High definition colonoscopy vs. standard video endoscopy for the detection of colonic polyps: a meta-analysis

One in three adenomas could be missed by white-light colonoscopy - findings from a systematic review and meta-analysis

BACKGROUND

White light (conventional) colonoscopy (WLC) is widely used for colorectal cancer screening, diagnosis and surveillance but endoscopists may fail to detect adenomas. Our goal was to assess and synthesize overall and subgroup-specific adenoma miss rates (AMR) of WLC in daily practice.

METHODS

We conducted a systematic review in MEDLINE, EMBASE, Cochrane Library, and grey literature on studies evaluating diagnostic WLC accuracy in tandem studies with novel-colonoscopic technologies (NCT) in subjects undergoing screening, diagnostic or surveillance colonoscopy. Information on study design, AMR overall and specific for adenoma size, histology, location, morphology and further outcomes were extracted and reported in standardized evidence tables. Study quality was assessed using the QUADAS-2 tool. Random-effects meta-analyses and meta-regression were performed to estimate pooled estimates for AMR with 95% confidence intervals (95% CI) and to explain heterogeneity.

RESULTS

Out of 5,963 identified studies, we included sixteen studies with 4,101 individuals in our meta-analysis. One in three adenomas (34%; 95% CI: 30-38%) was missed by WLC in daily practice individuals. Subgroup analyses showed significant AMR differences by size (36%, adenomas 1-5 mm; 27%, adenomas 6-9 mm; 12%, adenomas ≥ 10 mm), histology (non-advanced: 42%, advanced: 21%), morphology (flat: 50%, polypoid: 27%), but not by location (distal: 36%, proximal: 36%).

CONCLUSIONS

Based on our meta-analysis, one in three adenomas could be missed by WLC. This may significantly contribute to interval cancers. Our results should be considered in health technology assessment when interpreting sensitivity of fecal occult blood or other screening tests derived from studies using WLC as "gold standard".

The application of the combination between artificial intelligence and endoscopy in gastrointestinal tumors

Gastrointestinal (GI) tumors have always been a major type of malignant tumor and a leading cause of tumor‐related deaths worldwide. The main principles of modern medicine for GI tumors are early prevention, early diagnosis, and early treatment, with early diagnosis being the most effective measure. Endoscopy, due to its ability to visualize lesions, has been one of the primary modalities for screening, diagnosing, and treating GI tumors. However, a qualified endoscopist often requires long training and extensive experience, which to some extent limits the wider use of endoscopy. With advances in data science, artificial intelligence (AI) has brought a new development direction for the endoscopy of GI tumors. AI can quickly process large quantities of data and images and improve diagnostic accuracy with some training, greatly reducing the workload of endoscopists and assisting them in early diagnosis. Therefore, this review focuses on the combined application of endoscopy and AI in GI tumors in recent years, describing the latest research progress on the main types of tumors and their performance in clinical trials, the application of multimodal AI in endoscopy, the development of endoscopy, and the potential applications of AI within it, with the aim of providing a reference for subsequent research.

Colorectal Neoplasia in Asian Americans Undergoing First Time Asymptomatic Average-risk Screening Colonoscopies

GOALS

We identified the prevalence and subtype of colorectal neoplasia removed during index screening colonoscopies in a large Asian American population.

BACKGROUND

Asian Americans are the fastest growing demographic group in the United States yet there is a paucity of data on the characteristics of colorectal neoplasia found in this cohort.

STUDY

Cross-sectional study of 2208 index colonoscopies performed on average-risk Asian and White patients at a large, tertiary academic center. Patients were identified via diagnostic or procedure codes between 2015 and 2020, with retrospective classification of polyp histopathology. Univariate and multivariate analysis were performed to identify risk factors associated with colorectal neoplasia.

RESULTS

A total of 2208 patients were identified, of which 1085 were Asian. When adjusted for age and sex, Asians were as likely as Whites to have any type of colorectal neoplasia [44.2% vs. 43.5%, odds ratio (OR)=0.93, (CI: 0.78-1.11)]. On multivariate analysis, Asians were less likely to have sessile serrated polyps (5.5% vs. 9.9%, OR=0.53, 95% CI: 0.38-0.73) and more likely to have tubular adenomas in the left colon (22.6% vs. 18.0%, OR=1.33, 95% CI: 1.08-1.64) compared with Whites.

CONCLUSIONS

Quality measures, such as sessile serrated polyp detection rates, may need to take into account demographic factors such as race. The prevalence of colorectal neoplasia among Asian Americans is substantial and warrants efforts to promote optimal uptake of colorectal cancer screening tests.

Precision in detecting colon lesions: A key to effective screening policy but will it improve overall outcomes?

Colonoscopy is the gold standard for the screening and diagnosis of colorectal cancer, resulting in a decrease in the incidence and mortality of colon cancer. However, it has a 21% rate of missed polyps. Several strategies have been devised to increase polyp detection rates and improve their characterization and delimitation. These include chromoendoscopy (CE), the use of other devices such as Endo cuffs, and major advances in endoscopic equipment [high definition, magnification, narrow band imaging, i-scan, flexible spectral imaging color enhancement, texture and color enhancement imaging (TXI), etc.]. In the retrospective study by Hiramatsu et al, they compared white-light imaging with CE, TXI, and CE + TXI to determine which of these strategies allows for better definition and delimitation of polyps. They concluded that employing CE associated with TXI stands out as the most effective method to utilize. It remains to be demonstrated whether these results are extrapolatable to other types of virtual CE. Additionally, further investigation is needed in order to ascertain whether this strategy could lead to a reduction in the recurrence of excised lesions and potentially lower the occurrence of interval cancer.

Changes in Adenoma Detection Rate From Full-Spectrum Endoscopy to Standard Forward-Viewing Endoscopy

GOALS

The aim was to investigate the adenoma detection rate (ADR) of endoscopists who have used full-spectrum endoscopy (Fuse) for 3 years and revert back to traditional forward-viewing endoscopes (R-TFV) at an ambulatory surgical center.

BACKGROUND

Traditional forward viewing (TFV) endoscopes have 1 camera and provide an angle of view of 140 to 170 degrees, whereas Fuse provides a 330 degrees view through the addition of 2 side cameras. It has previously been reported that Fuse increased the ADR by 5.4% when compared with previous rates using TFV. Fuse is no longer commercially available. The ADR of endoscopists who revert back to TFV is unknown.

STUDY

We conducted a retrospective analysis of data examining the ADR from average risk screening colonoscopies at a 5-room ambulatory surgical center where endoscopists transitioned from TFV to Fuse in April 2014 and then reverted back to TFV in 2016. The primary outcome was ADR. Secondary outcomes were ADR for advanced and right-sided adenomas.

RESULTS

A total of 6110 procedures were reviewed. The ADR was 23.70% for TFV, 29.02% for Fuse and 28.88% for R-TFV. The ADR for advanced adenomas was 3.8% for TFV, 6.0% for Fuse and 7.3% for R-TFV. The ADR for right-sided adenomas was 13.0% for TFV, 16.7% for Fuse and 16.0% for R-TFV. The results for all 3 categories showed a statistical difference between TFV and Fuse as well as between TFV and R-TFV. There were no statistical differences between the ADR of Fuse compared with R-TFV.

CONCLUSIONS

During R-TFV, endoscopists are able to maintain their increased ability to detect adenomas. This would suggest that there was a change in behavior in endoscopists using Fuse that was durable.

Quality indicators in colonoscopy: observational study in a supplementary health system

PURPOSE

Colorectal cancer is responsible for 9.4% of cancer deaths, and low polyp detection rate and cecal intubation rate increase the risks of interval colorectal cancer. Despite several population studies that address colonoscopy quality measures, there is still a shortage of these studies in Latin America. The aim of this study was to assess quality indicators in colonoscopy, enabling future strategies to improve colorectal cancer prevention.

METHODS

An observational retrospective study, in which all colonoscopies performed in 11 hospitals were evaluated through a review of medical records. Information such as procedure indication, colorectal polyp detection rate, cecal intubation rate, quality of colonic preparation, and immediate adverse events were collected and analyzed.

