Polyp detection at colonoscopy: Endoscopist and technical factors

The impact of endoscopist performance and patient factors on distal adenoma detection and colorectal cancer incidence

BACKGROUND

High quality endoscopy is key for detecting and removing precursor lesions to colorectal cancer (CRC). Adenoma detection rates (ADRs) measure endoscopist performance. Improving other components of examinations could increase adenoma detection.

AIMS

To investigate how endoscopist performance at flexible sigmoidoscopy (FS) affects adenoma detection and CRC incidence.

METHODS

Among 34,139 participants receiving FS screening by the main endoscopist at one of 13 centres in the UK FS Screening Trial, median follow-up was 17 years. Factors examined included family history of CRC, bowel preparation quality, insertion and withdrawal time, bowel segment reached, patient pain and ADR. Odds ratios (OR) for distal adenoma detection were estimated by logistic regression. Hazard ratios (HR) for distal CRC incidence were estimated by Cox regression.

RESULTS

At screening, 4,104 participants had distal adenomas detected and 168 participants developed distal CRC during follow-up. In multivariable models, a family history of CRC (yes vs. no: OR 1.40, 95%CI 1.21-1.62), good or adequate bowel preparation quality (vs. excellent: OR 0.84, 95%CI 0.74-0.95; OR 0.56, 95%CI 0.49-0.65, respectively) and longer insertion and withdrawal times (≥ 4.00 vs. < 2.00 min: OR 1.96, 95%CI 1.68-2.29; OR 32.79, 95%CI 28.22-38.11, respectively) were associated with adenoma detection. Being screened by endoscopists with low or intermediate ADRs, compared to high ADRs, was positively associated with CRC incidence (multivariable: HR 4.71, 95%CI 2.65-8.38; HR 2.16, 95%CI 1.22-3.81, respectively).

CONCLUSIONS

Bowel preparation quality and longer insertion and withdrawal time are key for improving distal adenoma detection. Higher ADRs were associated with a lower risk of distal CRC.

Evaluation of computer aided detection during colonoscopy among Veterans: Randomized clinical trial

BACKGROUND

There has been significant interest in use of computer aided detection (CADe) devices in colonoscopy to improve polyp detection and reduce miss rate.

AIM

To investigate the use of CADe amongst veterans.

METHODS

Between September 2020 and December 2021, we performed a randomized controlled trial to evaluate the impact of CADe. Patients at Veterans Affairs Palo Alto Health Care System presenting for screening or low-risk surveillance were randomized to colonoscopy performed with or without CADe. Primary outcomes of interest included adenoma detection rate (ADR), adenomas per colonoscopy (APC), and adenomas per extraction. In addition, we measured serrated polyps per colonoscopy, non-adenomatous, non-serrated polyps per colonoscopy, serrated polyp detection rate, and procedural time.

RESULTS

A total of 244 patients were enrolled (124 with CADe), with similar patient characteristics (age, sex, body mass index, indication) between the two groups. Use of CADe was found to have decreased number of adenomas (1.79 vs 2.53, P = 0.030) per colonoscopy compared to without CADe. There was no significant difference in number of serrated polyps or non-adenomatous non-serrated polyps per colonoscopy between the two groups. Overall, use of CADe was found to have lower ADR (68.5% vs 80.0%, P = 0.041) compared to without use of CADe. Serrated polyp detection rate was lower with CADe (3.2% vs 7.5%) compared to without CADe, but this was not statistically significant (P = 0.137). There was no significant difference in withdrawal and procedure times between the two groups or in detection of adenomas per extraction (71.4% vs 73.1%, P = 0.613). No adverse events were identified.

CONCLUSION

While several randomized controlled trials have demonstrated improved ADR and APC with use of CADe, in this RCT performed at a center with high ADR, use of CADe was found to have decreased APC and ADR. Further studies are needed to understand the true impact of CADe on performance quality among endoscopists as well as determine criteria for endoscopists to consider when choosing to adopt CADe in their practices.

Evaluation of Computer-Aided Detection During Colonoscopy in the Community (AI-SEE): A Multicenter Randomized Clinical Trial

INTRODUCTION

There has been increasing interest in artificial intelligence in gastroenterology. To reduce miss rates during colonoscopy, there has been significant exploration in computer-aided detection (CADe) devices. In this study, we evaluate the use of CADe in colonoscopy in community-based, nonacademic practices.

METHODS

Between September 28, 2020, and September 24, 2021, a randomized controlled trial (AI-SEE) was performed evaluating the impact of CADe on polyp detection in 4 community-based endoscopy centers in the United States Patients were block-randomized to undergoing colonoscopy with or without CADe (EndoVigilant). Primary outcomes measured were adenomas per colonoscopy and adenomas per extraction (the percentage of polyps removed that are adenomas). Secondary end points included serrated polyps per colonoscopy; nonadenomatous, nonserrated polyps per colonoscopy; adenoma and serrated polyp detection rates; and procedural time.

