Detection rate and predictive factors of sessile serrated polyps in an organised colorectal cancer screening programme with immunochemical faecal occult blood test: the EQuIPE study (Evaluating Quality Indicators of the Performance of Endoscopy)

GI genius endoscopy module: a clinical profile

INTRODUCTION

The identification of early-stage colorectal cancers (CRC) and the resection of pre-cancerous neoplastic lesions through colonoscopy allows to decrease both CRC incidence and mortality. However, colonoscopy miss rates up to 26% for adenomas and 9% for advanced adenomas have been reported. In recent years, artificial intelligence (AI) systems have been emerging as easy-to-use tools, potentially lowering the risk of missing lesions.

AREAS COVERED

This review paper focuses on GI Genius device (Medtronic Co. Minneapolis, MN, U.S.A.) a computer-assisted tool designed to assist endoscopists during standard white-light colonoscopies in detecting mucosal lesions.

EXPERT OPINION

Randomized controlled trials (RCTs) suggest that GI Genius is a safe and effective tool for improving adenoma detection, especially in CRC screening and surveillance colonoscopies. However, its impact seems to be less significant among experienced endoscopists and in real-world clinical scenarios compared to the controlled conditions of RCTs. Furthermore, it appears that GI Genius mainly enhances the detection of non-advanced, small polyps, but does not significantly impact the identification of advanced and difficult-to-detect adenoma. When using GI Genius, no complications were documented. Only a small number of studies reported an increased in withdrawal time or the removal of non-neoplastic lesions.

Prevalence and predictive factors of colorectal sessile serrated lesions in younger individuals

BACKGROUND

Sessile serrated lesions (SSLs) are obscured lesions predominantly in the right-sided colon and associated with interval colorectal cancer; however, their prevalence and risk factors among younger individuals remain unclear.

METHODS

This retrospective study enrolled individuals who underwent index colonoscopy. The primary outcome was the SSL prevalence in the younger (<50 years) and older (≥50 years) age groups, while the secondary outcomes included clinically significant serrated polyps (CSSPs). Multivariable logistic regression was employed to identify predictors.

RESULTS

Of the 9854 eligible individuals, 4712 (47.8%) were categorized into the younger age group. Individuals in the younger age group exhibited lower prevalences of adenomas (22.6% vs. 46.2%; P<0.001) and right-sided adenomas (11.2% vs. 27.2%; P<0.001) compared with their older counterparts. However, both groups exhibited a similar prevalence of SSLs (7.2% vs. 6.5%; P=0.16) and CSSPs (10.3% vs. 10.3%;P=0.96). Multivariable analysis revealed that age 40-49 years (odds ratio [OR] 1.81, 95%CI 1.01-3.23), longer withdrawal time (OR 1.17, 95%CI 1.14-1.20, per minute increment), and endoscopist performance (OR 3.35, 95%CI 2.44-4.58) were independent predictors of SSL detection in the younger age group. No significant correlation was observed between adenoma and SSL detection rates among endoscopists.

CONCLUSION

SSLs are not uncommon among younger individuals. Moreover, diligent effort and expertise are of paramount importance in SSL detection. Future studies should explore the clinical significance of SSLs in individuals of younger age.

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

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

Cost-utility analysis of real-time artificial intelligence-assisted colonoscopy in Italy

Background and study aims Artificial intelligence (AI)-assisted colonoscopy has proven to be effective compared with colonoscopy alone in an average-risk population. We aimed to evaluate the cost-utility of GI GENIUS, the first marketed real-time AI system in an Italian high-risk population. Methods A 1-year cycle cohort Markov model was developed to simulate the disease evolution of a cohort of Italian individuals positive on fecal immunochemical test (FIT), aged 50 years, undergoing colonoscopy with or without the AI system. Adenoma or colorectal cancer (CRC) were identified according to detection rates specific for each technique. Costs were estimated from the Italian National Health Service perspective. Results Colonoscopy+AI system was dominant with respect to standard colonoscopy. The GI GENIUS system prevented 155 CRC cases (-2.7%), 77 CRC-related deaths (-2.8%), and improved quality of life (+0.027 QALY) with respect to colonoscopy alone. The increase in screening cost (+€10.50) and care for adenoma (+€3.53) was offset by the savings in cost of care for CRC (-€28.37), leading to a total savings of €14.34 per patient. Probabilistic sensitivity analysis confirmed the cost-efficacy of the AI system (almost 80% probability). Conclusions The implementation of AI detection tools in colonoscopy after patients test FIT-positive seems to be a cost-saving strategy for preventing CRC incidence and mortality.

Surveillance after colorectal polyp resection

Post-polypectomy surveillance has proven to reduce colorectal cancer (CRC) incidence in patients with high-risk polyps, but it implies a major burden on colonoscopy units. Therefore, it should be targeted to individuals with a higher risk. Different societies have published guidelines on surveillance after resection of polyps, with notable discrepancies among them, and many recommendations come from low-quality evidence based on surrogate measures, such as risk of advanced adenoma, and not CRC risk. In this review, we aimed to summarize the evidence supporting post-polypectomy surveillance, compare the recently updated major guidelines, and discuss the existing discrepancies on this topic. Briefly, patients with adenomas ≥10 mm or high-grade dysplasia and patients with serrated polyps ≥10 mm or dysplasia are generally considered to have an increased risk of metachronous CRC and require surveillance, whereas the indication of surveillance is not clearly established in patients without these high-risk features.

Colorectal cancer risk after removal of polyps in fecal immunochemical test based screening

Background

Colonoscopy surveillance intervals are based on the predicted risk of metachronous colorectal cancer (CRC) after polyp removal. However, risk estimation per polyp subtype is difficult due to the fact that many patients have multiple polyps. To enable risk estimation per polyp subtypes we examined the metachronous CRC risk of subgroups based on presence or absence of co-occurring findings.

Methods

Using high-quality screening colonoscopies performed after a positive fecal immunochemical test between 2014 and 2020 within the Dutch CRC screening program, we applied Cox regression analysis to evaluate the association between findings at baseline colonoscopy and metachronous CRCs. For our primary outcome, we appointed each patient to unique subgroups based on removed polyp subtypes that were present or absent at baseline colonoscopy and used the groups without polyps as reference. High-risk subgroups were individuals with high-risk serrated polyps, defined as serrated polyp ≥10 mm, sessile serrated lesions with dysplasia, or traditional serrated adenomas, as well as high-risk adenomas, defined as adenoma ≥10 mm or containing high-grade dysplasia.

Findings

In total 253,833 colonoscopies were included. Over a median follow-up of 36 months (IQR, 21-57), we identified 504 metachronous CRCs. Hazard ratios for metachronous CRC was 1.70 (95% CI, 1.07-2.69) for individuals with high-risk serrated polyps without high-risk adenomas, 1.22 (0.96-1.55) for individuals with high-risk adenomas without high-risk serrated polyps, and 2.00 (1.19-3.39) for individuals with high-risk serrated polyps and high-risk adenomas, compared to patients without polyps.

Interpretation

Accounting for co-occurring findings, we observed an increased metachronous CRC risk for individuals that had high-risk serrated polyps with the presence of high-risk adenomas, or individuals with high-risk serrated polyps without high-risk adenomas. These findings could provide more evidence to support post-polypectomy surveillance guidelines.

Funding

None.

Cost-effectiveness of Artificial Intelligence-Aided Colonoscopy for Adenoma Detection in Colon Cancer Screening

Background and Aims

Artificial intelligence-aided colonoscopy significantly improves adenoma detection. We assessed the cost-effectiveness of the GI Genius technology, an artificial intelligence-aided computer diagnosis for polyp detection (CADe), in improving colorectal cancer outcomes, adopting a Canadian health care perspective.

Methods

A Markov model with 1-year cycles and a lifetime horizon was used to estimate incremental cost-effectiveness ratio comparing CADe to conventional colonoscopy polyp detection amongst patients with a positive faecal immunochemical test. Outcomes were life years (LYs) and quality-adjusted life years (QALY) gained. The analysis applied costs associated with health care resource utilization, including procedures and follow-ups, from a provincial payer's perspective using 2022 Canadian dollars. Effectiveness and cost data were sourced from the literature and publicly available databases. Extensive probabilistic and deterministic sensitivity analyses were performed, assessing model robustness.

Results

Life years and QALY gains for the CADe and conventional colonoscopy groups were 19.144 versus 19.125 and 17.137 versus 17.113, respectively. CADe and conventional colonoscopies' overall per-case costs were $2990.74 and $3004.59, respectively. With a willingness-to-pay pre-set at $50,000/QALY, the incremental cost-effectiveness ratio was dominant for both outcomes, showing that CADe colonoscopy is cost-effective. Deterministic sensitivity analysis confirmed that the model was sensitive to the incidence risk ratio of adenoma per colonoscopy for large adenomas. Probabilistic sensitivity analysis showed that the CADe strategy was cost-effective in up to 73.4% of scenarios.

Conclusion

The addition of CADe solution to colonoscopy is a dominant, cost-effective strategy when used in faecal immunochemical test-positive patients in a Canadian health care setting.

