Fecal DNA versus fecal occult blood for colorectal-cancer screening in an average-risk population

Screening and Surveillance of Colorectal Cancer: A Review of the Literature

Colorectal cancer (CRC) has the highest mortality rate among men and is the second highest among women under fifty, with incidence and mortality rates rising in younger populations. Studies indicate that up to one-third of patients diagnosed before fifty have a family history or genetic factors, highlighting the need for earlier screening. Contrariwise, diagnosis in healthy subjects through screening strategies enables early-stage detection of the tumor and better clinical outcomes. In recent years, mortality rates of CRC in Western countries have been on a steady decline, which is largely attributed to widespread screening programs and advancements in treatment modalities. Indeed, early detection through screening significantly improves prognosis, with stark differences in survival rates between localized and metastatic disease. This article aims to provide a comprehensive review of the existing literature, delving into the performance and efficacy of various CRC screening strategies. It navigates through available screening tools, evaluating their efficacy and cost-effectiveness. The discussion extends to delineating target populations for screening, emphasizing the importance of tailored approaches for individuals at heightened risk.

Serum biomarkers REG1A and REG3A combined with the traditional CEA represent a novel nomogram for the screening and risk stratification of colorectal cancer

BACKGROUND

To develop and validate a serum protein nomogram for colorectal cancer (CRC) screening.

METHODS

The serum protein characteristics were extracted from an independent sample containing 30 colorectal cancer and 12 polyp tissues along with their paired samples, and different serum protein expression profiles were validated using RNA microarrays. The prediction model was developed in a training cohort that included 1345 patients clinicopathologically confirmed CRC and 518 normal participants, and data were gathered from November 2011 to January 2017. The lasso logistic regression model was employed for features selection and serum nomogram building. An internal validation cohort containing 576 CRC patients and 222 normal participants was assessed.

RESULTS

Serum signatures containing 27 secreted proteins were significantly differentially expressed in polyps and CRC compared to paired normal tissue, and REG family proteins were selected as potential predictors. The C-index of the nomogram1 (based on Lasso logistic regression model) which contains REG1A, REG3A, CEA and age was 0.913 (95% CI, 0.899 to 0.928) and was well calibrated. Addition of CA199 to the nomogram failed to show incremental prognostic value, as shown in nomogram2 (based on logistic regression model). Application of the nomogram1 in the independent validation cohort had similar discrimination (C-index, 0.912 [95% CI, 0.890 to 0.934]) and good calibration. The decision curve (DCA) and clinical impact curve (ICI) analysis demonstrated that nomogram1 was clinically useful.

CONCLUSIONS

This study presents a serum nomogram that included REG1A, REG3A, CEA and age, which can be convenient for screening of colorectal cancer.

Designing cancer screening trials for reduction in late-stage cancer incidence

Before implementing a biomarker test for early cancer detection into routine clinical care, the test must demonstrate clinical utility, that is, the test results should lead to clinical actions that positively affect patient-relevant outcomes. Unlike therapeutical trials for patients diagnosed with cancer, designing a randomized controlled trial (RCT) to demonstrate the clinical utility of an early detection biomarker with mortality and related endpoints poses unique challenges. The hurdles stem from the prolonged natural progression of the disease and the lack of information regarding the time-varying screening effect on the target asymptomatic population. To facilitate the study design of screening trials, we propose using a generic multistate disease history model and derive model-based effect sizes. The model links key performance metrics of the test, such as sensitivity, to primary endpoints like the incidence of late-stage cancer. It also incorporates the practical implementation of the biomarker-testing program in real-world scenarios. Based on the chronological time scale aligned with RCT, our method allows the assessment of study powers based on key features of the new program, including the test sensitivity, the length of follow-up, and the number and frequency of repeated tests. The calculation tool from the proposed method will enable practitioners to perform realistic and quick evaluations when strategizing screening trials for specific diseases. We use numerical examples based on the National Lung Screening Trial to demonstrate the method.

Sessile serrated polyp detection rates after fecal immunochemical test or multitarget stool DNA test: Systematic review and meta-analysis

Background and study aims Published studies report a higher adenoma detection rate (ADR) for FIT-DNA as compared with FIT. Data are less replete about the performance of stool-based tests for sessile serrated polyp (SSP) detection. We performed a meta-analysis to evaluate the performance of FIT and FIT-DNA testing for SSP detection rate (SSPDR) in patients undergoing colonoscopy for follow up of positive noninvasive tests. Methods A comprehensive literature search of multiple databases (until September 2022) was performed to identify studies reporting SSPDR in patients with positive FIT or FIT-DNA tests. The outcome was overall colonoscopy detection of any SSPs and advanced serrated polyps (ASP: SSP ≥ 10 mm and/or dysplasia). Results Included were 482,405 patients (52.4% females) with a mean age of 62.3 ± 4.4 years from 23 studies. The pooled SSPDR for all positive stool-based tests was 5.3% and higher for FIT-DNA (15.0%, 95% confidence interval [CI] 8.3-25.7) versus FIT (4.1%, 95% CI 3.0-5.6; P = 0.0002). The overall pooled ASP detection rate was 1.4% (95% CI 0.81-2.3) and higher for FIT-DNA (3.8 %, 95% CI 1.7-8.6) compared with FIT (0.71%, 95% CI 0.36-1.4; P <0.01). SSPDR with FIT-DNA was also significantly higher than FIT when the FIT cutoff was >10 ug/g and in FIT-positive patients in studies conducted in North America ( P <0.05). Conclusions FIT-DNA outperformed FIT in both SSP and ASP detection including FIT with a lower threshold cutoff of >10 ug/g. Further comparative studies are needed to assess the impact of our findings on colorectal cancer reduction.

Next-generation Multi-target Stool DNA Panel Accurately Detects Colorectal Cancer and Advanced Precancerous Lesions

The multi-target stool DNA (mt-sDNA) test screens for colorectal cancer by analyzing DNA methylation/mutation and hemoglobin markers to algorithmically derive a qualitative result. A new panel of highly discriminant candidate methylated DNA markers (MDM) was recently developed. Performance of the novel MDM panel, with hemoglobin, was evaluated in a simulated screening population using archived stool samples weighted to early-stage colorectal cancer and prospectively collected advanced precancerous lesions (APL). Marker selection study (MSS) and separate preliminary independent verification studies (VS) were conducted utilizing samples from multi-center, case-control studies. Sample processing included targeted MDM capture, bisulfite conversion, and MDM quantitation. Fecal hemoglobin was quantified using ELISA. Samples were stratified into 75%/25% training-testing sets; model outcomes were cross-validated 1,000 times. All laboratory operators were blinded. The MSS included 232 cases (120 colorectal cancer/112 APLs) and 490 controls. The VS featured 210 cases (112 colorectal cancer/98 APLs) and 567 controls; APLs were 86.7% adenomas and 13.3% sessile serrated lesions (SSL). Average age was 65.5 (cases) and 63.2 (controls) years. Mean sensitivity in the VS from cross-validation was 95.2% for colorectal cancer and 57.2% for APLs, with specificities of 89.8% (no CRC/APLs) and 92.4% (no neoplasia). Subgroup analyses showed colorectal cancer sensitivities of 93.4% (stage I) and 94.2% (stage II). APL sensitivity was 82.9% for high-grade dysplasia, 73.4% for villous lesions, 49.8% for tubular lesions, and 30.2% for SSLs. These data support high sensitivity and specificity for a next-generation mt-sDNA test panel. Further evaluation of assay performance will be characterized in a prospective, multi-center clinical validation study (NCT04144738).

PREVENTION RELEVANCE

This study highlights performance of the next-generation mt-sDNA test, which exhibits high sensitivity and specificity for detecting colorectal cancer and APLs. This noninvasive option has potential to increase screening participation and clinical outcomes. A multi-center, clinical validation trial is underway. See related commentary by Bresalier, p. 93.