RESULTS

A total of 769 patients were enrolled (387 with CADe), with similar patient demographics between the 2 groups. There was no significant difference in adenomas per colonoscopy in the CADe and non-CADe groups (0.73 vs 0.67, P = 0.496). Although the use of CADe did not improve identification of serrated polyps per colonoscopy (0.08 vs 0.08, P = 0.965), the use of CADe increased identification of nonadenomatous, nonserrated polyps per colonoscopy (0.90 vs 0.51, P < 0.0001), resulting in detection of fewer adenomas per extraction in the CADe group. The adenoma detection rate (35.9 vs 37.2%, P = 0.774) and serrated polyp detection rate (6.5 vs 6.3%, P = 1.000) were similar in the CADe and non-CADe groups. Mean withdrawal time was longer in the CADe group compared with the non-CADe group (11.7 vs 10.7 minutes, P = 0.003). However, when no polyps were identified, there was similar mean withdrawal time (9.1 vs 8.8 minutes, P = 0.288). There were no adverse events.

DISCUSSION

The use of CADe did not result in a statistically significant difference in the number of adenomas detected. Additional studies are needed to better understand why some endoscopists derive substantial benefits from CADe and others do not. ClinicalTrials.gov number: NCT04555135.

Performing High-Quality, Safe, Cost-Effective, and Efficient Basic Colonoscopy in 2023: Advice From Two Experts

Based on published evidence and our expert experience, we provide recommendations to maximize the efficacy, safety, efficiency, and cost-effectiveness of routine colonoscopy. High-quality colonoscopy begins with colon preparation using a split or same-day dose and preferably a low-volume regimen for optimal patient tolerance and compliance. Successful cecal intubation can be achieved by choosing the correct colonoscope and using techniques to facilitate navigation through challenges such as severe angulations and redundant colons. Safety is a primary goal, and complications such as perforation and splenic rupture can be prevented by avoiding pushing through fixed resistance and avoiding loops in proximal colon. Furthermore, barotrauma can be avoided by converting to water filling only (no gas insufflation) in every patient with a narrowed, angulated sigmoid. Optimal polyp detection relies primarily on compulsive attention to inspection as manifested by adequate inspection time, vigorous probing of the spaces between haustral folds, washing and removing residual debris, and achieving full distention. Achieving minimum recommended adenoma detection rate thresholds (30% in men and 20% in women) is mandatory, and colonoscopists should aspire to adenoma detection rate approaching 50% in screening patients. Distal attachments can improve mucosal exposure and increase detection while shortening withdrawal times. Complete resection of polyps complements polyp detection in preventing colorectal cancer. Cold resection is the preferred method for all polyps < 10 mm. For effective cold resection, an adequate rim of normal tissue should be captured in the snare. Finally, cost-effective high-quality colonoscopy requires the procedure not be overused, as demonstrated by following updated United States Multi Society Task Force on Colorectal Cancer postpolypectomy surveillance recommendations.

The Relationship Between Colonoscopy Practice Style, Operator Ergonomics and Procedure Quality

OBJECTIVE

We aimed to compare three endoscopy operators who performed colonoscopy in three different styles in terms of procedure results, colonoscopy quality, and operator comfort during the procedure.

PATIENTS AND METHODS

A total of 246 patients, who underwent routine screening colonoscopy for precancerous lesions between May and December 2022 in Istanbul Haydarpaşa Numune Education and Research Hospital, Istanbul, Turkey, were prospectively analyzed. The results of three different styles (single operator sitting, single operator standing, and two operators standing) were compared with each other. The following criteria were examined: polyp/adenoma detection rate, number of polyps detected per patient, cecal intubation rate, total procedure time, number of endoscope corrective maneuvers, number of patient position corrections during the procedure, and the endoscopist's subjective pain scale after the procedure.

RESULTS

 The number of corrections and changes in scope position, rates of changing the patient's position during the procedure, and the postprocedural fatigue degree of the endoscopist were the highest for the single-operator standing style (p<0.001). The total processing time and post-procedure fatigue degree of the endoscopist were the lowest for the single-operator sitting style (p<0.001). The adenoma detection rate was the highest for single-operator standing style (37.8% vs 22.0% and 29.3%). The strongest predictive factors for the total procedure time were the colonoscopy style and patient age. The strongest predictive factors for the change in the total number of detected polyps were colonoscopy style, patient gender, and patient age. Independent of all other factors, the total detected number of polyps was statistically significantly higher for the single-operator standing style compared to other styles (B=-0.217, 95% confidence interval: -0.369 - -0.066 and p=0.005) (B=-0.172, 95% confidence interval: -0.326 - -0.017 and p=0.029).

CONCLUSIONS

Two conclusions were drawn from this study. For routine screening colonoscopy, the single-operator sitting style seems to be superior to other styles in terms of the shortest procedure time and the least tiring. However, the widely used single-operator standing style should be preferred over other styles in terms of the highest adenoma detection rate although it is most tiring and time-consuming.

Self-supervised monocular depth estimation for gastrointestinal endoscopy

BACKGROUND AND OBJECTIVE

Gastrointestinal (GI) endoscopy represents a promising tool for GI cancer screening. However, the limited field of view and uneven skills of endoscopists make it remains difficult to accurately identify polyps and follow up on precancerous lesions under endoscopy. Estimating depth from GI endoscopic sequences is essential for a series of AI-assisted surgical techniques. Nonetheless, depth estimation algorithm of GI endoscopy is a challenging task due to the particularity of the environment and the limitation of datasets. In this paper, we propose a self-supervised monocular depth estimation method for GI endoscopy.