RESULTS

In 17,448 colonoscopies performed by 86 endoscopists, 57.9% were in patients aged 50 to 74 years old. Colon preparation was adequate in 94.4% procedures, with rates of cecal intubation and polyp detection of 94 and 36.6%, respectively. Acute adverse events occurred in 0.2%. In 53.9%, high-definition imaging equipment was used. The procedure location, colon preparation and high-definition equipment influenced polyp detection rates (p < 0.001).

CONCLUSIONS

The extraction and analysis of electronic medical records showed that there are opportunities for improvement in colonoscopy quality indicators in the participating hospitals.

Mucosal imaging in colon polyps: New advances and what the future may hold

An expanding range of advanced mucosal imaging technologies have been developed with the goal of improving the detection and characterization of lesions in the gastrointestinal tract. Many technologies have targeted colorectal neoplasia given the potential for intervention prior to the development of invasive cancer in the setting of widespread surveillance programs. Improvement in adenoma detection reduces miss rates and prevents interval cancer development. Advanced imaging technologies aim to enhance detection without significantly increasing procedural time. Accurate polyp characterisation guides resection techniques for larger polyps, as well as providing the platform for the "resect and discard" and "do not resect" strategies for small and diminutive polyps. This review aims to collate and summarise the evidence regarding these technologies to guide colonoscopic practice in both interventional and non-interventional endoscopists.

Factors associated with the risk of colorectal neoplasia in young adults under age 40

BACKGROUND/AIMS

Recent epidemiologic studies have shown a continued increase in colorectal cancer incidence among younger adults. Little is known about the factors that contribute to the development of young-onset colorectal neoplasia (CRN).

METHODS

A cross-sectional analysis was performed for individuals younger than 40 years who underwent colonoscopy in Seoul St. Mary's Hospital and its affiliated health screening center. High-risk CRN was defined as adenoma or sessile serrated lesion ≥ 10 mm, with three or more adenomas, villous histology, high grade dysplasia, or carcinoma.

RESULTS

Of these 13,621 included participants, 2,023 (14.9%) had one and more CRN. Young patients with CRN tended to be elderly, male, obese, smoker, having a habit of drinking, and having comorbidities such as hypertension, dyslipidemia, diabetes, and chronic kidney disease. In a multivariate analysis adjusted for age, sex, obesity, smoking status, and alcohol intake, old age (odds ratio [OR], 1.086; 95% confidence interval [CI], 1.054 to 1.119), male sex (OR, 1.748; 95% CI, 1.247 to 2.451), obesity (OR, 1.439; 95% CI, 1.133 to 1.828), and smoking (OR, 1.654; 95% CI, 1.287 to 2.127) were independent risk factors for overall CRN. Obesity and smoking as two modifiable factors increased the risk for high-risk CRN even more than for overall CRN (OR, 1.734; 95% CI, 1.168 to 2.575 and OR, 1.797; 95% CI, 1.172 to 2.753, respectively).

CONCLUSION

Obesity and smoking were modifiable risk factors for CRN in young adults. They increased the risk for highrisk CRN even more than for overall CRN. A colonoscopy might be beneficial for young individuals with these factors.

Colonoscopy - When quality matters

Colonoscopy technical quality is a primary determinant of clinical outcome. Unfortunately, there is enough evidence available for significant variability in endoscopists' performance. An assessment of the factors determining these differences will be crucial for designing measures to ensure effectiveness and safety in these procedures.

Colorectal cancer screening knowledge and uptake in lebanon: a national survey

OBJECTIVE

The main aim of this national survey was to identify the levels of colorectal cancer screening knowledge and uptake in Lebanon.

METHODS

A total of 1200 participants were enrolled in this cross-sectional household survey targeting the Lebanese population aged 50 years and above. The sample was recruited using a two-stage stratified cluster sampling approach.

RESULTS

Of the total sample, 38.3% knew about any screening test for colorectal cancer but only 7.5% had ever used any. Thirty-nine percent of the participants rated their risk of getting colorectal cancer as very low or low, and only 53.5% were confident in their ability to undertake a screening test. Almost all participants agreed that medical advice and test reimbursement would encourage them to do a screening test. At the multivariate analysis level, hearing of an awareness campaign in the last two years showed the strongest association with the knowledge of a colorectal cancer screening test with an estimated OR_adj = 5.12 (95%CI: 3.67 - 7.15). Other factors that were significantly associated with this knowledge variable included: a family history of colorectal cancer, a personal history of colorectal illness, having a health coverage, and knowledge of colorectal cancer signs and symptoms.

DISCUSSION

This national study highlights an alarming lack of uptake and low levels of knowledge of colorectal cancer screening tests even though it is among the most prevalent cancers in Lebanon and its prevalence has been continuously increasing in the past years. The evidence suggests that people who had an experience with colorectal cancer diagnostic tests, either personally or through a family member, and those who have heard of an awareness campaign about colorectal cancer in the last two years are more likely to know its screening tests.

CONCLUSION

Colorectal cancer screening knowledge and uptake in Lebanon are limited and justify the need for public health interventions. This study gives evidence that awareness campaigns, coupled with the involvement of medical providers and the reimbursement of screening test fees, would alleviate the burden of colorectal cancer in Lebanon.

Factors Associated with Polyp Detection Rate in European Colonoscopy Practice: Findings of The European Colonoscopy Quality Investigation (ECQI) Group

Background: The European Colonoscopy Quality Investigation (ECQI) Group aims to raise awareness for improvement in colonoscopy standards across Europe. We analysed data collected on a sample of procedures conducted across Europe to evaluate the achievement of the polyp detection rate (PDR) target. We also investigated factors associated with PDR, in the hope of establishing areas that could lead to a quality improvement. Methods: 6445 form completions from 12 countries between 2 June 2016 and 30 April 2018 were considered for this analysis. We performed an exploratory analysis looking at PDR according to European Society of Gastrointestinal Endoscopy (ESGE) definition. Stepwise multivariable logistic regression analysis was conducted to determine the most influential associated factors after adjusting for the other pre-specified variables. Results: In our sample there were 3365 screening and diagnostic procedures performed in those over 50 years. The PDR was 40.5%, which is comparable with the ESGE minimum standard of 40%. The variables found to be associated with PDR were in descending order: use of high-definition equipment, body mass index (BMI), patient gender, age group, and the reason for the procedure. Use of HD equipment was associated with a significant increase in the reporting of flat lesions (14.3% vs. 5.7%, p < 0.0001) and protruded lesions (34.7% vs. 25.4%, p < 0.0001). Conclusions: On average, the sample of European practice captured by the ECQI survey meets the minimum PDR standard set by the ESGE. Our findings support the ESGE recommendation for routine use of HD colonoscopy.

Enhancing polyp detection: technological advances in colonoscopy imaging

The detection and removal of polyps at colonoscopy is core to the current colorectal cancer (CRC) prevention strategy. However, colonoscopy is flawed with a well described miss rate and variability in detection rates associated with incomplete protection from CRC. Consequently, there is significant interest in techniques and technologies which increase polyp detection with the aim to remedy colonoscopy's ills. Technologic advances in colonoscope imaging are numerous and include; increased definition of imaging, widening field of view, virtual technologies to supplant conventional chromocolonoscopy (CC) and now computer assisted detection. However, despite nearly two decades of technologic advances, data on gains in detection from individual technologies have been modest at best and heterogenous and conflicted as a rule. This state of detection technology science is exacerbated by use of relatively blunt metrics of improvement without consensus, the myopic search for gains over single generations of technology improvement and an unhealthy focus on adenomatous lesions. Yet there remains cause for optimism as detection gains from new technology, while small, may still improve CRC prevention. The technologies are also readily available in current generation colonoscopes and have roles beyond simply detection such as lesion characterization, further improving their worth. Coupled with the imminent expansion of computer assisted detection the detection future from colonoscope imaging advances looks bright. This review aims to cover the major imaging advances and evidence for improvement in polyp detection.

Detection Accuracy and Latency of Colorectal Lesions with Computer-Aided Detection System Based on Low-Bias Evaluation

We developed a computer-aided detection (CADe) system to detect and localize colorectal lesions by modifying You-Only-Look-Once version 3 (YOLO v3) and evaluated its performance in two different settings. The test dataset was obtained from 20 randomly selected patients who underwent endoscopic resection for 69 colorectal lesions at the Jikei University Hospital between June 2017 and February 2018. First, we evaluated the diagnostic performances using still images randomly and automatically extracted from video recordings of the entire endoscopic procedure at intervals of 5 s, without eliminating poor quality images. Second, the latency of lesion detection by the CADe system from the initial appearance of lesions was investigated by reviewing the videos. A total of 6531 images, including 662 images with a lesion, were studied in the image-based analysis. The AUC, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.983, 94.6%, 95.2%, 68.8%, 99.4%, and 95.1%, respectively. The median time for detecting colorectal lesions measured in the lesion-based analysis was 0.67 s. In conclusion, we proved that the originally developed CADe system based on YOLO v3 could accurately and instantaneously detect colorectal lesions using the test dataset obtained from videos, mitigating operator selection biases.

