in urine, stools and saliva, liquid biopsy is becoming the future of clinical oncology. Despite the current lack of a standardization for its workflows, that makes it hard to be reproduced, liquid biopsy has already obtained promising results for cancer screening, diagnosis, prognosis, and risk of recurrence.Through a more accessible molecular profiling of tumors, it could become easier to identify biomarkers predictive of response to treatment, such as EGFR mutations in non-small cell lung cancer and KRAS mutations in colorectal cancer, or Microsatellite Instability and Mismatch Repair as predictive markers of pembrolizumab response.By monitoring circulating tumor DNA in longitudinal repeated sampling of blood we could also predict Minimal Residual Disease and the risk of recurrence in already radically resected patients.In this review we will discuss about the current knowledge of limitations and strengths of the different forms of liquid biopsies for its inclusion in normal cancer management, with a brief nod to their newest biomarkers and its future implications.

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.

Attributes in stated preference elicitation studies on colorectal cancer screening and their relative importance for decision-making among screenees: a systematic review

INTRODUCTION

The SIGMO study (Sigmoidoscopy as an evidence-based colorectal cancer screening test - a possible option?) examines screening eligible populations' preferences for colorectal cancer (CRC) screening in Germany using a discrete choice experiment (DCE). Attribute identification and selection are essential for the construction of choice tasks and should be evidence-based. As a part of the SIGMO study this systematic review provides an overview of attributes included in studies eliciting stated preferences for CRC screening tests and their relative importance for decision-making.

METHODS

Systematic search (November 2021) for English-language studies published since January 2000 in PubMed, Embase, Web of Science, Biomedical Reference Collection: Corporate Edition, LIVIVO and PsycINFO. DCEs and conjoint analysis ranking or rating tasks on screening eligible populations' preferences for stool testing, sigmoidoscopy, and/or colonoscopy were included. Attributes were extracted and their relative importance was calculated and ranked. Risk of bias (RoB) of included studies was assessed using a modified GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Study selection and RoB rating were carried out independently by two reviewers. Data were extracted by one reviewer and checked by another one.

RESULTS

A total of 23 publications on 22 studies were included. Overall RoB was rated as serious/critical for 21 studies and as moderate for 2 studies. Main reasons for high RoB were non-random sampling, low response rates, lack of non-responder analyses, and, to a lesser extent, weaknesses in the measurement instrument and data analysis. Extracted attributes (n = 120) referred to procedure-related characteristics (n = 42; 35%), structural characteristics of health care (n = 24; 20%), test characteristics (n = 23; 19%), harms (n = 16; 13%), benefits (n = 13; 11%), and level of evidence (n = 2; 2%). Most important attributes were reduction in CRC mortality (and incidence) (n = 7), test sensitivity (n = 7), out-of-pocket costs (n = 4), procedure (n = 3), and frequency (n = 2).

CONCLUSIONS

Health preference studies on CRC were found to have a high RoB. The composition of choice tasks revealed a lack of attributes on patient-important outcomes (like incidence reduction), while attributes not considered relevant for individual screening decisions (like sensitivity) were frequently used. Future studies eliciting stated preferences in cancer screening should apply the principles of informed decision-making in attribute identification and selection.

Circulating tumour DNA - looking beyond the blood

Over the past decade, various liquid biopsy techniques have emerged as viable alternatives to the analysis of traditional tissue biopsy samples. Such surrogate 'biopsies' offer numerous advantages, including the relative ease of obtaining serial samples and overcoming the issues of interpreting one or more small tissue samples that might not reflect the entire tumour burden. To date, the majority of research in the area of liquid biopsies has focused on blood-based biomarkers, predominantly using plasma-derived circulating tumour DNA (ctDNA). However, ctDNA can also be obtained from various non-blood sources and these might offer unique advantages over plasma ctDNA. In this Review, we discuss advances in the analysis of ctDNA from non-blood sources, focusing on urine, cerebrospinal fluid, and pleural or peritoneal fluid, but also consider other sources of ctDNA. We discuss how these alternative sources can have a distinct yet complementary role to that of blood ctDNA analysis and consider various technical aspects of non-blood ctDNA assay development. We also reflect on the settings in which non-blood ctDNA can offer distinct advantages over plasma ctDNA and explore some of the challenges associated with translating these alternative assays from academia into clinical use.