An Updated Review on Molecular Biomarkers in Diagnosis and Therapy of Colorectal Cancer

Colorectal cancer is one of the most common cancer types worldwide. Since colorectal cancer takes time to develop, its incidence and mortality can be treated effectively if it is detected in its early stages. As a result, non-invasive or invasive biomarkers play an essential role in the early diagnosis of colorectal cancer. Many experimental studies have been carried out to assess genetic, epigenetic, or protein markers in feces, serum, and tissue. It may be possible to find biomarkers that will help with the diagnosis of colorectal cancer by identifying the genes, RNAs, and/or proteins indicative of cancer growth. Recent advancements in the molecular subtypes of colorectal cancer, DNA methylation, microRNAs, long noncoding RNAs, exosomes, and their involvement in colorectal cancer have led to the discovery of novel biomarkers. In small-scale investigations, most biomarkers appear promising. However, large-scale clinical trials are required to validate their effectiveness before routine clinical implementation. Hence, this review focuses on small-scale investigations and results of big data analysis that may provide an overview of the biomarkers for the diagnosis, therapy, and prognosis of colorectal cancer.

Tumor circulating biomarkers in colorectal cancer

CRC is a major global health concern and is responsible for a significant number of cancer-related deaths each year. The successful treatment of CRC becomes more difficult when it goes undetected until it has advanced to a later stage. Diagnostic biomarkers can play a critical role in the early detection of CRC, which leads to improved patient outcomes and increased survival rates. It is important to develop reliable biomarkers for the early detection of CRC to enable timely diagnosis and treatment. To date, CRC detection methods such as endoscopy, blood, and stool tests are imperfect and often only identify cases in the later stages of the disease. To overcome these limitations, researchers are turning to molecular biomarkers as a promising avenue for improving CRC detection. Diagnostic information can be provided more reliably through a noninvasive approach using biomarkers such as mRNA, circulating cell-free DNA, micro-RNA, long non-coding RNA, and proteins. These biomarkers can be found in blood, tissue, feces, and volatile organic compounds. The identification of molecular biomarkers with high sensitivity and specificity for early detection of CRC that are safe, cost-effective, and easily measurable remains a significant challenge for researchers. In this article, we will explore the latest advancements in blood-based diagnostic biomarkers for CRC and their potential impact on improving patient survival rates.

Analyzing aberrant DNA methylation in colorectal cancer uncovered intangible heterogeneity of gene effects in the survival time of patients

Colorectal cancer (CRC) involves epigenetic alterations. Irregular gene-methylation alteration causes and advances CRC tumor growth. Detecting differentially methylated genes (DMGs) in CRC and patient survival time paves the way to early cancer detection and prognosis. However, CRC data including survival times are heterogeneous. Almost all studies tend to ignore the heterogeneity of DMG effects on survival. To this end, we utilized a sparse estimation method in the finite mixture of accelerated failure time (AFT) regression models to capture such heterogeneity. We analyzed a dataset of CRC and normal colon tissues and identified 3406 DMGs. Analysis of overlapped DMGs with several Gene Expression Omnibus datasets led to 917 hypo- and 654 hyper-methylated DMGs. CRC pathways were revealed via gene ontology enrichment. Hub genes were selected based on Protein-Protein-Interaction network including SEMA7A, GATA4, LHX2, SOST, and CTLA4, regulating the Wnt signaling pathway. The relationship between identified DMGs/hub genes and patient survival time uncovered a two-component mixture of AFT regression model. The genes NMNAT2, ZFP42, NPAS2, MYLK3, NUDT13, KIRREL3, and FKBP6 and hub genes SOST, NFATC1, and TLE4 were associated with survival time in the most aggressive form of the disease that can serve as potential diagnostic targets for early CRC detection.

Current advances in detecting genetic and epigenetic biomarkers of colorectal cancer

Colorectal carcinoma (CRC) is the third most common cancer in terms of diagnosis and the second in terms of mortality. Recent studies have shown that various proteins, extracellular vesicles (i.e., exosomes), specific genetic variants, gene transcripts, cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and altered epigenetic patterns, can be used to detect, and assess the prognosis of CRC. Over the last decade, a plethora of conventional methodologies (e.g., polymerase chain reaction [PCR], direct sequencing, enzyme-linked immunosorbent assay [ELISA], microarray, in situ hybridization) as well as advanced analytical methodologies (e.g., microfluidics, electrochemical biosensors, surface-enhanced Raman spectroscopy [SERS]) have been developed for analyzing genetic and epigenetic biomarkers using both optical and non-optical tools. Despite these methodologies, no gold standard detection method has yet been implemented that can analyze CRC with high specificity and sensitivity in an inexpensive, simple, and time-efficient manner. Moreover, until now, no study has critically reviewed the advantages and limitations of these methodologies. Here, an overview of the most used genetic and epigenetic biomarkers for CRC and their detection methods are discussed. Furthermore, a summary of the major biological, technical, and clinical challenges and advantages/limitations of existing techniques is also presented.

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.

COLORECTAL CANCER: ASSOCIATION BETWEEN SOCIODEMOGRAPHIC VARIABLES AND THE ADHERENCE TO CANCER SCREENING

BACKGROUND

Colorectal cancer (CRC) is a worldwide health problem whose control depends on public policy establishment and effective prevention and screening programs. In Brazil, there are few studies related to adherence to screening methods.

AIMS

The aim of this study was to evaluate the association between demographic and socioeconomic to adherence to CRC screening with fecal immunochemical test (FIT) among average-risk individuals for CRC.

METHODS

In this prospective cross-sectional study, conducted between March 2015 and April 2016, 1,254 asymptomatic individuals aged 50-75 years, participating in a hospital screening campaign in Brazil, were invited to participate in the study.

RESULTS

The adherence rate to FIT was 55.6% (697/1,254). In the multivariable logistic regression analysis, patients aged 60-75 years (odds ratio (OR)=1.30; 95% confidence interval (CI): 1.02-1.66; p=0.03), religious belief (OR=2.04; 95% CI: 1.34-3.11; p<0.01), previous fecal occult blood test (OR=2.07; 95% CI: 1.55-2.76; p<0.01), and full/part-time working status (OR=0.66; 95% CI: 0.49-0.89; p<0.01) were independently associated with adherence to CRC screening.

CONCLUSION

The results of the present study highlight the importance of considering the labor aspects when implementing screening programs, suggesting that campaigns conducted in the workplace and repeated over the years may be more effective.

Fecal biomarkers: Non-invasive diagnosis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world in terms of morbidity and mortality, which brings great health hazards and economic burdens to patients and society. A fecal examination is an effective method for clinical examination and the most commonly used method for the census. It is simple, non-invasive, and suitable for large-scale population screening. With the development of molecular biology, lots of efforts have been made to discover new fecal biomarkers for the early screening of colorectal cancer. In this review, we summarize and discuss the recent advances of fecal biomarkers for CRC screening or diagnosis, including DNA biomarkers, RNA biomarkers, protein biomarkers, gut microbes and volatile organic compounds focusing on their diagnostic evaluation for CRC, which can provide a basis for the further development of new and effective CRC fecal screening and early diagnosis techniques.

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.

Guaiac-based faecal occult blood tests versus faecal immunochemical tests for colorectal cancer screening in average-risk individuals

BACKGROUND

Worldwide, many countries have adopted colorectal cancer (CRC) screening programmes, often based on faecal occult blood tests (FOBTs). CRC screening aims to detect advanced neoplasia (AN), which is defined as CRC or advanced adenomas. FOBTs fall into two categories based on detection technique and the detected blood component: qualitative guaiac-based FOBTs (gFOBTs) and faecal immunochemical tests (FITs), which can be qualitative and quantitative. Screening with gFOBTs reduces CRC-related mortality.

OBJECTIVES

To compare the diagnostic test accuracy of gFOBT and FIT screening for detecting advanced colorectal neoplasia in average-risk individuals.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, BIOSIS Citation Index, Science Citation Index Expanded, and Google Scholar. We searched the reference lists and PubMed-related articles of included studies to identify additional studies.

SELECTION CRITERIA

We included prospective and retrospective studies that provided the number of true positives, false positives, false negatives, and true negatives for gFOBTs, FITs, or both, with colonoscopy as reference standard. We excluded case-control studies. We included studies in which all participants underwent both index test and reference standard ("reference standard: all"), and studies in which only participants with a positive index test underwent the reference standard while participants with a negative test were followed for at least one year for development of interval carcinomas ("reference standard: positive"). The target population consisted of asymptomatic, average-risk individuals undergoing CRC screening. The target conditions were CRC and advanced neoplasia (advanced adenomas and CRC combined).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected studies for inclusion. In case of disagreement, a third review author made the final decision. We used the Rutter and Gatsonis hierarchical summary receiver operating characteristic model to explore differences between tests and identify potential sources of heterogeneity, and the bivariate hierarchical model to estimate sensitivity and specificity at common thresholds: 10 µg haemoglobin (Hb)/g faeces and 20 µg Hb/g faeces. We performed indirect comparisons of the accuracy of the two tests and direct comparisons when both index tests were evaluated in the same population.

