Prevention of colorectal cancer by flexible endoscopy and polypectomy. A case-control study of 32,702 veterans

Risk of Colorectal Cancer among Patients with One or Multiple Metabolic Syndrome Components

Background/Objectives: Dysfunctions of metabolic syndrome (MetS) have been identified as a significant risk factor for colorectal cancer (CRC). However, current colon cancer guidelines do not classify patients with MetS as high risk, thereby leaving these individuals vulnerable. Consequently, we explored the relationship between MetS, its individual components, and the development of CRC in a cohort of patients with MetS to assess the necessity for CRC screening in these individuals. Methods: This study included patients ages 18 and older that received a service from the Marshall-Health (MH) practice plan, Cabell-Huntington Hospital (CHH), MU/JCESOM's Edwards Comprehensive Cancer Center (ECCC), or the University of Kentucky HealthCare (UKHC) system between 2010 and 2018. We implemented log-binomial regression models to assess the individual and collective effects of MetS components after adjusting other CRC risk factors. Results: Given that CRC prevalence increases in the older population (aged 65 years and above), and that multiple components of MetS are observed within the same population, we analyzed the concurrent impact of all MetS components on CRC. Log-binomial regression models were implemented to assess the risk of CRC due to MetS components after adjusting other risk factors. Conclusions: We identified specific components that markedly increased CRC risk, suggesting that individuals with these components should be prioritized for early screening. These findings could significantly influence early CRC screening protocols, with the ultimate aim to reduce mortality associated with the disease.

3D genomic mapping reveals multifocality of human pancreatic precancers

Pancreatic intraepithelial neoplasias (PanINs) are the most common precursors of pancreatic cancer, but their small size and inaccessibility in humans make them challenging to study1. Critically, the number, dimensions and connectivity of human PanINs remain largely unknown, precluding important insights into early cancer development. Here, we provide a microanatomical survey of human PanINs by analysing 46 large samples of grossly normal human pancreas with a machine-learning pipeline for quantitative 3D histological reconstruction at single-cell resolution. To elucidate genetic relationships between and within PanINs, we developed a workflow in which 3D modelling guides multi-region microdissection and targeted and whole-exome sequencing. From these samples, we calculated a mean burden of 13 PanINs per cm3 and extrapolated that the normal intact adult pancreas harbours hundreds of PanINs, almost all with oncogenic KRAS hotspot mutations. We found that most PanINs originate as independent clones with distinct somatic mutation profiles. Some spatially continuous PanINs were found to contain multiple KRAS mutations; computational and in situ analyses demonstrated that different KRAS mutations localize to distinct cell subpopulations within these neoplasms, indicating their polyclonal origins. The extensive multifocality and genetic heterogeneity of PanINs raises important questions about mechanisms that drive precancer initiation and confer differential progression risk in the human pancreas. This detailed 3D genomic mapping of molecular alterations in human PanINs provides an empirical foundation for early detection and rational interception of pancreatic cancer.

Preclinical Evaluation of a Microwave-Based Accessory Device for Colonoscopy in an In Vivo Porcine Model with Colorectal Polyps

BACKGROUND AND AIMS

Colonoscopy is currently the most effective way of detecting colorectal cancer and removing polyps, but it has some drawbacks and can miss up to 22% of polyps. Microwave imaging has the potential to provide a 360° view of the colon and addresses some of the limitations of conventional colonoscopy. This study evaluates the feasibility of a microwave-based colonoscopy in an in vivo porcine model.

METHODS

A prototype device with microwave antennas attached to a conventional endoscope was tested on four healthy pigs and three gene-targeted pigs with mutations in the adenomatous polyposis coli gene. The first four animals were used to evaluate safety and maneuverability and compatibility with endoscopic tools. The ability to detect polyps was tested in a series of three gene-targeted pigs.

RESULTS

the microwave-based device did not affect endoscopic vision or cause any adverse events such as deep mural injuries. The microwave system was stable during the procedures, and the detection algorithm showed a maximum detection signal for adenomas compared with healthy mucosa.

CONCLUSIONS

Microwave-based colonoscopy is feasible and safe in a preclinical model, and it has the potential to improve polyp detection. Further investigations are required to assess the device's efficacy in humans.

Image acquisition as novel colonoscopic quality indicator: a single-center retrospective study

PURPOSE

In order to reduce the incidence and mortality of colorectal cancer, improving the quality of colonoscopy is the top priority. At present, the adenoma detection rate is the most used index to evaluate the quality of colonoscopy. So, we further verified the relevant factors influencing the quality of colonoscopy and found out the novel quality indicators by studying the relationship between the influencing factors and the adenoma detection rate.

MATERIALS/METHODS

The study included 3824 cases of colonoscopy from January to December 2020. We retrospectively recorded the age and sex of the subjects; the number, size, and histological features of lesions; withdrawal time and the number of images acquired during colonoscopy. We analyzed the associated factors affecting adenoma and polyp detection, and verified their effectiveness with both univariate and multivariate logistic regression analyses.

RESULTS

Logistic regression analyses showed that gender, age, withdrawal time and the number of images acquired during colonoscopy could serve as independent predictors of adenoma/polyp detection rate. In addition, adenoma detection rate (25.36% vs. 14.29%) and polyp detection rate (53.99% vs. 34.42%) showed a marked increase when the number of images taken during colonoscopy was ≥29 (P<0.001).

CONCLUSIONS

Gender, age, withdrawal time and the number of images acquired during colonoscopy are influencing factors for the detection of colorectal adenomas and polyps. And we can gain higher adenoma/polyp detection rate when endoscopists capture more colonoscopic images.

Three-dimensional genomic mapping of human pancreatic tissue reveals striking multifocality and genetic heterogeneity in precancerous lesions

Pancreatic intraepithelial neoplasia (PanIN) is a precursor to pancreatic cancer and represents a critical opportunity for cancer interception. However, the number, size, shape, and connectivity of PanINs in human pancreatic tissue samples are largely unknown. In this study, we quantitatively assessed human PanINs using CODA, a novel machine-learning pipeline for 3D image analysis that generates quantifiable models of large pieces of human pancreas with single-cell resolution. Using a cohort of 38 large slabs of grossly normal human pancreas from surgical resection specimens, we identified striking multifocality of PanINs, with a mean burden of 13 spatially separate PanINs per cm3 of sampled tissue. Extrapolating this burden to the entire pancreas suggested a median of approximately 1000 PanINs in an entire pancreas. In order to better understand the clonal relationships within and between PanINs, we developed a pipeline for CODA-guided multi-region genomic analysis of PanINs, including targeted and whole exome sequencing. Multi-region assessment of 37 PanINs from eight additional human pancreatic tissue slabs revealed that almost all PanINs contained hotspot mutations in the oncogene KRAS, but no gene other than KRAS was altered in more than 20% of the analyzed PanINs. PanINs contained a mean of 13 somatic mutations per region when analyzed by whole exome sequencing. The majority of analyzed PanINs originated from independent clonal events, with distinct somatic mutation profiles between PanINs in the same tissue slab. A subset of the analyzed PanINs contained multiple KRAS mutations, suggesting a polyclonal origin even in PanINs that are contiguous by rigorous 3D assessment. This study leverages a novel 3D genomic mapping approach to describe, for the first time, the spatial and genetic multifocality of human PanINs, providing important insights into the initiation and progression of pancreatic neoplasia.

A Multi-Centre Study to Risk Stratify Colorectal Polyp Surveillance Patients Utilising Volatile Organic Compounds and Faecal Immunochemical Test

Simple Summary

A total of 15% of the annual colonoscopies are undertaken for polyp surveillance, and this causes strain on already stretched endoscopy services in the U.K. Hence, there is an urgent need to triage and prioritise patients with high-risk findings. The performance of the faecal immunochemical test is not adequate to be used within polyp surveillance. In light of this, we investigated the usefulness of urinary volatile organic compounds for the detection of high-risk findings. We confirmed that urinary volatile organic compounds can be used to triage patients with high-risk findings. It can be used alone or in combination with faecal immunochemical tests.

