Relative Efficacies of Interventions to Improve the Quality of Screening-Related Colonoscopy: A Systematic Review and Network Meta-analysis of Randomized Controlled Trials

BACKGROUND & AIMS

Significant variability exists in colonoscopy quality indicators, including adenoma detection rate (ADR). We synthesized evidence from randomized trials in a network meta-analysis on interventions to improve colonoscopy quality.

METHODS

We included trials from database inceptions to September 25, 2023, of patients undergoing screening-related colonoscopy and presented efficacies of interventions within domains (periprocedural parameters, endoscopist-directed interventions, intraprocedural techniques, endoscopic technologies, distal attachment devices, and additive substances) compared to standard colonoscopy. The primary outcome was ADR. We used a Bayesian random-effects model using Markov-chain Monte Carlo simulation, with 10,000 burn-ins and 100,000 iterations. We calculated odds ratios with 95% credible intervals and present surface under the cumulative ranking (SUCRA) curves.

RESULTS

We included 124 trials evaluating 37 interventions for the primary outcome. Nine interventions resulted in statistically significant improvements in ADR compared to standard colonoscopy (9-minute withdrawal time, dual observation, water exchange, iScan, linked color imaging, computer-aided detection, Endocuff, Endocuff Vision, and oral methylene blue). Dual observation (SUCRA, 0.84) and water exchange (SUCRA, 0.78) ranked highest among intraprocedural techniques; iScan (SUCRA, 0.95), linked color imaging (SUCRA, 0.85), and computer-aided detection (SUCRA, 0.78) among endoscopic technologies; WingCap (SUCRA, 0.87) and Endocuff (SUCRA, 0.85) among distal attachment devices and oral methylene blue (SUCRA, 0.94) among additive substances. No interventions improved detection of advanced adenomas, and only narrow-band imaging improved detection of serrated lesions (odds ratio, 2.94; 95% credible interval, 1.46-6.25).

CONCLUSIONS

Several interventions are effective in improving adenoma detection and overall colonoscopy quality, many of which are cost-free. These results can inform endoscopists, unit managers, and endoscopy societies on relative efficacies.

The Association between Red Meat Consumption and Advanced Colorectal Adenomas in a Population Undergoing a Screening-Related Colonoscopy in Alberta, Canada

The association between red meat consumption and colorectal cancer has been rigorously examined. However, a more comprehensive understanding of how the intake of unprocessed red meat contributes to the development of early precancerous colorectal lesions, such as advanced colorectal adenomas (ACRAs), requires further investigation. We examined the associations between different types of red meat intake and ACRAs in a sample population of 1083 individuals aged ≥ 50 years undergoing an initial screening colonoscopy in Calgary, Alberta, Canada. Associations between grams per day of total, processed, and unprocessed red meat from diet history questionnaires and ACRAs were evaluated with multivariable logistic regression models. We also applied cubic spline models fitted with three knots (10th, 50th, and 90th percentiles) to identify potential nonlinear associations. We did not observe a meaningful association between unprocessed red meat intake and the presence of ACRAs. In contrast, for every 10 g/d increase in total and processed meat intake, we observed an increase in the odds of ACRAs at the screening colonoscopy (adjusted odds ratio (OR) = 1.05, 95% [CI = 1.01-1.09], p = 0.04) and (adjusted OR = 1.11, 95% [CI = 1.02-1.20], p = 0.02), respectively. This study highlights the importance of differentiating between types of red meat consumption in the context of dietary risks associated with ACRAs.

Optimizing adenoma detection in screening-related colonoscopy

INTRODUCTION

Screening-related colonoscopy is a vital component of screening initiatives to both diagnose and prevent colorectal cancer (CRC), with prevention being reliant upon early and accurate detection of pre-malignant lesions. Several strategies, techniques, and interventions exist to optimize endoscopists' adenoma detection rates (ADR).

AREAS COVERED

This narrative review provides an overview of the importance of ADR and other colonoscopy quality indicators. It then summarizes the available evidence regarding the effectiveness of the following domains in terms of improving ADR: endoscopist factors, pre-procedural parameters, peri-procedural parameters, intra-procedural strategies and techniques, antispasmodics, distal attachment devices, enhanced colonoscopy technologies, enhanced optics, and artificial intelligence. These summaries are based on an electronic search of the databases Embase, Pubmed, and Cochrane performed on December 12, 2022.

EXPERT OPINION

Given the prevalence and associated morbidity and mortality of CRC, the quality of screening-related colonoscopy quality is appropriately prioritized by patients, endoscopists, units, and payers alike. Endoscopists performing colonoscopy should be up to date regarding available strategies, techniques, and interventions to optimize their performance.

Performance of the fecal immunochemical test for colorectal cancer and advanced neoplasia in individuals under age 50

The increased demand for colonoscopy combined with increased incidence of colorectal cancer (CRC) among younger populations presents a need to determine FIT performance among individuals in this age group. We conducted a systematic review to assess test performance characteristics of FIT in detecting CRC and advanced neoplasia in younger age populations. A search through December 2022 identified published articles assessing the sensitivity and specificity of FIT for advanced neoplasia or CRC among populations under age 50. Following the search, 3 studies were included in the systematic review. Sensitivity to detect advanced neoplasia ranged from 0.19 to 0.36 and specificity between 0.94 and 0.97 and the overall sensitivity and specificity were 0.23 (0.17-0.30) and 0.96 (0.94-0.98), respectively. Two studies that assessed these metrics in multiple age categories found similar sensitivity and specificity across all age groups 30-49. Sensitivity and specificity to detect CRC was assessed in one study and found no significant differences by age groups. These results suggest that FIT performance may be lower for younger individuals compared to those typically screened for CRC. However, there were few studies available for analysis. Given increasing recommendations to expand screening in younger age groups, more research is needed to determine whether FIT is an adequate screening tool in this population.