METHODS

A depth estimation network and a camera ego-motion estimation network are firstly constructed to obtain the depth information and pose information of the sequence respectively, and then the model is enabled to perform self-supervised training by calculating the multi-scale structural similarity with L1 norm (MS-SSIM+L1) loss function between the target frame and the reconstructed image as part of the loss of the training network. The MS-SSIM+L1 loss function is good for reserving high-frequency information and can maintain the invariance of brightness and color. Our model consists of the U-shape convolutional network with the dual-attention mechanism, which is beneficial to capture muti-scale contextual information, and greatly improves the accuracy of depth estimation. We evaluated our method qualitatively and quantitatively with different state-of-the-art methods.

RESULTS AND CONCLUSIONS

The experimental results manifest that our method has superior generality, achieving lower error metrics and higher accuracy metrics on both the UCL dataset and the Endoslam dataset. The proposed method has also been validated with clinical GI endoscopy, demonstrating the potential clinical value of the model.

Improving polyp detection at colonoscopy: Non-technological techniques

Colonoscopy and polypectomy remain the gold standard investigation for the detection and prevention of colorectal cancer. Halting the progression of colonic adenoma through adequate detection of pre-cancerous lesions interrupts the progression to carcinoma. The adenoma detection rate is a key performance indicator. Increasing adenoma detection rates are associated with reducing rates of interval colorectal cancer. Endoscopists with high baseline adenoma detection rate have a meticulous technique during colonoscopy withdrawal that improves their adenoma detection. This minireview article summarizes the evidence on the following simple operator techniques and their effects on the adenoma detection rate; minimum withdrawal times, dynamic patient position change and proximal colon retroflexion.

Is There a Difference in Adenoma Detection Rates According to Indication? An Experience in a Panamanian Colorectal Cancer Screening Program

Background

The benefit of colorectal cancer screening in reducing cancer risk and related death is unclear. There are quality measure indicators and multiple factors that affect the performance of a successful colonoscopy. The main objective of our study was to identify if there is a difference in polyp detection rate (PDR) and adenoma detection rate (ADR) according to colonoscopy indication and which factors might be associated.

Methods

We conducted a retrospective review of all colonoscopies performed between January 2018 and January 2019, in a tertiary endoscopic center. All patients ≥ 50 years old scheduled for a nonurgent colonoscopy and screening colonoscopy were included. We stratified the total number of colonoscopies into two categories according to the indication: screening vs. non-screening, and then calculated PDR, ADR and serrated polyp detection rate (SDR). We also performed logistic regression model to identify factors associated with detecting polyps and adenomatous polyps.

Results

A total of 1,129 and 365 colonoscopies were performed in the non-screening and screening group, respectively. In comparison with the screening group, PDR and ADR were lower for the non-screening group (33% vs. 25%; P = 0.005 and 17% vs. 13%; P = 0.005). SDR was non-significantly lower in the non-screening group when compared with the screening group (11% vs. 9%; P = 0.53 and 22% vs. 13%; P = 0.007).

Conclusion

In conclusion, this observational study reported differences in PDR and ADR depending on screening and non-screening indication. These differences could be related to factors related to the endoscopist, time slot allotted for colonoscopy, population background, and external factors.

Impact of colorectal cancer screening on incidence, mortality and surgery rates: Evidences from programs based on the fecal immunochemical test in Italy

Fecal immunochemical tests (FIT) are among the most commonly used tests for colorectal cancer (CRC) screening programs worldwide. However, no randomised controlled trials have been carried out evaluating the impact of FIT-based screening programs (FIT-progr) on CRC incidence and mortality rates. Italian FIT-progr represent one of the most widespread and established experience worldwide. This paper reviews the evidence on the impact of FIT-progr on CRC incidence, tumor stage at diagnosis, mortality and surgery rates, deriving from Italian routine programs, i.e., outside the research setting. Unfortunately, the application of FIT-progr in Italy can be considered as an unplanned experimental model, due to the differences between Regions, both in health system management and adherence of the target population to the screening programs. The analysis of the manuscripts considered in the review, confirms that FIT-progr are effective in reducing CRC incidence and mortality rates and in improving the rate of endoscopic treatment of early invasive lesions. The review also highlights that FIT-progr are less performing for proximal colon than for distal colon and rectum.

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.

Detection of colorectal adenomas with texture and color enhancement imaging: Multicenter observational study

OBJECTIVES

We aimed to evaluate the efficacy of texture and color enhancement imaging (TXI), which allows the acquisition of brighter images with enhanced color and surface structure in colorectal polyp detection compared to white light imaging.

METHODS

Patients who underwent colonoscopy with repeated ascending colon observation using TXI and white light imaging between August 2020 and January 2021 were identified in three institutions. The outcomes included the mean number of adenomas detected per procedure (MAP), adenoma detection rate (ADR), and ascending colonic adenoma miss rate (Ac-AMR). Logistic regression was used to determine the effects of the variables on the outcomes.

RESULTS

We included 1043 lesions from 470 patients in the analysis. The MAP, ADR, flat polyp detection rate, and Ac-AMR in TXI and white light imaging were 1.5% (95% confidence interval 1.3-1.6%) vs. 1.0% (0.9-1.1%), 58.2% (51.7-64.6%) vs. 46.8% (40.2-53.4%), 66.2% (59.8-72.2%) vs. 49.8% (43.2-56.4%), and 17.9% (12.1-25.2%) vs. 28.2% (20.0-37.6%), respectively. TXI, age, withdrawal time, and endoscopy type were identified as significant factors affecting the MAP and the ADR using multivariate regression analysis.

CONCLUSIONS

Our study indicates that TXI improve the detection of colorectal neoplastic lesions. However, prospective randomized trials are required to confirm these findings.