Abstract

(1) Background: The service capacity for colonoscopy remains constrained, and while efforts are being made to recover elective services, polyp surveillance remains a challenge. (2) Methods: This is a multi-centre study recruiting patients already on polyp surveillance. Stool and urine samples were collected for the faecal immunochemical test (FIT) and volatile organic compounds (VOC) analysis, and all participants then underwent surveillance colonoscopy. (3) Results: The sensitivity and specificity of VOC for the detection of a high-risk finding ((≥2 premalignant polyps including ≥1 advanced polyp or ≥5 premalignant polyps) were 0.94 (95% CI, 0.88 to 0.98) and 0.69 (95% CI, 0.64 to 0.75) respectively. For FIT, the sensitivity was (≥10 µg of haemoglobin (Hb) / g faeces) 0.54 (95% CI, 0.43 to 0.65) and the specificity was 0.79 (95% CI, 0.73 to 0.84). The probability reduction for having a high-risk finding following both negative VOC and FIT will be 24% if both tests are applied sequentially. (4) Conclusion: The diagnostic performance of VOC is superior to FIT for the detection of a high-risk finding. The performance further improves when VOC is applied together with FIT sequentially (VOC first and then FIT). VOC alone or the combination of VOC and FIT can be used as a triage tool for patients awaiting colonoscopy within a polyp surveillance population, especially in resource-constrained healthcare systems.

MiWEndo: Evaluation of a Microwave Colonoscopy Algorithm for Early Colorectal Cancer Detection in Ex Vivo Human Colon Models

This study assesses the efficacy of detecting colorectal cancer precursors or polyps in an ex vivo human colon model with a microwave colonoscopy algorithm. Nowadays, 22% of polyps go undetected with conventional colonoscopy, and the risk of cancer after a negative colonoscopy can be up to 7.9%. We developed a microwave colonoscopy device that consists of a cylindrical ring-shaped switchable microwave antenna array that can be attached to the tip of a conventional colonoscope as an accessory. The accessory is connected to an external unit that allows successive measurements of the colon and processes the measurements with a microwave imaging algorithm. An acoustic signal is generated when a polyp is detected. Fifteen ex vivo freshly excised human colons with cancer (n = 12) or polyps (n = 3) were examined with the microwave-assisted colonoscopy system simulating a real colonoscopy exploration. After the experiment, the dielectric properties of the specimens were measured with a coaxial probe and the samples underwent a pathology analysis. The results show that all the neoplasms were detected with a sensitivity of 100% and specificity of 87.4%.

Microwave-Based Colonoscopy: Preclinical Evaluation in an Ex Vivo Human Colon Model

Introduction

Microwave imaging can obtain 360° anatomical and functional images of the colon representing the existing contrast in dielectric properties between different tissues. Microwaves are safe (nonionizing) and have the potential of reducing the visualization problems of conventional colonoscopy. This study assessed the efficacy of a microwave-based colonoscopy device to detect neoplastic lesions in an ex vivo human colon model.

Methods

Fresh surgically excised colorectal specimens containing cancer or polyps were fixed to a 3D positioning system, and the accessory device was introduced horizontally inside the ex vivo colon lumen and moved along it simulating a real colonoscopy exploration. Measurements of the colon were taken every 4 mm with the microwave-based colonoscopy device and processed with a microwave imaging algorithm.

Results

14 ex vivo human colorectal specimens with carcinomas (n = 11) or adenomas with high grade dysplasia (n = 3) were examined with a microwave-based device. Using a detection threshold of 2.79 for the dielectric property contrast, all lesions were detected without false positives or false negatives.

Conclusions

This study demonstrates the use of a microwave-based device to be used as an accessory of a standard colonoscope to detect neoplastic lesions in surgically excised colorectal specimens.

Clinical Features and Genomic Characterization of Post-Colonoscopy Colorectal Cancer

INTRODUCTION

Some colorectal cancers (CRCs) may be missed during colonoscopies. We aimed to determine the clinicopathological, biological, and genomic characteristics of post-colonoscopy CRCs (PCCRCs).

METHODS

Of the 1,619 consecutive patients with 1,765 CRCs detected between 2008 and 2016, 63 patients with 67 PCCRCs, when colonoscopies were performed 6-60 months before diagnosis, were recruited. After excluding patients with inflammatory bowel disease, familial polyposis syndrome, CRCs that developed from diminutive adenomatous polyps, and recurrent CRCs after endoscopic resection, 32 patients with 34 PCCRCs were enrolled. The lesions' clinicopathological features, mismatch repair proteins (MMRs), and genomic alterations were investigated.

RESULTS

The overall PCCRC-5y rate, rate of intramucosal (Tis) lesions, and rate of T1 or more deeply invasive cancers were 3.7% (66/1,764), 3.9% (32/820), and 3.6% (34/944), respectively. Thirty-three patients' MMRs were investigated; 7 (21%) exhibited deficient MMRs (dMMRs), comprising 4 with T2 or more deeply invasive cancers and 5 whose lesions were in the proximal colon. Twenty-three tumors' genomic mutations were investigated; PIK3CA had mutated in 5 of 6 T2 or more deeply invasive cancers, of which, 4 were located in the proximal colon. Two patients with dMMRs and BRAF mutations had poor prognoses. Sixty-one percent (17/28) of the macroscopic type 0 lesions were superficial. All superficial Tis and T1 PCCRCs were detected <24 months after the negative colonoscopies. They were distributed throughout the colon and rectum.

DISCUSSION

PCCRCs may be invasive cancers in the proximal colon that exhibit dMMRs and/or PIK3CA mutations or missed early CRCs especially superficial lesions.

Advances in Imaging Modalities and Contrast Agents for the Early Diagnosis of Colorectal Cancer

Colorectal cancer is one of the most common gastrointestinal cancers worldwide. The mortality rate of colorectal cancer has declined by more than 20% due to the rapid development of early diagnostic techniques and effective treatment. At present, there are many diagnostic modalities available for the evaluation of colorectal cancer, such as the carcinoembryonic antigen test, the fecal occult blood test, endoscopy, X-ray barium meal, computed tomography, magnetic resonance imaging, and radionuclide examination. Sensitive and specific imaging modalities have played an increasingly important role in the diagnosis of colorectal cancer following the rapid development of novel contrast agents. This review discusses the applications and challenges of different imaging techniques and contrast agents applied to detect colorectal cancer, for the purpose of the early diagnosis and treatment of patients with colorectal cancer.

Long non-coding RNA ZFAS1 is a major regulator of epithelial-mesenchymal transition through miR-200/ZEB1/E-cadherin, vimentin signaling in colon adenocarcinoma

Colon adenocarcinoma is a common cause of cancer-related deaths worldwide. Epithelial-mesenchymal transition is a major regulator of cancer metastasis, and increased understanding of this process is essential to improve patient outcomes. Long non-coding RNA (lncRNA) are important regulators of carcinogenesis. To identify lncRNAs associated with colon carcinogenesis, we performed an exploratory differential gene expression analysis comparing paired colon adenocarcinoma and normal colon epithelium using an RNA-sequencing data set. This analysis identified lncRNA ZFAS1 as significantly increased in colon cancer compared to normal colon epithelium. This finding was validated in an institutional cohort using laser capture microdissection. ZFAS1 was also found to be principally located in the cellular cytoplasm. ZFAS1 knockdown was associated with decreased cellular proliferation, migration, and invasion in two colon cancer cell lines (HT29 and SW480). MicroRNA-200b and microRNA-200c (miR-200b and miR-200c) are experimentally validated targets of ZFAS1, and this interaction was confirmed using reciprocal gene knockdown. ZFAS1 knockdown regulated ZEB1 gene expression and downstream targets E-cadherin and vimentin. Knockdown of miR-200b or miR-200c reversed the effect of ZFAS1 knockdown in the ZEB1/E-cadherin, vimentin signaling cascade, and the effects of cellular migration and invasion, but not cellular proliferation. ZFAS1 knockdown was also associated with decreased tumor growth in an in vivo mouse model. These results demonstrate the critical importance of ZFAS1 as a regulator of the miR-200/ZEB1/E-cadherin, vimentin signaling cascade.

Association Between Colonic Diverticulosis and Colorectal Polyps, Advanced Neoplastic Lesions, and Colorectal Carcinomas: A Cross-Sectional, Retrospective Study

PURPOSE

The aim of the present study was to evaluate the association of diverticulosis with colorectal polyps, advanced neoplastic lesions (ANLs), and colorectal cancers (CRCs).

METHODS

The first-time colonoscopy records of 3496 patients were evaluated in this retrospective, cross-sectional cohort study. Data on clinical indications, presence of diverticulosis and diverticulitis, location of diverticula and polps, the size and number of polyps, and results of histopathologic examinations of polypectomies were noted. Categorical data were analyzed with χ test or the Fisher exact probability. P-values <0.05 (2 sided) were considered statistically significant. Statistical analyses were conducted with SPSS, version 18.