Efficacy of oral sulfate tablets for bowel preparation and adenoma detection rate

BACKGROUND AND AIM

The adenoma detection rate (ADR), which is closely related to bowel preparation, is the most important factor for colonoscopy quality assessment. New oral sulfate tablets (OSTs) have been developed to improve bowel preparation compliance. This study evaluated the efficacy of OSTs in terms of the ADR and bowel preparation status.

METHODS

Medical records of subjects under the age of 65 who underwent colonoscopy from March 2019 to February 2021 were retrospectively reviewed. Polyethylene glycol with ascorbic acid (PEG-A) was used as a bowel preparation for the first half of the study period, and OSTs were used for the second half. In total, 16 971 subjects were included in the study: 9199 (54.2%) used PEG-A, and 7772 (45.8%) used OSTs. Bowel cleansing quality was assessed by the Boston Bowel Preparation Scale (BBPS).

RESULTS

The average age was 50 years. The rate of adequate bowel preparation was higher in the OST group than in the PEG-A group (97.2% vs 95.0%, P < 0.001). The mean BBPS was also higher in the OST group (8.02 vs 7.75, P < 0.001). The adenomas per colonoscopy (APC), the ADR and the sessile serrated polyp detection rate (SSPDR) were higher in the OST group than in the PEG-A group (APC 0.56 ± 1.01 vs 0.48 ± 0.91, P < 0.001; ADR 34.5% vs 30.7%, P < 0.001; SSPDR 5.2% vs 3.3%, P < 0.001).

CONCLUSIONS

Compared with PEG-A, OSTs yielded superior APC, ADRs, SSPDRs, and better bowel cleanliness. Therefore, OSTs are a good alternative for patients who have difficulty taking large-volume bowel preparation formulations.

Modeling the Natural History and Screening Effects of Colorectal Cancer Using Both Adenoma and Serrated Neoplasia Pathways: The Development, Calibration, and Validation of a Discrete Event Simulation Model

Background. Existing colorectal cancer (CRC) screening models mostly focus on the adenoma pathway of CRC development, overlooking the serrated neoplasia pathway, which might result in overly optimistic screening predictions. In addition, Bayesian inference methods have not been widely used for model calibration. We aimed to develop a CRC screening model accounting for both pathways, calibrate it with approximate Bayesian computation (ABC) methods, and validate it with large CRC screening trials. Methods. A discrete event simulation (DES) of the CRC natural history (DECAS) was constructed using the adenoma and serrated pathways in R software. The model simulates CRC-related events in a specific birth cohort through various natural history states. Calibration took advantage of 74 prevalence data points from the German screening colonoscopy program of 5.2 million average-risk participants using an ABC method. CRC incidence outputs from DECAS were validated with the German national cancer registry data; screening effects were validated using 17-y data from the UK Flexible Sigmoidoscopy Screening sigmoidoscopy trial and a German screening colonoscopy cohort study. Results. The Bayesian calibration rendered 1,000 sets of posterior parameter samples. With the calibrated parameters, the observed age- and sex-specific CRC prevalences from the German registries were within the 95% DECAS-predicted intervals. Regarding screening effects, DECAS predicted a 41% (95% intervals 30%-51%) and 62% (95% intervals 55%-68%) reduction in 17-y cumulative CRC mortality for a single screening sigmoidoscopy and colonoscopy, respectively, falling within 95% confidence intervals reported in the 2 clinical studies used for validation. Conclusions. We presented DECAS, the first Bayesian-calibrated DES model for CRC natural history and screening, accounting for 2 CRC tumorigenesis pathways. The validated model can serve as a valid tool to evaluate the (cost-)effectiveness of CRC screening strategies.

Highlights

This article presents a new discrete event simulation model, DECAS, which models both adenoma-carcinoma and serrated neoplasia pathways for colorectal cancer (CRC) development and CRC screening effects.DECAS is calibrated based on a Bayesian inference method using the data from German screening colonoscopy program, which consists of more than 5 million first-time average-risk participants aged 55 years and older in 2003 to 2014.DECAS is flexible for evaluating various CRC screening strategies and can differentiate screening effects in different parts of the colon.DECAS is validated with large screening sigmoidoscopy and colonoscopy clinical study data and can be further used to evaluate the (cost-)effectiveness of German colorectal cancer screening strategies.

Advanced serrated polyps as a target of screening: detection rate and positive predictive value within a fecal immunochemical test-based colorectal cancer screening population

BACKGROUND : Advanced serrated polyps (ASPs) have a comparable risk to advanced adenomas for progression to colorectal cancer (CRC). The yield of most CRC screening programs, however, is based on advanced adenomas and CRC only. We assessed the ASP detection rate, and positive predictive value (PPV) including ASPs in a fecal immunochemical test (FIT)-based screening program. METHODS : We analyzed the findings of follow-up colonoscopies of FIT-positive screenees in the Dutch CRC screening program from 2014 until 2020. Data were retrieved from the national screening and pathology database. An ASP was defined as any serrated polyp of ≥ 10 mm, sessile serrated lesion with dysplasia, or traditional serrated adenoma. The ASP detection rate was defined as the proportion of colonoscopies with ≥ 1 ASP. PPV was originally defined as the proportion of individuals with a CRC or advanced adenoma. The updated PPV definition included CRCs, advanced adenomas, and/or ASPs. RESULTS : 322 882 colonoscopies were included in the analyses. The overall detection rate of ASPs was 5.9 %. ASPs were detected more often in women than men (6.3 % vs. 5.6 %; P < 0.001). ASP detection rates in individuals aged 55-59, 60-64, 65-69, and 70 + were 5.2 %, 6.1 %, 6.1 %, and 5.9 %, respectively (P < 0.001). The PPV for CRCs and advanced adenomas was 41.1 % and increased to 43.8 % when including ASPs. The PPV increase was larger in women than in men (3.2 vs. 2.4 percentage points). CONCLUSIONS : 5.9 % of FIT-positive screenees had ASPs, but half of these were detected in combination with a CRC or advanced adenoma. Therefore, including ASPs results in a small increase in the yield of FIT-based screening.

Transcriptome of sessile serrated adenoma/polyps is associated with MSI-high colorectal cancer and decreased expression of CDX2

The objective of this study was to elucidate the molecular background of sessile serrated adenoma/polyp (SSA/P) endoscopically resected with comprehensive gene expression analysis. Gene expression profiling was performed for 10 tumor-normal pairs of SSA/P. Cluster analysis, gene set enrichment analysis (GSEA), and consensus molecular subtype (CMS) classification of colorectal cancer (CRC) were applied to our transcriptome analysis. Unsupervised cluster analysis showed that the gene expression profile of SSA/Ps is different from that of adjacent normal epithelial cells, even in the very early stage of tumorigenesis. According to the CMS classification, our microarray data indicated that SSA/Ps were classified as CMS1. GSEA demonstrated a strong association between SSA/P and microsatellite instability-high (MSI-H) CRC (p < 10^-5 ). Transcriptome analysis of five MSI-related genes (MSH2, MSH6, MLH1, PMS1, and PMS2) and five CRC-related genes (BRAF, KRAS, APC, TP53, and CDX2) showed that CDX2 expression was most severely decreased in SSA/P. Immunohistochemical staining confirmed that CDX2 protein was reduced compared with the surrounding mucosa. Direct sequencing of the BRAF gene showed that the BRAF V600E mutation was detected in only nine of 36 cases. In a mouse model, BRAF, APC, or CDX2 deficiency indicated that the gene expression pattern with loss of CDX2 is more similar to our SSA/Ps compared with those induced by BRAF or APC mutation. Transcriptome analysis of SSA/Ps showed characteristic gene expression with a strong resemblance to MSI-H CRC. Downregulation of CDX2 expression is an essential molecular mechanism involved in the initial stage of SSA/P tumorigenesis. (UMIN000027365).

Adenoma detection rate is enough to assess endoscopist performance: a population-based observational study of FIT-positive colonoscopies

Background and study aims  Neoplasia-related indicators, such as adenoma detection rate (ADR), are a priority in the quality improvement process for colonoscopy. Our aim was to assess and compare different detection and characterization indicators in fecal immunochemical test (FIT)-positive colonoscopies, to determine associated factors, and to propose benchmarks. Patients and methods  Retrospective analysis of prospectively collected data from all colonoscopies performed between 2015 and 2019 after a positive quantitative FIT in the population-based colorectal cancer screening program conducted in Alsace, part of the French national program. Detection indicators included ADR, mean number of adenomas per colonoscopy, and proximal serrated lesion (SL) detection rate. Characterization indicators included rate of non-neoplastic polyp (NNP) detection. Results  Overall, 13,067 FIT-positive colonoscopies were evaluated, performed by 80 community gastroenterologists. The overall ADR was 57.6 %, and a 10 µg/g increase in fecal hemoglobin concentration was significantly associated with higher ADR (odds ratio [95 % confidence interval] = 1.02 [1.02-1.03]). Endoscopists whose ADR was ≥ 55 % were high detectors for all neoplasia, including proximal SLs and number of adenomas. The rate of detection of NNPs was 39.5 % in highest detectors (ADR > 70 %), significantly higher than in lower detectors (21.4 %) ( P  < 0.001). There was a strong correlation between detection and characterization indicators, e. g. between rates of detection of proximal SLs and NNPs (Pearson = 0.73; P  < 0.01). Conclusions  A single indicator, ADR, is enough to assess endoscopist performance for both detection and characterization in routine practice provided the minimum target standard is raised and a maximum standard is added: 55 % and 70 % for FIT-positive colonoscopies, respectively.