Outcomes of colonoscopy with non-anesthesiologist-administered propofol (NAAP): an equivalence trial

Background and study aims  Efficacy and safety of NAAP for gastrointestinal endoscopy have been widely documented, although there is no information about the outcomes of colonoscopy when the endoscopist supervises the sedation. In this context, the aim of this trial was to determine the equivalence of adenoma detection rate (ADR) in colorectal cancer (CRC) screening colonoscopies performed with non-anesthesiologist-administered propofol (NAAP) and performed with monitored anesthesia care (MAC). Patients and methods  This was a single-blind, non-randomized controlled equivalence trial that enrolled adults from a national CRC screening program (CRCSP). Patients were blindly assigned to undergo either colonoscopy with NAAP or MAC. The main outcome measure was the ADR in CRCSP colonoscopies performed with NAAP. Results  We included 315 patients per group. The median age was 59.76 ± 5.81 years; 40.5 % of patients were women. The cecal intubation rate was 97 %, 81.8 % of patients had adequate bowel preparation, withdrawal time was > 6 minutes in 98.7 %, and the median global exploration time was 24.25 ± 8.86 minutes (range, 8-70 minutes). The ADR was 62.9 % and the complication rate (CR) was 0.6 %. Analysis by intention-to-treat showed an ADR in the NAAP group of 64.13 % compared with 61.59 % in the MAC group, a difference (δADR) of 2.54 %, 95 %CI: -0.10 to 0.05. Analysis by per-protocol showed an ADR in the NAAP group of 62.98 %, compared with 61.94 % in the MAC group, δADR: 1.04 %, 95 %CI: -0.09 to 0.07. There was no difference in CR (NAAP: 0,63 vs. MAC: 0.63); P  = 1.0. Conclusions  ADR in colorectal cancer screening colonoscopies performed with NAAP was equivalent to that in those performed with MAC. Similarly, there was no difference in complication rates.

Serrated polyps of the colon and rectum: a concise review

"Serrated polyps" is the term used for epithelial lesions of the colon and rectum that have a "sawtooth" pattern on the polyp's surface and crypt epithelium. The so-called serrated pathway describes the progression of sessile serrated adenomas and traditional serrated adenomas to colorectal cancer. Said pathway is well recognized as an alternative mechanism of carcinogenesis and accounts for 15-30% of the cases of colorectal cancer. It also explains a large number of the cases of interval colorectal cancer. Thus, due to their usually aggressive and uncertain behavior, serrated polyps are of the utmost importance in colorectal cancer screening. Our aim was to review the history, current nomenclature, pathophysiology, morphology, treatment, and surveillance of serrated polyps.

Implementation and results of a gastrointestinal cancer screening program in an Amazon rainforest village: A descriptive study

Background and study aims  Gastrointestinal cancer is an important cause of death worldwide. Remote populations are especially vulnerable to these conditions due to reduced access to screening and adequate treatment. In this context, the Belterra project was designed as a pilot taskforce to deliver gastrointestinal screening to an underserved Amazonian population and to spread knowledge and practice to local health workers. This study aimed to describe the implementation and present the results of the Belterra Project. Patients and methods  The project took place between October 2014 and December 2017 in Belterra, Pará, Brazil. Public-private partnerships were obtained and were essential for funding. The project required complex logistic solutions to provide gastrointestinal screening to every inhabitant between 50 and 70 years of age, including medical equipment and personal transportation to a remote area. Subjects were asked about their medical history, and received a physical examination, endoscopic examinations, and stool tests. Results  Over the course of 19 expeditions, we screened 2,022 inhabitants of Belterra, aged 50 to 70 years. Five colorectal and six gastric adenocarcinomas were diagnosed, as were several lower-stage lesions. Overall, 26 % of the participants undergoing colonoscopy showed some type of colonic lesion. Conclusions  Notwithstanding the geographical, cultural, and financial barriers, this study suggests that the implementation of a gastrointestinal cancer screening program for remote Brazilian populations is feasible, reaching high adherence. Although logistics is very demanding, such campaigns may be a good strategy to provide mass gastrointestinal cancer screening for underserved populations.

Super-Resolution Enhanced Medical Image Diagnosis With Sample Affinity Interaction

The degradation in image resolution harms the performance of medical image diagnosis. By inferring high-frequency details from low-resolution (LR) images, super-resolution (SR) techniques can introduce additional knowledge and assist high-level tasks. In this paper, we propose a SR enhanced diagnosis framework, consisting of an efficient SR network and a diagnosis network. Specifically, a Multi-scale Refined Context Network (MRC-Net) with Refined Context Fusion (RCF) is devised to leverage global and local features for SR tasks. Instead of learning from scratch, we first develop a recursive MRC-Net with temporal context, and then propose a recursion distillation scheme to enhance the performance of MRC-Net from the knowledge of the recursive one and reduce the computational cost. The diagnosis network jointly utilizes the reliable original images and more informative SR images by two branches, with the proposed Sample Affinity Interaction (SAI) blocks at different stages to effectively extract and integrate discriminative features towards diagnosis. Moreover, two novel constraints, sample affinity consistency and sample affinity regularization, are devised to refine the features and achieve the mutual promotion of these two branches. Extensive experiments of synthetic and real LR cases are conducted on wireless capsule endoscopy and histopathology images, verifying that our proposed method is significantly effective for medical image diagnosis.

≥3 Nonadvanced Adenomas are More Common in the Era of Contemporary Colonoscopy and Not Associated With Metachronous Advanced Neoplasia

INTRODUCTION

Data from standard definition colonoscopy era demonstrate patients with an advanced adenoma (≥10 mm, villous features or high-grade dysplasia) or ≥3 nonadvanced adenomas are considered high-risk for metachronous advanced neoplasia (MAN). Low-risk adenoma (LRA) patients are those with 1 to 2, <10 mm tubular adenomas. High definition colonoscopy, split-dose bowel preparation, and attention to adenoma detection enhance diminutive adenoma detection. We compared baseline adenoma characteristics between patients undergoing colonoscopy in a historic cohort (HC) and contemporary cohort (CC) to determine if number of patients with ≥3 nonadvanced adenomas are increased in CC, and if those features are associated with MAN in CC.

MATERIALS AND METHODS

Patients undergoing their first colonoscopy in HC (<2006) and CC (≥2006) at age 50 and above were identified through natural language processing. Multivariable regression analysis compared baseline adenoma characteristics between HC and CC, and determined the association between baseline characteristics and MAN in CC patients.

RESULTS

In total, 255,074 colonoscopies were performed between 1990 and 2015. A total of 9773 colonoscopies performed in the HC and 59,531 in the CC were included. At baseline, CC patients were more likely to have ≥3 nonadvanced adenomas [odds ratio (OR): 2.1, 95% confidence interval (CI): 1.7-2.6]. In 3,377 CC patients undergoing follow-up colonoscopy, the risk of MAN did not differ between patients with LRA versus those with ≥3 nonadvanced adenomas (6.3% vs. 4.6%, OR: 1.4, CI: 0.58-3.5) including 3-4 (6.1%, OR: 1.4, CI: 0.52-3.6) and ≥5 (7.7%, OR: 1.8, CI: 0.23-14.6), although few patients had ≥5 nonadvanced adenomas.

CONCLUSIONS

Colonoscopy in the contemporary era increases detection of patients with ≥3 nonadvanced adenomas, which do not increase the risk of MAN compared with LRA patients. A similar surveillance to LRA patients should be considered for those patients.

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.