RESULTS

Of the 3496 patients, 1691 were male individuals (48.4%) and 1805 (51.6%) were female individuals. Diverticulosis was present in 12.6% of patients. A total of 870 polyps were detected in 716 patients. A total of 170 polyps (19.5%) were classified as ANLs. CRC was diagnosed in 112 (3.2%) patients. A significant relationship between diverticulosis and colorectal polyps (odds ratio: 1.99; 95% confidence interval: 1.59-0.2.48, P<0.001) was found. Similarly, adenomas and ANLs were more frequent in diverticulosis (P<0.05). There was no significant relationship between diverticulosis and CRCs (P=0.243).

CONCLUSIONS

Adenomatous polyps and ANLs were more frequently observed in patients with diverticulosis, but no significant relationship was found between CRC and diverticulosis. The results of this retrospective cross-sectional study need to be confirmed by longitudinal prospective cohort studies.

Circulating plasma microRNAs in colorectal neoplasia: A pilot study in assessing response to therapy

•

This pilot study examines a microRNA panel as a biomarker for response to surgical resection in colorectal cancer or colorectal advanced adenoma.

•

A panel of 11 microRNAs was developed through screening and previous studies.

•

Six miRNA are significantly increased following colorectal cancer resection.

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Three miRNA are significantly increased following colorectal advanced adenoma resection.

•

The results of this study suggest that serum microRNA expression could be followed as a marker for response to therapy.

Introduction

Current serological surveillance markers to monitor colorectal cancer (CRC) or colorectal advanced adenomas (CAA) are hampered by poor sensitivity and specificity. The aim of this study is to identify and validate a panel of plasma microRNAs which change in expression after resection of such lesions.

Methods

A prospectively maintained colorectal surgery database was queried for patients in whom both pre- and post-procedural serum samples had been obtained. An initial screening analysis of CRC and CAA patients (5 each) was conducted using screening cards for 380 miRNAs. Four identified miRNAs were combined with a previously described panel of 7 miRNAs that were diagnostically predictive of CRC and CAA. Differential miRNA expression was assessed using quantitative real-time polymerase chain reaction(qRT-PCR).

Results

Fifty patients were included (n = 27 CRC, n = 23 CAA). There was no difference in age, gender, or race profile of CRC patients compared to CAA patients. Six miRNA were significantly increased after CRC resection (miR-324, let7b, miR-454, miR-374a, miR-122, miR-19b, all p<0.05), while three miRNAs were significantly increased following CAA resection (miR-454, miR-374a, miR-122, all p<0.05). Three miRNA were increased in common for both (miR-454, miR-374a, miR-122).

Discussion

The expression of miRNAs associated with neoplasia (either CRC or CAA) was significantly increased following surgical resection or endoscopic removal of CRC or CAA. Future studies should focus on the evaluation of these miRNAs in CRC and CAA prognosis.

Segmental Withdrawal During Screening Colonoscopy Does Not Increase Adenoma Detection Rate

OBJECTIVES

The aim of this study was to compare a standard versus segmental withdrawal during screening colonoscopy and its effect on the adenoma detection rate (ADR).

METHODS

We performed a single-center clinical trial of average-risk patients 50 years of age and older undergoing screening colonoscopy. Patients were randomized into four groups: a standard withdrawal of at least 6 or 8 minutes and a segmental withdrawal, in which ≥3 or ≥4 minutes were dedicated to the right side of the colon, with a minimum withdrawal time of at least 6 or 8 minutes, respectively.

RESULTS

There were 311 patients in the study. There was no difference in ADR between the standard and segmental groups (relative ratio [RR] 0.91, P = 0.50), even after stratifying for right-sided adenomas. During standard withdrawal, an increased continuous withdrawal time was associated with a higher ADR (RR 1.08, P <0.001) and total adenomas per patient (RR 1.12, P < 0.001). A binary analysis of ≥8 minutes or <8 minutes withdrawal was associated with an increased adenomas per colonoscopy (RR 1.86, P = 0.04). These differences were not observed in the segmental group.

CONCLUSIONS

Overall, there was no benefit from a segmental withdrawal protocol on ADR, but this may have been the result of the inherent limitations in the study design. After sensitivity analysis, a segmental withdrawal protocol led to an improvement in the detection of adenomas per colonoscopy and polyps per colonoscopy. A larger sample size is needed to confirm these findings.

Colonoscopic screening is associated with reduced Colorectal Cancer incidence and mortality: a systematic review and meta-analysis

It is the great priority to detect colorectal cancer (CRC) as early as possible, finally to reduce the incidence and mortality of CRC. However, although colonoscopy is recommended in many consensuses, yet no one systematic review is conducted to figure out how colonoscopy could change the incidence and mortality. In our study, we conducted a comprehensive meta-analysis to evaluate the association between colonoscopy screening and the incidence or mortality of CRC. PubMed, EMBASE, and PMC database were systematically searched from their inception to June 2020. A total of 13 cohort and 16 case-control studies comprising 4,713,778 individuals were obtained in this review. Our results showed that colonoscopy was associated with a 52% RR reduction in incidence of CRC (RR: 0.48, 95% CI: 0.46-0.49) and 62% RR reduction in mortality of CRC (RR: 0.38, 95% CI: 0.36-0.40). Subgroup analysis of different interventions, study design, country, sample size, age or sex showed that the incidence and mortality reduction remained consistent, and colonoscopy screening had the same effect on people below and above 50. Our study indicated that colonoscopy could significantly reduce the incidence and mortality of CRC.

Long non-coding RNA (lncRNA) and epithelial-mesenchymal transition (EMT) in colorectal cancer: a systematic review

BACKGROUND

Colorectal cancer (CRC) is a leading cause of cancer-related death. Epithelial-mesenchymal transition (EMT) is a major process in tumor metastasis development. This systematic review aims to describe the role of long non-coding RNA (lncRNA) in EMT in CRC.

METHODS

The electronic databases, PubMed, Cochrane, and EMBASE, were searched from January1990 to June 2019 to identify studies examining lncRNA and their role in mediating EMT in CRC. Studies examining clinical specimens and/or in vitro experiments were included.

RESULTS

In 61 identified studies, 54 lncRNAs were increased in CRC compared to normal colorectal epithelium. Increased lncRNA expression was frequently associated with worse survival. Many lncRNAs mediate their effect through competitive endogenous RNA or transcription factor regulation. The ZEB1, 2/E-cadherin, Wnt/β-catenin signaling, and chromatin remodeling pathways are discussed in particular.

CONCLUSIONS

lncRNAs are major regulators of EMT and predictor adverse outcome in CRC patients. Future research must focus on delineating lncRNA function prior to potential clinical use.

Investigation of the Local Recurrence Rate after Colorectal Endoscopic Mucosal Resection: Is Incomplete Polyp Resection Really a Clinically Important Problem? Analysis of the Rationale for the "Resect and Discard" Strategy

BACKGROUND/AIMS

The "Resect and Discard" strategy is a potentially useful strategy. At present, only the lesion size and accuracy of diagnosis are cited as considerations for clinical adoption of this strategy. On the other hand, histopathology of the resected specimens after Endoscopic Mucosal Resection (EMR) reveals often an unclear or positive-margin status, implying Incomplete Polyp Resection (IPR). If IPR indeed increased the risk of local recurrence, histopathological evaluation of the margin would be indispensable and clinical adoption of this strategy is difficult. The aim of this study is to verify the association between IPR and the risk of local recurrence.

METHODS

The 1872 polyps and 603 EMR cases in 597 patients who had EMR between May 2013 and May 2014 were enrolled. The local recurrence rate until 3 years after the EMR in cases with the target lesions of the "Resect and Discard" strategy was determined in the negative-margin and IPR groups.

RESULTS

The final analysis was performed using the data of 1092 polyps, and 222 were categorized into the IPR group. There were no cases of recurrence in either of the groups.

CONCLUSION

This is the world's first report conducted to examine the correlation of IPR and the local recurrence rate for clinical practice of "Resect and Discard" strategy. There is the possibility that pathological evaluation of the margins after EMR in patients with small polyps can be skipped.

Colorectal Polyps in Childhood Cancer Survivors Treated with Radiation Therapy

BACKGROUND

Cancer survivors treated with abdominal or pelvic radiation therapy (RT) for childhood cancer have an increased risk of colorectal cancer. However, clinical guidelines are inconsistent on recommendations regarding the early initiation of screening in these patients due to the lack of supporting evidence that these patients pass through a pre-invasive phase, in which adenomatous polyps can be detected and removed.