MAIN RESULTS

We ran the initial search on 25 June 2019, which yielded 63 studies for inclusion. We ran a top-up search on 14 September 2021, which yielded one potentially eligible study, currently awaiting classification. We included a total of 33 "reference standard: all" published articles involving 104,640 participants. Six studies evaluated only gFOBTs, 23 studies evaluated only FITs, and four studies included both gFOBTs and FITs. The cut-off for positivity of FITs varied between 2.4 μg and 50 µg Hb/g faeces. For each Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability than gFOBTs for AN (P < 0.001) and CRC (P = 0.004). For the detection of AN, the summary sensitivity of gFOBTs was 15% (95% confidence interval (CI) 12% to 20%), which was significantly lower than FITs at both 10 μg and 20 μg Hb/g cut-offs with summary sensitivities of 33% (95% CI 27% to 40%; P < 0.001) and 26% (95% CI 21% to 31%, P = 0.002), respectively. Results were simulated in a hypothetical cohort of 10,000 screening participants with 1% CRC prevalence and 10% AN prevalence. Out of 1000 participants with AN, gFOBTs missed 850, while FITs missed 670 (10 μg Hb/g cut-off) and 740 (20 μg Hb/g cut-off). No significant differences in summary specificity for AN detection were found between gFOBTs (94%; 95% CI 92% to 96%), and FITs at 10 μg Hb/g cut-off (93%; 95% CI 90% to 95%) and at 20 μg Hb/g cut-off (97%; 95% CI 95% to 98%). So, among 9000 participants without AN, 540 were offered (unnecessary) colonoscopy with gFOBTs compared to 630 (10 μg Hb/g) and 270 (20 μg Hb/g) with FITs. Similarly, for the detection of CRC, the summary sensitivity of gFOBTs, 39% (95% CI 25% to 55%), was significantly lower than FITs at 10 μg and 20 μg Hb/g cut-offs: 76% (95% CI 57% to 88%: P = 0.001) and 65% (95% CI 46% to 80%; P = 0.035), respectively. So, out of 100 participants with CRC, gFOBTs missed 61, and FITs missed 24 (10 μg Hb/g) and 35 (20 μg Hb/g). No significant differences in summary specificity for CRC were found between gFOBTs (94%; 95% CI 91% to 96%), and FITs at the 10 μg Hb/g cut-off (94%; 95% CI 87% to 97%) and 20 μg Hb/g cut-off (96%; 95% CI 91% to 98%). So, out of 9900 participants without CRC, 594 were offered (unnecessary) colonoscopy with gFOBTs versus 594 (10 μg Hb/g) and 396 (20 μg Hb/g) with FITs. In five studies that compared FITs and gFOBTs in the same population, FITs showed a higher discriminative ability for AN than gFOBTs (P = 0.003). We included a total of 30 "reference standard: positive" studies involving 3,664,934 participants. Of these, eight were gFOBT-only studies, 18 were FIT-only studies, and four studies combined both gFOBTs and FITs. The cut-off for positivity of FITs varied between 5 µg to 250 µg Hb/g faeces. For each QUADAS-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability for detecting CRC than gFOBTs (P < 0.001). The summary sensitivity for CRC of gFOBTs, 59% (95% CI 55% to 64%), was significantly lower than FITs at the 10 μg Hb/g cut-off, 89% (95% CI 80% to 95%; P < 0.001) and the 20 μg Hb/g cut-off, 89% (95% CI 85% to 92%; P < 0.001). So, in the hypothetical cohort with 100 participants with CRC, gFOBTs missed 41, while FITs missed 11 (10 μg Hb/g) and 11 (20 μg Hb/g). The summary specificity of gFOBTs was 98% (95% CI 98% to 99%), which was higher than FITs at both 10 μg and 20 μg Hb/g cut-offs: 94% (95% CI 92% to 95%; P < 0.001) and 95% (95% CI 94% to 96%; P < 0.001), respectively. So, out of 9900 participants without CRC, 198 were offered (unnecessary) colonoscopy with gFOBTs compared to 594 (10 μg Hb/g) and 495 (20 μg Hb/g) with FITs. At a specificity of 90% and 95%, FITs had a higher sensitivity than gFOBTs.

AUTHORS' CONCLUSIONS

FITs are superior to gFOBTs in detecting AN and CRC in average-risk individuals. Specificity of both tests was similar in "reference standard: all" studies, whereas specificity was significantly higher for gFOBTs than FITs in "reference standard: positive" studies. However, at pre-specified specificities, the sensitivity of FITs was significantly higher than gFOBTs.

Evaluation of combined detection of multigene mutation and SDC2/SFRP2 methylation in stool specimens for colorectal cancer early diagnosis

PURPOSE

Molecular diagnostics of colorectal cancer (CRC) can be used as an auxiliary approach for patients recommended for colonoscopy, providing more CRC supplemental diagnosis options. This study investigated whether combined detection of KRAS/BRAF/APC mutation and SDC2/SFRP2 methylation can serve as auxiliary diagnostics in clinical management.

METHODS

KRAS/BRAF/APC mutation and SDC2/SFRP2 methylation in stool samples from healthy donors, patients with CRC, advanced adenoma (AA), non-advanced adenoma (NAA), or other gastroenterological diseases were evaluated using quantitative PCR (qPCR) or methylation-specific quantitative PCR (MSP). Test accuracy was determined by evaluating the tests' sensitivity, specificity, positive/negative predictive value (PPV/NPV), or positive/negative likelihood ratio (PLR/NLR).

RESULTS

The combined fecal KRAS/BRAF/APC mutation and SFRP2/SDC2 methylation detection test achieved a sensitivity of 88.57% with a PPV of 93.64% and a PLR of 7.10 for CRC patients. In comparison, the corresponding parameters for multigene mutation were 46.67%, 92.59%, and 36.26 and 83.81%, 93.94%, and 7.47, for DNA methylation, separately. The sensitivity of the combined test, gene mutation test, and DNA methylation test approach was 75%, 28.26%, and 72.83%. Furthermore, the specificity of this approach in the NAA group was 79.49%. Meanwhile, the overall diagnostic specificity for the combined test in NAA, healthy control, and interference groups was 88.42%. In addition, the sensitivity of the combined detection method increased with the disease stage in CRC patients and elevated along with the lesion size (≥ 1 cm) in AA patients.

CONCLUSION

Combined detection of fecal KRAS/BRAF/APC mutation and SFRP2/SDC2 methylation has potential application value for the auxiliary diagnosis of CRC and AA.

Start of an era: circulating cell-free DNA for early detection of cancers

Effective screening modalities are currently available for only a small subset of cancers, and they generally have suboptimal performance with complicated procedures. Therefore, there is an urgent need to develop simple, accurate, and non-invasive methods for early detection of cancers. Genetic and epigenetic alterations in plasma circulating cell-free DNA (cfDNA) have shown the potential to revolutionize methods of early detection of cancers and facilitate subsequent diagnosis to improve survival of patients. The medical interest in cfDNA assays has been inspired by emerging single- and multi-early detection of cancers studies. This review summarizes current technological and clinical advances, in the hopes of providing insights into the development and applications of cfDNA assays in various cancers and clinical scenarios. The key phases of clinical development of biomarkers are highlighted, and the future developments of cfDNA-based liquid biopsies in early detection of cancers are outlined. It is hoped that this study can boost the potential integration of cfDNA-based early detection of cancers into the current clinical workflow.

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Liquid biopsy, characterized by minimal invasiveness and user friendliness, can identify multiple cancers at the early stage and localize the tissue of origin

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The state-of-the-art technology facilitates the application of circulating cell-free DNA (cfDNA) assays in the early detection of cancers

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cfDNA assays are expected to be integrated into the clinical workflow after technological refinement and clinical trial validation

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The development and application strategies of cfDNA assays in various cancers and clinical scenarios can vary, and the harm-and-benefit should be balanced carefully

New Studies of the Aberrant Alterations in Fibrillin-1 Methylation During Colorectal Cancer Development

Background

Fibrillin-1 (FBN1) methylation risk from control to colorectal cancer (CRC), the variation regularities of FBN1 methylation, and DNA methyltransferase (DNMT) catalyzed with FBN1 methylation had not been reported yet; these were all studied in this paper.