Effect of Disposable Elevator Cap Duodenoscopes on Persistent Microbial Contamination and Technical Performance of Endoscopic Retrograde Cholangiopancreatography: The ICECAP Randomized Clinical Trial

Importance

Infection transmission following endoscopic retrograde cholangiopancreatography (ERCP) can occur due to persistent contamination of duodenoscopes despite high-level disinfection to completely eliminate microorganisms on the instrument.

Objective

To determine (1) contamination rates after high-level disinfection and (2) technical performance of duodenoscopes with disposable elevator caps compared with those with standard designs.

Design, Setting, and Participants

In this parallel-arm multicenter randomized clinical trial at 2 tertiary ERCP centers in Canada, all patients 18 years and older and undergoing ERCP for any indication were eligible.

Intervention

The intervention was use of duodenoscopes with disposable elevator caps compared with duodenoscopes with a standard design.

Main Outcomes and Measures

Coprimary outcomes were persistent microbial contamination of the duodenoscope elevator or channel, defined as growth of at least 10 colony-forming units of any organism or any growth of gram-negative bacteria following high-level disinfection (superiority outcome), and technical success of ERCP according to a priori criteria (noninferiority outcome with an a priori noninferiority margin of 7%), assessed by blinded reviewers.

Results

From December 2019 to February 2022, 518 patients were enrolled (259 disposable elevator cap duodenoscopes, 259 standard duodenoscopes). Patients had a mean (SD) age of 60.7 (17.0) years and 258 (49.8%) were female. No significant differences were observed between study groups, including in ERCP difficulty. Persistent microbial contamination was detected in 11.2% (24 of 214) of standard duodenoscopes and 3.8% (8 of 208) of disposable elevator cap duodenoscopes (P = .004), corresponding to a relative risk of 0.34 (95% CI, 0.16-0.75) and number needed to treat of 13.6 (95% CI, 8.1-42.7) to avoid persistent contamination. Technical success using the disposable cap scope was noninferior to that of the standard scope (94.6% vs 90.7%, P = .13). There were no differences between study groups in adverse events and other secondary outcomes.

Conclusions and Relevance

In this randomized clinical trial, disposable elevator cap duodenoscopes exhibited reduced contamination following high-level disinfection compared with standard scope designs, without affecting the technical performance and safety of ERCP.

Trial Registration

ClinicalTrials.gov Identifier: NCT04040504.

Existing Bowel Preparation Quality Scales Are Reliable in the Setting of Centralized Endoscopy Reading

BACKGROUND

Development of bowel preparation products has been based upon colon cleansing rating by a local endoscopist. It is unclear how bowel preparation scales perform when centrally evaluated.

AIMS

To evaluate the reliability of bowel preparation quality scales when assessed by central readers.

METHODS

Four central readers evaluated 52 videos in triplicate, 2 weeks apart, during the entire endoscopic procedure (insertion/withdrawal of the colonoscope) and exclusively on colonoscope withdrawal using the Boston Bowel Preparation Scale (BBPS), Chicago Bowel Preparation scale, Harefield Cleansing Scale, Ottawa Bowel Preparation Quality Scale (OBPQS), Aronchick score, a visual analogue scale, and additional items proposed in a modified Research and Development/University of California Los Angeles appropriateness process. Reliability was assessed with intraclass correlation coefficients.

RESULTS

Intraclass correlation coefficients (95% confidence interval) for inter-rater reliability of the quality scales ranged from 0.51 to 0.65 (consistent with moderate to substantial inter-rater reliability) during the entire procedure. Corresponding intraclass correlation coefficients for intra-rater reliability ranged from 0.69 to 0.77 (consistent with substantial intra-rater reliability). Reliability was highest in the right colon and lowest in the left colon. No differences were observed in reliability when assessed for the procedure overall (insertion/withdrawal) relative to assessment on withdrawal alone.

CONCLUSION

All five bowel preparation quality scales had moderate to substantial inter-rater reliability. Panelists considered the Aronchick score too simplistic for clinical trials and recognized that assessment of residual fluid in the Ottawa Bowel Preparation Quality Scale was not amenable to central assessment.

Long-term Use of Hormone Replacement Therapy is Associated With a Lower Risk of Developing High-risk Serrated Polyps in Women

GOALS/BACKGROUND

Hormone replacement therapy (HRT) and parity have been suggested protective factors against the development of colorectal polyps. However, there are a limited number of studies that have examined the relationship of these factors with high-risk adenomatous polyps (HRAP) or high-risk serrated polyps (HRSP), which may have different causes and therefore implications for screening programs.

STUDY

Data from a cross-sectional study of 1384 women undergoing screening-related colonoscopy between 2008 and 2016 were analyzed. Modified Poisson regression models with robust error variance were used to determine the relative risk of developing adenomatous polyps, serrated polyps, HRAPs, and HRSPs associated with pregnancy, menopausal status, and the use of HRT (duration and type).