Key factors for improving adenoma detection rate

INTRODUCTION

Colonoscopy is a fundamental tool in colorectal cancer (CRC) prevention. Nevertheless, one-fourth of colorectal neoplasms are still missed during colonoscopy, potentially being the main reason for post-colonoscopy colorectal cancer (PCCRC). Adenoma detection rate (ADR) is currently known as the best quality indicator correlating with PCCRC incidence.

AREAS COVERED

We performed a literature review in order to summarize evidences investigating key factors affecting ADR: endoscopists education and training, patient management, endoscopic techniques, improved navigation (exposition defect), and enhanced lesions recognition (vision defect) were considered.

EXPERT OPINION

'Traditional' factors, such as split dose bowel preparation, adequate withdrawal time, and right colon second view, held a significant impact on ADR. Several devices and technologies have been developed to promote high-quality colonoscopy, however artificial intelligence may be considered the most promising tool for ADR improvement, provided that endoscopists education and recording are guaranteed.

Colonoscopy Findings in FIT+ and mt-sDNA+ Patients versus in Colonoscopy-only Patients: New Hampshire Colonoscopy Registry Data

Few studies compare fecal immunochemical test (FIT) and multi-target stool DNA (mt-sDNA) outcomes in practice. We compared colonoscopy yield following FIT+ or mt-sDNA+ tests to colonoscopies without preceding stool tests in the comprehensive population-based New Hampshire Colonoscopy Registry (NHCR). Outcomes were any neoplasia and an ordered outcome: adenocarcinoma, advanced neoplasia (adenoma/serrated polyp ≥ 1 cm/villous/high-grade dysplasia), nonadvanced neoplasia, or normal. Our total sample included 306 mt-sDNA+ (average age ± SD 67.0 ± 7.9), 276 FIT+ (66.6 ± 8.7), and 50,990 colonoscopy-only patients (61.8 ± 8.1). Among average-risk patients (N = 240 mt-sDNA+, N = 194 FIT+, N = 26,221 colonoscopy only), mt-sDNA+ patients had a higher risk for any neoplasia (67.1%) compared with FIT+ (54.6%, P = 0.00098) or colonoscopy (40.8%, P < 0.0001). Severity of findings and histology subtypes differed across the three groups (P < 0.0001 for both), with a higher yield of advanced findings in mt-sDNA+ patients. In particular, clinically relevant serrated polyps (hyperplastic polyps ≥10 mm/traditional serrated adenomas/sessile serrated polyps) were detected at a higher frequency in mt-sDNA+ patients as compared with FIT+ or colonoscopy-only patients. Even after adjustment, patients with positive mt-sDNA [OR = 2.82; 95% confidence interval (CI), 2.00-4.02] or FIT+ tests (OR = 1.67; 95% CI, 1.19-2.36) were more likely to have histologically more advanced findings than colonoscopy alone. At follow-up colonoscopy, mt-sDNA+ tests were more likely to predict neoplasia than FIT+, largely due to increased detection of serrated polyps. Prevention Relevance: Colorectal cancer screening options include colonoscopy and stool-based tests, including the fecal immunochemical test (FIT) and the multi-target stool DNA (mt-sDNA) test which, if positive, must be followed by a colonoscopy. Assessing "real-world" outcomes of colonoscopies following positive stool tests can inform their clinical use. See related Spotlight, p. 417.

Serrated Lesion Detection in a Population-based Colon Screening Program

BACKGROUND

Serrated lesions give rise to 15% to 30% of all colorectal cancers, driven predominantly by the sessile serrated polyp (SSP). Fecal immunochemical test (FIT), has low sensitivity for SSPs. SSP detection rate (SSPDR) is influenced by performance of both endoscopists and pathologists, as diagnosis can be subtle both on endoscopy and histology.

GOALS

To evaluate the SSPDR in a population-based screening program, and the influence of subspecialty trained pathologists on provincial reporting practices.

STUDY

The colon screening program database was used to identify all FIT-positive patients that received colonoscopy between January 2014 and June 2017. Patient demographics, colonoscopy quality indicators, pathologic diagnoses, and FIT values were collected. This study received IRB approval.

RESULTS

A total of 74,605 colonoscopies were included and 26.6% had at least 1 serrated polyp removed. The SSPDR was 7.0%, with 59% of the SSPs detected having a concurrent conventional adenoma. The mean FIT value for colonoscopies with only serrated lesions was less than that for colonoscopies with a conventional adenoma or colorectal cancer (P<0.0001). Centers with a gastrointestinal subspecialty pathologist diagnosed proportionally more SSPs (P<0.0001), and right-sided SSPs than centers without subspecialists.

CONCLUSIONS

Serrated lesions often occur in conjunction with conventional adenomas and are associated with lower FIT values. Knowledge of the characteristics of SSPs is essential for pathologists to ensure accurate diagnosis of SSPs.

A Polyp Worth Removing: A Paradigm for Measuring Colonoscopy Quality and Performance of Novel Technologies for Polyp Detection

Leaving no significant polyp behind while avoiding risks due to unnecessary resections is a commonsense strategy to safely and effectively prevent colorectal cancer (CRC) with colonoscopy. It also alludes to polyps worth removing and, therefore, worth finding. The majority of "worthy" precancerous polyps are adenomas, which for over 2 decades, have received the most attention in performance research and metrics. Consequently, the detection rate of adenomas is currently the only validated, outcome-based measure of colonoscopy demonstrated to correlate with reduced risk of postcolonoscopy CRC. However, a third or more of postcolonoscopy CRCs originate from sessile serrated polyps (SSPs), which are notoriously difficult to find, diagnose and completely resect. Among serrated polyps, the agreement among pathologists differentiating SSPs from non-neoplastic hyperplastic polyps is moderate at best. This lack of ground truth precludes SSPs from consideration in primary metrics of colonoscopy quality or performance of novel polyp detection technologies. By instead leveraging the distinct endoscopic and clinical features of serrated polyps, including those considered important due to proximal location and larger size, clinically significant serrated polyps represent serrated polyps worth removing, enriched with subtle precancerous SSPs. With the explosion of technologies to assist polyp detection, now is the time to broaden benchmarks to include clinically significant serrated polypss alongside adenomas, a measure that is relevant both for assessing the performance of endoscopists, and for assessing new polyp detection technologies.

Evaluation of the Serrated Lesions Detection Rate and Its Role as a Colonoscopy Quality Criteria

Objectives To evaluate the serrated lesion detection rate in colonoscopy at a specialized clinic and its role as quality criteria for endoscopic examination.

Methods This is an observational cross-sectional study with all patients that underwent colonoscopy between October 2018 and May 2019, performed by an experimented physician. A questionnaire was answered before the examination by the patient, and another questionnaire after the colonoscopy was answered by the medical team. All polyps identified were removed and sent to the same pathologist for analysis.

Results A total of 1,000 colonoscopies were evaluated. The average age of the patients was 58.9 years old, and most of them were female (60.6%). In 62.5% of the procedures, polyps were removed, obtaining a total of 1,730 polyps, of which 529 were serrated lesions, being 272 sessile serrated lesions (SSL). This data resulted in a serrated lesion detection rate (SDR) of 29.2%, and of 14% when considering only the SSL detection rate (SSLDR). The right colon had higher rates, with 22.3% SDR and 15.3% SSLDR. Screening colonoscopies also presented a higher serrated detection rate, of 20%, followed by diagnostics and follow-up exams. Smoking was the only risk factor associated with higher serrated detection rate.

Conclusions The serrated lesion detection rate is higher than the ones already previously suggested and the have the higher rates were stablished in the right colon and on screening exams.

Latest Generation High-Definition Colonoscopy Increases Adenoma Detection Rate by Trainee Endoscopists

BACKGROUND

Adenoma detection rate (ADR) is an important quality indicator of colonoscopy. High-definition (HD) colonoscopy has been reported to increase ADR compared to standard-definition (SD) colonoscopy. Although there are few reports comparing the latest generation and the previous generation of HD colonoscopy equipment, there are reports that the latest generation colonoscopy equipment improves ADR. However, there are no reports on the impact of the latest generation HD colonoscopy on the ADR of trainee endoscopists.

AIMS

The aim of this study was to investigate whether the latest generation HD colonoscopy increases the ADR of trainee endoscopists compared with the previous generation HD colonoscopy.

METHOD

We conducted a retrospective review of medical records of patients aged 40-79 years old, who underwent screening or surveillance colonoscopy performed by nine gastroenterology fellows at Dong-A University Hospital from March 2019 to February 2020. We calculated the overall ratios of the ADR: the ADRs of the group using the older generation HD colonoscopy equipment and the group using the latest HD colonoscopy equipment. Polyp detection rate (PDR), sessile serrated polyp detection rate (SSPDR), and advanced neoplasia detection rate (ANDR) were calculated for each group. Factors related to adenoma detection were identified using logistic regression analysis.