Methods

FBN1 methylation roles were investigated with big data and meta-analysis.

Results

The 6 independent studies were searched including 702 tissue and 448 feces. FBN1 methylation frequencies of CRC, adenoma or polyp, and control in tissue were 79.1%, 69.4%, and 2.7%, respectively; those in feces were 74.6%, 50.7%, and 10.8%, respectively. FBN1 methylation of control samples was used as a standard reference; this study showed that ORs (95% CI) of FBN1 methylation in CRC and control tissues were 124.79 (62.86-248.35); those in feces were detected to be 30.87 (16.48-57.85). FBN1 methylation risk in tissue was higher than that in feces; there was a quadratic equation between the methylation rate of tissue and that of feces. There was another quadratic curve in the variation process of FBN1 methylation; this curve reflected the overall metabolism regularity of DNMT.

Conclusions

The transcriptional inactivation of FBN1 gene might start from normal colonic epithelium; the quadratic curve of FBN1 methylation catalyzed by DNMT can gradually produce powerful strength, accelerate expansion, and eventually lead to CRC. The overall metabolism regularity of DNMT maintains the changing process of FBN1 methylation; it has the changing feature of the same quadratic curve. FBN1 methylation is a promising biomarker. FBN1 methylation risk size in feces reflects that in tissue in non-invasive detection.

Systematic review: non-endoscopic surveillance for colorectal neoplasia in individuals with Lynch syndrome

BACKGROUND

Individuals with Lynch syndrome are at high risk for colorectal cancer (CRC). Regular colonoscopies have proven to decrease CRC incidence and mortality. However, colonoscopy is burdensome and interval CRCs still occur. Hence, an accurate, less-invasive screening method that guides the timing of colonoscopy would be of important value.

AIM

To outline the performance of non-endoscopic screening modalities for Lynch-associated CRC and adenomas.

METHODS

Systematic literature search in MEDLINE and EMBASE to identify studies investigating imaging techniques and biomarkers for detection of CRC and adenomas in Lynch syndrome. The QUADAS-2 tool was used for the quality assessment of included studies.

RESULTS

Seven of 1332 screened articles fulfilled the inclusion criteria. Two studies evaluated either CT colonography or MR colonography; both techniques were unable to detect CRC and (advanced) adenomas <10 mm. The other five studies evaluated plasma methylated-SEPTIN9, faecal immunochemical test (FIT), faecal tumour DNA markers (BAT-26, hMLH1, p53, D9S171, APC, D9S162, IFNA and DCC) and faecal microbiome as screening modalities. Sensitivity for CRC varied from 33% (BAT-26) to 70% (methylated-SEPTIN9) to 91% (hMLH1). High specificity (94-100%) for CRC and/or adenomas was observed for methylated-SEPTIN9, FIT and BAT-26. Desulfovibrio was enriched in the stool of patients having adenomas. However, all these studies were characterised by small populations, high/unclear risk of bias and/or low prevalence of adenomas.

CONCLUSIONS

Imaging techniques are unsuitable for colon surveillance in Lynch syndrome, whereas biomarkers are understudied. Having outlined biomarker research in Lynch-associated and sporadic CRC/adenomas, we believe that these non-invasive markers may hold potential (whether or not combined) for this population. As they could be of great value, (pre-)clinical studies in this field should be prioritised.

Diagnostic Accuracy of Multitarget Stool DNA Testing for Colorectal Cancer Screening: A Systematic Review and Meta-analysis

This study aimed to collect and summarize test data and conduct a meta-analysis, with respect to the Multitarget Stool DNA test sensitivity and specificity, compared to colonoscopy. All manuscripts were screened for eligibility according to inclusion criteria. Participants were a normal population at an average risk of developing CRC. Intervention was Stool based and DNA panel tests compared with colonoscopy, and outcome was detection of CRC and any pre-cancerous lesions. Inter-study and inconsistency (using the I-squared test) were assessed. Meta-analyses of the Mt-sDNA test showed a combined sensitivity of 89%, 51%, and 76% for the detection of CRC, advanced adenoma (AA), and combined CRC and AA, respectively. The overall specificity was 91%, 89%, and 90% for the detection of CRC, AA, and combined CRC and AA, respectively. Mt-sDNA had significantly acceptable diagnostic accuracy for CRC and AA diagnosis, but still has lower sensitivity and specificity than colonoscopy.

The impact of DNA testing on management of patients with colorectal cancer

Knowledge of the genetic basis of colorectal cancer has evolved over the past decades, allowing for the pre-symptomatic identification of affected patients in those with familial syndromes and to the understanding of the multi-step progression to carcinogenesis in tumors. Knowledge of the genes and pathways involved in colorectal cancer has allowed for targeted therapies in patients in addition to standard chemotherapy for those with metastases. Next-generation sequencing technologies have now also allowed for the sensitive detection of circulating mutations derived from tumors, which can give insight into the presence of residual disease and has implications for changing the standard paradigms for treatment. This article will specifically review advances in targeted therapy in metastatic colon cancer and the progress being made in using circulating tumor DNA in patient management.

Superiority of fecal carcinoembryonic antigen as diagnosis marker for adenomatous polyposis coli and asymptomatic colorectal cancer

BACKGROUND

Non-invasive diagnostic tools of adenomatous polyposis coli (APC) and asymptomatic colorectal cancer (CRC) are urgently needed. Although fecal carcinoembryonic antigen (FCEA) has been documented in some studies, the diagnostic potential for the detection of APC and asymptomatic CRC has not been described yet.

METHODS

This is a retrospective study. The pre-diagnostic serum carcinoembryonic antigen (SCEA) and fecal occult blood test (FOBT) levels were retrospectively analyzed in 212 patients with intestinal diseases group (IDG) and 224 controls. The levels of FCEA across all the studied groups were measured using electronic chemiluminescence immunoassay (ECLIA), and their sensitivity and specificity were used to evaluate their diagnostic potential. The individual diagnostic accuracy of the three indices, as well as their combined diagnostic potential, was compared using the receiver operating characteristic (ROC) curve and chi-square test.

RESULTS

The FCEA had low sensitivity (50%) and high specificity (93.91%) for the diagnosis of IDG, with the area under the curve (AUC) value of 0.781. The AUC of FCEA was higher than that of SCEA for the diagnosis of APC and CRC in the APC, asymptomatic CRC, and APC + CRC-stage I patients. The AUCs of FCEA were 0.708 and 0.691 for the 'double-negative patients' and 'triple-negative patients', respectively. In addition, FCEA could diagnose 45.5% of the 'double-negative' patients, 43.3% of the asymptomatic patients, and 42.9% of the 'triple-negative' patients. The combination of FCEA and FOBT improved the diagnostic value (AUC = 0.916).

CONCLUSION

FCEA has been demonstrated to be a favorable diagnostic marker in intestinal diseases, especially in the APC, asymptomatic CRC, and 'double-negative' or 'triple-negative' CRC patients.

Evaluating the Clinical Performance of a Dual-Target Stool DNA Test for Colorectal Cancer Detection

Previous work indicated that the dual-target stool DNA test, iColocomf, showed potential utility for colorectal cancer (CRC) detection, but its clinical accuracy was not validated on larger groups. This study aimed to evaluate the performance of iColocomf in a multicenter clinical trial. In this double-blinded case-control study, we enrolled 1164 participants from three independent hospitals, including 320 CRC patients, 148 adenomas, 396 interfering diseases, and 300 healthy controls. The primary indicators of sensitivity, specificity, and accuracy were estimated. Stool samples of participants were collected and tested by the assay. The test results were then verified by Sanger sequencing and retesting of resected participants. The sensitivity and specificity for CRC detection were 95.31% and 96.67%, respectively, with an accuracy of 90.29%. When combining the interfering diseases, the specificity was 88.39%. No statistically significant variations of positive detection rates were observed for the test in different patients' clinical features. For advanced adenomas (n = 38) and nonadvanced adenomas (n = 110), the sensitivities were 63.16% and 33.64%, respectively. The average accuracy was 99.62% for the methylation status of 375 samples verified by Sanger sequencing, and 94.12% for 34 participants who received the test second after surgical resection. The iColocomf test showed robust performance for the early detection of colorectal cancer and potential monitoring ability in clinical practice.