EndoL2H: Deep Super-Resolution for Capsule Endoscopy

Although wireless capsule endoscopy is the preferred modality for diagnosis and assessment of small bowel diseases, the poor camera resolution is a substantial limitation for both subjective and automated diagnostics. Enhanced-resolution endoscopy has shown to improve adenoma detection rate for conventional endoscopy and is likely to do the same for capsule endoscopy. In this work, we propose and quantitatively validate a novel framework to learn a mapping from low-to-high-resolution endoscopic images. We combine conditional adversarial networks with a spatial attention block to improve the resolution by up to factors of 8× , 10× , 12× , respectively. Quantitative and qualitative studies demonstrate the superiority of EndoL2H over state-of-the-art deep super-resolution methods Deep Back-Projection Networks (DBPN), Deep Residual Channel Attention Networks (RCAN) and Super Resolution Generative Adversarial Network (SRGAN). Mean Opinion Score (MOS) tests were performed by 30 gastroenterologists qualitatively assess and confirm the clinical relevance of the approach. EndoL2H is generally applicable to any endoscopic capsule system and has the potential to improve diagnosis and better harness computational approaches for polyp detection and characterization. Our code and trained models are available at https://github.com/CapsuleEndoscope/EndoL2H.

[Endoscopic diagnosis, treatment, and follow-up of polyps of the lower gastrointestinal tract]

BACKGROUND

The endoscopic management of polyps of the lower gastrointestinal tract (l-GIT) has emerged in recent years as a result of numerous technological innovations. However, proven expertise and experience are essential.

OBJECTIVES

Presentation of novel and standard techniques and best-practice recommendations for the characterization and resection of l‑GIT polyps.

METHODS

Recent specialist literature and current guidelines.

RESULTS

High-definition endoscopy should be the standard when performing colonoscopy. The (virtual) chromoendoscopy can improve detection and characterization of polyps, but always requires special expertise and experience of the endoscopist in advanced endoscopic imaging. In this regard, computer-aided-diagnosis (CAD) systems have the potential to support endoscopists in the future. Pedunculated polyps should be removed with a hot snare. Small flat polyps can be resected by cold snare or large forceps. Large, non-pedunculated polyps should be treated in an interdisciplinary approach at a referral center with long-standing experience depending on its malignancy potential. After complete resection of small adenoma without high grade dysplasia, surveillance endoscopy is recommended after 5-10 years. Patients with large adenoma or high grade dysplasia should undergo endoscopy after 3 years and patients with multiple adenoma earlier than 3 years. After incomplete or piecemeal resection or insufficient bowel preparation, near-term endoscopy is recommended.

CONCLUSIONS

Adequate characterization and treatment are essential for the appropriate management of l‑GIT polyps.

Modified Kudo classification can improve accuracy of virtual chromoendoscopy with FICE in endoscopic surveillance of ulcerative colitis

Background and study aims  Virtual chromoendoscopy with Fuji Intelligent Color Enhancement (FICE) has never been studied in prospective trials of endoscopic surveillance for ulcerative colitis (UC). We compared FICE and white light endoscopy (WLE) in differentiation of visible lesions in UC. Patients and methods  In a prospective parallel study, we compared consecutive outpatients with UC submitted to surveillance colonoscopy with FICE or WLE. At least one visible polypoid or non-polypoid lesion for each patient was required. Random biopsies from normal mucosa, targeted biopsies or removal of suspected neoplastic lesions and targeted biopsies of unsuspected lesions were performed. In the FICE arm, neoplasia was suspected according to a modified Kudo classification (FICE-KUDO/inflammatory bowel disease [IBD]). Sensitivity (SE), specificity (SP), positive and negative likelihood ratios (LR) and negative predictive value (NPV) were analyzed. Results  One hundred patients were submitted to FICE (n = 46) or WLE (n = 54). Twenty-two patients (11 in WLE, 11 in FICE) had a least one neoplastic lesion. No neoplasia was found in random biopsies. Among 275 lesions, 17 of 136 by FICE and 27 of 139 by WLE were suspected neoplasia, but 28 (14 in each arm) were true neoplastic lesions. The accuracy of FICE-KUDO/IBD vs WLE (per lesion) was: SE 93 % vs 64 % ( P  = 0.065), SP 97 % vs 86 % ( P  = 0.002), positive-LR 28.3 vs 4.5 ( P  = 0.001), negative-LR 0.07 vs 0.42 ( P  = 0.092), NPV 99 % vs 96 % ( P  = 0.083). FICE-KUDO/IBD detected more non-polypoid lesions than WLE ( P  = 0.016). Conclusions  Targeted biopsies of polypoid and non-polypoid lesions, using the modified Kudo classification with FICE are more accurate than WLE in UC surveillance.

The Case for High-Quality Colonoscopy Remaining a Premier Colorectal Cancer Screening Strategy in the United States

Most colorectal cancer screening in the United States occurs in the opportunistic setting, where screening is initiated by a patient-provider interaction. Colonoscopy provides the longest-interval protection, and high-quality colonoscopy is ideally suited to the opportunistic setting. Both detection and colonoscopic resection have improved as a result of intense scientific investigation. Further improvements in detection are expected with the introduction of artificial intelligence programs into colonoscopy platforms. We may expect recommended intervals or colonoscopy after negative examinations performed by high-quality detectors to expand beyond 10 years. Thus, high-quality colonoscopy remains an excellent approach to colorectal cancer screening in the opportunistic setting.

Colorectal Cancer Screening for the Serrated Pathway

Serrated polyps are classified into hyperplastic polyps, sessile serrated adenomas/polyps, and traditional serrated adenomas. Although all serrated polyps share characteristic colonic crypts serrations, distinguishing hyperplastic polyps from sessile serrated adenomas/polyps is challenging. Traditional serrated adenomas are cytologically dysplastic lesions; sessile serrated adenomas/polyps develop cytologic dysplasia as they progress to colorectal cancer. A flat and pale appearance of serrated polyps may make detection difficult. Endoscopic mucosal resection has higher rates of complete resection. Close surveillance is recommended for sessile serrated adenomas/polyps, sessile serrated adenomas/polyp with dysplasia, hyperplastic polyps ≥10 mm, and traditional serrated adenomas.

Optical imaging technology in colonoscopy: Is there a role for photometric stereo?

Colonoscopy screening for the detection and removal of colonic adenomas is central to efforts to reduce the morbidity and mortality of colorectal cancer. However, up to a third of adenomas may be missed at colonoscopy, and the majority of post-colonoscopy colorectal cancers are thought to arise from these. Adenomas have three-dimensional surface topographic features that differentiate them from adjacent normal mucosa. However, these topographic features are not enhanced by white light colonoscopy, and the endoscopist must infer these from two-dimensional cues. This may contribute to the number of missed lesions. A variety of optical imaging technologies have been developed commercially to enhance surface topography. However, existing techniques enhance surface topography indirectly, and in two dimensions, and the evidence does not wholly support their use in routine clinical practice. In this narrative review, co-authored by gastroenterologists and engineers, we summarise the evidence for the impact of established optical imaging technologies on adenoma detection rate, and review the development of photometric stereo (PS) for colonoscopy. PS is a machine vision technique able to capture a dense array of surface normals to render three-dimensional reconstructions of surface topography. This imaging technique has several potential clinical applications in colonoscopy, including adenoma detection, polyp classification, and facilitating polypectomy, an inherently three-dimensional task. However, the development of PS for colonoscopy is at an early stage. We consider the progress that has been made with PS to date and identify the obstacles that need to be overcome prior to clinical application.

High-definition colonoscopy for improving adenoma detection: a systematic review and meta-analysis of randomized controlled studies

BACKGROUND AND AIMS

Previous meta-analysis showed marginal benefit of high-definition white-light endoscopy (HD-WLE) over standard-definition colonoscopy (SDC) for adenoma detection, but with residual uncertainty due to inclusion of nonrandomized studies. We aimed to further assess the effect of HD-WLE on adenoma detection by including only randomized controlled trials (RCTs).