RESULTS

Altogether, 2189 patients were included in the study (the older HD colonoscopy group comprising 1183 and the latest HD colonoscopy group comprising 1006). We found that PDR (45.98 vs. 51.69%, p = 0.008) and ADR (35.67 vs. 40.85%, p = 0.013) were significantly higher in the latest generation HD colonoscopy group. The generational differences were not statistically significant for SSPDR (1.94 vs. 2.78%, p = 0.195) or ANDR (4.65 vs. 4.97%, p = 0.726). In the multivariate regression analysis, age, male sex, the latest generation HD colonoscopy, and long withdrawal time were the most significant factors affecting adenoma detection.

CONCLUSIONS

The latest generation HD colonoscopy improved PDR and ADR by trainee endoscopists. These findings suggest that latest generation, higher-resolution colonoscopy equipment can improve the quality of colonoscopy for less experienced endoscopists.

Overtreatment in nonmalignant lesions detected in a colorectal cancer screening program: a retrospective cohort study

Background

Although colorectal cancer (CRC) screening programs reduce CRC incidence and mortality, they are associated with risks in healthy subjects. However, the risk of overtreatment and overdiagnosis has not been determined yet. The aim of this study was to report the surgery rates in patients with nonmalignant lesions detected within the first round of a fecal immunochemical test (FIT) based CRC screening program and the factors associated with it.

Methods

We included in this analysis all patients with nonmalignant lesions detected between May 2013 and June 2019 in the Galician (Spain) CRC screening program. We calculated surgery rate according to demographic variables, the risk classification according to the colonoscopy findings (European guidelines for quality assurance), the endoscopist’s adenoma detection rate (ADR) classified into quartiles and the hospital’s complexity level. We determined which variables were independently associated with surgery rate and expressed the association as Odds Ratio and its 95% confidence interval (CI).

Results

We included 15,707 patients in the analysis with high (19.9%), intermediate (26.9%) low risk (23.3%) adenomas and normal colonoscopy (29.9%) detected in the analyzed period. Colorectal surgery was performed in 162 patients (1.03, 95% CI 0.87–1.19), due to colonoscopy complications (0.02, 95% CI 0.00–0.05) and resection of colorectal benign lesions (1.00, 95% CI 0.85–1.16). Median hospital stay was 6 days with 17.3% patients developing minor complications, 7.4% major complications and one death. After discharge, complications developed in 18.4% patients. In benign lesions, an endoscopic resection was performed in 25.4% and a residual premalignant lesion was detected in 89.9%. The variables independently associated with surgery in the multivariable analysis were age (≥60 years = 1.57, 95% CI 1.11–2.23), sex (female = 2.10, 95% CI 1.52–2.91), the European guidelines classification (high risk = 67.94, 95% CI 24.87–185.59; intermediate risk = 5.63, 95% CI 1.89–16.80; low risk = 1.43; 95% CI 0.36–5.75), the endoscopist’s ADR (Q4 = 0.44, 95% CI 0.28–0.68; Q3 = 0.44, 95% CI 0.27–0.71; Q2 = 0.71, 95% CI 0.44–1.14) and the hospital (tertiary = 0.54, 95% CI 0.38–0.79).

Conclusions

In a CRC screening program, the surgery rate and the associated complications in patients with nonmalignant lesions are low, and related to age, sex, endoscopic findings, endoscopist’s ADR and the hospital’s complexity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08606-w.

The conversion factor for predicting adenoma detection rate from polyp detection rate varies according to colonoscopy indication and patient sex

The adenoma detection rate (ADR) is the primary quality indicator for colonoscopies. The polyp detection rate (PDR) is available from administrative data and does not depend on histology verification. The correlation between PDR and ADR and the ADR/PDR conversion factor in preventive colonoscopies were evaluated. In the prospective study, asymptomatic individuals aged 45-75 years with preventive colonoscopy in 2012-2016 were included. Spearman's correlation coefficient was used to assess PDR/ADR for each endoscopist. Conversion factor predicting ADR from PDR was obtained by linear regression and subsequently compared with adenoma to polyp detection rate quotient. One thousand six hundred fourteen preventive colonoscopies performed by 16 endoscopists in 8 screening colonoscopy centres in the Czech Republic were analysed. Correlation between PDR and ADR in all preventive colonoscopies was high and statistically significant (Rs 0.82; P < 0.001). There was a strong correlation between PDR and ADR in men (Rs 0.74; P = 0.002) and in screening colonoscopies (Rs 0.85; P < 0.001). The conversion factor to convert ADR from PDR was 0.72 in all preventive colonoscopies, 0.76 in FOBT+ colonoscopies and 0.67 in screening colonoscopies. ADR may be replaced by PDR in the assessment of colonoscopy quality. The value of the conversion factor varies according to colonoscopy indication and gender of examined individuals; in this Czech study, it was 0.72 in all preventive colonoscopies. The minimum requested ADR of 25 % corresponds to a PDR of 35 %, when converted with the appropriate conversion factor.

Higher adenoma detection, sessile serrated lesion detection and proximal sessile serrated lesion detection are associated with physician specialty and performance on Direct Observation of Procedural Skills

OBJECTIVE

Adenoma detection rate (ADR) and sessile serrated lesion detection rate (SSLDR) vary among physicians. We sought to determine physician characteristics associated with ADR and SSLDR in a population-based colon screening programme.

DESIGN

Retrospective study of 50-74 year olds with positive faecal immunochemical test and colonoscopy from 15/11/2013 to 31/12/2018. Physician characteristics included: gender, specialty, year and country of medical school graduation, colonoscopy volume and Direct Observation of Procedural Skills (DOPS) performance. Multivariable regression was performed on the following dependent variables: ADR, advanced ADR, proximal and distal ADR, SSLDR, proximal and distal SSLDR.

RESULTS

104 326 colonoscopies were performed by 261 physicians. A higher ADR was associated with gastroenterology (OR for general surgery 0.87, 95% CI 0.80 to 0.95; OR for general/family/internal medicine 0.70, 95% CI 0.55 to 0.88), fewer years since graduation (OR for graduation >2000 10.48, 95% CI 1.30 to 1.69 compared with <1980) and DOPS performance (OR for lowest DOPS performance 0.64, 95% CI 0.50 to 0.82 compared with highest DOPS performance). SSLDR was associated with gastroenterology (OR for general surgery 0.89, 95%, CI 0.81 to 0.97; OR for general/family/internal medicine 0.67, 95% CI 0.49 to 0.92) and DOPS performance (OR for lowest DOPS performance 0.71, 95% CI 0.51 to 0.99 compared with highest DOPS performance). Proximal SSLDR was associated with gastroenterology (OR for general surgery 0.90, 95% CI 0.82 to 0.99; OR for general/family/internal medicine 0.69, 95% CI 0.50 to 0.97) and DOPS performance (OR for lowest DOPS performance 0.68, 95% CI 0.47 to 0.99).

CONCLUSION

Higher ADR, SSLDR and proximal SSLDR was associated with gastroenterology specialty and improved performance on DOPS.

[Post-colonoscopy Colorectal Cancer: Causes and Prevention of Interval Colorectal Cancer]

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the fourth leading cause of cancer death in the worldwide. Colonoscopy is the gold standard for screening and surveillance of CRC. Removing adenomas by colonoscopy has lowered the incidence and mortality of CRC. However, colonoscopy is imperfect for detection of colorectal neoplasia. After a colonoscopy that is negative for malignancy, CRC can be diagnosed. These are termed as post-colonoscopy CRC (PCCRC). The proportion of PCCRC, among all CRC was reported to be 1.8% to 9.0%. It occurred 2.4 times more in the right colon than in the left colon. The causes of PCCRC are missed lesions, incomplete resection, and new lesions. Among these causes, missed lesion and incomplete resection are procedural factors and preventable. Therefore, it is necessary to improve the quality of colonoscopy to minimize the occurrence of PCCRC.

Sessile serrated lesion detection rates during average risk screening colonoscopy: A systematic review and meta-analysis of the published literature

Background and study aims  Sessile serrated lesion (SSL) detection rate has been variably reported and unlike adenoma detection rate (ADR) is not currently a quality indicator for screening colonoscopy. Composite detection rates of SSL in patients undergoing average risk screening colonoscopy are not available. Methods  Electronic database search (Medline, Embase and Cochrane) was conducted for studies reporting detection rates of serrated polyps (SSL, Hyperplastic polyp, traditional serrated adenoma) among average risk subjects undergoing screening colonoscopy. Primary outcomes were pooled SDR (SSL detection rate) and proximal serrated polyp detection rate (PSPDR). Pooled proportion rates were calculated with 95 %CI with assessment of heterogeneity (I ² ). Publication bias, regression test and 95 %prediction interval were calculated. Results  A total of 280,370 screening colonoscopies among average risk subjects that were eligible with 48.9 % males and an average age of 58.7 years (± 3.2). The pooled SDR was available from 16 studies: 2.5 % (1.8 %-3.4 %) with significant heterogeneity (I ²  = 98.66 %) and the 95 % prediction interval ranging from 0.6 % to 9.89 %. When analysis was restricted to large (n > 1000) and prospective studies (n = 4), SDR was 2 % (1.1 %-3.3 %). Pooled PSPDR was 10 % (8.5 %-11.8 %; 12 studies). There was evidence of publication bias ( P  < 0.01). Conclusion  Definitions of SSL have been varying over years and there exists significant heterogeneity in prevalence reporting of serrated polyps during screening colonoscopy. Prevalence rate of 2 % for SSL and 10 % for proximal serrated polyps could serve as targets while robust high-quality data is awaited to find a future benchmark showing reduction in colorectal cancer arising from serrated pathway.