State-of-the-Art: Exosomes in Colorectal Cancer

Colorectal cancer (CRC) has a high prevalence and mortality rate, globally. To date, the progression mechanisms of CRC are still elusive. Exosomes (~100 nm in diameter) correspond to a subset of extracellular vesicles formed by an array of cancerous cells and stromal cells. These particular nanovesicles carry and transmit bioactive molecules, like proteins, lipids, and genetic materials, which mediate the crosstalk between cancer cells and the microenvironment. Accumulating evidence has shown the decisive functions of exosomes in the development, metastasis, and therapy resistance of CRC. Furthermore, some recent studies have also revealed the abilities of exosomes to function as either biomarkers or therapeutic targets for CRC. This review focuses on the specific mechanisms of exosomes in regulating CRC progression, and summarizes the potential clinical applications of exosomes in the diagnosis and therapy of CRC.

Beyond liquid biopsy: Toward non-invasive assays for distanced cancer diagnostics in pandemics

Liquid biopsy technologies have seen a significant improvement in the last decade, offering the possibility of reliable analysis and diagnosis from several biological fluids. The use of these technologies can overcome the limits of standard clinical methods, related to invasiveness and poor patient compliance. Along with this there are now mature examples of lab-on-chips (LOC) which are available and could be an emerging and breakthrough technology for the present and near-future clinical demands that provide sample treatment, reagent addition and analysis in a sample-in/answer-out approach. The possibility of combining non-invasive liquid biopsy and LOC technologies could greatly assist in the current need for minimizing exposure and transmission risks. The recent and ongoing pandemic outbreak of SARS-CoV-2, indeed, has heavily influenced all aspects of life worldwide. Ordinary tasks have been forced to switch from “in presence” to “distanced”, limiting the possibilities for a large number of activities in all fields of life outside of the home. Unfortunately, one of the settings in which physical distancing has assumed noteworthy consequences is the screening, diagnosis and follow-up of diseases.

In this review, we analyse biological fluids that are easily collected without the intervention of specialized personnel and the possibility that they may be used -or not-for innovative diagnostic assays. We consider their advantages and limitations, mainly due to stability and storage and their integration into Point-of-Care diagnostics, demonstrating that technologies in some cases are mature enough to meet current clinical needs.

Multiple Biomarker-Combined Screening for Colorectal Cancer Based on Bisulfate Conversion-Free Detection of Fecal DNA Methylation

To evaluate the applicability of bisulfate conversion-free methylation assay based on enzyme digestion in fecal screening for colorectal cancer (CRC). Stool samples were collected from a total of 1142 participants with intestinal abnormalities, including 180 positive cases, 60 advanced adenomas, and 902 negative cases. DNA from reference cell lines and clinical samples was extracted and digested with an enzyme to detect the methylation of CRC markers SEPT9, SDC2, NDRG4, SFRP2, and BMP3 genes. Statistical analysis was then used to determine the ability of the markers, both individually and in combination, to detect CRC and adenoma. Our results showed that the enzyme digestion method could suitably detect DNA marker methylation in as low as 1% of the cell lines. BMP3 had a considerably low detection rate in all clinical samples, with only 6 positive cases detected out of 180 cancer samples. Our findings showed that the combination of SEPT9, SDC2, and SFRP2 had an area under the receiver operation curve of 0.937, sensitivity of 94.11%, and specificity of 89.21% for detecting CRC. Moreover, the detection sensitivity of adenoma can also reach 38.33%. After innovatively utilizing bisulfate conversion-free methylation assay for CRC screening, this study verified the potential clinical applicability of combining multiple biomarkers for CRC screening in a large number of samples.

Recent advances in fecal gene detection for colorectal cancer diagnosis

There has been a gradual increase in the incidence of colorectal cancer (CRC) in recent years. Most patients lack obvious early symptoms, but are commonly in mid and advanced stages when the symptoms become evident, with rather high mortalities. Early diagnosis, treatment and recurrence monitoring are crucial to improving the recovery rate of CRC. Studies have shown that tumor-related genes can be detected in the feces of CRC patients. Owing to non-invasiveness, convenient sampling and continuous dynamic monitoring, fecal gene detection may be applicable to CRC screening, diagnosis, prognostic assessment and recurrence monitoring. Herein, we review the research advances in fecal gene detection for CRC diagnosis.

Nanotechnology in Colorectal Cancer for Precision Diagnosis and Therapy

Colorectal cancer (CRC) is the third most frequently occurring tumor in the human population. CRCs are usually adenocarcinomatous and originate as a polyp on the inner wall of the colon or rectum which may become malignant in the due course of time. Although the therapeutic options of CRC are limited, the early diagnosis of CRC may play an important role in preventive and therapeutic interventions to decrease the mortality rate. The CRC-affected tissues exhibit several molecular markers that may be exploited as the novel strategy to develop newer approaches for the treatment of the disease. Nanotechnology consists of a wide array of innovative and astonishing nanomaterials with both diagnostics and therapeutic potential. Several nanomaterials and nano formulations such as Carbon nanotubes, Dendrimer, Liposomes, Silica Nanoparticles, Gold nanoparticles, Metal-organic frameworks, Core-shell polymeric nano-formulations, Nano-emulsion System, etc can be used to targeted anticancer drug delivery and diagnostic purposes in CRC. The light-sensitive photosensitizer drugs loaded gold and silica nanoparticles can be used to diagnose as well as the killing of CRC cells by the targeted delivery of anticancer drugs to cancer cells. This review is focused on the recent advancement of nanotechnology in the diagnosis and treatment of CRC.

A Pilot Study Investigating the Expression Levels of Pluripotency-Associated Genes in Rectal Swab Samples for Colorectal Polyp and Cancer Diagnosis and Prognosis

Change in gene expression is inevitable in cancer development. With more studies demonstrating the contributions of cancer stem cells (CSCs) in colorectal cancer (CRC) development, this study is aimed at investigating whether rectal swab specimen serves as a tool for detection of dysregulation of CSC or stem cell (SC) markers and at evaluating its potential as a new promising screening method for high-risk patients. Expression levels of 15 pluripotency-associated genes were assessed by quantitative PCR in 53 rectal swab specimens referred for endoscopic screening. Dysregulated genes and joint panels based on such genes were examined for their diagnostic potentials for both polyp and CRC. Out of 15 genes, Oct4, CD26, c-MYC, and CXCR4 showed significantly differential expression among normal, polyp, and CRC patients. A panel of Oct4 and CD26 showed an AUC value of 0.80 (p = 0.003) in identifying CRC patients from polyp/normal subjects, with sensitivity and specificity of 84.6% and 69.2%. A panel of c-MYC and CXCR4 achieved CRC/polyp identification with an AUC value of 0.79 (p = 0.002), with a sensitivity of 82.8% and specificity of 80.0%. The sensitivity for polyp and CRC was 80.0% and 85.7%, respectively. Further analysis showed that higher c-MYC and CXCR4 level was detected in normal subjects who developed polyps after 5-6 years, in comparison with subjects with no lesion developed, and the AUC of the c-MYC and CXCR4 panel increased to 0.88 (p < 0.001), with sensitivity and specificity of 84.4% and 92.3%, respectively, when these patients were included in the polyp group. This study suggests that the Oct4 and CD26 panel is a promising biomarker for distinguishing CRC from normal and polyp patients, whereas the c-MYC and CXCR4 panel may identify polyp and CRC from normal individuals.

ACG Clinical Guidelines: Colorectal Cancer Screening 2021

Colorectal cancer (CRC) is the third most common cancer in men and women in the United States. CRC screening efforts are directed toward removal of adenomas and sessile serrated lesions and detection of early-stage CRC. The purpose of this article is to update the 2009 American College of Gastroenterology CRC screening guidelines. The guideline is framed around several key questions. We conducted a comprehensive literature search to include studies through October 2020. The inclusion criteria were studies of any design with men and women age 40 years and older. Detailed recommendations for CRC screening in average-risk individuals and those with a family history of CRC are discussed. We also provide recommendations on the role of aspirin for chemoprevention, quality indicators for colonoscopy, approaches to organized CRC screening and improving adherence to CRC screening. CRC screening must be optimized to allow effective and sustained reduction of CRC incidence and mortality. This can be accomplished by achieving high rates of adherence, quality monitoring and improvement, following evidence-based guidelines, and removing barriers through the spectrum of care from noninvasive screening tests to screening and diagnostic colonoscopy. The development of cost-effective, highly accurate, noninvasive modalities associated with improved overall adherence to the screening process is also a desirable goal.