AIMS

To determine the prevalence of adenomatous polyps in cancer survivors treated with RT for childhood cancer; the prevalence in average-risk patients aged 17-49; and the prevalence in average-risk patients aged 50-75.

METHODS

We conducted a retrospective study comparing the prevalence of adenomatous polyps among three patient groups: childhood cancer survivors aged 17-49 with prior RT who underwent colonoscopy screening from 2006 to 2017; age- and gender-matched patients in the average-risk population; and average-risk patients aged 50-75.

RESULTS

One hundred and forty-five patients were included in the study. The proportion of patients with adenomatous polyps in the cancer survivor group was significantly higher than that in the age- and gender-matched average-risk group (58.6 vs 17.2%, p = 0.00) and higher than the average-risk group aged 50-75 (58.6 vs 27.6%, p = 0.009). The prevalence of adenomas with high-risk features was higher in the survivor group compared to patients aged 50-75 (20.7 vs 3.5%, p = 0.015).

CONCLUSIONS

Cancer survivors treated with RT for childhood cancer have a higher prevalence of adenomatous polyps compared to the average-risk population. These findings support the early initiation of colonoscopy screening 10 years after radiation therapy, even in patients who have received RT doses below 30 Gy.

Impact of fellowship training level on colonoscopy quality and efficiency metrics

BACKGROUND AND AIMS

Previous studies have described variable effects of fellow involvement on the adenoma detection rate (ADR), but few have stratified this effect by level of training. We aimed to evaluate the "fellow effect" on multiple procedural metrics including a newly defined adenoma management efficiency index, which may have a role in documenting colonoscopy proficiency for trainees. We also describe the impact of level of training on moderate sedation use.

METHODS

We performed a retrospective review of 2024 patients (mean age, 60.9 ± 10 years; 94% men) who underwent outpatient colonoscopy between June 2012 and December 2014 at our Veterans Affairs Medical Center. Colonoscopies were divided into 5 groups. The first 2 groups were first-year fellows in the first 6 months and last 6 months of the training year. Second- and third-year fellows and attending-only procedures accounted for 1 group each. We collected data on doses of sedatives used, frequency of adjunctive agent use, procedural times, and location, size, and histology of polyps. We defined the adenoma management efficiency index as average time required per adenoma resected during withdrawal.

RESULTS

Of the colonoscopies performed, 1675 involved a fellow and 349 were performed by the attending alone. There was no difference in ADR between fellows according to level of training (P = .8) or between fellows compared with attending-only procedures (P = .67). Procedural times decreased consistently during training and declined further for attending-only procedures. This translated into improvement in the adenoma management efficiency index (fellow groups by ascending level of training: 23.5 minutes vs 18.3 minutes vs 13.7 minutes vs 13.4 minutes vs attending group 11.7 minutes; P < .001). There was no difference in the average doses of midazolam and fentanyl used among fellow groups (P = .16 and P = .1, respectively). Compared with attending-only procedures, fellow involvement was associated with higher doses of fentanyl and midazolam and more frequent use of diphenhydramine and glucagon (P < .0001, P = .0002, P < .0001, and P = .01, respectively).

CONCLUSIONS

ADR was similar at different stages of fellowship training and comparable with the attending group. Efficiency of detecting and resecting polyps improved throughout training without reaching the attending level. Fellow involvement led to a greater use of moderate sedation, which may relate to a longer procedure duration and an evolving experience in endoscopic technique.

Dielectric properties of colon polyps, cancer, and normal mucosa: Ex vivo measurements from 0.5 to 20 GHz

PURPOSE

Colorectal cancer is highly preventable by detecting and removing polyps, which are the precursors. Currently, the most accurate test is colonoscopy, but still misses 22% of polyps due to visualization limitations. In this paper, we preliminary assess the potential of microwave imaging and dielectric properties (e.g., complex permittivity) as a complementary method for detecting polyps and cancer tissue in the colon. The dielectric properties of biological tissues have been used in a wide variety of applications, including safety assessment of wireless technologies and design of medical diagnostic or therapeutic techniques (microwave imaging, hyperthermia, and ablation). The main purpose of this work is to measure the complex permittivity of different types of colon polyps, cancer, and normal mucosa in ex vivo human samples to study if the dielectric properties are appropriate for classification purposes.

METHODS

The complex permittivity of freshly excised healthy colon tissue, cancer, and histological samples of different types of polyps from 23 patients was characterized using an open-ended coaxial probe between 0.5 and 20 GHz. The obtained measurements were classified into five tissue groups before applying a data reduction step with a frequency dispersive single-pole Debye model. The classification was finally compared with pathological analysis of tissue samples, which is the gold standard.

RESULTS

The complex permittivity progressively increases as the tissue degenerates from normal to cancer. When comparing to the gold-standard histological tissue analysis, the sensitivity and specificity of the proposed method is the following: 100% and 95% for cancer diagnosis; 91% and 62% for adenomas with high-grade dysplasia; 100% and 61% for adenomas with low-grade dysplasia; and 100% and 74% for hyperplastic polyps, respectively. In addition, complex permittivity measurements were independent of the lesion shape and size, which is also an interesting property comparing to current colonoscopy techniques.

CONCLUSIONS

The contrast in complex permittivities between normal and abnormal colon tissues presented here for the first time demonstrate the potential of these measurements for tissue classification. It also opens the door to the development of a microwave endoscopic device to complement the outcomes of colonoscopy with functional tissue information.

Mutation analysis of adenomas and carcinomas of the colon: Early and late drivers

Colorectal cancer (CRC) accounts for about 8% of all new cancer cases diagnosed in the US. We used whole exome sequence data from triplet samples (colon carcinoma, colon adenoma, and normal tissue) from 18 individuals to assess gene mutation rates. Of the 2 204 genes that were mutated, APC, TTN, TP53, KRAS, OBSCN, SOX9, PCDH17, SIGLEC10, MYH6, and BRD9 were consistent with genes being an early driver of carcinogenesis, in that they were mutated in multiple adenomas and multiple carcinomas. Fifty-two genes were mutated in ≥12.5% of microsatellite stable (MSS) carcinomas but not in any of the adenomas, in line with the profile of a late driver event involved in tumor progression. Thirty-eight genes were sequenced in a larger independent set of 148 carcinoma/normal tissue pairs to obtain more precise mutation frequencies. Eight of the genes, APC, TP53, ATM, CSMD3, LRP1B, RYR2, BIRC6, and MUC17, contained mutations in >20% of the carcinomas. Interestingly, mutations in four genes in addition to APC that are associated with dysregulation of Wnt signaling, were all classified as early driver events. Most of the genes that are commonly associated with colon cancer, including APC, TP53, and KRAS, were all classified as being early driver genes being mutated in both adenomas and carcinomas. Classifying genes as potential early and late driver events points to candidate genes that may help dissect pathways involved in both tumor initiation and progression.

Risk of Colorectal Cancer following Colonoscopic Polypectomy

Aims and Background

To follow a cohort of patients who had undergone polypectomies in order to assess the overall risk of subsequent colorectal cancer in relation with various adenomas characteristics.

Methods

A total of 1,063 patients with adenomatous polyps of the large intestine were treated between 1979 and 1996 at the National Cancer Institute of Milan, during a screening program for colorectal carcinoma. Data on patients who had undergone colonoscopies were collected prospectively. The relation between colorectal cancer and adenomas characteristics was assessed by computing the hazard ratio (HR) values and corresponding confidence intervals (95% CI), according to Cox.

Results

Of the 1,063 patients who met the eligibility requirements, 672 had single adenomas (63.2%) and 391 had multiple adenomas (36.8%). Histological examination revealed 743 cases of tubular adenoma, 196 cases of tubulo-villous adenoma, and 96 cases of villous adenoma. High-grade dysplasia was found in 3.1% of the cases. During the 8,906 persons/year of follow-up, adenocarcinomas of the large bowel developed in 11 patients. Several adenomas’ characteristics at index polypectomy were significant predictors of colorectal cancer occurrence. In univariate analysis the risk of colon cancer was significantly related with multiple adenomas (HR 4.2, 95% CI 1.1-6.5), high-grade dysplasia adenomas (HR 10.0, 95% CI 2.6-38.1) and with adenomas larger than 2 cm (HR 5.0, 95% CI 1.2-20.4). A multivariate stepwise procedure confirmed that the presence of multiple adenomas and presence of high-grade dysplasia are the most important predictors of carcinomas. Hazard ratios for colorectal cancer occurrence, from multivariate Cox's model, were 5.1 (95% CI 1.2-19.9) for multiple compared to single adenomas, and 13.0 (95% CI 3.6-50.7) for adenomas with high-grade dysplasia compared to those with low-grade dysplasia.