PROXIMAL SERRATED POLYP DETECTION RATE: A COMPLEMENTARY QUALITY INDICATOR FOR ADENOMA DETECTION RATE?

BACKGROUND

The effectiveness of colonoscopy for colorectal cancer (CRC) screening depends on quality indicators, which adenoma detection rate (ADR) being the most important. Proximal serrated polyp detection rate (pSPDR) has been studied as a potential quality indicator for colonoscopy.

OBJECTIVE

The aim is to analyze and compare the difference in ADR and pSPDR between patients undergoing screening colonoscopy and an unselected population with other indications for colonoscopy, including surveillance and diagnosis.

METHODS

This is a historical cohort of patients who underwent colonoscopy in the digestive endoscopy service of a tertiary hospital. Out of 1554 colonoscopies performed, 573 patients were excluded. The remaining 981 patients were divided into two groups: patients undergoing screening colonoscopy (n=428; 43.6%); patients with other indications including surveillance and diagnosis (n=553; 56.4%).

RESULTS

Adenoma detection rate of the group with other indications (50.6%) was higher than that of the screening group (44.6%; P=0.03). In regarding pSPDR, there was no difference between pSPDR in both groups (screening 13.6%; other indications 13.7%; P=0.931). There was no significant difference in the mean age (P=0.259) or in the proportion of men and women (P=0.211) between both groups.

CONCLUSION

Proximal serrated polyp detection rate showed an insignificant difference between groups with different indications and could be used as a complementary indicator to adenoma detection rate. This could benefit colonoscopists with low colonoscopy volume or low volume of screening colonoscopies.

Correlation of Fecal Immunochemical Testing Levels With Pathology Results in a National Colorectal Cancer Screening Program

INTRODUCTION

Fecal immunochemical testing (FIT) positivity is determined by a threshold decided by individual screening programs. Data are limited on correlation between FIT levels and pathology identified at colonoscopy. Our aim was to examine the correlation between FIT levels and pathology identified in a national colorectal cancer screening program.

METHODS

FIT levels (n = 9,271) were analyzed and correlated with patient demographics and pathology identified, including adenomas, sessile serrated lesions, number/size of adenomas, and presence of dysplasia. Levels were divided into 2 categories: FIT levels were defined as "high" or "low" based on whether they were above or below the median (479 ngHb/mL). Multivariate analysis was performed.

RESULTS

A total of 8,084 patients (87%) underwent colonoscopy. Those younger than 65 years (odds ratio [OR] 1.267, 95% confidence interval [CI] 1.107-1.45, P = 0.001), those with an adenoma >10 mm (OR 1.736, 95% CI 01.512-1.991, P < 0.001), and those with left-sided adenomas (OR 1.484, 95% CI 1.266-1.74, P < 0.001) had higher FIT levels. Cancers (OR 2.8, 95% CI 2.09-3.75, P < 0.001) and high-grade dysplasia (OR 1.356, 95% CI 1.08-1.7, P = 0.008) had higher FIT levels, but varied greatly. The number of adenomas was not significant.

DISCUSSION

In this study, FIT levels were high for left-sided and large adenomas, suggesting that FIT has poor sensitivity for detection of diminutive and right-sided neoplasia. FIT levels had no association with gender and declined with age. Adenoma burden did not correlate with FIT levels; this is a novel finding. FIT levels vary greatly even in those with advanced neoplasia; therefore, FIT is unlikely to be useful as a risk stratification tool.

Serrated lesions of the colon and rectum: Emergent epidemiological data and molecular pathways

In 2010, serrated polyps (SP) of the colon have been included in the WHO classification of digestive tumors. Since then a large corpus of evidence focusing on these lesions are available in the literature. This review aims to analyze the present data on the epidemiological and molecular aspects of SP. Hyperplastic polyps (HPs) are the most common subtype of SP (70–90%), with a minimal or null risk of malignant transformation, contrarily to sessile serrated lesions (SSLs) and traditional serrated adenomas (TSAs), which represent 10–20% and 1% of adenomas, respectively. The malignant transformation, when occurs, is supported by a specific genetic pathway, known as the serrated-neoplasia pathway. The time needed for malignant transformation is not known, but it may occur rapidly in some lesions. Current evidence suggests that a detection rate of SP ≥15% should be expected in a population undergoing screening colonoscopy. There are no differences between primary colonoscopies and those carried out after positive occult fecal blood tests, as this screening test fails to identify SP, which rarely bleed. Genetic similarities between SP and interval cancers suggest that these cancers could arise from missed SP. Hence, the detection rate of serrated-lesions should be evaluated as a quality indicator of colonoscopy. There is a lack of high-quality longitudinal studies analyzing the long-term risk of developing colorectal cancer (CRC), as well as the cancer risk factors and molecular tissue biomarkers. Further studies are needed to define an evidence-based surveillance program after the removal of SP, which is currently suggested based on experts’ opinions.

Patient and Physician Factors Associated with Adenoma and Sessile Serrated Lesion Detection Rates

BACKGROUND AND AIMS

Sessile serrated lesions (SSLs) have been increasingly recognized as precursors to colorectal cancer. Unlike adenoma detection rate (ADR), there is currently no agreed-upon benchmark for SSL detection rate (SSLDR), and data on factors that impact SSL detection are limited. We aimed to identify patient, endoscopist, and procedural factors associated with SSL and adenoma detection.

METHODS

We used a single-center electronic endoscopy database to identify all patients ages ≥ 50 years who underwent outpatient screening colonoscopy from January 1, 2012, to June 30, 2018. Univariable Chi-square analysis was used to determine patient, endoscopist, and procedure-related factors associated with SSL or adenoma detection. We used logistic regression with generalized estimating equations, accounting for clustering by individual endoscopist, to determine factors independently associated with ADR and SSLDR.

RESULTS

We identified 10,538 unique patients who underwent colonoscopy performed by 28 endoscopists. Overall SSLDR was 2.2%, and overall ADR was 29.1%. On multivariable analysis, patient age, sex, BMI, smoking, endoscopist withdrawal time, and year of colonoscopy were independent predictors of ADR. Smoking and year of colonoscopy were independent predictors of SSLDR. Sub-optimal bowel preparation was inversely associated with SSL detection but not ADR.

CONCLUSIONS

In this large study of patients undergoing average-risk screening colonoscopy, overall SSLDR was low, indicating that methods for increasing SSLDR are needed. Our findings suggest that endoscopists may take into account risk factors for SSLs, such as smoking history, and recognize that the detection of such lesions, even more so than for adenomas, is dependent on optimal bowel preparation.

Are adenoma and serrated polyp detection rates correlated with endoscopists' sensitivity of optical diagnosis?

INTRODUCTION : Endoscopists with a high adenoma detection rate (ADR) and proximal serrated polyp detection rate (PSPDR) detect these polyps more frequently, which may be attributable to better recognition of their endoscopic features. Little is known about the association between endoscopic lesion detection and differentiation skills. Therefore, we evaluated the correlation between the ADR, PSPDR, and the sensitivity of optical diagnosis for adenomas and serrated polyps.

METHODS

We performed an exploratory post-hoc analysis of the DISCOUNT-2 study, including complete colonoscopies after a positive fecal immunochemical test (FIT) performed by endoscopists who performed ≥ 50 colonoscopies. The correlations between the ADR, PSPDR, and the sensitivity of optical diagnosis were calculated using Pearson's rho correlation coefficient.

RESULTS

24 endoscopists performed ≥ 50 colonoscopies, resulting in a total of 2889 colonoscopies. The overall ADR was 84.5 % (range 71.4 % - 95.3 %) and overall PSPDR was 13.7 % (4.3 % - 29.0 %). The sensitivity of optical diagnosis for adenomas and serrated polyps were 94.5 % (83.3 % - 100 %) and 74.0 % (37.5 % - 94.1 %), respectively. No correlation could be demonstrated between the ADR and the sensitivity of optical diagnosis for adenomas (-0.20; P = 0.35) or between the PSPDR and the sensitivity of optical diagnosis for serrated polyps (-0.12; P = 0.57).

CONCLUSIONS

In a homogeneous FIT-positive population, no correlation between the ADR, PSPDR, and the sensitivity of optical diagnosis for adenomas and serrated polyps could be demonstrated. These exploratory results suggest that lesion detection and differentiation require different endoscopic skills. Further prospective studies are needed; until then, monitoring of both performance indicators is important to secure optimal efficacy of FIT-based colorectal cancer screening.