RESULTS

Women that used HRT for ≥6 years were at a significantly lower risk of developing a HRSP [risk ratios (RR): 0.53; 95% confidence interval (CI): 0.29-0.97]. Irrespective of the duration of use, the use of HRT that included progesterone alone or with estrogen was associated with a significantly lower risk of developing a HRSP (RR: 0.54; 95% CI: 0.30-0.95). The use HRT with progesterone for ≥6 years was associated with a nonsignificant lower risk of developing a HRSP (RR: 0.42; 95% CI: 0.17-1.04). None of the reproductive factors assessed or HRT were associated with the development of adenomatous polyps or HRAPs.

CONCLUSIONS

The results of this study suggests that the long-term use of HRT, and therapies that include progesterone are associated with a lower risk of developing HRSPs. These results could have implications for targeted screening for serrated polyps among women.

The efficacy of chemopreventive agents on the incidence of colorectal adenomas: A systematic review and network meta-analysis

Colorectal cancer (CRC) is the fourth most common cancer and third leading cause of cancer-related death worldwide. Use of chemopreventive agents (CPAs) to reduce the incidence of precursor colorectal adenomas could lower the future burden of CRC. Many classes of potential CPAs have been investigated. To identify the most effective CPAs, we conducted a systematic review and a network meta-analysis (NMA). An electronic search was performed through August 2020 to identify all randomized controlled trials (RCTs) assessing the efficacy of CPAs in reducing the incidence of colorectal adenomas at the time of surveillance colonoscopy among patients who had previously undergone polypectomy during an index colonoscopy. In total, 33 RCTs were included in the NMA, which was conducted under a Bayesian inference framework. Random effects models were used with adjustment for follow-up length and control group event rates to yield relative risks (RRs) and 95% credible intervals (CrIs). Our full network consisted of 13 interventions in addition to a placebo arm. Of 20,925 included patients, 7766 had an adenoma. Compared to placebo, the combination of difluoromethylornithine (DFMO) + Sulindac (RR 0.24, CrI 0.10-0.55) demonstrated a protective effect, while aspirin had a RR of 0.77 (CrI 0.60-1.00), celecoxib 800 mg had a RR of 0.56 (CrI 0.31-1.01) and metformin had a RR of 0.56 (CrI 0.22-1.39). Our results suggest that select CPAs may be efficacious in preventing the development of adenomas. Further studies are needed to identify those patients most likely to benefit and the minimum effective dosages of CPAs.

Association Between Endoscopist Specialty and Colonoscopy Quality: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Colonoscopy quality indicators provide measurable assessments of performance, but significant provider-level variations exist. We performed a systematic review and meta-analysis to assess whether endoscopist specialty is associated with adenoma detection rate (ADR) - the primary outcome - or cecal intubation rate, adverse event rates, and post-colonoscopy colorectal cancer rates.

METHODS

We searched EMBASE, Google Scholar, MEDLINE, and the Cochrane Central Registry of Controlled Trials from inception to December 14, 2020. Two reviewers independently screened titles and abstracts. Citations underwent duplicate full-text review, with disagreements resolved by a third reviewer. Data were abstracted in duplicate. The DerSimonian and Laird random effects model was used to calculate pooled odds ratios (ORs) with respective 95% confidence intervals (CIs). Risk of bias was assessed using Risk of Bias in Non-randomised Studies of Interventions.

RESULTS

Of 11,314 citations, 36 studies representing 3,500,832 colonoscopies were included. Compared with colonoscopies performed by gastroenterologists, those by surgeons were associated with lower ADRs (OR, 0.81; 95% CI, 0.74-0.88) and lower cecal intubation rates (OR, 0.76; 95% CI, 0.63-0.92). Compared with colonoscopies performed by gastroenterologists, those by other (non-gastroenterologist, non-surgeon) endoscopists were associated with lower ADRs (OR, 0.91; 95% CI, 0.87-0.96), higher perforation rates (OR, 3.02; 95% CI, 1.65-5.51), and higher post-colonoscopy colorectal cancer rates (OR, 1.23; 95% CI, 1.14-1.33). Substantial to considerable heterogeneity existed for most analyses, and overall certainty in the evidence was low according to the Grading of Recommendations, Assessment, Development, and Evaluations framework.

CONCLUSION

Colonoscopies performed by surgeons or other endoscopists were associated with poorer quality metrics and outcomes compared with those performed by gastroenterologists. Targeted quality improvement efforts may be warranted.

Treatment patterns and survival outcomes of early-onset colorectal cancer patients in Alberta, Canada: a population-based study

BACKGROUND

The incidence of early-onset (<50) colorectal cancer (eoCRC) has been increasing in Canada. Little is known about treatment patterns and outcomes among this patient population in Canada.

PATIENTS AND METHODS

We conducted a retrospective population-based cohort study of CRC patients in Alberta (2010-2018) using electronic medical records and administrative claims data. Treatment patterns and CRC-specific mortality were compared between early-onset age groups (<40 and 40-49) and average age-at-onset (60-70) (aoCRC) patients with multivariable logistic regression and cox proportional hazard models.

RESULTS

There were 334 and 935 patients in the early-onset groups and 4606 in the aoCRC group. Compared with aoCRC, patients <40 were more likely to receive chemotherapy in stage II colon (OR 3.41, CI 1.75-6.47) and stage III rectal (OR 3.01, CI 1.18-10.21), and to receive systemic therapy (OR 2.40, CI 1.46-4.12) and radiation in stage IV CRC (OR 2.70, CI 1.48-4.92). The 40-49 age group was more likely to receive chemotherapy in stage II colon (OR 2.13, CI 1.25-3.56), and chemoradiation in stage II rectal (OR 2.16, CI 1.25-3.80) and stage III rectal (OR 1.63, CI 1.13-2.40), as well as systemic therapy in stage IV CRC (OR 2.46, CI 1.75-3.52). Survival did not differ between <40 and 60-70 age groups. Survival was significantly higher for the 40-49 age group, but only in stage IV (HR 0.79, CI 0.67-0.94).