Early detection of colorectal neoplasia: application of a blood-based serological protein test on subjects undergoing population-based screening

BACKGROUND

Blood-based biomarkers used for colorectal cancer screening need to be developed and validated in appropriate screening populations. We aimed to develop a cancer-associated protein biomarker test for the detection of colorectal cancer in a screening population.

METHODS

Participants from the Danish Colorectal Cancer Screening Program were recruited. Blood samples were collected prior to colonoscopy. The cohort was divided into training and validation sets. We present the results of model development using the training set. Age, sex, and the serological proteins CEA, hsCRP, TIMP-1, Pepsinogen-2, HE4, CyFra21-1, Galectin-3, ferritin and B2M were used to develop a signature test to discriminate between participants with colorectal cancer versus all other findings at colonoscopy.

RESULTS

The training set included 4048 FIT-positive participants of whom 242 had a colorectal cancer. The final model for discriminating colorectal cancer versus all other findings at colonoscopy had an AUC of 0.70 (95% CI: 0.66-0.74) and included age, sex, CEA, hsCRP, HE4 and ferritin.

CONCLUSION

The performance of the biomarker signature in this FIT-positive screening population did not reflect the positive performance of biomarker signatures seen in symptomatic populations. Additional biomarkers are needed if the serological biomarkers are to be used as a frontline screening test.

Trans-Renal Cell-Free Tumor DNA for Urine-Based Liquid Biopsy of Cancer

Cancer biomarkers are a promising tool for cancer detection, personalization of therapy, and monitoring of treatment response or recurrence. “Liquid biopsy” commonly refers to minimally invasive or non-invasive sampling of a bodily fluid (i.e., blood, urine, saliva) for detection of cancer biomarkers such as circulating tumor cells or cell-free tumor DNA (ctDNA). These methods offer a means to collect frequent tumor assessments without needing surgical biopsies. Despite much progress with blood-based liquid biopsy approaches, there are limitations—including the limited amount of blood that can be drawn from a person and challenges with collecting blood samples at frequent intervals to capture ctDNA biomarker kinetics. These limitations are important because ctDNA is present at extremely low levels in plasma and there is evidence that measuring ctDNA biomarker kinetics over time can be useful for clinical prediction. Additionally, blood-based assays require access to trained phlebotomists and often a trip to a healthcare facility. In contrast, urine is a body fluid that can be self-collected from a patient’s home, at frequent intervals, and mailed to a laboratory for analysis. Multiple reports indicate that fragments of ctDNA pass from the bloodstream through the kidney’s glomerular filtration system into the urine, where they are known as trans-renal ctDNA (TR-ctDNA). Accumulating studies indicate that the limitations of blood based ctDNA approaches for cancer can be overcome by measuring TR-ctDNA. Here, we review current knowledge about TR-ctDNA in urine as a cancer biomarker approach, and discuss its clinical potential and open questions in this research field.

Role of Biomarkers in the Diagnosis and Treatment of Inflammatory Bowel Disease

The number of patients with inflammatory bowel disease (IBD) is increasing worldwide. Endoscopy is the gold standard to assess the condition of IBD. The problem with this procedure is that the burden and cost on the patient are high. Therefore, the identification of a reliable biomarker to replace endoscopy is desired. Biomarkers are used in various situations such as diagnosis of IBD, evaluation of disease activity, prediction of therapeutic effect, and prediction of relapse. C-reactive protein and fecal calprotectin have a lot of evidence as objective biomarkers of disease activity in IBD. The usefulness of the fecal immunochemical test, serum leucine-rich glycoprotein, and urinary prostaglandin E major metabolite have also been reported. Herein, we comprehensively review the usefulness and limitations of biomarkers that can be used in daily clinical practice regarding IBD. To date, no biomarker is sufficiently accurate to replace endoscopy; however, it is important to understand the characteristics of each biomarker and use the appropriate biomarker at the right time in daily clinical practice.

Attributes Used for Cancer Screening Discrete Choice Experiments: A Systematic Review

BACKGROUND

Evidence from discrete choice experiments can be used to enrich understanding of preferences, inform the (re)design of screening programmes and/or improve communication within public campaigns about the benefits and harms of screening. However, reviews of screening discrete choice experiments highlight significant discrepancies between stated choices and real choices, particularly regarding willingness to undergo cancer screening. The identification and selection of attributes and associated levels is a fundamental component of designing a discrete choice experiment. Misspecification or misinterpretation of attributes may lead to non-compensatory behaviours, attribute non-attendance and responses that lack external validity.