Prophylactic Clipping After Colorectal Endoscopic Resection Prevents Bleeding of Large, Proximal Polyps: Meta-analysis of Randomized Trials

BACKGROUND & AIMS

The benefits of prophylactic clipping to prevent bleeding after polypectomy are unclear. We conducted an updated meta-analysis of randomized trials to assess the efficacy of clipping in preventing bleeding after polypectomy, overall and according to polyp size and location.

METHODS

We searched the MEDLINE/PubMed, Embase, and Scopus databases for randomized trials that compared the effects of clipping vs not clipping to prevent bleeding after polypectomy. We performed a random-effects meta-analysis to generate pooled relative risks (RRs) with 95% CIs. Multilevel random-effects metaregression analysis was used to combine data on bleeding after polypectomy and estimate associations between rates of bleeding and polyp characteristics.

RESULTS

We analyzed data from 9 trials, comprising 71897 colorectal lesions (22.5% 20 mm or larger; 49.2% with proximal location). Clipping, compared with no clipping, did not significantly reduce the overall risk of postpolypectomy bleeding (2.2% with clipping vs 3.3% with no clipping; RR, 0.69; 95% confidence interval [CI], 0.45-1.08; P = .072). Clipping significantly reduced risk of bleeding after removal of polyps that were 20 mm or larger (4.3% had bleeding after clipping vs 7.6% had bleeding with no clipping; RR, 0.51; 95% CI, 0.33-0.78; P = .020) or that were in a proximal location (3.0% had bleeding after clipping vs 6.2% had bleeding with no clipping; RR, 0.53; 95% CI, 0.35-0.81; P < .001). In multilevel metaregression analysis that adjusted for polyp size and location, prophylactic clipping was significantly associated with reduced risk of bleeding after removal of large proximal polyps (RR, 0.37; 95% CI, 0.22-0.61; P = .021) but not small proximal lesions (RR, 0.88; 95% CI, 0.48-1.62; P = .581).

CONCLUSIONS

In a meta-analysis of randomized trials, we found that routine use of prophylactic clipping does not reduce risk of postpolypectomy bleeding overall. However, clipping appeared to reduce bleeding after removal of large (more than 20 mm) proximal lesions.

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.

The cumulative false-positive rate in colorectal cancer screening: a Markov analysis

BACKGROUND

Faecal occult blood testing is widely used in colorectal cancer screening. However, there is little empirical long-term evidence on the accumulation of false-positive test results over several screening rounds. We aimed to systematically explore and quantify the cumulative false-positive rate for various scenarios of colorectal cancer screening.

METHODS

Using a Markov analysis, we estimated the lifetime cumulative number of false-positive test results (cumFP) per 100 000 50-year-old persons. We varied the screening interval and the specificity of a single screening test and the starting age of screening.

RESULTS

For a test with a specificity of 98% used from 50 to 74 years, the cumFP at age 74 was 26 260 (1-year interval), 15 102 (2-year interval), and 10 819 (3-year interval), respectively. For a test with a specificity of, respectively, 95 and 92% used at a 2-year interval, the cumFP at age 74 was 2.2 times and 3.0 times higher as compared to a test with a specificity of 98%. The cumFP at age 74 was 18% lower for screening persons aged 54-74 years vs. 50-74 years.

CONCLUSION

Our findings quantitatively illustrate the large variation of the cumFP in colorectal cancer screening between screening strategies, which is relevant to informed decision making and adequate resource planning.

Quality indicators in colonoscopy: an evolving paradigm

The year 1969 marked a revolution in the diagnosis of colorectal cancer (CRC). It is when Dr Wolff developed the colonoscope and quickly realized its potential in both diagnosis and treatment of colonic neoplasms. Over the past 50 years there has been exponential increase in utilization of colonoscopy with over 1 million colonoscopies performed annually throughout Australasia. Endoscopic removal of pre-malignant lesions has been proven to reduce the incidence and mortality of colorectal. Although timing and frequency of surveillance colonoscopy plays a crucial role in risk reduction of CRC, this is dependent upon the findings of the index colonoscopy. The goal of screening colonoscopy is to detect CRC and identify and remove pre-malignant neoplasms that risk progression to CRC. With increasing uptake of bowel screening throughout Australasia, there is increasing pressure to ensure all endoscopists and endoscopy units perform at a universal high-quality. All too often high demand and constant delays compromise colonoscopy quality. Without clear and concise quality indicators with transparent measurement and audit, these flaws can quickly jeopardize screening goals and patient outcomes. This review aims to explore six key quality indicators and explore the evidence behind the current recommended standards. These key indicators include; rate of adequate bowel preparation, caecal intubation rate, adenoma detection rate, withdrawal time, complication rates and surveillance intervals.

Diagnostic Accuracy of Stool Tests for Colorectal Cancer Surveillance in Hodgkin Lymphoma Survivors

BACKGROUND

Hodgkin lymphoma (HL) survivors have an increased colorectal cancer (CRC) risk. Diagnostic accuracy of quantitative fecal immunochemical testing (FIT, OC Sensor) and/or a multi-target stool DNA test (mt-sDNA, Cologuard^®) for advanced neoplasia (AN) was evaluated.

METHODS

101 HL survivors underwent a surveillance colonoscopy and were asked to perform two stool tests (FIT and mt-sDNA). Advanced adenoma (AA), advanced serrated lesion (ASL), and AN (AA, ASL, CRC) were evaluated. Sensitivity, specificity, and area under the curve (AUC) for AN were calculated for different FIT cut-offs and mt-sDNA with colonoscopy as reference.

RESULTS

FIT and mt-sDNA were analyzed in 73 (72%) and 82 (81%) participants, respectively. AN was detected in 19 (26%) and 22 (27%), respectively. AN sensitivities for FIT cut-off of 10 ug Hb/g feces (FIT10) and mt-sDNA were 37% (95% confidence interval (CI): 16-62) and 68% (95% CI: 45-86), with corresponding specificities of 91% (95% CI: 80-97) and 70% (95% CI: 57-86), respectively. AUC for FIT was 0.68 (95% CI: 0.54-0.82) and for mt-sDNA 0.76 (95% CI: 0.63-0.89).

CONCLUSIONS

In HL survivors, mt-sDNA showed highest sensitivity but with relatively low specificity for AN. Cost-effectiveness analyses is necessary to determine the optimal surveillance strategy.

Quality measures improving endoscopic screening of colorectal cancer: a review of the literature

INTRODUCTION

Colorectal cancer (CRC) is a major health-care problem all over the world and CRC screening is effective in reducing mortality and increasing the 5-year survival. Colonoscopy has a central role in CRC screening. It can be performed as a primary test, as a recall policy after a positive result of another screening test, and for surveillance. Since effectiveness of endoscopic screening depends on adequate detection and removal of colonic polyps, consistent quality measures, which are useful in enhancing the diagnostic yield of examination, are essential. Areas covered: The aim of this review is to analyze current evidence from literature supporting quality measures able to refine endoscopic screening of colorectal cancer. Expert commentary: Quality measures namely a) time slot allotted to colonoscopy, b) assessment of indication, c) bowel preparation, d) Cecal intubation, e) withdrawal time, f) adenoma detection rate, g) proper management of lesions (polypectomy technique, polyps retrieval rate and tattooing of resection sites), and h) adequate follow-up intervals play a key role in identifying malignant and at-risk lesions and improving the outcome of screening. Adherence to these quality measures is critical to maximize the effectiveness of CRC screening, as well as, a proper technique of colonoscopy and a quality report of the procedure. Among all recommended measures, adenoma detection rate is the most important and must be kept above the recommended quality threshold by all physicians practicing in the setting of screening.

Quality assurance of colonoscopy within the Dutch national colorectal cancer screening program

Colorectal cancer (CRC) screening is capable of reducing CRC-related morbidity and mortality. Colonoscopy is the reference standard to detect CRC, also providing the opportunity to detect and resect its precursor lesions: colorectal polyps. Therefore, colonoscopy is either used as a primary screening tool or as a subsequent procedure after a positive triage test in screening programs based on non-invasive stool testing or sigmoidoscopy. However, in both settings, colonoscopy is not fully protective for the occurrence of post-colonoscopy CRCs (PCCRCs). Because most PCCRCs are the result of colonoscopy-related factors, a high-quality procedure is of paramount importance to assure optimal effectiveness of CRC screening programs. For this reason, at the start of the Dutch fecal immunochemical test (FIT)-based screening program, quality criteria for endoscopists performing colonoscopies in FIT-positive screenees, as well as for endoscopy centers, were defined. In conjunction, an accreditation and auditing system was designed and implemented. In this report, we describe the quality assurance process for endoscopists participating in the Dutch national CRC screening program, including a detailed description of the evidence-based quality criteria. We believe that our experience might serve as an example for colonoscopy quality assurance programs in other CRC screening programs.