Artificial intelligence-based assessments of colonoscopic withdrawal technique: a new method for measuring and enhancing the quality of fold examination

BACKGROUND

This study aimed to develop an artificial intelligence (AI)-based system for measuring fold examination quality (FEQ) of colonoscopic withdrawal technique. We also examined the relationship between the system's evaluation of FEQ and FEQ scores from experts, and adenoma detection rate (ADR) and withdrawal time of colonoscopists, and evaluated the system's ability to improve FEQ during colonoscopy.

METHODS

First, we developed an AI-based system for measuring FEQ. Next, 103 consecutive colonoscopies performed by 11 colonoscopists were collected for evaluation. Three experts graded FEQ of each colonoscopy, after which the recorded colonoscopies were evaluated by the system. We further assessed the system by correlating its evaluation of FEQ against expert scoring, historical ADR, and withdrawal time of each colonoscopist. We also conducted a prospective observational study to evaluate the system's performance in enhancing fold examination.

RESULTS

The system's evaluations of FEQ of each endoscopist were significantly correlated with experts' scores (r = 0.871, P < 0.001), historical ADR (r = 0.852, P = 0.001), and withdrawal time (r = 0.727, P = 0.01). For colonoscopies performed by colonoscopists with previously low ADRs (< 25 %), AI assistance significantly improved the FEQ, evaluated by both the AI system (0.29 [interquartile range (IQR) 0.27-0.30] vs. 0.23 [0.17-0.26]) and experts (14.00 [14.00-15.00] vs. 11.67 [10.00-13.33]) (both P < 0.001).

CONCLUSION

The system's evaluation of FEQ was strongly correlated with FEQ scores from experts, historical ADR, and withdrawal time of each colonoscopist. The system has the potential to enhance FEQ.

Colonoscope retraction technique and predicting adenoma detection rate: a multicenter study

BACKGROUND AND AIMS

The success of preventing colorectal cancer relies on the expertise of the colonoscopists. Studies suggest that the retraction technique is a powerful indicator of expertise in distinguishing endoscopists with various adenoma detection rates (ADRs). We aimed to develop a retraction technique score and explore the correlation between endoscopists' retraction technique and their ADRs.

METHODS

In a prospective, multicenter study, 8 colonoscopist nurses and physicians with various ADRs were included. Data from patients admitted for a colonoscopy, as part of the Danish nationwide screening program, were gathered directly from the Olympus ScopeGuide system (UPD-3; Olympus Optical, Tokyo, Japan) providing XYZ-coordinates from the coils along the length of the colonoscope. Motor skill measures were developed based on tip retraction, retraction efficiency, and retraction distance. The principal component analysis was used to study the association among the 3 measures and the historical ADR to create a combined score, the colonoscopy retraction score (CoRS).

RESULTS

Three hundred thirty-three recordings were analyzed. We demonstrated a significant and strong correlation between CoRS and ADR (.90, P < .01). Conversely, withdrawal time did not correlate significantly with ADR (.33, P = .42). In procedures without polypectomies or biopsy sampling, a significant and strong correlation was found between CoRS and ADR (.88, P < .01) and between withdrawal time and ADR (.75, P = .03).

CONCLUSIONS

This study presents a novel, real-time computerized and unbiased assessment tool for colonoscopy withdrawal. CoRS strongly correlated with ADR with and without therapeutic interventions during withdrawal and could be used to ensure quality instead of minimal withdrawal time. (Clinical trial registration number: NCT03587935.).

Unsupervised Monocular Depth Estimation for Colonoscope System Using Feedback Network

A colonoscopy is a medical examination used to check disease or abnormalities in the large intestine. If necessary, polyps or adenomas would be removed through the scope during a colonoscopy. Colorectal cancer can be prevented through this. However, the polyp detection rate differs depending on the condition and skill level of the endoscopist. Even some endoscopists have a 90% chance of missing an adenoma. Artificial intelligence and robot technologies for colonoscopy are being studied to compensate for these problems. In this study, we propose a self-supervised monocular depth estimation using spatiotemporal consistency in the colon environment. It is our contribution to propose a loss function for reconstruction errors between adjacent predicted depths and a depth feedback network that uses predicted depth information of the previous frame to predict the depth of the next frame. We performed quantitative and qualitative evaluation of our approach, and the proposed FBNet (depth FeedBack Network) outperformed state-of-the-art results for unsupervised depth estimation on the UCL datasets.

Deep learning to find colorectal polyps in colonoscopy: A systematic literature review

Colorectal cancer has a great incidence rate worldwide, but its early detection significantly increases the survival rate. Colonoscopy is the gold standard procedure for diagnosis and removal of colorectal lesions with potential to evolve into cancer and computer-aided detection systems can help gastroenterologists to increase the adenoma detection rate, one of the main indicators for colonoscopy quality and predictor for colorectal cancer prevention. The recent success of deep learning approaches in computer vision has also reached this field and has boosted the number of proposed methods for polyp detection, localization and segmentation. Through a systematic search, 35 works have been retrieved. The current systematic review provides an analysis of these methods, stating advantages and disadvantages for the different categories used; comments seven publicly available datasets of colonoscopy images; analyses the metrics used for reporting and identifies future challenges and recommendations. Convolutional neural networks are the most used architecture together with an important presence of data augmentation strategies, mainly based on image transformations and the use of patches. End-to-end methods are preferred over hybrid methods, with a rising tendency. As for detection and localization tasks, the most used metric for reporting is the recall, while Intersection over Union is highly used in segmentation. One of the major concerns is the difficulty for a fair comparison and reproducibility of methods. Even despite the organization of challenges, there is still a need for a common validation framework based on a large, annotated and publicly available database, which also includes the most convenient metrics to report results. Finally, it is also important to highlight that efforts should be focused in the future on proving the clinical value of the deep learning based methods, by increasing the adenoma detection rate.