CONCLUSIONS

EoCRC patients tended to receive more therapy than average age CRC patients with minimal survival gains. Additional research to identify optimal treatment strategies for eoCRC patients is required.

Risk Factors for Early-Onset Colorectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Despite the widespread increase in the incidence of early-onset colorectal cancer (EoCRC), the reasons for this increase remain unclear. The objective of this study was to determine risk factors for the development of EoCRC.

METHODS

We conducted a systematic literature review and meta-analysis of studies examining non-genetic risk factors for EoCRC, including demographic factors, comorbidities, and lifestyle factors. Random effects meta-analyses were conducted for risk factors that were examined in at least three studies. Heterogeneity was investigated using the Q-test and I² statistic.

RESULTS

From 3304 initial citations, 20 studies were included in this review. Significant risk factors for EoCRC included CRC history in a first-degree relative (RR 4.21, 95% CI 2.61-6.79), hyperlipidemia (RR 1.62, 95% CI 1.22-2.13), obesity (RR 1.54, 95% CI 1.01-2.35), and alcohol consumption (high vs. non-drinkers) (RR 1.71, 95% CI 1.62-1.80). While smoking was suggestive as a risk factor, the association was not statistically significant (RR 1.35, 95% CI 0.81-2.25). With the exception of alcohol consumption, there was considerable heterogeneity among studies (I² > 60%). Other potential risk factors included hypertension, metabolic syndrome, ulcerative colitis, chronic kidney disease, dietary factors, sedentary behaviour, and occupational exposure to organic dusts, but these were only examined in one or two studies.

CONCLUSIONS

The results of this study advance the understanding of the etiology of EoCRC. High-quality studies conducted on generalizable populations and that comprehensively examine risk factors for EoCRC are required to inform primary and secondary prevention strategies.

The Bowel CLEANsing National Initiative: High-Volume Split-Dose Vs Low-Volume Split-Dose Polyethylene Glycol Preparations: A Randomized Controlled Trial

BACKGROUND & AIMS

The aim of this study was to compare high-volume polyethylene glycol (PEG) with low-volume PEG with bisacodyl split-dosing regimens.

METHODS

Adult outpatients in 10 Canadian tertiary hospitals were randomized, stratified by morning or afternoon colonoscopy, to high-volume split-dose PEG (2 L + 2 L) (High-SD) or low volume (1 L + 1 L) + bisacodyl (15 mg) PEG (Low-SD), with a second randomization to liquid or low-residue diets. The primary end point, using noninferiority hypothesis testing, was adequate bowel cleansing (Boston Bowel Preparation Scale total score of ≥6, with each of 3 colonic segments subscores ≥2). Secondary objectives were willingness to repeat the preparation, withdrawal time, cecal intubation, and polyp detection rates.

RESULTS

Over 29 months, 2314 subjects were randomized to High-SD (N = 1157) or Low-SD (N = 1157) (mean age, 56.2 ± 13.4 y; 52.1% women). Colonoscopy indications were 38.2% diagnostic, 36.8% screening, and 25.0% surveillance, with no between-group imbalances in patient characteristics. Low-SD satisfied noninferiority criteria vs High-SD for adequate bowel cleanliness with only marginally inferior results (90.1% vs 88.1%; P = .02; difference, 2.0%; 95% CI [0.0%; 4.5%]). High-SD was associated with lower willingness to repeat (66.9% vs 91.9%; P < .01), was less well tolerated (7.3 ± 2.3 vs 8.1 ± 1.9; P < .01), causing more symptoms. No differences in procedural outcomes were noted except for more frequent cecal intubation rates after High-SD (97.4% vs 95.6%; P = .02). Among the High-SD group, adequate bowel preparation was greater after a clear liquid diet (93.6% vs 87.9%; P < .01), a finding not seen in the Low-SD group.

CONCLUSIONS

Low-SD is noninferior to High-SD in providing adequate bowel preparation. Low-SD results in fewer symptoms, with greater willingness to repeat and tolerability. The overall impact of diet was modest.The study was approved by the research ethic boards from all sites and was registered at ClinicalTrials.gov (NCT02547571).

Trends and Projections in National United States Health Care Spending for Gastrointestinal Malignancies (1996-2030)

BACKGROUND & AIMS

The management of gastrointestinal (GI) cancers is associated with high health care spending. We estimated trends in United States (US) health care spending for patients with GI cancers between 1996 and 2016 and developed projections to 2030.

METHODS

We used economic data, adjusted for inflation, developed by the Institute for Health Metrics and Evaluations for the Disease Expenditure Project. Corresponding US age-adjusted prevalence of GI cancers was estimated from the Global Burden of Diseases Study. Prevalence-adjusted temporal trends in the US health care spending in patients with GI cancers, stratified by cancer site, age, and setting of care, were estimated using joinpoint regression, expressed as annual percentage change (APC) with 95% confidence intervals (CIs). Autoregressive integrated moving average models were used to project spending to 2030.