OBJECTIVES

We aimed to synthesise evidence on attribute development, alongside an in-depth review of included attributes and methodological challenges, to provide a resource for researchers undertaking future studies in cancer screening.

METHODS

A systematic review was conducted to identify discrete choice experiments estimating preferences towards cancer screening, dated between 1990 and December 2020. Data were synthesised narratively. In-depth analysis of attributes led to classification into four categories: test specific, service delivery, outcomes and monetary. Attribute significance and relative importance were also analysed. The International Society for Pharmacoeconomics and Outcomes Research conjoint analysis checklist was used to assess the quality of reporting.

RESULTS

Forty-nine studies were included at full text. They covered a range of cancer sites: over half (26/49) examined colorectal screening. Most studies elicited general public preferences (34/49). In total, 280 attributes were included, 90% (252/280) of which were significant. Overall, test sensitivity and mortality reduction were most frequently found to be the most important to respondents.

CONCLUSIONS

Improvements in reporting the identification, selection and construction of attributes used within cancer screening discrete choice experiments are needed. This review also highlights the importance of considering the complexity of choice tasks when considering risk information or compound attributes. Patient and public involvement and stakeholder engagement are recommended to optimise understanding of unavoidably complex choice tasks throughout the design process. To ensure quality and maximise comparability across studies, further research is needed to develop a risk-of-bias measure for discrete choice experiments.

Colorectal Cancer Screening: Have We Addressed Concerns and Needs of the Target Population?

Despite the recognized benefits of colorectal cancer (CRC) screening, uptake is still suboptimal in many countries. In addressing this issue, one important element that has not received sufficient attention is population preference. Our review provides a comprehensive summary of the up-to-date evidence relative to this topic. Four OVID databases were searched: Ovid MEDLINE® ALL, Biological Abstracts, CAB Abstracts, and Global Health. Among the 742 articles generated, 154 full texts were selected for a more thorough evaluation based on predefined inclusion criteria. Finally, 83 studies were included in our review. The general population preferred either colonoscopy as the most accurate test, or fecal occult blood test (FOBT) as the least invasive for CRC screening. The emerging blood test (SEPT9) and capsule colonoscopy (nanopill), with the potential to overcome the pitfalls of the available techniques, were also favored. Gender, age, race, screening experience, education and beliefs, the perceived risk of CRC, insurance, and health status influence one’s test preference. To improve uptake, CRC screening programs should consider offering test alternatives and tailoring the content and delivery of screening information to the public’s preferences. Other logistical measures in terms of the types of bowel preparation, gender of endoscopist, stool collection device, and reward for participants can also be useful.

Population-Based Data Reveal Factors Associated with Organised and Non-Organised Colorectal Cancer Screening: An Important Step towards Improving Coverage

We investigated factors associated with organised and non-organised colorectal cancer screening using faecal occult blood tests, based on data from 308 municipalities in Flanders (6.6 million residents, 57% of Belgium) during 2015-2017. Logistic regression with generalized estimating equations was used to assess the associations between municipal characteristics and organised and non-organised screening coverages. Factors associated negatively with both organised and non-organised screening: percentage of people aged 70-74 in the target population [OR (odds ratios) = 0.98, 95%CI (confidence interval): 0.97-0.99 and OR = 0.98, 95%CI: 0.96-0.999, respectively]; negatively with organised screening: average income [OR = 0.97, 95%CI: 0.96-0.98], percentage of people with a non-Belgian/Dutch nationality [OR = 0.962, 95%CI: 0.957-0.967]; positively with organised screening: percentages of men in the target population [OR = 1.13, 95%CI: 1.11-1.14], jobseekers [OR = 1.12, 95%CI: 1.09-1.15] and people with at least one general practitioner (GP) visit in the last year [OR = 1.04, 95%CI: 1.03-1.05]; positively with non-organised screening: number of patients per GP [OR = 1.021, 95%CI: 1.016-1.026], percentage of people with a global medical dossier handled by a preferred GP [OR = 1.025, 95%CI: 1.018-1.031]. This study helps to identify the hard-to-reach subpopulations in CRC screening, and highlights the important role of GPs in the process of promoting screening among non-participants and encouraging non-organised participants to switch to organised screening.