Conclusions

High-grade dysplasia, number and size of adenomas were confirmed as the major cancer predictors. Based on this conclusion, a subgroup of patients, who may benefit from intensive surveillance colonoscopy, can be identifiable.

Diagnostic yield is not influenced by the timing of screening endoscopy: morning versus afternoon

BACKGROUND

Previous studies have shown the colonoscopy quality affected by the endoscopist's fatigue. This study was aimed to evaluate this potential factor in a colorectal cancer-screening cohort of Chinese patients.

METHODS

The attendances at department of gastroenterology for colorectal cancer screening between 2013 and 2015 were retrospectively analyzed. The procedure time-of-day and hours elapse were recorded. The primary outcome was defined as adenoma detection rate (ADR).

RESULTS

A total of 1342 screening colonoscopies were performed by 19 gastroenterologists in the study. Detection rates were 7.7% for all polyps and 20.0% for adenomas. Time-of-day was not significantly associated with ADR. With time elapsing, the first climax for ADR was presented at 09:00-10:00, and persistently rose again after the lunch break. Significant inclined trend in ADR was noted for each hour blocks of a full day (p =  .0021).

CONCLUSIONS

The procedure time-of-day, morning versus afternoon, did not affect the diagnostic efficacy of screening endoscopy in Chinese patients.

Comparisons of Rigid Proctoscopy, Flexible Colonoscopy, and Digital Rectal Examination for Determining the Localization of Rectal Cancers

BACKGROUND

Rigid proctoscopy is considered essential for rectal tumor localization, although the current gold standard for detection of colorectal cancers is colonoscopy. The European Society for Medical Oncology Guidelines indicate that rigid and flexible endoscopies afford essentially identical results, although little evidence is yet available to support this.

OBJECTIVE

The purpose of this study was to determine the accuracy of colonoscopy in identifying the location of rectal cancer and to compare the results with those of rigid proctoscopy and digital rectal examination.

DESIGN

This was a retrospective analysis of a prospective database.

SETTINGS

The study was conducted at a single tertiary colorectal surgery referral center.

PATIENTS

A total of 173 patients scheduled for curative surgery for histologically verified rectal adenocarcinoma between December 2009 and February 2015 were entered into the study, after having given informed consent.

MAIN OUTCOME MEASURES

The main study measure was the mean difference and limits of agreement in assessment of the height of the distal edge of rectal cancer from the anal verge, using the Bland and Altman method.

RESULTS

The mean difference between rigid proctoscopy and flexible colonoscopy was -0.2 cm (95% CI, -2.0 to 1.6 cm). The mean difference between rigid proctoscopy and digital rectal examination was 0.3 cm (95% CI, 1.9 to 2.4 cm). Intermethod variability larger than the 95% CI between rigid and flexible endoscopes was correlated to the tumor height (OR, 4.27 (95% CI, 1.84-3.10); p = 0.021).

LIMITATIONS

This study was conducted in a single center.

CONCLUSIONS

The limits of agreement (-2.0 and 1.6 cm) in identifying the height of rectal cancers from the anal verge are sufficiently small to support the view that flexible colonoscopy provides similar tumor locations to those measured by rigid proctoscopy, although the discrepancy occasionally exceeded 2 cm for tumors >5 cm above the anal verge. See Video Abstract at http://links.lww.com/DCR/A405.

Screening of colorectal cancer: present and future

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

Colonoscopy vs. Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM): Rationale for Study Design

RATIONALE

Colorectal cancer (CRC) is preventable through screening, with colonoscopy and fecal occult blood testing comprising the two most commonly used screening tests. Given the differences in complexity, risk, and cost, it is important to understand these tests' comparative effectiveness.

STUDY DESIGN

The CONFIRM Study is a large, pragmatic, multicenter, randomized, parallel group trial to compare screening with colonoscopy vs. the annual fecal immunochemical test (FIT) in 50,000 average risk individuals. CONFIRM examines whether screening colonoscopy will be superior to a FIT-based screening program in the prevention of CRC mortality measured over 10 years. Eligible individuals 50-75 years of age and due for CRC screening are recruited from 46 Veterans Affairs (VA) medical centers. Participants are randomized to either colonoscopy or annual FIT. Results of colonoscopy are managed as per usual care and study participants are assessed for complications. Participants testing FIT positive are referred for colonoscopy. Participants are surveyed annually to determine if they have undergone colonoscopy or been diagnosed with CRC. The primary endpoint is CRC mortality. The secondary endpoints are (1) CRC incidence (2) complications of screening colonoscopy, and (3) the association between colonoscopists' characteristics and neoplasia detection, complications and post-colonoscopy CRC. CONFIRM leverages several key characteristics of the VA's integrated healthcare system, including a shared medical record with national databases, electronic CRC screening reminders, and a robust national research infrastructure with experience in conducting large-scale clinical trials. When completed, CONFIRM will be the largest intervention trial conducted within the VA (ClinicalTrials.gov identifier: NCT01239082).

A Highly Predictive Model for Diagnosis of Colorectal Neoplasms Using Plasma MicroRNA: Improving Specificity and Sensitivity

OBJECTIVE

To develop a plasma-based microRNA (miRNA) diagnostic assay specific for colorectal neoplasms, building upon our prior work.

BACKGROUND

Colorectal neoplasms [colorectal cancer (CRC) and colorectal advanced adenoma (CAA)] frequently develop in individuals at ages when other common cancers also occur. Current screening methods lack sensitivity, specificity, and have poor patient compliance.

METHODS

Plasma was screened for 380 miRNAs using microfluidic array technology from a "Training" cohort of 60 patients, (10 each) control, CRC, CAA, breast cancer, pancreatic cancer, and lung cancer. We identified uniquely dysregulated miRNAs specific for colorectal neoplasia (P < 0.05, false discovery rate: 5%, adjusted α = 0.0038). These miRNAs were evaluated using single assays in a "Test" cohort of 120 patients. A mathematical model was developed to predict blinded sample identity in a 150 patient "Validation" cohort using repeat-sub-sampling validation of the testing dataset with 1000 iterations each to assess model detection accuracy.

RESULTS

Seven miRNAs (miR-21, miR-29c, miR-122, miR-192, miR-346, miR-372, and miR-374a) were selected based upon P value, area under the curve (AUC), fold change, and biological plausibility. Area under the curve (±95% confidence interval) for "Test" cohort comparisons were 0.91 (0.85-0.96) between all neoplasia and controls, 0.79 (0.70-0.88) between colorectal neoplasia and other cancers, and 0.98 (0.96-1.0) between CRC and colorectal adenomas. In our "Validation" cohort, our mathematical model predicted blinded sample identity with 69% to 77% accuracy, 67% to 76% accuracy, and 86% to 90% accuracy for each comparison, respectively.

CONCLUSIONS

Our plasma miRNA assay and prediction model differentiate colorectal neoplasia from patients with other neoplasms and from controls with higher sensitivity and specificity compared with current clinical standards.

Cap-Assisted Colonoscopy Increases Detection of Advanced Adenomas and Polyps

BACKGROUND

Cap-assisted colonoscopy (CAC) has been reported to increase the adenoma detection rate (ADR) in Asian population. However, CAC trials in non-Asian population have had conflicting results. Studies in North America have shown an improvement in ADRs with the use of CAC, but it mainly included white and African American patients. Given the lack of prospective studies of CAC in Hispanics, we conducted this randomized controlled trial.

MATERIALS AND METHODS

This is a randomized controlled trial comparing CAC with standard colonoscopy (SC) in patients undergoing screening or surveillance colonoscopy. Our primary outcome was the ADR. Secondary outcomes were polyp detection rate, mean polyp and ADR, advanced ADR (AADR) and detection rates based on polyp morphology and location.

RESULTS

A total of 440 patients were included in the study (88.5% Hispanic). Cecal and terminal ileum intubation rates were similar in both groups (CAC: 97% and 86% versus SC: 99% and 81%, respectively). CAC did not improve ADR in comparison with SC (0.65 versus 0.52; P = 0.079); however, CAC had a higher AADR in comparison with SC (9.9% versus 4.6%; P = 0.049). CAC detected significantly more pedunculated polyps as compared with flat and sessile polyps (P = 0.011). Complication rates were similar in the CAC and SC groups (0.9% versus 0%).

CONCLUSIONS

In a predominantly Hispanic population, no difference was seen in the mean ADR with the use of CAC. However, CAC, when compared with SC, resulted in an increased AADR and mean polyp detection rate.