Contribution of the OC Sensor® immunoassay in comparison to the Hemoccult II® guaiac-test in organized colorectal cancer screening

Colorectal cancer (CRC) is a major cause of cancer-related death of worldwide with high incidence and mortality rate, accessible to a screening program in France, first with guaiac- based fecal occult blood test (g-FOBT) then with fecal immunochemical tests (FIT), since 2015, because of better accuracy. The aim of our study was to compare the characteristics of screen-detected lesions in two successive CRC screening campaigns, using two different tests (Hemoccult II^® and OC Sensor^®) in the department of Maine-et-Loire, and to precise the performance of these tests [participation rate, detection rates (DR), positive predictive value (PPV)]. Participants, invited by CAP SANTE 49, with polyps or cancer at the colonoscopy after a positive screening test between 01/01/2013 and 31/12/2016 were included. A guaiac-based fecal occult blood test (g-FOBT) was used from January 2013 to December 2014 and a FIT was used from June 2015 to December 2016). 2575 participants, 642 in g-FOBT group and 1933 in FIT group had lesions. Participation rate was not different between tests (p = 0.104), whereas DR and PPV were statistically higher in FIT for all lesions (2.61, 95% CI [2.50-2.70] vs 0.93, 95% CI [0.90-1.00], p < 0.0001 and 64.84, 95% CI [63.10-66.60], 50.00, 95% CI [47.30-52.70], p < 0.0001 respectively). FIT detects more precancerous lesions (adenomas, p < 0.001, and advanced adenomas, p < 0.001) than g-FOBT but g-FOBT detects more serrated polyps (p = 0.025). AAs were more in right colon in FIT than g-FOBT (p = 0.035). No different participation rate was detected between FIT and g-FOBT but DR and PPV of all lesions was higher with FIT.

Divergent Long-Term Detection Rates of Proximal and Distal Advanced Neoplasia in Fecal Immunochemical Test Screening Programs: A Retrospective Cohort Study

BACKGROUND

Short-term studies have reported that the fecal immunochemical test (FIT) is less accurate in detecting proximal than distal colorectal neoplasia.

OBJECTIVE

To assess the long-term detection rates for advanced adenoma and colorectal cancer (CRC), according to anatomical location.

DESIGN

Retrospective study.

SETTING

Population-based, organized screening program in the Veneto region of Italy.

PARTICIPANTS

Persons aged 50 to 69 years who completed 6 rounds of FIT screening.

MEASUREMENTS

At each screening round, the detection rates for advanced adenoma and cancer, as well as the proportional interval cancer rate (PICR), were calculated by anatomical location (proximal colon, distal colon, or rectum).

RESULTS

Between 2002 and 2014, a total of 123 347 participants had 441 647 FITs. The numbers of advanced adenomas and cancer cases detected, respectively, were 1704 and 200 in the proximal colon, 3703 and 324 in the distal colon, and 1220 and 209 in the rectum. Although the detection rate for proximal colon cancer declined only from the first to the second screening round (0.63 to 0.36 per 1000 screenees), the rate for both distal colon and rectal cancer steadily decreased across 6 rounds (distal colon, 1.65 in the first round to 0.17 in the sixth; rectum, 0.82 in the first round to 0.17 in the sixth). Similar trends were found for advanced adenoma (proximal colon, 5.32 in the first round to 4.22 in the sixth; distal colon, 15.2 in the first round to 5.02 in the sixth). Overall, 150 cases of interval cancer were diagnosed. The PICR was higher in the proximal colon (25.2% [95% CI, 19.9% to 31.5%]) than the distal colon (6.0% [CI, 3.9% to 8.9%]) or rectum (9.9% [CI, 6.9% to 13.7%]).

LIMITATIONS

Participants with irregular attendance were censored. Those who had a false-positive result on a previous FIT but negative colonoscopy results were included in subsequent rounds.

CONCLUSION

This FIT-based, multiple-round, long-term screening program had a negligible reduction in detection rates for neoplastic lesions in the proximal versus the distal colon after the first round. This was related to a higher PICR in the proximal colon and suboptimal efficacy in preventing the age-related proximal shifting of CRC.

PRIMARY FUNDING SOURCE

None.

Detection of serrated lesions in proximal colon by simulated sigmoidoscopy vs faecal immunochemical testing in a multicentre, pragmatic, randomised controlled trial

Background

The diagnostic yield of the faecal immunochemical test and sigmoidoscopy in detecting proximal serrated polyps in a colorectal cancer screening programme has not been fully assessed.

Aim

We determined the detection rate of proximal serrated polyps by simulated sigmoidoscopy and faecal immunochemical test compared with total colonoscopy in a population-based, multicentre, nationwide, randomised controlled trial (ColonPrev study).

Methods

Sigmoidoscopy yield was simulated based on the UK-Flexible Sigmoidoscopy Trial for total colonoscopy referral. Definitions were: proximal serrated polyp (proximal serrated polyp): sessile serrated polyp or hyperplastic polyp of any size and proximal at-risk serrated polyp (at-risk proximal serrated polyp): sessile serrated polyp of any size or hyperplastic polyp ≥ 10 mm, both located proximally to the splenic flexure.

Results

A total of 10,611 individuals underwent faecal immunochemical test and 5059 underwent total colonoscopy and were evaluated by simulated sigmoidoscopy. Sigmoidoscopy and faecal immunochemical test were less accurate in detecting proximal serrated polyps (odds ratio: 0.13; 95% confidence interval: 0.10-0.18 and 0.13; 0.09-0.18, p < 0.0001, respectively). Both tests were inferior to colonoscopy in detecting at-risk proximal serrated polyps, and sigmoidoscopy was inferior to faecal immunochemical test in detecting these lesions (odds ratio: 0.17; 95% confidence interval: 0.10-0.30 and 0.25; 0.17-0.37, p < 0.0001, respectively).

Conclusion

Sigmoidoscopy and faecal immunochemical test are less accurate in detecting proximal serrated polyps than colonoscopy, particularly in women.

Routine Prophylactic Endoscopic Clipping Is Not Efficacious in the Prevention of Delayed Post-Polypectomy Bleeding: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background and Aims

Colorectal cancer (CRC) can be prevented through colonoscopic polypectomy, but this exposes patients to risks, including delayed post-polypectomy bleeding (DPPB). Endoscopists increasingly use clips prophylactically with the aim of preventing DPPB. However, clips are costly, and data to support their efficacy in this context are inconsistent. We performed a systematic review and meta-analysis of randomized controlled trials to assess the efficacy of prophylactic clipping for preventing DPPB.

Methods

We searched electronic databases and other relevant sources for randomized controlled trials assessing the efficacy of prophylactic clipping versus no clipping for the prevention of DPPB. Pooled relative risks were determined using a fixed-effects model. Subgroup analyses were also performed.

Results

A total of 2305 citations were initially screened. Seven randomized controlled trials satisfied all criteria for inclusion. The quality of included studies was generally low to moderate. A total of 2851 patients underwent 5405 polypectomies. Delayed post-polypectomy bleeding occurred at an overall pooled rate of 2.5%. No overall benefit of clipping for preventing DPPB was observed, with a pooled relative risk of 0.86 (95% confidence interval [CI], 0.55 to 1.36). No significant patient or polyp factors predicting DPPB were found through subgroup analyses. No publication bias was identified.

Conclusions

Randomized trials to date do not demonstrate a protective effect of prophylactic clipping for the prevention of DPPB, and therefore, the practice of routine prophylactic clipping appears unjustified. Additional high quality randomized trials are required to identify higher-risk groups that may benefit from prophylactic clipping.

Sessile Serrated Adenomas: How to Detect, Characterize and Resect

Serrated polyps are important contributors to the burden of colorectal cancers (CRC). These lesions were once considered to have no malignant potential, but currently up to 30% of all CRC are recognized to arise from the serrated neoplasia pathway. The primary premalignant lesions are sessile serrated adenomas/polyps (SSA/Ps), although traditional serrated adenomas are relatively uncommon. Compared to conventional adenomas, SSA/Ps are morphologically subtle with indistinct borders, may be difficult to detect endoscopically, are more prevalent than previously thought, are associated with synchronous and metachronous advanced neoplasia, and have a higher risk of incomplete resection. Although many lesions remain “dormant,” progressive disease is associated with the development of dysplasia and more rapid progression to CRC. As a result, SSA/Ps are strongly implicated in the development of interval cancers. These factors represent unique challenges that require a meticulous approach to their management. In this review, we summarize the contemporary literature on the characterization, detection and resection of SSA/Ps.

Endoscopic detection rate of sessile serrated lesions in Lynch syndrome patients is comparable with an age- and gender-matched control population: case-control study with expert pathology review

BACKGROUND AND AIMS

Carcinogenesis in Lynch syndrome involves fast progression of adenomas to colorectal cancer (CRC) because of microsatellite instability. The role of sessile serrated lesions (SSLs) and the serrated neoplasia pathway in these patients is unknown. The aim of this matched case-control study was to compare endoscopic detection rates and distribution of SSLs in Lynch syndrome patients with a matched control population.