Association between improved adenoma detection rates and interval colorectal cancer rates after a quality improvement program

BACKGROUND AND AIMS

Although colonoscopy reduces colorectal cancer (CRC) risk, interval CRCs (iCRCs) still occur. We aimed to determine iCRC incidence, assess the relationship between adenoma detection rates (ADRs) and iCRC rates, and evaluate iCRC rates over time concomitant with initiation of an institutional colonoscopy quality improvement (QI) program.

METHODS

We performed a retrospective cohort study of patients who underwent colonoscopy at an academic medical center (January 2003 to December 2015). We identified iCRCs through our data warehouse and reviewed charts to confirm appropriateness for study inclusion. iCRC was defined as a cancer diagnosed 6 to 60 months and early iCRC as a cancer diagnosed 6 to 36 months after index colonoscopy. We measured the relationship between provider ADRs and iCRC rates and assessed iCRC rates over time with initiation of a QI program that started in 2010.

RESULTS

A total of 193,939 colonoscopies were performed over the study period. We identified 186 patients with iCRC. The overall iCRC rate was .12% and the early iCRC rate .06%. Average-risk patients undergoing colonoscopy by endoscopists in the highest ADR quartile (34%-52%) had a 4-fold lower iCRC risk (relative risk, .23; 95% confidence interval, .11-.48) than those undergoing colonoscopy by endoscopists in the lowest quartile (12%-21%). After QI program initiation, overall iCRC rates improved from .15% to .08% (P < .001) and early iCRC rates improved from .07% to .04% (P = .004).

CONCLUSIONS

We confirmed that iCRC rate is inversely correlated with provider ADR. ADRs increased and iCRC rates decreased over time, concomitant with a QI program focused on split-dose bowel preparation, quality metric measurement, provider education, and feedback. iCRC rate measurement should be considered a feasible, outcomes-driven institutional metric of colonoscopy quality.

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

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

Accuracy of colon capsule endoscopy for advanced neoplasia

BACKGROUND AND AIMS

Second-generation colon capsule endoscopy (CCE-2) has shown promising accuracy for the diagnosis of overall neoplasia. Advanced neoplasia (AN) represents the main target of colorectal cancer screening programs. Our aim was to assess the diagnostic accuracy of CCE-2 for the detection of AN in patients with a positive result for the fecal immunochemical test (FIT) who are undergoing screening.

METHODS

Patients aged 50 to 69 years with a positive result for the FIT in 4 population screening programs in Italy and Spain were enrolled. Screenees were asked to undergo CCE-2, followed by traditional colonoscopy (TC). TC was performed the same day or the following morning. Bowel preparation included a split-dose polyethylene glycol-based regimen, with sodium phosphate (NaP) with gastrografin as boosters. The CCE-2 video was read by an endoscopist blinded to the results of TC. The main outcomes were CCE-2 accuracy in terms of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for AN when using 2 different size thresholds for TC referral (ie, polyps ≥6 mm and ≥10 mm).

RESULTS

Two hundred twenty-two patients were enrolled, and 178 patients completed both CCE-2 and TC (87.7%). Overall, 59 cases of AN were detected at TC. CCE-2 sensitivity was 90%, specificity was 66.1%, PPV was 57.4%, and NPV was 92.9% for AN when using a 6-mm cut-off (TC referral rate, 52.8%) and 76.7%, 90.7%, 80.7%, and 88.4% when using a 10-mm cut-off (TC referral rate, 32%), respectively. CCE-2 detected that 8 of 9 already developed colorectal cancers. Among the 41 false positives at the 6-mm cut-off, 34 (82.9%) presented with a nonadvanced adenoma at TC. Mean transit time was 4 hours and 4 minutes, and ≥70% of patients excreted the capsule within 5 hours.

CONCLUSIONS

In an enriched disease setting, we showed the high sensitivity of CCE-2 for the diagnosis of AN at a 6-mm cut-off. The apparently low CCE-2 specificity is related to the choice of AN as the main outcome. (Clinical trial registration number: ISRCTN 62158762.).

Effect of video monitor size on polyp detection: a prospective, randomized, controlled trial

BACKGROUND AND AIMS

The adenoma detection rate (ADR) is the most important quality metric for colonoscopy. Numerous factors are known to influence ADR. However, no data on the effect of monitor size on ADR exist. The aim of this study was to compare the ADR and polyp detection rate (PDR) achieved using 2 different-size video monitors (19-inch diagonal and 32-inch diagonal).

METHODS

In a single-center, prospective, randomized clinical trial, endoscopists were randomized on a daily basis to perform routine ambulatory colonoscopies with either a 32-inch diagonal or a 19-inch diagonal video monitor.