Screening for colorectal cancer

This review will comprise a general overview of colorectal cancer (CRC) screening. We will cover the impact of CRC, CRC risk factors, screening modalities, and guideline recommendations for screening in average-risk and high-risk individuals. Based on this data, we will summarize our approach to CRC screening.

Blood-based microRNAs as biomarkers for the diagnosis of colorectal cancer: a systematic review and meta-analysis

Background:

Colorectal cancer (CRC) is common and associated with significant mortality. Current screening methods for CRC lack patient compliance. microRNAs (miRNAs), identified in body fluids, are negative regulators of gene expression and are dysregulated in many cancers, including CRC. This paper summarises studies identifying blood-based miRNAs dysregulated in CRC compared with healthy controls in an attempt to evaluate their use as a screening tool for the diagnosis of CRC.

Methods:

A search of electronic databases (PubMed and EMBASE) and grey literature was performed between January 2002 and April 2016. Studies reporting plasma or serum miRNAs in the diagnosis of CRC compared with healthy controls were selected. Patient demographics, type of patient sample (serum or plasma), method of miRNA detection, type of normalisation, and the number of significantly dysregulated miRNAs identified were recorded. Statistical evaluation of dysregulated miRNAs using sensitivity, specificity, and area under the curve (AUC) was performed.

Results:

Thirty-four studies investigating plasma or serum miRNAs in the diagnosis of CRC were included. A total of 31 miRNAs were found to be either upregulated (n=17) or downregulated (n=14) in CRC cases as compared with controls. Fourteen studies identified panels of ⩾2 dysregulated miRNAs. The highest AUC, 0.943, was identified using a panel of 4 miRNAs with 83.3% sensitivity and 93.1% specificity. Meta-analysis of studies identifying a single dysregulated miRNA in CRC cases compared with controls was performed. Overall sensitivity and specificity of 28 individual miRNAs in the diagnosis of CRC were 76% (95% CI 72%–80%) and 76% (95% CI 72%–80%), respectively, indicating good discriminative ability of miRNAs as biomarkers for CRC. These data did not change with sensitivity analyses.

Conclusions:

Blood-based miRNAs distinguish patients with CRC from healthy controls with high sensitivity and specificity comparable to other common and invasive currently used screening methods for CRC. In future, miRNAs may be used as a relatively non-invasive blood-based marker for detection of CRC.

Validation of a Patient Satisfaction Scale in Patients Undergoing Bowel Preparation Prior to Colonoscopy

BACKGROUND

Colonoscopy is the most widely used test to screen for colorectal cancer but its use may be hindered by patients' inability to complete the bowel preparation. Patient-reported satisfaction with bowel-cleansing preparations has received little attention. We assessed the reliability and validity of a patient satisfaction survey used in two large, multicenter, randomized, assessor-blinded colonoscopy trials.

METHODS

Datasets from two pivotal trials were combined. Patients in both trials included men and women aged 18-80 years who were scheduled for an elective outpatient colonoscopy. Questions relevant to satisfaction with bowel preparation prior to colonoscopy were identified from the literature and incorporated into a 7-item survey administered to patients on the day of colonoscopy. Domain 1 of the satisfaction measure assessed difficulty using bowel-cleansing preparations, ability to consume preparations, acceptability of taste, and overall experience; questions regarding acceptance or refusal of future use of the same bowel preparation were asked in Domain 2. Responses from each item of Domain 1 were transformed on a scale ranging from 0 to 100 and summed as total satisfaction scores. Cronbach's alpha was used to measure reliability; validity was assessed by evaluating relationship between total satisfaction (Domain 1) and willingness to use preparation in the future (Domain 2).

RESULTS

Mean age of the 1211 trial participants was 56: 61 % female, 89.5 % Caucasian. Domain 1 had a Cronbach's alpha of 0.79, with higher satisfaction predicting higher future acceptability (p < 0.0001).

CONCLUSION

The patient-reported satisfaction measure of bowel-cleansing preparations possesses good validity and reliability.

Annual colonoscopy volume and maintenance of competency for surgeons

INTRODUCTION

To determine whether the annual case volume of general surgeons (greater or less than 200 colonoscopies) is associated with quality outcomes.

METHODS

This retrospective cohort study involved all adults who underwent colonoscopy by a surgeon in the city of St. John's, NL, during the first 6 months of 2012. Subjects were identified through records from the health authority, and data were recorded on a standardized data sheet. Univariate analysis followed by stepwise multivariable logistic regression was performed to determine whether there was an association between quality outcomes (colonoscopy completion rate, adenoma detection rate) and predictors of these outcomes including annual colonoscopy volume, patient age, gender, indication for colonoscopy, and ASA score. A Chi-squared test was used to determine whether other outcomes were associated with annual colonoscopy volume.

RESULTS

Data were collected on 1060 patients. Mean age was 59.5 (sd 12.2) years with 550 females. A total of 13 surgeons were studied, of which 7 performed less than 200 annual colonoscopies over the previous 2 years (low-volume group) and 6 performed more than 200 annual colonoscopies over the previous 2 years (high-volume group). While there was a significant difference in the colonoscopy completion rate favoring the high-volume group (82.2 vs. 91.1 %, p < 0.001), no difference was noted in the adenoma detection rate between groups (16.7 vs. 17.7 %, p = 0.762). The regression model revealed that colonoscopy completion was also associated with an indication of screening or surveillance and an ASA score of 1 or 2. The adenoma detection rate was associated with older age and male gender. There was no statistically significant association between annual colonoscopy volume and other safety outcome measures.

CONCLUSION

Performing over 200 colonoscopies annually is associated with higher colonoscopy completion rates, but does not appear to be associated with other quality measures.

Diagnostic yield of endomicroscopy for dysplasia in primary sclerosing cholangitis associated inflammatory bowel disease: a feasibility study

BACKGROUND AND STUDY AIMS

Primary sclerosing cholangitis associated inflammatory bowel disease (PSC-IBD) is characterized by a high risk of colorectal dysplasia. Surveillance colonoscopies with random biopsies have doubtful power for dysplasia detection. Our aim was to prospectively investigate the feasibility and efficacy of pCLE in surveillance colonoscopies in patients with PSC-IBD.

PATIENTS AND METHODS

Sixty-nine patients with PSC-IBD underwent colonoscopy in 2 steps. On the way from rectum to cecum, the mucosa was inspected with high definition endoscopy (HDE) and random biopsies were taken according to the standard routine. On the way from cecum to rectum, fluorescein-enhanced pCLE and chromoendoscopy were performed. Regions where random biopsies had been taken, as well as visible lesions, were examined with pCLE and targeted biopsies were taken of lesions suspicious for dysplasia. Two investigators, blinded to histology and endoscopy results, analyzed all pCLE videos off-line.

RESULTS

Nineteen biopsies obtained in 13 patients (17 targeted biopsies, 2 random biopsies) revealed the presence of low-grade dysplasia. Thirteen lesions with dysplasia were endoscopically visible but by using pCLE-targeted biopsies, additional endoscopically invisible dysplasias in 4 biopsies obtained from 3 patients were detected. The sensitivity, specificity, and accuracy of pCLE in predicting dysplasia were respectively 89 % (95 % CI: 65 - 98), 96 % (95 % CI: 94 - 97), and 96 % (95 % CI: 94 - 97). pCLE showed a good performance for differentiating neoplastic from non-neoplastic mucosa with negative predictive value of 99 %.

CONCLUSIONS

pCLE in PSC-IBD surveillance is feasible and may be a good complement to HDE. Future research should aim at elucidating whether real-time pCLE is applicable in PSC-IBD surveillance.

Colorectal cancer development and advances in screening

Most colon tumors develop via a multistep process involving a series of histological, morphological, and genetic changes that accumulate over time. This has allowed for screening and detection of early-stage precancerous polyps before they become cancerous in individuals at average risk for colorectal cancer (CRC), which may lead to substantial decreases in the incidence of CRC. Despite the known benefits of early screening, CRC remains the second leading cause of cancer-related deaths in the United States. Hence, it is important for health care providers to have an understanding of the risk factors for CRC and various stages of disease development in order to recommend appropriate screening strategies. This article provides an overview of the histological/molecular changes that characterize the development of CRC. It describes the available CRC screening methods and their advantages and limitations and highlights the stages of CRC development in which each screening method is most effective.