METHODS

We collected data of Lynch syndrome patients with a proven germline mutation who underwent colonoscopy between January 2011 and April 2016 in 2 tertiary referral hospitals. Control subjects undergoing elective colonoscopy from 2011 and onward for symptoms or surveillance were selected from a prospectively collected database. Patients were matched 1:1 for age, gender, and index versus surveillance colonoscopy. An expert pathology review of serrated polyps was performed. The primary outcomes included the detection rates and distribution of SSLs.

RESULTS

We identified 321 patients with Lynch syndrome who underwent at least 1 colonoscopy. Of these, 223 Lynch syndrome patients (mean age, 49.3; 59% women; index colonoscopy, 56%) were matched to 223 control subjects. SSLs were detected in 7.6% (95% confidence interval, 4.8-11.9) of colonoscopies performed in Lynch syndrome patients and in 6.7% (95% confidence interval, 4.1-10.8) of control subjects (P = .86). None of the detected SSLs in Lynch syndrome patients contained dysplasia.

CONCLUSIONS

The detection rate of SSLs in Lynch syndrome patients undergoing colonoscopy is comparable with a matched population. These findings suggest that the role of the serrated neoplasia pathway in CRC development in Lynch syndrome seems to be comparable with that in the general population.

Impact of differences in adenoma and proximal serrated polyp detection rate on the long-term effectiveness of FIT-based colorectal cancer screening

BACKGROUND

Both the adenoma detection rate (ADR) and proximal serrated polyp detection rate (PSPDR) vary among endoscopists. It is unclear how these variations influence colorectal cancer (CRC) screening effectiveness. We evaluated the effect of variation in these detection rates on the long-term impact of fecal immunochemical test (FIT) based screening.

METHODS

The Adenoma and Serrated pathway to Colorectal CAncer (ASCCA) model was set up to simulate the Dutch national biennial FIT-based CRC screening program between 2014 and 2044. Adherence to FIT and colonoscopy was 73 and 92%. Besides a 'no screening scenario', several screening scenarios varying in ADR and PSPDR were evaluated. Using the available literature on colonoscopy miss rates led to a base-case ADR of 59% and PSPDR of 11%, which were varied with intervals of 3 and 2%.

RESULTS

Compared to no screening, FIT-screening in the base-case scenario reduced long-term mortality with 51.8%. At a fixed PSPDR of 11%, an increase in ADR from 44 to 62% would result in a 10.7% difference in mortality reduction. Using a fixed ADR of 59%, changing the PSPDR from 3 to 15% did not substantially influence long-term mortality (51.0 to 52.3%).

CONCLUSIONS

An increase in ADR gradually reduces CRC burden in a FIT-based screening program, whereas an increase in PSPDR only minimally influences long-term outcomes at a population-level. The limited effect of the PSPDR can be explained by the limited sensitivity of FIT for serrated polyps (SPs). Other triage modalities aiming to detect relevant SPs should be explored.

Sessile serrated adenoma detection rate is correlated with adenoma detection rate

AIM

To investigated the association between adenoma detection rate (ADR) and sessile serrated ADR (SSADR) and significant predictors for sessile serrated adenomas (SSA) detection.

METHODS

This study is a retrospective, single-center analysis. Total colonoscopies performed by the gastroenterologists at the University of Tokyo Hospital between January and December 2014 were retrospectively identified. Polyps were classified as low-grade or high-grade adenoma, cancer, SSA, or SSA with cytological dysplasia, and the prevalence of each type of polyp was investigated. Predictors of adenoma and SSA detection were examined using logistic generalized estimating equation models. The association between ADR and SSADR for each gastroenterologist was investigated by calculating a correlation coefficient weighted by the number of each gastroenterologist’s examination.

RESULTS

A total of 3691 colonoscopies performed by 35 gastroenterologists were assessed. Overall, 978 (26.5%) low- and 84 (2.2%) high-grade adenomas, 81 (2.2%) cancers, 66 (1.8%) SSAs, and 2 (0.1%) SSAs with cytological dysplasia were detected. Overall ADR was 29.5% (men 33.2%, women 23.8%) and overall SSADR was 1.8% (men 1.7%, women 2.1%). In addition, 672 low-grade adenomas (68.8% of all the detected low-grade adenomas), 58 (69.9%) high-grade adenomas, 29 (34.5%) cancers, 52 (78.8%) SSAs, and 2 (100%) SSAs with cytological dysplasia were found in the proximal colon. Adenoma detection was the only significant predictor of SSA detection (adjusted OR: 2.53, 95%CI: 1.53-4.20; P < 0.001). The correlation coefficient between ADR and SSADR weighted by the number of each gastroenterologist’s examinations was 0.606 (P < 0.001).

CONCLUSION

Our results demonstrated that ADR is correlated to SSADR. In addition, patients with adenomas had a higher prevalence of SSAs than those without adenomas.

Findings in young adults at colonoscopy from a hospital service database audit

BACKGROUND

Colorectal cancer (CRC) diagnosed at <50 years is predominantly located in the distal colon and rectum. Little is known about which lesion subtypes may serve as CRC precursors in young adults. The aim of this work was to document the prevalence and histological subtype of lesions seen in patients aged <50 years, and any associated clinical features.

METHODS

An audit of the colonoscopy database at The Queen Elizabeth Hospital in Adelaide, South Australia over a 12-month period was undertaken. Findings were recorded from both colonoscopy reports and corresponding histological examination of excised lesions.

RESULTS

Data were extracted from colonoscopies in 2064 patients. Those aged <50 comprised 485 (24%) of the total. CRC precursor lesions (including sessile serrated adenoma/polyps (SSA/P), traditional serrated adenomas, tubular adenomas ≥10 mm or with high-grade dysplasia, and conventional adenomas with villous histology) were seen in 4.3% of patients aged <50 and 12.9% of patients aged ≥50 (P <0.001). Among colonoscopies yielding CRC precursor lesions in patients under 50 years, SSA/P occurred in 52% of procedures (11/21), compared with 27% (55/204) of procedures in patients aged 50 and older (P = 0.02). SSA/P were proximally located in (10/11) 90% of patients aged under 50, and 80% (43/54) of those aged 50 and older (P = 0.46).

CONCLUSIONS

SSA/P were the most frequently observed CRC precursor lesions in patients aged <50. Most CRCs in this age group are known to arise in the distal colon and rectum suggesting that lesions other than SSA/P may serve as the precursor for the majority of early-onset CRC.

Enhanced flat adenoma detection rate with high definition colonoscopy plus i-scan for average-risk colorectal cancer screening

BACKGROUND AND AIM

The usefulness of high definition colonoscopy plus i-scan (HD+i-SCAN) for average-risk colorectal cancer screening has not been fully assessed. The detection rate of adenomas and other measurements such as the number of adenomas per colonoscopy and the flat adenoma detection rate have been recognized as markers of colonoscopy quality. The aim of the present study was to compare the diagnostic performance of an HD+i-SCAN with that of standard resolution white-light colonoscope.

METHODS

This is a retrospective analysis of a prospectively collected screening colonoscopy database. A comparative analysis of the diagnostic yield of an HD+i-SCAN or standard resolution colonoscopy for average-risk colorectal screening was conducted.

RESULTS

During the period of study, 155/163 (95.1%) patients met the inclusion criteria. The mean age was 56.9 years. Sixty of 155 (39%) colonoscopies were performed using a HD+i-SCAN. Adenoma-detection-rates during the withdrawal of the standard resolution versus HD+i-SCAN colonoscopies were 29.5% and 30% (p = n.s.). Adenoma/colonoscopy values for standard resolution versus HD+i-SCAN colonoscopies were 0.46 (SD = 0.9) and 0.72 (SD = 1.3) (p = n.s.). A greater number of flat adenomas were detected in the HD+i-SCAN group (6/60 versus 2/95) (p < .05). Likewise, serrated adenomas/polyps per colonoscopy were also higher in the HD+i-SCAN group.

CONCLUSIONS

A HD+i-SCAN colonoscopy increases the flat adenoma detection rate and serrated adenomas/polyps per colonoscopy compared to a standard colonoscopy in average-risk screening population. HD+i-SCAN is a simple, available procedure that can be helpful, even for experienced providers. The performance of HD+i-SCAN and substantial prevalence of flat lesions in our average-risk screening cohort support its usefulness in improving the efficacy of screening colonoscopies.

Performance measures for lower gastrointestinal endoscopy: a European Society of Gastrointestinal Endoscopy (ESGE) quality improvement initiative

The European Society of Gastrointestinal Endoscopy and United European Gastroenterology present a short list of key performance measures for lower gastrointestinal endoscopy. We recommend that endoscopy services across Europe adopt the following seven key performance measures for lower gastrointestinal endoscopy for measurement and evaluation in daily practice at a center and endoscopist level: 1 rate of adequate bowel preparation (minimum standard 90%); 2 cecal intubation rate (minimum standard 90%); 3 adenoma detection rate (minimum standard 25%); 4 appropriate polypectomy technique (minimum standard 80%); 5 complication rate (minimum standard not set); 6 patient experience (minimum standard not set); 7 appropriate post-polypectomy surveillance recommendations (minimum standard not set). Other identified performance measures have been listed as less relevant based on an assessment of their importance, scientific acceptability, feasibility, usability, and comparison to competing measures.