RESULTS

The study was conducted between October 2013 and April 2014 in an outpatient center of a tertiary referral hospital. Fifteen endoscopists performed 1795 outpatient colonoscopies (mean age, 55 years; 56% women; screening, 56%). There was no substantial difference in baseline patient characteristics between the 2 arms. The overall ADR (27.4% vs 27.9%; P = .80) and PDR (32.8% vs 34.4%; P = .50) were not significantly different between the 32-inch and 19-inch monitor group, respectively. The findings were not significantly altered when stratified by indication, cecal intubation, bowel preparation, operator experience, and time of endoscopy as well as in a multivariable model that included these variables as potential confounders (all P > .05). Overall, the ADR and PDR for each individual endoscopist did not appear to be influenced by monitor size.

CONCLUSIONS

The results of this trial do not support the notion that larger video monitors improve ADR. Future efforts to increase ADR should focus on other aspects of colonoscopy. (Clinical trial registration number: NCT01952418.).

Managing the Measurement of Colonoscopy Quality

The adenoma detection rate (ADR) is our current best colonoscopy quality indicator, but it is not without limitations. In this issue of the Journal, novel ADR benchmarks are proposed based on historical local colonoscopy results. These minimally acceptable, standard of care, and aspirational benchmarks may encourage continuous quality improvement through the explicit determination of notably higher but proven achievable ADR targets, although validation in clinical practice is needed. Ultimately, we must transition from ADR measurement to the implementation of robust quality improvement processes that assure the best outcomes for our patients.

Effect of time of day and specialty on polyp detection rates in Australia

BACKGROUND AND AIM

Adenoma detection rate (ADR) is an important quality metric in colonoscopy. However, there is conflicting evidence around factors that influence ADR. This study aims to investigate the effect of time of day and endoscopist background on ADR and sessile serrated adenoma/polyp detection rate (SSA/P-DR) for screening colonoscopies.

METHODS

Consecutive patients undergoing colonoscopy in 2016 were retrospectively evaluated. Primary outcome was the effect of time of day and endoscopist specialty on screening ADR. Secondary outcomes included evaluation of the same factors on SSA/P-DR and other metrics and collinearity of ADR and SSA/P-DR. Linear regression models were used for association between ADR, time of day, and endoscopist background. Bowel preparation, endoscopist, session, patient age, and gender were adjusted for. Linear regression model was also used for comparing ADR and SSA/P-DR. Chi-square was used for difference of proportions.

RESULTS

Two thousand six hundred fifty-seven colonoscopies, of which 558 were screening colonoscopies, were performed. The adjusted mean ADR (screening) was 36.8% in the morning compared with 30.5% in the afternoon (P < 0.0001) and was 36.8% for gastroenterologists compared with 30.4% for surgeons (P < 0.0001). For every 1-h delay in commencing the procedure, there was a reduction in mean ADR by 3.4%. Using a linear regression model, a statistically significant positive association was found between ADR and SSA/P-DR (P < 0.0001).

CONCLUSIONS

Morning and afternoon sessions and gastroenterologists and surgeons achieved the minimum standards recommended for ADR. Afternoon lists and surgeons were associated with a lower ADR compared with morning and gastroenterologists, respectively. Additionally, SSA/P-DR showed collinearity with ADR.

Implicit domain adaptation with conditional generative adversarial networks for depth prediction in endoscopy

PURPOSE

Colorectal cancer is the third most common cancer worldwide, and early therapeutic treatment of precancerous tissue during colonoscopy is crucial for better prognosis and can be curative. Navigation within the colon and comprehensive inspection of the endoluminal tissue are key to successful colonoscopy but can vary with the skill and experience of the endoscopist. Computer-assisted interventions in colonoscopy can provide better support tools for mapping the colon to ensure complete examination and for automatically detecting abnormal tissue regions.

METHODS

We train the conditional generative adversarial network pix2pix, to transform monocular endoscopic images to depth, which can be a building block in a navigational pipeline or be used to measure the size of polyps during colonoscopy. To overcome the lack of labelled training data in endoscopy, we propose to use simulation environments and to additionally train the generator and discriminator of the model on unlabelled real video frames in order to adapt to real colonoscopy environments.

RESULTS

We report promising results on synthetic, phantom and real datasets and show that generative models outperform discriminative models when predicting depth from colonoscopy images, in terms of both accuracy and robustness towards changes in domains.

CONCLUSIONS

Training the discriminator and generator of the model on real images, we show that our model performs implicit domain adaptation, which is a key step towards bridging the gap between synthetic and real data. Importantly, we demonstrate the feasibility of training a single model to predict depth from both synthetic and real images without the need for explicit, unsupervised transformer networks mapping between the domains of synthetic and real data.

Advances in Endoscopic Imaging of the Biliary Tree

Direct endoscopic imaging of the biliary tree is increasingly performed by endoscopists since the introduction of digital single-operator cholangioscopy. In parallel, there have been several advances to overcome the challenges associated with direct peroral cholangioscopy with development of multibending cholangioscopes and new devices to enable direct placement of an endoscope into the biliary tree without a supporting duodenoscope. The indications for cholangioscopy are also evolving with newer indications, such as intraductal lithotripsy, foreign body (mostly stent) removal, guide wire cannulation of specific ducts, photodynamic therapy for cholangiocarcinoma, and performance of fluoroscopy-free cholangiography. There has also been progress in image enhancement during cholangioscopy and additional imaging techniques, such as intraductal ultrasound, confocal laser endomicroscopy, and optical coherence tomography.

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.

Does Increased Adenoma Detection Reduce the Risk of Colorectal Cancer, and How Good Do We Need to Be?