RESULTS

In 2016, total spending for GI cancers was primarily attributable to colorectal ($10.50 billion; 95% CI, $9.35-$11.70 billion) and pancreatic cancer ($2.55 billion; 95% CI, $2.23-$2.82 billion), and primarily for inpatient care (64.5%). Despite increased total spending, more recent per-patient spending for pancreatic (APC 2008-2016, -1.4%; 95% CI, -2.2% to -0.7%), gallbladder/biliary tract (APC 2010-2016, -4.3%; 95% CI, -4.8% to -3.8%), and gastric cancer (APC 2011-2016, -4.4%; 95% CI, -5.8% to -2.9%) decreased. Increasing price and intensity of care provision was the largest driver of higher expenditures. By 2030, it is projected more than $21 billion annually will be spent on GI cancer management.

CONCLUSIONS

Total spending for GI cancers in the US is substantial and projected to increase. Expenditures are primarily driven by inpatient care for colorectal cancer, although per-capita spending trends differ by GI cancer type.

Implications of the United States recommendations for early-age-at-onset colorectal cancer screening in Canada

The United States Preventive Services Task Force (USPSTF) recently issued an updated recommendation for population-based colorectal cancer (CRC) screening starting at age 45, due to a sustained increase in the incidence of early-age-at-onset CRC (eoCRC). A similar increase in the incidence of eoCRC has been observed in Canada since the early 2000s. However, the inherent differences between the US and Canadian health care systems with many different reimbursement and capacity considerations limit the applicability of the recommendations to the Canadian context. In order to facilitate further discussion around Canadian guidelines and recommendations, several research gaps need to be addressed: 1) a detailed understanding of trends in histology, topography, initial stage at diagnosis, and mortality among eoCRC; 2) a detailed analysis of cost-effectiveness outlining the impacts to the current screening programs with potential harms and benefits; 3) a comprehensive understanding of risk factor profiles that may lead to meaningful recommendations for screening decisions within the 40-49 age group in the absence of wide-spread screening programs; and 4) an evaluation of the effectiveness of current and novel screening tests or biomarkers specifically in the 40-49 age group. In the meantime, we suggest that physicians and patients begin discussions about screening at age 45 by reviewing family history and alerting patients to symptoms of CRC, which may increase screening adherence at age 50. This issue will remain an active area of debate with Canada as a careful laggard in changing recommendations, while attempting to balance system considerations with eoCRC trends and patient outcomes.

Endocuff Vision improves adenoma detection rate in a large screening-related cohort

Background and study aims  Endocuff Vision (ECV) increases adenoma detection rate (ADR) in randomized clinical trials; however, observational effectiveness data are lacking. We evaluated the effectiveness, safety, and practical aspects of ECV use in a large screening-related real-world cohort. Patients and methods  In this observational study, patients undergoing screening-related colonoscopy from November 2018 to April 2019 comprised the baseline period, and those undergoing it from June to November 2019 comprised the ECV period, where ECV use was discretionary. The primary outcome was ADR, compared: 1) between ECV use and standard colonoscopy across both periods; and 2) between time periods. Secondary outcomes included indication-specific ADR, sessile serrated ADR (SSADR), cecal intubation rate (CIR), procedure times, patient comfort scores, and sedation use. Multilevel logistic regression was performed, yielding adjusted odds ratios (AOR) with 95 % confidence intervals (CIs). Results  In 15,814 colonoscopies across both time periods, ADR was 46.7 % with standard colonoscopy and 54.6 % when ECV was used ( P  < 0.001). Endoscopists used ECV in 77.6 % of procedures in the ECV period, during which overall ADR rose to 53.2 % compared to 46.3 % in the baseline period ( P  < 0.001). ECV use was significantly associated with higher ADR (AOR 1.24, 95 % CI 1.10 to 1.40) after adjusting for relevant covariates including time period. ECV use did not result in lower CIR, longer procedure time, increased sedation use, or poorer comfort scores. Conclusions  ECV use is associated with improved ADR without negatively impacting other key procedure and patient-related factors. Future studies should evaluate the cost-effectiveness of incorporating ECV into routine screening-related practice.

Risk of adverse events associated with upper and lower endoscopic ultrasound: a population-based cohort study

Background and study aim  Endoscopic ultrasound (EUS) enables diagnostic evaluation and therapeutic interventions but is associated with adverse events. We conducted a population-based cohort study to determine the risk of adverse events for upper and lower EUS with and without fine-needle aspiration (FNA). Patients and methods  All adults who underwent EUS and resided in Calgary in 2007-2013 were included. Endoscopy and provincial databases were used to identify EUS procedures, unplanned emergency department visits, and hospital admissions within 30 days of the procedures, which were then characterized through formal chart review. Adverse events were defined a priori and classified as definitely, possibly, or not related to EUS. The primary outcome was 30-day risk of adverse events classified as definitely or possibly related to EUS. Univariable and multivariable analyses were conducted with risk factors known to be associated with EUS adverse events. Results  2895 patients underwent 3552 EUS procedures: 3034 (85 %) upper EUS, of which 710 (23 %) included FNA, and 518 (15 %) lower EUS, of which 23 (4 %) involved FNA. Overall, 69 procedures (2 %) involved an adverse event that was either definitely or possibly related to EUS, with 33 (1 %) requiring hospitalization. None of the adverse events required intensive care or resulted in death. On multivariable analysis, only FNA was associated with increased risk of adverse events (odds ratio 6.43, 95 % confidence interval 3.92-10.55; P  < 0.001). Conclusion  Upper and lower EUS were generally safe but FNA substantially increased the risk of adverse events. EUS-related complications requiring hospitalization were rare.