"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.

Surrogate markers of mucosal healing in inflammatory bowel disease: A systematic review

BACKGROUND

Mucosal healing (MH) has emerged as a key therapeutic target in inflammatory bowel disease (IBD), and achievement of this goal is documented by endoscopy with biopsy. However, colonoscopy is burdensome and invasive, and substitution with an accurate noninvasive biomarker is desirable.

AIM

To summarize published data regarding the performance of noninvasive biomarkers in assessing MH in IBD patients.

METHODS

We conducted a systematic review of studies that reported the performance of biomarkers in diagnosing MH in patients with IBD. The main outcome measure was to review the diagnostic accuracy of serum and fecal markers that showed promising utility in assessing MH.

RESULTS

We screened 1301 articles, retrieved 46 manuscripts and included 23 articles for full-text analysis. The majority of the included manuscripts referred to fecal markers (12/23), followed by circulatory markers (8/23); only 3/23 of the included manuscripts investigated combined markers (serum and/or fecal markers). Fecal calprotectin (FC) was the most investigated fecal marker for assessing MH. In ulcerative colitis, for cutoff levels ranging between 58 mcg/g and 490 mcg/g, the sensitivity was 89.7%-100% and the specificity was 62%-93.3%. For Crohn's disease, the cutoff levels of FC ranged from 71 mcg/g to 918 mcg/g (sensitivity 50%-95.9% and specificity 52.3%-100%). The best performance for a serum marker was observed for the endoscopic healing index, which showed a comparable accuracy to the measurement of FC and a higher accuracy than the measurement of serum C-reactive protein.

CONCLUSION

Several promising biomarkers of MH are emerging but cannot yet substitute for endoscopy with biopsy due to issues with reproducibility and standardization.

The Roadmap of Colorectal Cancer Screening

Colorectal cancer (CRC) is the third most common form of cancer in terms of incidence and the second in terms of mortality worldwide. CRC develops over several years, thus highlighting the importance of early diagnosis. National screening programs based on fecal occult blood tests and subsequent colonoscopy have reduced the incidence and mortality, however improvements are needed since the participation rate remains low and the tests present a high number of false positive results. This review provides an overview of the CRC screening globally and the state of the art in approaches aimed at improving accuracy and participation in CRC screening, also considering the need for gender and age differentiation. New fecal tests and biomarkers such as DNA methylation, mutation or integrity, proteins and microRNAs are explored, including recent investigations into fecal microbiota. Liquid biopsy approaches, involving novel biomarkers and panels, such as circulating mRNA, micro- and long-non-coding RNA, DNA, proteins and extracellular vesicles are discussed. The approaches reported are based on quantitative PCR methods that could be easily applied to routine screening, or arrays and sequencing assays that should be better exploited to describe and identify candidate biomarkers in blood samples.

A review of potential microbiome-gut-brain axis mediated neurocognitive conditions in persons living with HIV

The microbiome-gut-brain axis, or the various interactions between the gut microbiome and the brain, has been of recent interest in the context of precision medicine research for a variety of disease states. Persons living with human immunodeficiency virus (PLWH) experience higher degrees of neurocognitive decline than the general population, correlating with a disruption of the normal gut microbiome composition (i.e. dysbiosis). While the nature of this correlation remains to be determined, there is the potential that the microbiome-gut-brain axis contributes to the progression of this disease. Previous research has established that the pathology associated with HIV induces alterations in the composition of gut microbiome, including a shift from Bacteroides to Prevotella dominance, and compromises gut barrier integrity, which may promote microbial translocation and consequent systemic inflammation and exacerbation of neuroinflammation. Further, though the use of antiretroviral therapy has been found to partially counteract HIV-related dysbiosis, it may also induce its own dysbiosis patterns, presenting a unique challenge for this research. More recent research has suggested the gut microbiome as a target for therapeutic interventions to improve symptoms associated with a variety of disease states, including HIV. Early findings are promising and warrant further research regarding the gut microbiome as a potential modifiable factor to improve health outcomes for PLWH. This review will discuss the current knowledge concerning the neuropathogenesis of HIV in the brain, role of the gut microbiome in neuroinflammation, and the relationship between HIV-status and the gut microbiome, followed by a conclusion that synthesizes this information within the context of the microbiome-gut-brain axis among PLWH. This review will also highlight the limitations of existing studies and propose future directions of this research.