Human Gut Microbiome-Based Knowledgebase as a Biomarker Screening Tool to Improve the Predicted Probability for Colorectal Cancer

Colorectal cancer (CRC) is a common clinical malignancy globally ranked as the fourth leading cause of cancer mortality. Some microbes are known to contribute to adenoma-carcinoma transition and possess diagnostic potential. Advances in high-throughput sequencing technology and functional studies have provided significant insights into the landscape of the gut microbiome and the fundamental roles of its components in carcinogenesis. Integration of scattered knowledge is highly beneficial for future progress. In this study, literature review and information extraction were performed, with the aim of integrating the available data resources and facilitating comparative research. A knowledgebase of the human CRC microbiome was compiled to facilitate understanding of diagnosis, and the global signatures of CRC microbes, sample types, algorithms, differential microorganisms and various panels of markers plus their diagnostic performance were evaluated based on statistical and phylogenetic analyses. Additionally, prospects about current changelings and solution strategies were outlined for identifying future research directions. This type of data integration strategy presents an effective platform for inquiry and comparison of relevant information, providing a tool for further study about CRC-related microbes and exploration of factors promoting clinical transformation (available at: http://gsbios.com/index/experimental/dts_ mben?id=1).

Faecal tests in the early detection of colorectal cancer

Colorectal cancer is one of the most common cancers in the world. It is the second most common cause of cancer deaths in both genders in Poland. Screening tests allow for early cancer detection, resulting in reduced mortality and better prognosis. Tests include a stool test for occult blood, checking for biomarkers in faeces, and stool DNA testing. Colonoscopy remains the gold standard in the diagnosis of cancer, both in Poland and around the world. To convince patients of the importance of such testing, it is necessary to have a wider knowledge of all the available diagnostic tests, to understand their advantages and disadvantages. This article will give descriptions of the respective tests and compare their effectiveness in the diagnosis of colorectal cancer.

Identification of circular RNA hsa_circ_0044556 and its effect on the progression of colorectal cancer

Background

Circular RNAs (circRNAs) are a novel class of noncoding RNAs. Increasing evidence indicates that circRNAs play an important role in the occurrence and development of tumors. However, the role of circRNA hsa_circ_0044556 in the progression of colorectal cancer (CRC) remains unclear.

Methods

First, we searched for differentially expressed circRNAs using a circRNA microarray in paired CRC and adjacent normal tissues. The circRNA hsa_circ_0044556 was screened out from the existing CRC circRNA microarray in the Gene Expression Omnibus database and our microarray. The clinical significance of hsa_circ_0044556 expression level in CRC patients was then investigated. Finally, the functions of the targets of this circRNA were determined in CRC cell lines.

Results

Hsa_circ_0044556 was highly expressed in CRC patients and was positively correlated with tumor stage and lymph node metastasis. In CRC cell lines, the proliferation, migration, and invasion of cancer cells were inhibited by knocking down hsa_circ_0044556 expression.

Conclusion

Hsa_circ_0044556 promoted the progression of CRC. It is possible that hsa_circ_0044556 will become a novel biomarker or therapeutic target for CRC.

The prognostic value of combined tumor markers and systemic immune-inflammation index in colorectal cancer patients

PURPOSE

This study evaluated the significance of combining tumor markers (TM) and systemic immune-inflammation index (SII) for postoperative complications and long-term outcomes in colorectal cancer (CRC) patients.

METHODS

CRC patients (662) who underwent surgery between 2012 and 2014 were retrospectively enrolled into our study. Factors affecting postoperative complications were evaluated by logistic regression analysis. Prognostic factors were assessed using Kaplan-Meier and Cox proportional hazards models. Nomograms were constructed to predict the risk of postoperative complications and survival. A consistency index and a calibration curve were used to evaluate the predictive accuracy of nomograms.

RESULTS

TM-SII score was established by combining TM and SII. Logistic regression analyses showed that TM-SII score was an important predictor of postoperative complications in CRC patients. Kaplan-Meier analyses showed that TM-SII score was favorable for prognostic risk stratification. In addition, multivariate analyses indicated that TM-SII score was an independent prognostic indicator for disease-free survival and overall survival. TM-SII based nomograms had a moderate prediction accuracy.

CONCLUSION

TM-SII score is a good prognostic indicator for CRC patients. It may be used as a useful risk stratification tool for advanced CRC patients. TM-SII-based nomograms could be used to identify CRC patients with poor outcomes.

Fecal microRNAs as Innovative Biomarkers of Intestinal Diseases and Effective Players in Host-Microbiome Interactions

Over the past decade, short non-coding microRNAs (miRNAs), including circulating and fecal miRNAs have emerged as important modulators of various cellular processes by regulating the expression of target genes. Recent studies revealed the role of miRNAs as powerful biomarkers in disease diagnosis and for the development of innovative therapeutic applications in several human conditions, including intestinal diseases. In this review, we explored the literature and summarized the role of identified dysregulated fecal miRNAs in intestinal diseases, with particular focus on colorectal cancer (CRC) and celiac disease (CD). The aim of this review is to highlight one fascinating aspect of fecal miRNA function related to gut microbiota shaping and bacterial metabolism influencing. The role of miRNAs as "messenger" molecules for inter kingdom communications will be analyzed to highlight their role in the complex host-bacteria interactions. Moreover, whether fecal miRNAs could open up new perspectives to develop novel suitable biomarkers for disease detection and innovative therapeutic approaches to restore microbiota balance will be discussed.

Magnetic resonance spectroscopy and its application in colorectal cancer diagnosis and screening: A narrative review

There are several slightly invasive methods to detect colorectal carcinoma (CRC) including colonoscopy and sigmoidoscopy; but there is no noninvasive, accurate screening test. It is recommended to initiate screening at the age of 50 for non-familial CRC. Laboratory tests are routinely suggested if internal observation and imaging are recommended for further evaluation. Spectroscopic-based imaging, such as magnetic resonance spectroscopy (MRS) is an interesting and promising tool with the potential to be an alternative to some minimally invasive procedures, such as biopsy. Accordingly, MRS might be a suitable substitution for invasive methods, such as colonoscopy. This article aimed to review the studies that have evaluated the MRS technique as a screening tool in CRC.

Identification and Validation of Novel Serum Autoantibody Biomarkers for Early Detection of Colorectal Cancer and Advanced Adenoma

Background: Colorectal cancer (CRC) comprises a large proportion of malignant tumors, and early detection of CRC is critical for effective treatment and optimal prognosis. We aimed to discover and validate serum autoantibodies for early detection of CRC.

Methods: Combined with CRC-associated autoantibodies discovered by serological proteome and multiplex analyses, 26 predefined autoantibodies were evaluated in 315 samples (130 CRCs, 75 advanced adenomas, and 110 healthy controls) by protein microarray analysis. Autoantibodies with potential detection value were verified by enzyme-linked immunosorbent assays (ELISAs). Receiver operating characteristic (ROC) curve analysis was conducted to evaluate the accuracy of the biomarkers.

Results: Four serum autoantibodies (ALDH1B1, UQCRC1, CTAG1, and CENPF) showed statistically different levels between patients with advanced neoplasm (CRC or advanced adenoma) and controls in microarray analysis, which were validated by ELISAs. Among the four biomarkers, the ALDH1B1 autoantibody showed the highest detection value with area under the curve (AUC) values of 0.70 and 0.74 to detect CRC and advanced adenoma with sensitivities of 75.68 and 62.31% and specificities of 63.06 and 73.87%, respectively. By combining the four biomarkers, the performance was improved with an AUC of 0.79 to detect CRC and advanced adenomas.

Conclusion: The ALDH1B1 autoantibody has a good potential for early detection of CRC and advanced adenoma, and measuring serum autoantibodies against tumor-associated antigens may improve detection of early CRC.