METHODS

A literature search was performed for RCTs evaluating HD-WLE versus SDC in terms of adenoma, advanced adenoma, and serrated sessile adenoma detection rates as well as the mean number of adenomas per colonoscopy (MAC), the mean number of advanced adenomas per colonoscopy (MAAC), and the mean number of sessile serrated adenomas per colonoscopy (MSSAC). The effect size on study outcomes is presented as the risk ratio (RR; 95% confidence interval [CI]) or mean difference (MD; 95% CI). We assessed the strength of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Six RCTs involving 4594 individuals (HD-WLE, 2323; SDC, 2271) were included. Clinical indications were screening (1 study), positive result for fecal occult blood test, personal/family history of colorectal cancer (1 study), and mixed indications (4 studies). Withdrawal time was similar between the 2 arms (MD, -0.06; 95% CI, -0.25 to 0.12; P = .50). The adenoma detection rate was significantly higher in the HD-WLE arm compared with the SDC arm (40% vs 35%; RR, 1.13; 95% CI, 1.05-1.22; P = .001; I2 = 0%; GRADE, low). This effect was consistent for advanced and sessile serrated adenoma detection rates (RR, 1.33; 95% CI, 1.03-1.72; P = .03; I2 = 0%; GRADE, low; and RR, 1.55; 95% CI, 1.05-2.28; P = .03; I2 = 0%; GRADE, low, respectively). In contrast, the difference was not significant for MAC, MAAC, and MSSAC.

CONCLUSIONS

Meta-analyses of RCT data support the use of HD-WLE in clinical practice, although the additional benefit is limited.

White-Light Endoscopy Is Adequate for Lynch Syndrome Surveillance in a Randomized and Noninferiority Study

BACKGROUND & AIMS

Dye-based pancolonic chromoendoscopy is recommended for colorectal cancer surveillance in patients with Lynch syndrome. However, there is scarce evidence to support its superiority to high-definition white-light endoscopy. We performed a prospective study assess whether in the hands of high detecting colonoscopists, high-definition, white-light endoscopy is noninferior to pancolonic chromoendoscopy for detection of adenomas in patients with Lynch syndrome.

METHODS

We conducted a parallel controlled study, from July 2016 through January 2018 at 14 centers in Spain of adults with pathogenic germline variants in mismatch repair genes (60% women; mean age, 47 ± 14 years) under surveillance. Patients were randomly assigned to groups that underwent high-definition white-light endoscopy (n = 128) or pancolonic chromoendoscopy (n = 128) evaluations by 24 colonoscopists who specialized in detection of colorectal lesions in high-risk patients for colorectal cancer. Adenoma detection rates (defined as the proportion of patients with at least 1 adenoma) were compared between groups, with a noninferiority margin (relative difference) of 15%.

RESULTS

We found an important overlap of confidence intervals (CIs) and no significant difference in adenoma detection rates by pancolonic chromoendoscopy (34.4%; 95% CI 26.4%-43.3%) vs white-light endoscopy (28.1%; 95% CI 21.1%-36.4%; P = .28). However, pancolonic chromoendoscopy detected serrated lesions in a significantly higher proportion of patients (37.5%; 95% CI 29.5-46.1) than white-light endoscopy (23.4%; 95% CI 16.9-31.4; P = .01). However, there were no significant differences between groups in proportions of patients found to have serrated lesions of 5 mm or larger (9.4% vs 7.0%; P = .49), of proximal location (11.7% vs 10.2%; P = .68), or sessile serrated lesions (3.9% vs 5.5%; P = .55), respectively. Total procedure and withdrawal times with pancolonic chromoendoscopy (30.7 ± 12.8 minutes and 18.3 ± 7.6 minutes, respectively) were significantly longer than with white-light endoscopy (22.4 ± 8.7 minutes and 13.5 ± 5.6 minutes; P < .001).

CONCLUSIONS

In a randomized parallel trial, we found that for Lynch syndrome surveillance, high-definition white-light endoscopy is not inferior to pancolonic chromoendoscopy if performed by experienced and dedicated endoscopists. ClinicalTrials.gov no: NCT02951390.

Artificial Intelligence and Polyp Detection

PURPOSE OF REVIEW

This review highlights the history, recent advances, and ongoing challenges of artificial intelligence (AI) technology in colonic polyp detection.

RECENT FINDINGS

Hand-crafted AI algorithms have recently given way to convolutional neural networks with the ability to detect polyps in real-time. The first randomized controlled trial comparing an AI system to standard colonoscopy found a 9% increase in adenoma detection rate, but the improvement was restricted to polyps smaller than 10 mm and the results need validation. As this field rapidly evolves, important issues to consider include standardization of outcomes, dataset availability, real-world applications, and regulatory approval.

SUMMARY

AI has shown great potential for improving colonic polyp detection while requiring minimal training for endoscopists. The question of when AI will enter endoscopic practice depends on whether the technology can be integrated into existing hardware and an assessment of its added value for patient care.

Advanced Endoscopic Imaging in Colonic Neoplasia

BACKGROUND

Endoscopic imaging is a rapidly evolving field with a constant influx of new concepts and technologies. Since the introduction of video endoscopy and subsequently high-definition imaging as the first revolutions in gastrointestinal endoscopy, several technologies of virtual chromoendoscopy have been developed and brought to the market in the past decade, which have shaped and revolutionized for a second time our approach to endoscopic imaging. In parallel to these developments, microscopic imaging technologies, such as endomicroscopy and endocytoscopy, allow us to examine single cells within the mucosa in real time, thereby enabling histological diagnoses during ongoing endoscopy.

SUMMARY

In this review, we provide an overview on the technical background of different technologies of advanced endoscopic imaging, and then review and discuss their role and applications for the diagnosis and management of colorectal neoplasms as well as limitations and challenges that exist despite all technological improvements.

KEY MESSAGES

Technologies of advanced endoscopic imaging have profound impact not only on our imaging capabilities, they are also about to fundamentally change our approach to managing lesions in the gastrointestinal tract: not every lesion found during colonoscopy has to be excised or sent for histopathologic evaluation. However, before this becomes widespread reality, major obstacles such as patient acceptance, adoption by less trained endoscopists, and also legal aspects need to carefully addressed. The development of computer-aided diagnosis and artificial intelligence algorithms hold the potential to overcome the obstacles associated with the concept of optical biopsy and will most likely fundamentally facilitate, shape, and change decision making in the management of colorectal lesions.

Surveying ADR Knowledge and Practices Among US Gastroenterologists

BACKGROUND

The adenoma detection rate (ADR) is of primary importance to the quality of screening colonoscopy. An online survey was conducted to assess knowledge and practices on ADR.

METHODS

Paid questionnaire distributed by email. Eligible respondents were board certified gastroenterologists who perform >80 colonoscopies per month with 3 to 35 years practice after fellowship.

RESULTS

There were 250 respondents. In total, 39% were unaware that ADR applies only to screening colonoscopies and 76% incorrectly answered that ADR includes sessile-serrated polyps/adenomas. A total of 51% of respondents incorrectly believe the threshold is set at 25% because 25% is a national ADR average. Many also believe the threshold depends on the patient population (current evidence suggests adjusting ADR for factors other than age and sex is unnecessary). 75% ranked ADR as highly important. 80% reported tracking ADR. A busy practice was the most common reason for not tracking ADR. Caps, chromoendoscopy, and good bowel preparation were viewed as valuable for improving ADR (this is true except for caps). High-definition colonoscopes and education were considered less valuable, despite evidence indicating that both are associated with improved ADR. In total, 57% reported not sharing ADR information with their patients, and 59% reported that no patients in the last 6 months asked for their ADR.

CONCLUSIONS

The importance of ADR as a quality measure is well understood, but there are misconceptions among gastroenterologists regarding the definition and measurement of ADR, and which methods are proven to increase ADR. Patients are having very little impact on ADR measurement.

Optimizing the Quality of Colorectal Cancer Screening Worldwide

Screening, followed by colonoscopic polypectomy (or surgery for malignant lesions), prevents incident colorectal cancer and mortality. However, there are variations in effective application of nearly every aspect of the screening process. Screening is a multistep process, and failure in any single step could result in unnecessary morbidity and mortality. Awareness of variations in operator- and system-dependent performance has led to detailed, comprehensive recommendations in the United States and Europe on how colonoscopy screening should be performed and measured. Likewise, guidance has been provided on quality assurance for nonprimary colonoscopy-based screening programs, including strategies to maximize adherence. Quality improvement is now a validated science, and there is clear evidence that higher quality prevents incident cancer and cancer death. Quality must be addressed at the levels of the system, provider, and individuals, to maximize the benefits of screening for any population. We review the important aspects of measuring and improving the quality of colorectal cancer screening.