Adverse events associated with endoscopic retrograde cholangiopancreatography: protocol for a systematic review and meta-analysis

INTRODUCTION

Endoscopic retrograde cholangiopancreatography (ERCP) is performed to diagnose and manage conditions of the biliary and pancreatic ducts. Though effective, it is associated with common adverse events (AEs). The purpose of this study is to systematically review ERCP AE rates and report up-to-date pooled estimates.

METHODS AND ANALYSIS

A comprehensive electronic search will be conducted of relevant medical databases through 10 November 2020. A study team of eight data abstracters will independently determine study eligibility, assess quality and abstract data in parallel, with any two concordant entries constituting agreement and with discrepancies resolved by consensus. The primary outcome will be the pooled incidence of post-ERCP pancreatitis, with secondary outcomes including post-ERCP bleeding, cholangitis, perforation, cholecystitis, death and unplanned healthcare encounters. Secondary outcomes will also include rates of specific and overall AEs within clinically relevant subgroups determined a priori. DerSimonian and Laird random effects models will be used to perform meta-analyses of these outcomes. Sources of heterogeneity will be explored via meta-regression. Subgroup analyses based on median dates of data collection across studies will be performed to determine whether AE rates have changed over time.

ETHICS AND DISSEMINATION

Ethics approval is not required for this study as it is a planned meta-analysis of previously published data. Participant consent is similarly not required. Dissemination is planned via presentation at relevant conferences in addition to publication in peer-reviewed journals.PROSPERO registration numberCRD42020220221.

Development and validation of a patient-reported scale for tolerability of endoscopic procedures using conscious sedation

BACKGROUND AND AIMS

Patient-reported experience measures (PREMs) assessing the tolerability of endoscopic procedures are scarce. In this study, we designed and validated a PREM to assess tolerability of endoscopy using conscious sedation.

METHODS

The patient-reported scale for tolerability of endoscopic procedures (PRO-STEP) consists of questions within 2 domains and is administered to outpatients at discharge from the endoscopy unit. Domain 1 (intraprocedural) consists of 2 questions regarding discomfort/pain and awareness, whereas domain 2 (postprocedural) consists of 4 questions on pain, nausea, distention, and either throat or anal pain. All questions are scored on a Likert scale from 0 to 10. Cronbach's alpha was used to measure internal consistency of the questions. Multivariable logistic regression was performed to assess predictors of higher scores, reported using adjusted odds ratios and confidence intervals.

RESULTS

Two hundred fifty-five patients (91 colonoscopy, 73 gastroscopy, and 91 ERCP) were included. Colonoscopy was the least tolerable procedure by recall, with mean intraprocedural awareness and discomfort scores of 5.1 ± 3.8, and 2.6 ± 2.7, respectively. Consistency between intraprocedural awareness and discomfort/pain yielded an acceptable Cronbach's alpha of .71 (95% confidence interval, .62-.78). Higher use of midazolam during colonoscopy was inversely associated with an intraprocedural awareness score of 7 or higher (per additional mg: adjusted odds ratio, .23; 95% confidence interval, .09-.54).

CONCLUSIONS

PRO-STEP is a simple PREM that can be administered after multiple endoscopic procedures using conscious sedation. Future work should focus on its performance characteristics in adverse event prediction.

Development and validation of a risk prediction model for high-risk adenomas at the time of first screening colonoscopy among screening aged Canadians

The aim of this study was to develop a risk prediction model for high risk adenomas (HRAs) detected at screening colonoscopy based on readily available participant information. The cohort consisted of 3035 participants aged 50 to 74 years with no history of cancer who underwent a primary screening colonoscopy at a centralized colon cancer screening centre between 2008 and 2016. A multivariable logistic regression model was created using CRC risk factors identified from prior research. Model covariates were collected from a baseline questionnaire and included participant demographics (age and sex), lifestyle parameters (body mass index, alcohol, smoking, and vitamin D supplement use) and medical history (family history of CRC and diabetes). Mean participant age was 58.8 years, and 54.7% were male. 249 participants with HRAs were identified (8.2%). An adjusted c-statistic of 0.67 was calculated, and a specificity and negative predictive value of 97.2% (95% CI: 96.5-97.8) and 92.5% (95% CI: 92.2-92.8) for the detection of HRAs, respectively, were achieved using 20% predicted probability as a high-risk threshold. However, only a sensitivity of 12.1% (95% CI: 8.3-16.8) was achieved. Our model has moderate predictive ability, with strengths in being able to rule out those with an absence of HRAs on screening colonoscopy. Maximizing screening efficiency through improved risk prediction can enhance resource allocation. Ultimately, this model has the potential to improve patient care by reducing unnecessary colonoscopies, limiting this invasive procedure to those most likely to have significant findings.

The impact of episodic screening interruption: COVID-19 and population-based cancer screening in Canada

BACKGROUND

Population-based cancer screening can reduce cancer burden but was interrupted temporarily due to the COVID-19 pandemic. We estimated the long-term clinical impact of breast and colorectal cancer screening interruptions in Canada using a validated mathematical model.

METHODS

We used the OncoSim breast and colorectal cancers microsimulation models to explore scenarios of primary screening stops for 3, 6, and 12 months followed by 6-24-month transition periods of reduced screening volumes. For breast cancer, we estimated changes in cancer incidence over time, additional advanced-stage cases diagnosed, and excess cancer deaths in 2020-2029. For colorectal cancer, we estimated changes in cancer incidence over time, undiagnosed advanced adenomas and colorectal cancers in 2020, and lifetime excess cancer incidence and deaths.