Multitarget Stool DNA for Average Risk Colorectal Cancer Screening: Major Achievements and Future Directions

After 2 screen-setting studies showing high sensitivity for colorectal cancer and advanced precancerous lesions, multitarget stool DNA testing was endorsed by the US Preventative Services Task Force as a first-line colorectal cancer screening test. Uptake has increased exponentially since approval by the US Food and Drug Administration and Centers for Medicare and Medicaid Services. Adherence to testing is approximately 70%. Patients with positive results have high diagnostic colonoscopy completion rates in single-center studies. The positive predictive value for colorectal neoplasia in postapproval studies is high. Next-generation test prototypes show promise to extend specificity gains while maintaining high sensitivity.

Efficiency of Gastrointestinal Cancer Detection by Nematode-NOSE (N-NOSE)

BACKGROUND/AIM

Early detection of gastrointestinal cancer may reduce mortality. Recently, Caenorhabditis elegans has been reported to be capable of differentiating patients with cancers from healthy persons by the smell of urine. This novel technique using C. elegans olfaction has been named as Nematode-NOSE (N-NOSE).

MATERIALS AND METHODS

We collected 180 urine samples from patients with gastrointestinal cancer and 76 samples from healthy subjects. N-NOSE test was performed using these samples and N-NOSE index was obtained. Quantification of the olfactory behavior of C. elegans was performed as established in past studies. By receiver operating characteristic (ROC) analysis, we examined the diagnostic capability of N-NOSE.

RESULTS

ROC analysis revealed that N-NOSE showed an area under the curve value of more than 0.80, even in early-stage cancers.

CONCLUSION

C. elegans olfaction enabled the detection of gastrointestinal cancers from urine with high sensitivity, which can provide the basis for the development of N-NOSE as a gastrointestinal cancer screening test.

Novel biomarkers for the diagnosis and prognosis of colorectal cancer

Colorectal cancer (CRC) is among the most common malignancies and remains a major cause of cancer-related death worldwide. Despite recent advances in surgical and multimodal therapies, the overall survival of advanced CRC patients remains very low. Cancer progression, including invasion and metastasis, is a major cause of death among CRC patients. The underlying mechanisms of action resulting in cancer progression are beginning to unravel. The reported molecular and biochemical mechanisms that might contribute to the phenotypic changes in favor of carcinogenesis include apoptosis inhibition, enhanced tumor cell proliferation, increased invasiveness, cell adhesion perturbations, angiogenesis promotion, and immune surveillance inhibition. These events may contribute to the development and progression of cancer. A biomarker is a molecule that can be detected in tissue, blood, or stool samples to allow the identification of pathological conditions such as cancer. Thus, it would be beneficial to identify reliable and practical molecular biomarkers that aid in the diagnostic and therapeutic processes of CRC. Recent research has targeted the development of biomarkers that aid in the early diagnosis and prognostic stratification of CRC. Despite that, the identification of diagnostic, prognostic, and/or predictive biomarkers remains challenging, and previously identified biomarkers might be insufficient to be clinically applicable or offer high patient acceptability. Here, we discuss recent advances in the development of molecular biomarkers for their potential usefulness in early and less-invasive diagnosis, treatment, and follow-up of CRC.

Fundamental social causes of inequalities in colorectal cancer mortality: A study of behavioral and medical mechanisms

BACKGROUND

Fundamental cause theory posits that social conditions strongly influence the risk of health risks. This study identifies risk mechanisms that social conditions associated with socioeconomic status (SES) and race/ethnicity shape in the production of colorectal cancer (CRC) mortality.

METHODS

Two large datasets in the United States examining behavioral and medical preventive factors (N = 4.63-million people) were merged with population-level mortality data observing 761,100 CRC deaths among 3.31-billion person-years of observation to examine trends in CRC mortality from 1999-2012. Analyses examined the changing role of medical preventions and health behaviors in catalyzing SES and racial/ethnic inequalities in CRC mortality.

RESULTS

Lower SES as well as Black, Hispanic, Asian/Pacific Islander, and Native American race/ethnicity were associated with decreased access to age-appropriate screening and/or increased prevalence of behavioral risk factors. Analyses further revealed that SES and racial/ethnic inequalities were partially determined by differences in engagement in two preventive factors: use of colonoscopy, and participation in physical activity.

DISCUSSION

Social inequalities were not completely determined by behavioral risk factors. Nevertheless, a more equitable distribution of preventive medicines has the potential to reduce both the risk of, and social inequalities in, CRC mortality.

Biomarkers for detecting colorectal cancer non-invasively: DNA, RNA or proteins?

Colorectal cancer (CRC) is a global problem affecting millions of people worldwide. This disease is unique because of its slow progress that makes it preventable and often curable. CRC symptoms usually emerge only at advanced stages of the disease, consequently its early detection can be achieved only through active population screening, which markedly reduces mortality due to this cancer. CRC screening tests that employ non-invasively detectable biomarkers are currently being actively developed and, in most cases, samples of either stool or blood are used. However, alternative biological substances that can be collected non-invasively (colorectal mucus, urine, saliva, exhaled air) have now emerged as new sources of diagnostic biomarkers. The main categories of currently explored CRC biomarkers are: (1) Proteins (comprising widely used haemoglobin); (2) DNA (including mutations and methylation markers); (3) RNA (in particular microRNAs); (4) Low molecular weight metabolites (comprising volatile organic compounds) detectable by metabolomic techniques; and (5) Shifts in gut microbiome composition. Numerous tests for early CRC detection employing such non-invasive biomarkers have been proposed and clinically studied. While some of these studies generated promising early results, very few of the proposed tests have been transformed into clinically validated diagnostic/screening techniques. Such DNA-based tests as Food and Drug Administration-approved multitarget stool test (marketed as Cologuard®) or blood test for methylated septin 9 (marketed as Epi proColon® 2.0 CE) show good diagnostic performance but remain too expensive and technically complex to become effective CRC screening tools. It can be concluded that, despite its deficiencies, the protein (haemoglobin) detection-based faecal immunochemical test (FIT) today presents the most cost-effective option for non-invasive CRC screening. The combination of non-invasive FIT and confirmatory invasive colonoscopy is the current strategy of choice for CRC screening. However, continuing intense research in the area promises the emergence of new superior non-invasive CRC screening tests that will allow the development of improved disease prevention strategies.

Colon Cancer: A Clinician's Perspective in 2019

Colon cancer is a common preventable cancer. With the adoption of widespread colon cancer screening in the developed countries, the incidence and mortality of colon cancer have decreased in the targeted population. But unfortunately, the incidence and mortality of colorectal cancer (CRC) have been increasing over the last 25 years in the young adults below the age of 50. There is disparity in benefit, i.e. reduction in risk of death between right-sided and left-sided colon cancer by screening colonoscopy. The reason could be multifactorial and various measures have been taken to decrease this disparity. Although most of the screened populations are average risk individuals, a minority of the population have various risk factors for developing colon cancer and need to follow specific colon cancer screening guidelines. Gene mutations (adenomatous polyposis coli (APC), deleted in colon cancer (DCC), K-ras, p53, B-Raf proto-oncogene serine/threonine kinase (BRAF), mismatch repair genes) and microsatellite instability lead to the development of colon cancer. Although various non-invasive methods of colon cancer screening are now available, colonoscopy remains the gold standard of colon cancer screening and adenoma detection rate is now being used as the quality metrics in screening colonoscopy. Although Multi-Society Task Force (MSTF) and American College of Physicians (ACP) recommend initiating screening colonoscopy at age 50 years in all individuals except African Americans who should begin screening colonoscopy at age 45 years, the American Cancer Society (ACS) recommends initiating screening colonoscopy at age 45 years in all individuals irrespective of race and ethnicity. Low-volume split-dose prep has been found to be as effective as high-volume split-dose prep and more tolerable to patients with increased compliance. Boston bowel preparation scale is recommended to measure the quality of colon cleansing. CRC is curative if it is diagnosed at an early stage but various palliative treatment options (endoscopic, oncologic and surgical) are available in advanced stages of this cancer. Adequate number of lymph node assessment during surgery is essential in accurate staging of CRC. Checkpoint inhibitors have been found to have dramatic response and durable clinical benefit in dMMR/MSI-H metastatic CRC. Different genetic and immune-oncologic research trials are ongoing for early detection and better management of CRC.

Evaluation of Fecal M2PK as a Diagnostic Marker in Colorectal Cancer

BACKGROUND

Invasive colonoscopy is the gold standard for patients at risk for colorectal cancer. However, the need for non-invasive and specific markers is required.