Advances in endoscopy for colorectal polyp detection and classification

While colonoscopy is considered the gold standard for colon cancer screening, recent advancements in endoscopes have allowed for improved visualization of the colonic mucosa and improved polyp detection rates. Newer technologies also allow for assessment of structural changes for polyp discrimination and determination of histologic type. Classification of polyps prevents the need for a histopathologic report, which requires the additional time and expertise of a pathologist and adds to the overall cost. This review considered advances in endoscopic technologies reported in PubMed over the past 12 years. Technologies that allow for increased visual field of colonic mucosa and may lead to improved colon polyp detection rates include cap-assisted colonoscopy, RetroView, extra-wide-angle view colonoscope, full-spectrum endoscopy, Third Eye Retroscope, NaviAid G-EYE balloon colonoscope, EndoRings, and Endocuff. Image-enhancing methods allow for pit pattern analysis of colorectal lesions, which enables the physician to classify colorectal polyps according to certain polyp characteristics. Image-enhancing methods include chromoendoscopy, autofluorescence, and virtual chromoendoscopy, including narrow band imaging, i-SCAN, flexible spectral imaging chromoendoscopy, and STORZ professional image enhancement systems. In addition, advancements have been made in in vivo microscopic evaluation of colonic epithelium, including confocal laser endomicroscopy, endocytoscopy, optical coherence tomography, spectroscopy, and autofluorescence spectroscopy. Colon capsule endoscopy also has a role in colon polyp detection and classification. The advancements in polyp detection and classification have great promise for earlier detection and removal of advanced adenomas before they advance to colorectal cancer.

Randomized control trial of adenoma detection rate in Endocuff-assisted colonoscopy versus transparent hood-assisted colonoscopy

BACKGROUND AND AIM

Transparent hood-assisted colonoscopy (TAC) has been reported to improve the cecal insertion rate and adenoma detection rate (ADR). An endoscopic cap (Endocuff) with two rows of soft wings was recently developed to improve ADR, by flattening the mucosal folds during withdrawal. This randomized prospective control study aimed to compare ADR between Endocuff-assisted colonoscopy (EAC) and TAC.

METHODS

A total of 513 patients undergoing colon adenoma screening were included. EAC was performed in 256 patients and TAC in 260 patients. Cecal intubation rate, cecal intubation time, ADR, and mean adenoma number per patient (MAP) were investigated in both groups (clinical trial registration: UMIN000016278).

RESULTS

We excluded six patients in the EAC group and two patients in the TAC group because of colonic stenosis due to colonic adenocarcinomas. Finally, 250 patients (151 men/99 women, median age 62.1 years) were assigned to EAC and 258 patients (165 men/93 women, median age 64.3 years) were assigned to TAC. There were no significant differences in cecal intubation rate, intubation time, withdrawal time, and cleanliness score between groups. The ADR was 50.8% in EAC and 52.7% in TAC, with no significant difference (P = 0.666). The MAP was 1.35 in EAC and 1.20 in TAC, with no significant difference (P = 0.126). However, The MAP of diminutive adenomas (< 5 mm) tended to be higher in EAC than in TAC (P = 0.077). There was no significant difference in MAP in each segment between groups.

CONCLUSIONS

Endocuff-assisted colonoscopy might be equivalent to TAC in cecal intubation time, ADR, and MAP.

Optimizing Screening Colonoscopy: Strategies and Alternatives

Screening colonoscopy is the most effective screening procedure for the prevention of colorectal cancer. The efficacy of colonoscopy is highly dependent on the overall quality of how this procedure is indicated, planned, prepared, and performed. The quality is directly linked to the number of polyps and/or adenomas detected or, in other words, to the number of polyps or adenomas missed during the procedure. The quality has a direct impact on the rate of interval carcinoma and on the range of how the incidence and occurrence of colorectal cancer is reduced. This review summarizes the current status on general measures and procedure improvements and standards as well as technical advances which have been suggested and established to improve the quality of polyp and adenoma detection rate. This includes selection and preparation of the patients, planning, methodological and technical performance of the procedure, and technical advances of the endoscope technology in order to improve screening results. It also covers new technologies with wide angle endoscopes (Ewave) and IT-based approaches using artificial intelligence to such as ai4GI for the polyp detection and image analysis.

Incidence of Advanced Colorectal Neoplasia in Individuals With Untreated Diminutive Colorectal Adenomas Diagnosed by Magnifying Image-Enhanced Endoscopy

OBJECTIVES

Because of the increasing number of detected diminutive colorectal adenomas, the "diagnose-and-do-not-resect" approach has recently attracted attention as an alternative to resection. We evaluated the cumulative incidence of advanced colorectal neoplasia (ACN) in individuals with untreated diminutive adenomas and compared this incidence in individuals without adenomas.

METHODS

Data from 1,378 individuals who underwent first screening colonoscopy (CS) and at least one follow-up CS without polypectomy were analyzed. Patients with no adenomas or with only nonadvanced diminutive adenomas (<5 mm) diagnosed by magnifying image-enhanced endoscopy were scheduled to undergo a follow-up CS within 5 years after the initial CS without treatment. The participants were divided into 2 groups: those with untreated diminutive adenomas (group A) and those with no adenomas (group B). The cumulative incidence of ACN and the hazard ratio were assessed using Gray's test and the Fine and Gray model.

RESULTS

During the median follow-up period of 60.9 months, 21 ACNs were detected. The 5-year cumulative incidences of ACN in group A (n = 361) and group B (n = 1,017) were 1.4% (95% confidence interval [CI]: 0.5-3.4) and 0.8% (95% CI: 0.3-1.7), respectively, without a statistically significant difference (P = 0.23). No ACNs developed from unresected adenomas. The smoking status was significantly associated with the incidence of ACN, and the hazard ratio for ACN in group A vs group B adjusted for smoking status was 1.43 (95% CI: 0.52-3.90; P = 0.48).

DISCUSSION

The low 5-year cumulative incidence of ACN suggests the potential to adopt the "diagnose-and-do-not-resect" strategy as an alternative option for diminutive adenomas not requiring excessive surveillance.

Feasibility and economic assessment of chromocolonoscopy for detection of proximal serrated neoplasia within a population-based colorectal cancer screening programme (CONSCOP): an open-label, randomised controlled non-inferiority trial

BACKGROUND

Most post-colonoscopy interval colorectal cancers are proximal; serrated polyps are often precursors to these cancers and are considered difficult to detect. We assessed the safety, feasibility, and economic effect of chromocolonoscopy on detection of proximal serrated neoplasia.

METHODS

We did an open-label, multicentre, randomised, controlled non-inferiority trial including patients from Bowel Screening Wales centres. Participants who tested positive for faecal occult blood and who were eligible for and considered fit to have colonoscopy (patients with known cases of polyposis syndromes, Lynch syndrome, and chronic inflammatory disease were excluded) were randomly assigned (1:1; with the use of minimisation, stratified by centre with an 80:20 random element) to either standard white light colonoscopy (standard group) or chromocolonoscopy (indigo carmine dye [0·2%]; chromocolonoscopy group) using a secure, internet-based, computerised, randomisation system that used centralised, dynamic allocation. Participants were followed up for 1 year and data from index colonoscopies and associated clearance procedures were analysed. All proximal polyps were reviewed by an expert pathologist panel. The main outcome on which power was based was time taken to perform the colonoscopy procedure, defined as from the time when the scope was inserted to withdrawal from the anus, assessed in the per-protocol population. The non-inferiority margin was 15 min. This trial is complete and is registered with ClinicalTrials.gov, number NCT01972451.

FINDINGS

Between Nov 20, 2014, and June 16, 2016, 741 (72%) of 1031 patients screened were eligible and consented: 360 were randomly assigned to white light colonoscopy and 381 to chromocolonoscopy. In the chromocolonoscopy group, the procedure took a mean of 36·8 min (SD 15·0), compared with a mean of 30·6 min (13·7) in the standard group (mean difference 6·3 min [95% CI 4·2-8·4] longer with chromocolonoscopy than in the standard group). The mean difference was within the prespecified non-inferiority margin. Detection rates for proximal serrated lesions were significantly higher in the chromocolonoscopy group than in the control group (45 [12%] of 381 patients vs 23 [6%] of 360 patients; odds ratio 1·96 [95% CI 1·16-3·32]; p=0·012). Serious adverse events (four cases of postpolypectomy bleeding [two in each group], and one case of anxiety and hyperventilation [in the chromocolonoscopy group]), colonoscopy quality measures, comfort scores, and sedation were similar between groups.