PURPOSE OF REVIEW

Colorectal cancer (CRC) is largely preventable with colonoscopy and other screening modalities. However, the effectiveness of screening and surveillance depends on the quality of the colonoscopy exam. Adenoma detection rate (ADR) is the best-validated metric by which we measure individual physicians' performance.

RECENT FINDINGS

Recent evidence suggests that ADR benchmarks may be inappropriately low. There is proof that improving ADR leads to significant reductions in post-colonoscopy CRC (PCCRC). Two studies have demonstrated that when a colonoscopy is performed by physicians with higher ADRs, patients are less likely to have advanced adenomas on surveillance and less likely to develop or die from PCCRC. Finally, there is at least some evidence that higher ADRs do not lead to more cumulative surveillance exams. The ADR is a useful outcome measure that can provide individual endoscopists and their patients with information about the likelihood of developing PCCRC. To achieve the lowest possible PCCRC rate, we should be striving for higher ADRs. While strategies and innovations may help a bit in improving ADRs, our efforts should focus on ensuring a complete mucosal exam for each patient. Behavioral psychology theories may provide useful frameworks for studying motivating factors that drive a careful exam.

A prospective RCT comparing combined chromoendoscopy with water exchange (CWE) vs water exchange (WE) vs air insufflation (AI) in adenoma detection in screening colonoscopy

Background

A low adenoma detection rate (ADR) increases risks of interval cancers (ICs). Proximal colon flat polyps, e.g. serrated lesions (SLs), are difficult to find. Missed proximal colon flat lesions likely contribute to IC.

Aims

We compared chromoendoscopy with water exchange (CWE), water exchange (WE) and air insufflation (AI) in detecting adenomas in screening colonoscopy.

Methods

After split-dose preparation, 480 veterans were randomized to AI, WE and CWE.

Results

Primary outcome of proximal ADR (55.6% vs 53.4% vs 52.2%, respectively) were similar in all groups. Adenoma per colonoscopy (APC) and adenoma per positive colonoscopy (APPC) were comparable. Detection rate of proximal colon SLs was significantly higher for CWE and WE than AI (26.3%, 23.6% and 11.3%, respectively, p = 0.002). Limitations: single operator; SLs only surrogate markers of but not IC.

Conclusions

When an endoscopist achieves high-quality AI examinations with overall ADR twice (61.6%) the recommended standard (30%), use of WE and CWE does not produce further improvement in proximal or overall ADR. Comparable APC and APPC confirm equivalent withdrawal inspection techniques. WE alone is sufficient to significantly improve detection of proximal SLs. The impact of increased detection of proximal SLs by WE on prevention of IC deserves to be studied. This study is registered at ClinicalTrial.gov (NCT#01607255).

Burden and Cost of Gastrointestinal, Liver, and Pancreatic Diseases in the United States: Update 2018

BACKGROUND & AIMS

Estimates of disease burden can inform national health priorities for research, clinical care, and policy. We aimed to estimate health care use and spending among gastrointestinal (GI) (including luminal, liver, and pancreatic) diseases in the United States.

METHODS

We estimated health care use and spending based on the most currently available administrative claims from commercial and Medicare Supplemental plans, data from the GI Quality Improvement Consortium Registry, and national databases.

RESULTS

In 2015, annual health care expenditures for gastrointestinal diseases totaled $135.9 billion. Hepatitis ($23.3 billion), esophageal disorders ($18.1 billion), biliary tract disease ($10.3 billion), abdominal pain ($10.2 billion), and inflammatory bowel disease ($7.2 billion) were the most expensive. Yearly, there were more than 54.4 million ambulatory visits with a primary diagnosis for a GI disease, 3.0 million hospital admissions, and 540,500 all-cause 30-day readmissions. There were 266,600 new cases of GI cancers diagnosed and 144,300 cancer deaths. Each year, there were 97,700 deaths from non-malignant GI diseases. An estimated 11.0 million colonoscopies, 6.1 million upper endoscopies, 313,000 flexible sigmoidoscopies, 178,400 upper endoscopic ultrasound examinations, and 169,500 endoscopic retrograde cholangiopancreatography procedures were performed annually. Among average-risk persons aged 50-75 years who underwent colonoscopy, 34.6% had 1 or more adenomatous polyps, 4.7% had 1 or more advanced adenomatous polyps, and 5.7% had 1 or more serrated polyps removed.

CONCLUSIONS

GI diseases contribute substantially to health care use in the United States. Total expenditures for GI diseases are $135.9 billion annually-greater than for other common diseases. Expenditures are likely to continue increasing.

The contribution of endoscopy quality measures to the development of interval colorectal cancers in the screening population: a systematic review

BACKGROUND

Colon cancer is the second most common cause of cancer-related death and an important cause of morbidity. The natural history of carcinogenesis, via the adenoma-carcinoma sequence, permits screening, which reduces the relative risk of mortality by up to 16%. The efficacy of a screening programme is limited by the growth of interval colorectal cancers between screening examinations. Quantifying the rate of interval cancers and delineating contributing endoscopic factors are crucial to maximise the benefit of a screening program.

METHODS

A systematic review was performed in accordance with PRISMA principles. Electronic databases were interrogated with a considered search strategy, and reference lists of retrieved papers were surveyed. For inclusion, studies included the rate of interval cancer (stated or calculated) and reported at least one of a predefined list of endoscopy characteristics. The primary outcome was to establish the rate of interval cancers. The secondary outcome was to determine the association between endoscopy quality measures and interval cancers.