RESULTS

Our simulations projected a surge of cancer cases when screening resumes. For breast cancer screening, a three-month interruption could increase cases diagnosed at advanced stages (310 more) and cancer deaths (110 more) in 2020-2029. A six-month interruption could lead to 670 extra advanced cancers and 250 additional cancer deaths. For colorectal cancers, a six-month suspension of primary screening could increase cancer incidence by 2200 cases with 960 more cancer deaths over the lifetime. Longer interruptions, and reduced volumes when screening resumes, would further increase excess cancer deaths.

CONCLUSIONS

Interruptions in cancer screening will lead to additional cancer deaths, additional advanced cancers diagnosed, and a surge in demand for downstream resources when screening resumes. An effective strategy is needed to minimize potential harm to people who missed their screening.

Characteristics and Outcomes of ERCP at a Canadian Tertiary Centre: Initial Results from a Prospective High-Fidelity Biliary Endoscopy Registry

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) is an essential procedure in the management of pancreatic and biliary disease. While its role is firmly established, further well-designed prospective ERCP research is required, as a large portion of previous work has employed retrospective or administrative methodologies, both prone to potential biases. The aim of the Calgary Registry for Advanced and Therapeutic Endoscopy (CReATE) is to be a high-fidelity prospective multicentre registry.

METHODS

The study population consisted of consecutive adult ERCP patients from September 2018 to September 2019. Informed consent was acquired for each patient. All relevant preprocedural, procedural, peri-procedural and postprocedural data were captured in real time by a full-time third-party research assistant directly observing procedures. Outcomes were ascertained by comprehensive medical record review and patient phone interview 30 days after the index procedure.

RESULTS

Five endoscopists performed 895 ERCP procedures, 90.1% of which were deemed successful. Suspected choledocholithiasis was the most common indication for ERCP, followed by suspected or confirmed stricture(s), at 61.0% and 29.5%, respectively. 61.0% of procedures were performed on ERCP-naive patients. Post-ERCP pancreatitis occurred following 4.9% of procedures, with clinically significant bleeding or perforation occurring following 1.8% and 0.1% of procedures, respectively.

DISCUSSION

Through 12 months, CReATE captured 895 procedures prospectively, with each entry containing over 300 data fields. Active expansion to additional tertiary centres is underway, and this will enhance the existing data pool. CReATE has the potential to improve multiple facets of ERCP, including training, optimal procedural techniques, mitigation of adverse events and personalized patient care.

Prophylactic clipping to prevent delayed colonic post-polypectomy bleeding: meta-analysis of randomized and observational studies

BACKGROUND AND AIMS

Delayed post-polypectomy bleeding (DPPB) is a commonly described adverse event following polypectomy. Prophylactic clipping may prevent DPPB in some patient subgroups. We performed a meta-analysis to assess both the efficacy and real-world effectiveness of prophylactic clipping.

METHODS

We performed a database search through March 2020 for clinical trials or observational studies assessing prophylactic clipping and DPPB. Pooled risk ratios (RR) were calculated using random effects models. Subgroup, sensitivity, and meta-regression analyses were performed to elucidate clinical or methodological factors associated with effects on outcomes.

RESULTS

A total of 2771 citations were screened, with 11 randomized controlled trials (RCTs) and 9 observational studies included, representing 24,670 colonoscopies. DPPB occurred in 2.0% of patients overall. The pooled RR of DPPB was 0.47 (95% CI 0.29-0.77) from RCTs enrolling only patients with polyps ≥ 20 mm. Remaining pooled RCT data did not demonstrate a benefit for clipping. The pooled RR of DPPB was 0.96 (95% CI 0.61-1.51) from observational studies including all polyp sizes. For patients with proximal polyps of any size, the RR was 0.73 (95% CI 0.33-1.62) from RCTs. Meta-regression confirmed that polyp size ≥ 20 mm significantly influenced the effect of clipping on DPPB.

CONCLUSION

Pooled evidence demonstrates a benefit when clipping polyps measuring ≥ 20 mm, especially in the proximal colon. In lower-risk subgroups, prophylactic clipping likely results in little to no difference in DPPB.

A116 PROPHYLACTIC CLIPPING TO PREVENT DELAYED COLONIC POST-POLYPECTOMY BLEEDING: META-ANALYSIS OF RANDOMIZED AND OBSERVATIONAL STUDIES

Background

Delayed post-polypectomy bleeding (DPPB) is a commonly described adverse event following polypectomy. Prophylactic clipping may prevent DPPB in some patient subgroups. We performed a meta-analysis to assess both the efficacy and real-world effectiveness of prophylactic clipping.

Aims

We performed a meta-analysis to assess both the efficacy and real-world effectiveness of prophylactic clipping.

Methods

We performed a database search through March 2020 for clinical trials or observational studies assessing prophylactic clipping and DPPB. Pooled risk ratios (RR) were calculated using random effects models. Subgroup, sensitivity and meta-regression analyses were performed to elucidate clinical or methodological factors associated with effects on outcomes.