INTERPRETATION

Chromocolonoscopy is feasible within a population-based colorectal cancer screening programme, is safe, and has significantly increased detection of proximal serrated neoplasia and other polyp types compared with standard colonoscopy. Larger randomised trials of chromocolonoscopy, powered for improved detection of significant serrated polyps and for longer-term follow-up to investigate the effect on reduction of interval cancers within screening populations, are warranted.

FUNDING

Health and Care Research Wales (RfPPB-1021).

The benefit of adding oral simethicone in bowel preparation regimen for the detection of colon adenoma: A systematic review and meta-analysis

BACKGROUND AND AIM

Simethicone is an anti-foaming agent commonly used during colonoscopy. Although several randomized trials have shown that oral simethicone in the bowel preparation regimen may improve bowel cleanness, whether it improves adenoma detection rate (ADR) or polyp detection rate remains undetermined. The aim of this study was to determine if oral simethicone in bowel preparation regimen before colonoscopy improves the ADR.

METHODS

A comprehensive literature review was conducted using PubMed, SDOL, Cochrane Library, and ProQuest databases through December 2017. Randomized controlled trials that compared bowel preparation regimens with simethicone versus those without it were included. Effect estimates from each study were extracted and underwent meta-analysis using appropriate models. The primary outcomes were ADR and polyp detection rate, and secondary outcomes included bowel preparation, bubble score, and withdrawal time.

RESULTS

Twelve published randomized controlled studies with 6003 participants were included for meta-analysis. There was no difference in the overall ADR (pooled risk ratio = 1.06, 95% confidence interval = 0.91-1.24) and right-side ADR (risk ratio = 1.50, 95% confidence interval = 0.82-2.75) between the groups with or without simethicone. However, the addition of simethicone improved adenoma detected per patient (2.20 ± 1.36 vs 1.63 ± 0.89) according to one of the included studies. Meta-regression revealed that the baseline ADR < 25% of the included studies was associated with significant benefit of oral simethicone; the number needed to treat was 15.

CONCLUSIONS

The adjunction of oral simethicone significantly improved bowel preparation quality and might benefit adenoma detection in specific settings with low baseline ADR.

How to improve the adenoma detection rate in colorectal cancer screening? Clinical factors and technological advancements

INTRODUCTION

Colonoscopy has been widely regarded as the gold standard in colorectal cancer (CRC) screening. Within recent years different endoscopic imaging techniques have been introduced to improve the quality of colonoscopy. The adenoma detection rate (ADR) is the single most important quality indicator for colonoscopy. The aim of this study was to evaluate the quality of CRC screening expressed by ADR in two different eras of endoscopic technology advancement.

MATERIAL AND METHODS

We conducted a dual-center study that enrolled 24 055 patients, who underwent colonoscopy as part of a national screening program. Patients were sorted into two groups according to the advancement of endoscopic equipment used for colonoscopic examination: group I - 10 405 patients examined between 2004 and 2008 (standard electronic endoscopes); group II - 13 650 patients examined between 2009 and 2014 (modern endoscopes). The ADR in two different eras and the impact of endoscopic novelties were determined.

RESULTS

The ADR in group I was 29.14%, in group II 31.73% (p < 0.001). The overall ADR was 30.88% - 38.80% and 25.95% (p < 0.001) for the male and female patients, respectively. The mean adenoma number per colonoscopy was 0.366 (95% CI: 0.357-0.375; p < 0.001), 0.337 (0.321-0.352) and 0.380 (0.369-0.392) for patients in group I and group II, respectively.

CONCLUSIONS

Our study shows that technological innovation, novel endoscopy devices and diagnostic techniques improve the quality in CRC screening by increasing the ADR. However, we need to determine which of the technologies are supreme to achieve excellence in colorectal cancer screening.

Changes in Adenoma Detection Rate With Implementation of Full-spectrum Endoscopy: A Report of 3998 Screening Colonoscopies

GOALS

To investigate the effect of implementing full-spectrum endoscopy (Fuse) on adenoma detection rate (ADR) at an ambulatory surgical center (ASC).

BACKGROUND

Traditional forward viewing (TFV) endoscopes have 1 camera and provide an angle of view of 140 to 170 degrees, whereas Fuse provides a 330 degrees view through the addition of 2 side cameras. Although randomized studies have shown that Fuse decreases adenoma miss rates, its impact on ADR in a screening population is currently unknown.

STUDY

We conducted a retrospective analysis of data from average risk screening colonoscopies at a 5-room ASC. This ASC transitioned from TFV to Fuse in April 2014. The primary outcome was ADR defined as the percentage of patients who underwent screening colonoscopy and were found to have at least 1 adenomatous polyp.

RESULTS

A total of 1696 screening colonoscopies were performed with TFV and 2302 with Fuse. Overall ADR was 23.7% with TFV and 29.0% with Fuse (P<0.01), an absolute increase of 5.3%. ADR for the proximal colon increased from 13.0% with TFV to 16.7% with Fuse (3.8% increase, P<0.01). ADR for advanced adenomas improved from 3.8% with TFV to 6.0% with Fuse (2.2% increase; P<0.01). The mean number of adenomas detected per colonoscopy increased from 0.32 to 0.41 (P<0.01). In multivariate analysis, the adjusted odds ratio for detecting an adenoma with Fuse versus TFV was 1.30 (P<0.01; 95% confidence interval, 1.11-1.51).

CONCLUSIONS

ADR significantly increased after adopting Fuse endoscopes at an ASC. Further studies are warranted to further understand the effects of Fuse on ADR in real-world settings.

Impact of Changeover to Newer Endoscopic Systems on Quality and Efficiency of Screening and Surveillance Colonoscopy: Equipment or Endoscopist

GOALS

The goal of this study is to assess whether changeover to newer endoscopic systems impacts quality or efficiency, and quantify the relation between increased withdrawal time and detection rates of sessile serrated polyps (SSPDR) and adenomas (ADR) in real-world practice.

STUDY

Beginning 2 months after new endoscopic systems were implemented at 2 endoscopy units, we included all outpatients undergoing screening/surveillance colonoscopy for 4 months. Outpatients during the same 4-month period 1 year earlier comprised the control group. Quality endpoints included ADR, advanced ADR, SSPDR, polyp detection rate (PDR), and withdrawal time. The efficiency endpoint was procedure time. Statistical adjustment for potential confounding factors was performed with multivariable analysis.

RESULTS

Significant increases occurred in postchangeover (N=1122) versus prechangeover (N=1131) procedure time (difference=2.6 minutes; 1.6 to 3.6) and withdrawal time (difference=1.6 minutes; 0.8 to 2.5). Significant increases also occurred in ADR [435 (39%) vs. 380 (34%)], advanced ADR [82 (7%) vs. 50 (4%)], and PDR [664 (59%) vs. 611 (54%)], but these differences lost significance when withdrawal time was added to the multivariable model. For every minute increase in withdrawal time a significant increase was seen in ADR (OR=1.09; 1.08 to 1.11), advanced ADR (OR=1.10; 1.08 to 1.13), SSPDR (OR=1.07; 1.06 to 1.09), and PDR (OR=1.16; 1.14 to 1.18).

CONCLUSIONS

After changeover to newer endoscopy systems withdrawal times lengthened, resulting in increased procedure time, ADR, and advanced ADR. Regardless of endoscopic system, lengthening withdrawal time increased SSPDR, ADR, and advanced ADR: odds of detection increased 7% to 10% with every additional minute of withdrawal time. Greater attention to withdrawal time and endoscopist examination may be more productive than upgrading endoscopic systems.

Molecular imaging within the lower gastrointestinal tract: From feasibility to future

Molecular imaging is based on the labelling of defined molecular targets through the utilization of fluorescently linked probes and their subsequent detection with high-resolution endoscopic devices, thereby enabling visualization of single molecules including receptors. Whereas early studies have used molecular imaging for improved visualization and detection of early dysplasia and cancer as well as for assessing intestinal inflammation and inflammation-associated cancer within the gastrointestinal (GI) tract, more recent studies have impressively demonstrated that molecular imaging can also be used to characterize and visualize the molecular fingerprint of cancer and inflammation in vivo and in real time. With this, molecular imaging can be used to guide expression-tailored individualized therapy. With the rapid expansion and diversification of the repertoire of biological agents utilized in inflammatory bowel disease and cancer, this approach is gaining increasing attention. Within this review, we first summarize the technical components commonly used for molecular imaging and then review preclinical and clinical studies and evolving clinical applications on molecular imaging within the lower GI tract. Molecular imaging has the potential to significantly change endoscopic diagnosis and subsequent targeted therapy of gastrointestinal cancer and chronic gastrointestinal diseases.