RESULTS

The search yielded 2067 papers. Seventy-six full text papers were reviewed. Fifteen papers met the inclusion criteria. In total, there were 117,793 colon cancers, 7281 of which were interval lesions, giving an overall rate of 6.2%. The adenoma detection rate (ADR) of the endoscopist performing the index operation was the most consistent endoscopy factor associated with development of interval cancers. The impact of setting, volume and bowel preparation varied between papers.

CONCLUSION

Interval cancers reduce the efficacy of colorectal screening programmes. Ensuring the quality of the endoscopy process, specifically by increasing the ADR of practitioners, is crucial to the reduction of the rate of interval cancers.

Sodium picosulphate or polyethylene glycol before elective colonoscopy in outpatients? A systematic review and meta-analysis

AIM

To determine the best option for bowel preparation [sodium picosulphate or polyethylene glycol (PEG)] for elective colonoscopy in adult outpatients.

METHODS

A systematic review of the literature following the PRISMA guidelines was performed using Medline, Scopus, EMBASE, Central, Cinahl and Lilacs. No restrictions were placed for country, year of publication or language. The last search in the literature was performed on November 20^th, 2017. Only randomized clinical trials with full texts published were included. The subjects included were adult outpatients who underwent bowel cleansing for elective colonoscopy. The included studies compared sodium picosulphate with magnesium citrate (SPMC) and PEG for bowel preparation. Exclusion criteria were the inclusion of inpatients or groups with specific conditions, failure to mention patient status (outpatient or inpatient) or dietary restrictions, and permission to have unrestricted diet on the day prior to the exam. Primary outcomes were bowel cleaning success and/or tolerability of colon preparation. Secondary outcomes were adverse events, polyp and adenoma detection rates. Data on intention-to-treat were extracted by two independent authors and risk of bias assessed through the Jadad scale. Funnel plots, Egger’s test, Higgins’ test (I²) and sensitivity analyses were used to assess reporting bias and heterogeneity. The meta-analysis was performed by computing risk difference (RD) using Mantel-Haenszel (MH) method with fixed-effects (FE) and random-effects (RE) models. Review Manager 5 (RevMan 5) version 6.1 (The Cochrane Collaboration) was the software chosen to perform the meta-analysis.

RESULTS

662 records were identified but only 16 trials with 6200 subjects were included for the meta-analysis. High heterogeneity among studies was found and sensitivity analysis was needed and performed to interpret data. In the pooled analysis, SPMC was better for bowel cleaning [MH FE, RD 0.03, IC (0.01, 0.05), P = 0.003, I² = 33%, NNT 34], for tolerability [MH RE, RD 0.08, IC (0.03, 0.13), P = 0.002, I² = 88%, NNT 13] and for adverse events [MH RE, RD 0.13, IC (0.05, 0.22), P = 0.002, I² = 88%, NNT 7]. There was no difference in regard to polyp and adenoma detection rates. Additional analyses were made by subgroups (type of regimen, volume of PEG solution and dietary recommendations). SPMC demonstrated better tolerability levels when compared to PEG in the following subgroups: “day-before preparation” [MH FE, RD 0.17, IC (0.13, 0.21), P < 0.0001, I² = 0%, NNT 6], “preparation in accordance with time interval for colonoscopy” [MH RE, RD 0.08, IC (0.01, 0.15), P = 0.02, I² = 54%, NNT 13], when compared to “high-volume PEG solutions” [MH RE, RD 0.08, IC (0.01, 0.14), I² = 89%, P = 0.02, NNT 13] and in the subgroup “liquid diet on day before” [MH RE, RD 0.14, IC (0.06,0.22), P = 0.0006, I² = 81%, NNT 8]. SPMC was also found to cause fewer adverse events than PEG in the “high-volume PEG solutions” [MH RE, RD -0.18, IC (-0.30, -0.07), P = 0.002, I² = 79%, NNT 6] and PEG in the “low-residue diet” subgroup [MH RE, RD -0.17, IC (-0.27, 0.07), P = 0.0008, I² = 86%, NNT 6].

CONCLUSION

SPMC seems to be better than PEG for bowel preparation, with a similar bowel cleaning success rate, better tolerability and lower prevalence of adverse events.

Increase your adenoma detection rate without using fancy adjunct tools

The correlation between a low adenoma detection rate (ADR) and interval cancers (ICs) has made ADR one of the most important quality indicators for colonoscopy. Data from nation-wide colorectal cancer (CRC) screening programs showed that there is room for improvement in ADR in order to reduce ICs in Taiwan. Measures with and without adjunct tools have been shown to have the potential to increase ADR, with the latter being more convenient to apply without additional cost. Optimal withdrawal techniques coupled with sufficient withdrawal time, training endoscopists with emphasis on recognition of subtle characteristics of flat lesions, dynamic position changes during the withdrawal phase, removing small polyps found during insertion, and retroflexion in the right colon have all been associated with increased ADR. In particular, water exchange (WE), which is characterized using water in lieu of air and suction removal of infused water during insertion, appears to meet the needs of colonoscopy patients in Taiwan. Analyses of both primary and secondary outcome variables of recently published studies have consistently shown that WE yields higher ADR than traditional air insufflation, even in propofol-sedated patients. Colonoscopists participating in the nationwide CRC screening program in Taiwan should consider applying one or more of the above measures to improve ADR and hopefully reduce ICs.