OBJECTIVE

To evaluate the sensitivity of the glycolytic pyruvate kinase isoenzyme type M2 dimer (M2PK) as a diagnostic biomarker for colorectal cancer (CRC) and adenomatous colorectal polyps (CRP) screening.

DESIGN

Case-control.

PATIENTS

Twenty patients with CRC, 20 patients with CRP (lack criteria for colonic cancer by biopsy), and 20 normal subjects.

OUTCOME

Complete blood count (CBC), erythrocyte sedimentation rate (ESR), tumor markers: carcino embryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), fecal occult blood test (FOBT), and fecal M2PK. Pelvic and abdominal ultrasound (US), colonoscopy, and a histopathological examination.

RESULTS

Only weight loss and cachexia were significantly associated with CRC than CRP or control groups. M2PK was the most sensitive and specific test in differentiating CRC from CRP and the control subjects (sensitivity = 75%, specificity = 100%).

LIMITATIONS

(1) The selection of cases for three well-matched groups, as to perform colonoscopy in well-prepared cases and conditions. (2) Replicates in more than 20 cases for confirmation at the expense of enrolling new patients. (3) The cost associated with tumor markers analysis.

CONCLUSION

Fecal M2PK can be used as a precolonoscopy screening test for CRC patients, and is superior to other tumor markers, and in indicating the progress of colorectal adenomas > 1 cm. Thus being cost-effective and easy-to-perform test, it is a feasible tool to preselect patients who require colonoscopy.

Emerging Designs of Electronic Devices in Biomedicine

A long-standing goal of nanoelectronics is the development of integrated systems to be used in medicine as sensor, therapeutic, or theranostic devices. In this review, we examine the phenomena of transport and the interaction between electro-active charges and the material at the nanoscale. We then demonstrate how these mechanisms can be exploited to design and fabricate devices for applications in biomedicine and bioengineering. Specifically, we present and discuss electrochemical devices based on the interaction between ions and conductive polymers, such as organic electrochemical transistors (OFETs), electrolyte gated field-effect transistors (FETs), fin field-effect transistor (FinFETs), tunnelling field-effect transistors (TFETs), electrochemical lab-on-chips (LOCs). For these systems, we comment on their use in medicine.

Breath Volatile Organic Compound Profiling of Colorectal Cancer Using Selected Ion Flow-tube Mass Spectrometry

OBJECTIVE

BACKGROUND:: Breath VOCs have the potential to noninvasively diagnose cancer.

METHODS

Exhaled breath samples were collected using 2-L double-layered Nalophan bags, and were analyzed using selected-ion-flow-tube mass-spectrometry. Gold-standard test for comparison was endoscopy for luminal inspection and computed tomography (CT) to confirm cancer recurrence. Three studies were conducted: RESULTS:: CONCLUSION:: This study suggests the association of a single breath biomarker with the primary presence and recurrence of CRCa. Further multicenter validation studies are required to validate these findings.

Histotype influences emergency presentation and prognosis in colon cancer surgery

AIM

To investigate whether differences in histotype in colon cancer correlate with clinical presentation and if they might influence oncological outcomes and survival.

METHODS

Data regarding colon cancer patients operated both electively or in emergency between 2009 and 2014 were retrospectively collected from a prospectively maintained database and analyzed for the purpose of this study. Rectal cancer was excluded from this analysis. Statistical univariate and multivariate analyses were performed to investigate possible significant variables influencing clinical presentation, as well as oncological outcomes and survival.

RESULTS

Data from 219 patients undergoing colorectal resection for cancer of the colon only were retrieved. One hundred seventy-four patients had an elective procedure and forty-five had an emergency colectomy. Emergency presentation was more likely to occur in mucinous (p < 0.05) and signet ring cell (p < 0.01) tumors. No definitive differences in 5-year overall (44.7% vs. 60.6%, p = 0.078) and disease-free (51.2% vs. 64.4%, p = 0.09) survival were found between the two groups as a whole, but the T3 emergency patients showed worse prognosis than the elective (p < 0.03). Lymph node invasion, laparoscopy, histology, and blood transfusions were independent variables found to influence survival. Distribution assessed for pTNM stage showed T3 cancers were more common in emergency (p < 0.01).

CONCLUSIONS AND DISCUSSION

Mucinous and signet ring cell tumors are related to emergency presentation, pT3 stage, poorest outcomes, and survival. Disease-free survival in patients who had emergency surgery for T3 colon cancer seems related to the histotype.

An early report of a screening program for colorectal cancer in Guangzhou, China

Background

We launched a screening program for colorectal cancer (CRC) in Yuexiu District, Guangzhou, China, in 2014. Here we aimed to report the early results of the program and evaluate the benefits of a screening questionnaire.

Methods

Residents aged between 50 and 74 were eligible for the screening. A questionnaire and two consecutive fecal immunological tests (FITs) were used as primary screening methods. Subjects who were positive for any of the two tests were referred for further examination with colonoscopy. Neoplasms were removed either colonoscopically or by colectomy. Atypical adenoma and CRC were defined as advanced neoplasms.

Results

A total of 6,971 residents in Dadong Street, Yuexiu District were screened with a questionnaire, and among them, 5,343 underwent at least one FIT. Four thousand and two hundred eleven (60.4%) were female, and 2,760 (39.6%) were male, with a median age of 62.0 years. Questionnaire and FITs identified 1,219 candidates for further examination with colonoscopy, among whom only 647 (53.1%) comply. As of this writing, 623 colonoscopy results were obtained, among which 270 (43.3%) had positive findings. The adenoma detection rate (ADR) was 43.3% (270/623). The ADR was 43.3% (270/623). Of the 270 patients, 10 (3.07%) had CRC, 81 (30.0%) had advanced adenoma, 178 had low-grade adenoma or other benign polyps, one had carcinoid. Except for three advanced CRC, all neoplasms detected were benign or in an early stage.

Conclusions

Our screening program help identified patients with colonic neoplasms at an early stage, precluding them from developing into the malignant disease. The addition of the questionnaire significantly increased the sensitivity of primary screening, while also decreasing the specificity. Long-term results should evaluate the social and economic benefits of this program.

Assessment of a Noninvasive Exhaled Breath Test for the Diagnosis of Oesophagogastric Cancer

Question

What is the diagnostic accuracy of a breath test for esophagogastric cancer?

Findings

In a multicenter diagnostic study of 335 patients, including 172 patients with esophagogastric cancer, the breath test demonstrated good diagnostic accuracy.

Meaning

This study suggests the potential of breath analysis as a noninvasive tool in the diagnosis of esophagogastric cancer.

Importance

Early esophagogastric cancer (OGC) stage presents with nonspecific symptoms.

Objective

The aim of this study was to determine the accuracy of a breath test for the diagnosis of OGC in a multicenter validation study.

Design, Setting, and Participants

Patient recruitment for this diagnostic validation study was conducted at 3 London hospital sites, with breath samples returned to a central laboratory for selected ion flow tube mass spectrometry (SIFT-MS) analysis. Based on a 1:1 cancer:control ratio, and maintaining a sensitivity and specificity of 80%, the sample size required was 325 patients. All patients with cancer were on a curative treatment pathway, and patients were recruited consecutively. Among the 335 patients included; 172 were in the control group and 163 had OGC.

Interventions

Breath samples were collected using secure 500-mL steel breath bags and analyzed by SIFT-MS. Quality assurance measures included sampling room air, training all researchers in breath sampling, regular instrument calibration, and unambiguous volatile organic compounds (VOCs) identification by gas chromatography mass spectrometry.

Main Outcomes and Measures

The risk of cancer was identified based on a previously generated 5-VOCs model and compared with histopathology-proven diagnosis.

Results

Patients in the OGC group were older (median [IQR] age 68 [60-75] vs 55 [41-69] years) and had a greater proportion of men (134 [82.2%]) vs women (81 [47.4%]) compared with the control group. Of the 163 patients with OGC, 123 (69%) had tumor stage T3/4, and 106 (65%) had nodal metastasis on clinical staging. The predictive probabilities generated by this 5-VOCs diagnostic model were used to generate a receiver operator characteristic curve, with good diagnostic accuracy, area under the curve of 0.85. This translated to a sensitivity of 80% and specificity of 81% for the diagnosis of OGC.

Conclusions and Relevance

This study shows the potential of breath analysis in noninvasive diagnosis of OGC in the clinical setting. The next step is to establish the diagnostic accuracy of the test among the intended population in primary care where the test will be applied.