Colorectal cancer mortality reduction is associated with having at least 1 colonoscopy within the previous 10 years among a population-wide cohort of screening age

BACKGROUND AND AIMS

Colonoscopy has been demonstrated to be effective in colorectal cancer (CRC) mortality reduction, although current screening guidelines have yet to be evaluated. We assessed the protective benefit of colonoscopy within the previous 10 years and whether this effect is maintained with age.

METHODS

We used administrative data to compare risk of CRC death (CCD) across colonoscopy utilization among a population-wide cohort comprising individuals aged 60 to 80 years (N = 1,509,423). Baseline and time-dependent colonoscopy exposure models were assessed in the context of competing "other causes of death" (OCDs). Cumulative incidence of CCD and OCD across colonoscopy exposure, over follow-up, was estimated. Relative hazards were computed by age strata (60-69 years, 70-74 years, 75+ years) and proximal and distal cancer subsites.

RESULTS

At least 1 colonoscopy during 10 years before baseline was estimated to provide a 51% reduced hazard of CCD (hazard ratio [HR] 0.49; 95% confidence interval [CI], 0.45-0.54) over the following 8 years. When colonoscopy was modeled as a time-dependent covariate, the risk of CCD was further diminished (multivariable-adjusted HR 0.36; 95% CI, 0.33-0.38). Stratified analyses suggested moderately attenuated CCD risk reduction among the oldest age group; however, consideration of OCDs suggest that this is related to competing risks. CCD risk reduction related to colonoscopy was lower for proximal cancers.

CONCLUSIONS

Colonoscopy within the previous 10 years provides substantial protective benefit for average-risk individuals over 60 years. CCD risk reduction may be maintained well beyond 74 years, a common upper age limit recommended by screening guidelines.

Frequency of colonic adenomatous polyps in a tertiary hospital in Mumbai

INTRODUCTION

Incidence of colorectal carcinoma is increasing all over world. There is limited data on colorectal polyps from India. We evaluated the histomorphological features of colorectal polyps and determined risk stratification in adenomatous polyps.

METHODS

In 4970 consecutive colonoscopies, colorectal polyps were detected in 515 cases (10.3 %). Polyps were classified using standard histological criteria. Each polyp was evaluated for presence of dysplasia. Adenomatous polyps were classified as low-risk adenomas (1-2 tubular adenomas <10 mm) and high-risk adenomas characterized by villous histology, high-grade dysplasia, size ≥10 mm, or ≥3 adenomas.

RESULTS

Of 515 colorectal polyps, 270 (52.4 %) were adenomatous, followed by 78 (15.1 %) inflammatory, 78 (15.1 %) hyperplastic, 32 (6.2 %) hamartomatous polyps, 25 (4.8 %) benign epithelial polyps, 5 (0.9 %) cap polyps, 5 (0.9 %) lipomatous polyps, 3 (0.5 %) angiomatous polyps, 4 (0.7 %) lymphoid, and 15 (2.9 %) cases with adenocarcinoma masquerading as polyps. Mean (SD) age with colorectal polyps was 54.8 (33.0) years while for adenomatous polyps, 59.5 (14.8) years with male to female ratio of 2:1. Majority of adenomatous polyps 124 (45.9 %) were tubular adenomas present in rectosigmoid. High-grade dysplasia was found in 38 (14 %) adenomas. One hundred and fifty-five (57.4 %) were high risk of which majority were villous adenomas and nine (7.2 %) tubular adenomas.

CONCLUSION

The most common colorectal polyps found during routine colonoscopy were 270 adenomatous (52.4 %) cases. Of these, 155 (57.4 %) adenomatous polyps were high-risk category. Population prevalence data of colonic polyps in general population beyond the age of 50 years needs to be obtained.

Colorectal Cancer Screening: Do We Practice What We Preach?

Objective: Compliance rates for colorectal cancer screening have been reported as low, and ignorance is the most common factor sighted to explain this. The aim of this study was to determine screening compliance among colorectal surgeons assumed to be educated of the risks of colorectal cancer. Methods: A postal survey was distributed to the members of the American Society of Colon and Rectal Surgeons. Results: A total of 1195 members were surveyed. All respondents indicated that they advocate screening. Colonoscopy every 10 years and annual fecal occult blood testing were the most common strategies advocated to individuals with baseline risk. Colonoscopy every 5 years and annual fecal occult blood testing were the most common strategies advocated to patients with a first-degree relative with polyps or cancer. Most of these colorectal surgeons initiated their screening before 50 years of age. Conclusion: Colorectal cancer screening compliance is high among members of the American Society of Colon and Rectal Surgeons. These rates may be the result of awareness of the risks of colorectal cancer.

Improved survival of patients with colon cancer detected by screening colonoscopy

BACKGROUND

Screening for colon cancer (CC) may not only reduce its occurrence but has also the potential to reduce the overall mortality. So far, there has been little evidence that detection of colon cancer by screening colonoscopy results in different survival rates compared to symptomatic patients.

PATIENTS AND METHODS

Clinical, histological, diagnostic, and survival data of 1016 consecutive patients with CC from a prospectively expanded single-institutional database were analyzed for diagnostic, treatment, and prognostic factors. Findings were then stratified according to detection by screening colonoscopy vs. patients who became symptomatic prior to further diagnostic work-up.

RESULTS

7.1 % of all patients were identified by screening colonoscopy for colon cancer. Screened patients were younger (68.2 vs. 64.8 years), had smaller T stage (p = 0.032), lower tumor stage (p = 0.009), and a tendency to less lymph node metastasis. Overall survival was superior in screened patients, and stage-specific survival showed a tendency to improved survival, which was not statistically significant. Furthermore, a higher percentage of screened patients underwent adjuvant chemotherapy (84.6 vs. 55.0 %, p = 0.032).

CONCLUSION

Survival outcome and enrollment in a multimodal treatment was higher in screening-detected patients compared to patients diagnosed after the onset of clinical symptoms. Besides a potential occurrence of lead time bias, these findings strongly support the need for continued improvement of screening programs and the recruitment of more patients for colorectal cancer screening.

Colonoscopy Reduces Colorectal Cancer Incidence and Mortality in Patients With Non-Malignant Findings: A Meta-Analysis

OBJECTIVES

Observational studies have shown that colonoscopy reduces colorectal cancer (CRC) incidence and mortality in the general population. We aimed to conduct a meta-analysis quantifying the magnitude of protection by colonoscopy, with screening and diagnostic indications, against CRC in patients with non-malignant findings and demonstrating the potentially more marked effect of screening over diagnostic colonoscopy.

METHODS

PubMed, EMBASE, and conference abstracts were searched through 30 April 2015. The primary outcomes were overall CRC incidence and mortality. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random-effect models.

RESULTS

Eleven observational studies with a total of 1,499,521 individuals were included. Pooled analysis showed that colonoscopy was associated with a 61% RR reduction in CRC incidence (RR: 0.39; 95% CI: 0.26-0.60; I(2)=93.6%) and a 61% reduction in CRC mortality (RR: 0.39; 95% CI: 0.35-0.43; I(2)=12.0%) in patients with non-malignant findings, although there was high heterogeneity for the outcome of CRC incidence. After excluding one outlier study, there was low heterogeneity for the outcome of incidence (I(2)=44.7%). Subgroup analysis showed that the effect of screening colonoscopy was more prominent, corresponding to an 89% reduction in CRC incidence (RR: 0.11; 95% CI: 0.08-0.15), in comparison with settings involving diagnostic colonoscopy (RR: 0.51; 95% CI: 0.43-0.59; P<0.001).

CONCLUSIONS

On the basis of this meta-analysis of observational studies, CRC incidence and mortality in patients with non-malignant findings are significantly reduced after colonoscopy. The effect of screening colonoscopy on CRC incidence is more marked than diagnostic colonoscopy.

Ten-year incidence of colorectal cancer following a negative screening sigmoidoscopy: an update from the Colorectal Cancer Prevention (CoCaP) programme

OBJECTIVE

To examine the rates of colorectal cancer (CRC) following a negative screening sigmoidoscopy.

DESIGN

Cohort study.

SETTING

An integrated healthcare delivery organisation in California, USA.

PARTICIPANTS

72,483 men and women aged 50 years and above who had a negative screening sigmoidoscopy between 1994 and 1996. Those at elevated risk of CRC due to inflammatory bowel disease, prior polyps or CRC, or a strong family history of CRC were excluded.

MAIN OUTCOME MEASURES

Incidence rates of distal and proximal CRC. Standardised Incidence Ratios were used to compare annual incidence rates of distal and proximal CRC in the cohort to expected rates based on Surveillance, Epidemiology, and End Results data. Additionally, rate ratios (RR) and rate differences (RD) comparing the incidence rate of distal CRC in years 6+ postscreening with that in years 1-5 were calculated.