Triage May Improve Selection to Colonoscopy and Reduce the Number of Unnecessary Colonoscopies

Implementation of population screening for colorectal cancer by direct colonoscopy or follow-up colonoscopy after a positive fecal blood test has challenged the overall capacity of bowel examinations. Certain countries are facing serious colonoscopy capacity constraints, which have led to waiting lists and long time latency of follow-up examinations. Various options for improvement are considered, including increased cut-off values of the fecal blood tests. Results from major clinical studies of blood-based, cancer-associated biomarkers have, however, led to focus on a Triage concept for improved selection to colonoscopy. The Triage test may include subject age, concentration of hemoglobin in a feces test and a combination of certain blood-based cancer-associated biomarkers. Recent results have indicated that Triage may reduce the requirements for colonoscopy by around 30%. Such results may be advantageous for the capacity, the healthcare budgets and in particular, the subjects, who do not need an unnecessary, unpleasant and risk-associated bowel examination.

A validated risk stratification tool for detecting high-risk small bowel Crohn's disease

BACKGROUND

Delays in Crohn's disease (CD) diagnosis are positively associated with ileal location and an increased risk of complications.

AIM

To develop a simple risk assessment tool to enable primary care physicians to recognise potential ileal CD earlier, shortening the delay to specialist investigation METHODS: Three cohorts were acquired for this study. Cohort 1 included 61 patients retrospectively identified with ileal CD between 2000 and 2010 and 78 matched controls drawn from a cohort referred for investigation of abdominal symptoms. Cohort 2 included 42 individuals diagnosed with ileal CD and 57 controls identified prospectively. Cohort 3 included an additional 84 individuals with ileal CD and 495 without CD referred for colonoscopy. Clinical symptoms and serological biomarkers were acquired and used to develop a risk prediction algorithm. The algorithm was trained independently on each of the three cohorts and tested on the latter two cohorts.

RESULTS

Altered bowel habit with abdominal pain combined with derangements in white cell count (WCC), albumin and platelet counts were important features in predicting ileal CD (AUC = 0.92, 95% CI = 0.89-0.92). This was validated in cohorts 2 (AUC = 0.96, 95% CI = 0.95-0.98) and 3 (AUC = 0.94, 95% CI = 0.92-0.96). C-reactive protein was independently associated with ileal CD but non-signficant in a multivariate model.

CONCLUSION

A web-based risk stratification tool for ileal CD has been developed from objective and symptom-based criteria. This tool enables primary care physicians to more confidently request urgent specialist assessment for patients identified as at high risk for ileal CD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPACT

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

A Randomized Controlled Trial Testing Provision of Fecal and Blood Test Options on Participation for Colorectal Cancer Screening

Suboptimal participation is commonly observed in colorectal cancer screening programs utilizing fecal tests. This randomized controlled trial tested whether the offer of a blood test as either a "rescue" strategy for fecal test nonparticipants or an upfront choice, could improve participation. A total of 1,800 people (50-74 years) were randomized to control, rescue, or choice groups (n = 600/group). All were mailed a fecal immunochemical test (FIT, OC-Sensor, Eiken Chemical Company) and a survey assessing awareness of the screening tests. The rescue group was offered a blood test 12 weeks after FIT nonparticipation. The choice group was given the opportunity to choose to do a blood test (Colvera, Clinical Genomics) instead of FIT at baseline. Participation with any test after 24 weeks was not significantly different between groups (control, 37.8%; rescue, 36.9%; choice, 33.8%; P > 0.05). When the rescue strategy was offered after 12 weeks, an additional 6.5% participated with the blood test, which was greater than the blood test participation when offered as an upfront choice (1.5%; P < 0.001). Awareness of the tests was greater for FIT than for blood (96.2% vs. 23.1%; P < 0.0001). In a population familiar with FIT screening, provision of a blood test either as a rescue of FIT nonparticipants or as an upfront choice did not increase overall participation. This might reflect a lack of awareness of the blood test for screening compared with FIT.