Rates of metachronous adenoma after curative resection for left-sided or right-sided colon cancer

Background/Aims

We determined the rates of metachronous colorectal neoplasm in colorectal cancer (CRC) patients after resection for right (R)-sided or left (L)-sided cancer.

Methods

Consecutive CRC patients who had undergone surgical resection for curative intent in our hospital between 2001 and 2004 were identified. R-sided colonic cancers refer to cancer proximal to splenic flexure whereas L-sided cancers include rectal cancers. Patients were included only if they had a clearing colonoscopy performed either before or within 6 months after the operation. Findings of surveillance colonoscopy performed up to 5 years after colonic resection were included in the analysis.

Results

Eight hundred and sixty-three CRC patients underwent curative surgical resection during the study period. Three hundred and twenty-seven patients (107 R-sided and 220 L-sided) fulfilled the inclusion criteria and had at least 1 postoperative surveillance colonoscopy performed. The proportion of patients who had polyp and adenoma on surveillance colonoscopy was significantly higher among patients with L-sided than R-sided cancers (polyps: 30.9% vs. 19.6%, P=0.03; adenomas: 25.5% vs. 13.1%, P=0.01). The mean number of adenoma per patient on surveillance colonoscopy was also higher for patients with L-sided than R-sided tumors (0.52; 95% confidence interval [CI], 0.37–0.68 vs. 0.22; 95% CI, 0.08–0.35; P<0.01). Multivariate analysis showed that L-sided cancers, age, male gender and longer follow-up were independent predictors of adenoma detection on surveillance colonoscopy.

Conclusions

Patients with Lsided cancer had a higher rate of metachronous polyps and adenoma than those with R-sided cancer on surveillance colonoscopy.

Is narrow-band imaging a useful tool in screening colonoscopy performed by an experienced endoscopist? A prospective randomised study on 533 patients

Introduction

The detection of adenomas is the basic goal for colorectal cancer screening programs; therefore, every possibility to improve the adenoma detection rate is valuable.

Aim

To answer the question of whether narrow-band imaging (NBI) can enhance detection quality in screening for colonoscopy.

Material and methods

A group of 533 patients (202 men: 331 women; average age: 56.1 years) included in a colorectal cancer screening program were randomised into two groups (NBI n = 266 and white light (WL) n = 267). Five hundred and twenty-seven patients were finally included in the assessment. Examinations were performed by three experienced colonoscopists. The NBI was used only at the withdrawal of the instrument.

Results

Comparing WL and NBI colonoscopies, differences in the mean number of detected polyps per patient (1.36 ±2.79 WL vs. 1.65 ±2.11 NBI; p = 0.012), polyp detection rate (PDR) (48.5% WL vs. 57.2% NBI; p = 0.049), PDR for polyps ≤ 5 mm (44.7% WL vs. 54% NBI; p = 0.033), and PDR for left-sided polyps (43.3% WL vs. 52.7% NBI; p = 0.033) were observed. The difference in adenoma detection rate (ADR) as well as in adenomas/patient was not significant. Narrow-band imaging enhanced significantly one of three operators' ADR (15.6% WL vs. 25.7% NBI; p = 0.038).

Conclusions

It seems that NBI improves only detection of hyperplastic polyps, especially those that are diminutive and left-sided. However, after analysis of particular endoscopists, it can clearly be seen that some of them may benefit from NBI.

New technologies improve adenoma detection rate, adenoma miss rate, and polyp detection rate: a systematic review and meta-analysis

BACKGROUND AND AIMS

The need to increase the adenoma detection rate (ADR) for colorectal cancer screening has ushered in devices that mechanically or optically improve conventional colonoscopy. Recently, new technology devices (NTDs) have become available. We aimed to compare the ADR, polyp detection rate (PDR), and adenoma miss rate (AMR) between NTDs and conventional colonoscopy and between mechanical and optical NTDs.

METHODS

MEDLINE and Embase databases were searched from inception through September 2017 for articles or abstracts reporting ADR, PDR, and AMR with NTDs. Randomized controlled trials and case-control studies with >10 subjects were included. Primary outcomes included ADR, PDR, and AMR odds ratio (OR) between conventional colonoscopy and NTDs. Secondary outcomes included cecal intubation rates, adverse events, cecal intubation time, and total colonoscopy time.

RESULTS

From 141 citations, 45 studies with 20,887 subjects were eligible for ≥1 analyses. Overall, the ORs for ADR (1.35; 95% confidence interval [CI] 1.24-1.47; P < .01) and PDR (1.51; 95% CI, 1.37-1.67; P < .01) were higher with NTDs. Higher ADR (OR, 1.52 vs 1.25; P = .035) and PDR (OR, 1.63 vs 1.10; P ≤ .01) were observed with mechanical NTDs. The overall AMR with NTDs was lower compared with conventional colonoscopy (OR, .19; 95% CI, .14-.26; P < .01). Mechanical NTDs had lower AMRs compared with optical NTDs (OR, .10 vs .33; P < .01). No differences in cecal intubation rates, cecal intubation time, or total colonoscopy time were found.

CONCLUSIONS

Newer endoscopic technologies are an effective option to improve ADR and PDR and decrease AMR, particularly with mechanical NTDs. No differences in operability and safety were found.

Faster colonoscope withdrawal time without impaired detection using EndoRings

BACKGROUND AND STUDY AIMS

 Mucosal exposure devices on the colonoscope tip have improved detection. We evaluated detection and procedure times in colonoscopies performed with EndoRings.

PATIENTS AND METHODS

 We had 14 endoscopists in a university practice trial EndoRings. We compared detection and procedure times to age- and indication-matched procedures by the same endoscopists.

RESULTS

 There were 137 procedures with EndoRings. The adenoma detection rate was 44 % with EndoRings vs. 39 % without ( P  = 0.39). Mean adenomas per colonoscopy (standard deviation) was 1.2 (2.3) with EndoRings vs. 0.9 (1.6) without ( P  = 0.055). Mean insertion time with EndoRings was 6.2 (3.2) minutes vs. 6.6 (6.7) minutes without ( P  = 0.81). Mean withdrawal time with EndoRings in all patients with or without polypectomy was 12.2 (5.3) minutes and 16.1 (10.3) minutes without ( P  = 0.0005).

CONCLUSION

 EndoRings may allow faster withdrawal during colonoscopy without any reduction in detection. Prospective trials with mucosal exposure devices targeting procedure times as primary endpoints are warranted.

High-definition colonoscopy versus Endocuff versus EndoRings versus full-spectrum endoscopy for adenoma detection at colonoscopy: a multicenter randomized trial

BACKGROUND AND AIMS

Devices used to improve polyp detection during colonoscopy have seldom been compared with each other.

METHODS

We performed a 3-center prospective randomized trial comparing high-definition (HD) forward-viewing colonoscopy alone to HD with Endocuff to HD with EndoRings to the full spectrum endoscopy (FUSE) system. Patients were age ≥50 years and had routine indications and intact colons. The study colonoscopists were all proven high-level detectors. The primary endpoint was adenomas per colonoscopy (APC).

RESULTS

Among 1188 patients who completed the study, APC with Endocuff (APC mean ± standard deviation: 1.82 ± 2.58), EndoRings (1.55 ± 2.42), and standard HD colonoscopy (1.53 ± 2.33) were all higher than FUSE (1.30 ± 1.96; P < .001 for APC). The APC for Endocuff was higher than standard HD colonoscopy (P = .014). Mean cecal insertion times with FUSE (468 ± 311 seconds) and EndoRings (403 ± 263 seconds) were both longer than with Endocuff (354 ± 216 seconds; P = .006 and .018, respectively).

CONCLUSIONS

For high-level detectors at colonoscopy, forward-viewing HD instruments dominate the FUSE system, indicating that for these examiners image resolution trumps angle of view. Further, Endocuff is a dominant strategy over EndoRings and no mucosal exposure device on a forward-viewing HD colonoscope. (Clinical trial registration number: NCT02345889.).