RESULTS

Incidence rates of distal CRC were lower than those in the San Francisco Bay area population at large during each of the first 10 years postsigmoidoscopy screening. However, the incidence of distal CRC rose steadily, from 3 per 100,000 in the first year of follow-up to 40 per 100,000 in the 10th year. During the second half of follow-up, the rate of distal CRC was twice as high as in the first half (RR 2 .08, 95% CI 1.38 to 3.16; RD 14 per 100,000 person-years, 95% CI 6 to 22).

CONCLUSIONS

Though still below population levels, the incidence of CRC during years 6-10 following a negative sigmoiodoscopy is appreciably higher than during the first 5 years.

Effect of Colonoscopy Volume on Quality Indicators

Background. The purpose of this study is to determine if colonoscopy quality is associated with the annual case volume of endoscopists. Methods. A retrospective cohort study was performed on 3235 patients who underwent colonoscopy in the city of St. John's, NL, between January and June 2012. Data collected included completion of colonoscopy (CCR) and adenoma detection rates (ADR). Endoscopists were divided into quintiles based on annual case volume. To account for potential confounding variables, univariate analyses followed by multivariable logistic regression were used to identify variables independently associated with CCR and ADR. Results. A total of 13 surgeons and 8 gastroenterologists were studied. There was a significant difference in CCR (p < 0.001) and ADR (p < 0.001) based on annual volume. Following multivariable regression, predictors of successful colonoscopy completion included annual colonoscopy volume, lower age, male sex, an indication of screening or surveillance, and a low ASA score. Predictors of adenoma detection included older age, male sex, an indication of screening or surveillance, and gastroenterology specialty. Conclusion. Higher annual case volume is associated with better quality of colonoscopy in terms of completion. However, gastroenterology specialty appears to be a better predictor of ADR than annual case volume.

Colorectal cancer screening in a low-incidence area: general invitation versus family risk targeting: a comparative study from Montenegro

OBJECTIVES

Colorectal cancer (CRC) is one of the most common malignancies worldwide. The aim of this study was to compare the outcomes of two different screening approaches in a small country (Montenegro, 650,000 inhabitants) with a CRC incidence lower than the European average.

METHODS

Two structured invitation programs were compared with respect to compliance and neoplasia yield: (i) program A focused on first-degree relatives of CRC patients diagnosed in two hospitals (n=206), inviting them for colonoscopy; (ii) program B was an invitation program for fecal occult blood testing, followed by colonoscopy if positive, conducted in University Hospital, Podgorica, Montenegro, on 2760 randomly selected average-risk persons, age 50-74 years, living in a single municipality.

RESULTS

Of 710 first-degree relatives of 206 CRC patients approached, 540 presented for colonoscopy (76.05% uptake). Overall, 31 were diagnosed with a cancer, 58 with advanced adenoma, and 151 with adenoma in general. In the general screening program, of 2760 individuals invited, 920 underwent fecal immunochemical test (33.3% uptake) and colonoscopy was performed in all 95 positive cases (10.3%); six cancers was found in five patients (one patient had two cancers), 19 patients were diagnosed with advanced adenoma, and 26 with any adenomas. The risk-targeted screening program had a significantly higher yield for cancers in both per invited (31/710 vs. 5/2760, P<0.001) and per eligible person analysis (31/540 vs. 5/920, P<0.001).

CONCLUSION

In a low-incidence country with limited resources, it may be advisable to start with CRC screening targeted to risk groups.

Outcomes of endoscopic treatment of second recurrences of large nonpedunculated colorectal adenomas

BACKGROUND AND AIMS

Piecemeal endoscopic mucosal resection (EMR) of large nonpedunculated colorectal adenomas is associated with significant recurrence rates. After salvage endoscopic treatment of recurrences, there is a significant rate of second recurrences. There is a paucity of data on the efficacy and safety of continued endoscopic treatment after a second recurrence.

METHODS

Consecutive patients with recurrent adenomas after initial piecemeal EMR of nonpedunculated colorectal adenomas >2 cm were reviewed. We assessed the feasibility, safety and efficacy of continued endoscopic treatment in these patients.

RESULTS

Sixty-four patients with 70 recurrent lesions were identified. All were retreated endoscopically. Follow-up colonoscopy (mean interval 6.4 months) was performed on 62/70 lesions (89 %), and a second recurrence was found in 21/62 (34 %). One patient underwent surgery for a circumferential adenoma of the ileocecal valve. The other 20 lesions were treated endoscopically. Follow-up colonoscopy was performed on 15/20 (75 %) and demonstrated a third recurrence in 3/15 (20 %). One was a deep T1 cancer; curative surgery was performed. The other two patients each had one additional endoscopic treatment and both had no recurrence on subsequent colonoscopy. There were two complications: Both were delayed bleeds after treatment of the first recurrence. A mean of 1.3 endoscopic procedures was required to achieve a cure (range 1-3) for recurrent adenomas after piecemeal EMR.

CONCLUSION

Endoscopic treatment of patients with second recurrences is safe and effective, but is associated with a significant rate of additional recurrences. Continued endoscopic treatment of patients with multiple recurrences is associated with high cure rates, low complication rates and a low risk of progression to malignancy.

Protective association of colonoscopy against proximal and distal colon cancer and patterns in interval cancer

BACKGROUND

The protective effect of colonoscopy against proximal colorectal cancer is variable and depends on the detection and complete removal of precancerous polyps.

OBJECTIVE

To estimate the efficacy of colonoscopy in a medical center with open-access screening colonoscopy since 1998.

DESIGN

Nested case-control study with incidence density sampling.

SETTING

University-affiliated Veterans Affairs Medical Center.

PATIENTS

Colorectal cancer (CRC) cases and control subjects selected from screening age patients matched by age, gender, and date of first primary care visit.

MAIN OUTCOME MEASUREMENT

Colonoscopy preceding the CRC diagnosis date.

RESULTS

A total of 20.2% of CRC cases had a colonoscopy in the preceding 10 years compared with 49.0% of control subjects (adjusted odds ratio [aOR], 0.20; 95% confidence interval [CI], 0.11-0.34). Colonoscopy was strongly associated with decreased odds of both distal CRC (aOR, 0.16; 95% CI, 0.07-0.34) and proximal CRC (aOR, 0.26; 95% CI, 0.11-0.58). The fraction of cases attributed to interval cancers was 10.5%. Missed lesions predominantly localized to the cecum and rectum, and recurrent lesions clustered in the hepatic flexure. Cecal intubation rate was 93% (98% in adequately prepped patients), and the adenoma detection rate was 45.2% in the control group.

LIMITATIONS

Single-center, retrospective case-control design.

CONCLUSION

In an open access colonoscopy program characterized by a high cecal intubation rate and adenoma detection rate, colonoscopy was strongly associated with reduced odds of both distal and proximal CRC. Among interval cancers, missed lesions clustered in the cecum and rectum and recurrent lesions in the hepatic flexure.

(1)H NMR Spectroscopy of Fecal Extracts Enables Detection of Advanced Colorectal Neoplasia

Colorectal cancer (CRC) is a growing cause of mortality in developing countries, warranting investigation into its etiopathogenesis and earlier diagnosis. Here, we investigated the fecal metabolic phenotype of patients with advanced colorectal neoplasia and controls using (1)H-nuclear magnetic resonance (NMR) spectroscopy and multivariate modeling. The fecal microbiota composition was assessed by quantitative real-time PCR as well as Wif-1 methylation levels in stools, serum, and urine and correlated to the metabolic profile of each patient. The predictivity of the model was 0.507 (Q(2)Y), and the explained variance was 0.755 (R(2)Y). Patients with advanced colorectal neoplasia demonstrated increased fecal concentrations of four short-chain fatty acids (valerate, acetate, propionate, and butyrate) and decreased signals relating to β-glucose, glutamine, and glutamate. The predictive accuracy of the multivariate (1)H NMR model was higher than that of the guaiac-fecal occult blood test and the Wif-1 methylation test for predicting advanced colorectal neoplasia. Correlation analysis between fecal metabolites and bacterial profiles revealed strong associations between Faecalibacterium prausnitzii and Clostridium leptum species with short-chain fatty acids concentration and inverse correlation between Faecalibacterium prausnitzii and glucose. These preliminary results suggest that fecal metabonomics may potentially have a future role in a noninvasive colorectal screening program and may contribute to our understanding of the role of these dysregulated molecules in the cross-talk between the host and its bacterial microbiota.