Results

A total of 2,771 citations were screened, with 11 randomized controlled trials (RCTs) and 9 observational studies included, representing 24,670 colonoscopies. DPPB occurred in 2.0% of patients overall. The pooled RR of DPPB was 0.47 (95% CI 0.29 – 0.77) from RCTs enrolling only patients with polyps ≥ 20 mm. Remaining pooled RCT data did not demonstrate a benefit for clipping. The pooled RR of DPPB was 0.96 (95% CI 0.61 – 1.51) from observational studies including all polyp sizes. For patients with proximal polyps of any size, the RR was 0.73 (95% CI 0.33 - 1.62) from RCTs. Meta-regression confirmed that polyp size ≥ 20 mm significantly influenced the effect of clipping on DPPB.

Conclusions

Pooled evidence demonstrates a benefit when clipping polyps measuring ≥ 20 mm, especially in the proximal colon. In lower-risk subgroups, prophylactic clipping should not be performed.

Funding Agencies

None

Association of a Shortened Duration of Adjuvant Chemotherapy With Overall Survival Among Individuals With Stage III Colon Cancer

IMPORTANCE

Several real-world oncology studies have produced findings that contradict those from randomized clinical trials. Such disparities may be associated with methodological shortcomings.

OBJECTIVE

To examine the association between a shortened duration of adjuvant chemotherapy among individuals with stage III colon cancer using real-world data.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness study included individuals diagnosed with stage III colon cancer between January 2004 and December 2015 who initiated adjuvant chemotherapy at oncology clinics within the province of Alberta, Canada. Patients were identified through record linkage of various administrative databases and were followed up until September 2017. Eligibility criteria were modeled after those used in the International Duration Evaluation of Adjuvant (IDEA) trial. A target trial emulation and naive observational analysis were conducted. Results from both cohorts were benchmarked against findings from the IDEA trial. Data analysis was conducted from March to December 2020.

EXPOSURE

A shortened duration of adjuvant 5-fluorouracil/leucovorin plus oxaliplatin (FOLFOX) or capecitabine plus oxaliplatin (CAPOX) chemotherapy, defined as 3 to 5 months of treatment vs 6 months.

MAIN OUTCOMES AND MEASURES

Overall survival assessed via vital statistics. The per-protocol hazard ratio (HR) was estimated using a weighted pooled logistic regression model. Subgroup analyses were conducted by treatment regimen (ie, FOLFOX vs CAPOX) and cancer stage (ie, T1-3 and N1 vs T4 or N2).

RESULTS

From an initial cohort of 3086 patients, 485 (16%) were eligible for inclusion in the target trial analysis. The median age was 59 years (range, 19-81 years), and 230 (47%) were women. The maximum follow-up was 11.6 years. Median overall survival was not reached. A total of 90 patients (19%) died. The 5-year Kaplan Meier overall survival estimate was 0.79 (95% CI, 0.75-0.84). Estimates from the trial emulation were similar to those from the IDEA trial. For example, a shortened duration of adjuvant chemotherapy was not associated with overall survival among patients prescribed CAPOX in the IDEA trial (HR, 0.96; 95% CI, 0.85-1.08) or in the trial emulation (HR, 0.96; 95% CI, 0.43-2.14). In contrast, the naive observational analysis suggested that a shortened duration of CAPOX was significantly associated with worse survival (HR, 3.33; 95% CI, 1.04-10.65).

CONCLUSIONS AND RELEVANCE

In this study, the explicit emulation of a target trial better approximated results from an analogous well-conducted randomized clinical trial.

Cohort profile: The Forzani & MacPhail Colon Cancer Screening Centre biorepository, Calgary, Alberta

PURPOSE

The Colon Cancer Screening Centre (CCSC) biorepository (Calgary, Canada) supports a wide range of research topics related to colorectal cancer (CRC) by collecting, and storing biospecimens (blood, urine, normal colon tissue) from consenting patient participants. Housing unique biospecimens along with detailed participant lifestyle and health history questionnaire data, the CCSC biorepository can support a variety of research related to CRC risk factors, biomarkers, genetic causes and more.

PARTICIPANTS

Currently, 2292 average risk CRC patients have consented to participate in the CCSC cohort and have provided stored biospecimens. The collected samples and data provide important high-quality materials for research, discovery and evaluation related to CRC screening and carcinogenesis and is available for access by outside researchers. In addition to biological samples, the CCSC collects detailed patient information on their lifestyle, physical activity and dietary patterns through questionnaires at the time of their enrolment.

FINDINGS TO DATE

The majority of participants (75%) are between 50 and 64 years of age. Women make up 46% (1055) of the cohort. Additional characteristics of the cohort included 44% reporting a body mass index of 25-30 kg/m² (overweight), 53% having never smoked tobacco and 13% having a family member with CRC.

FUTURE PLANS

The CCSC cohort plans to include the recruitment of high risk CRC cohorts. High-risk participants would comprise patients with a positive faecal immunochemical test and family history of CRC.

Morphology of the major papilla predicts ERCP procedural outcomes and adverse events

BACKGROUND

The morphology of the major papilla affects the difficulty of endoscopic retrograde cholangiopancreatography (ERCP), but no associations with adverse events have previously been established. We aimed to assess whether papillary morphology predicts ERCP adverse events.

METHODS

A retrospective analysis was performed of a prospective registry of patients undergoing ERCP for biliary indications. The primary outcome was post-ERCP pancreatitis (PEP), with secondary outcomes including other adverse events and procedural outcomes such as inadvertent pancreatic duct cannulation, cannulation time, and attempts. Papillae were classified as normal (Type I), small or flat (Type II), bulging (Type IIIa), pendulous (Type IIIb), creased (Type IV), or peri-diverticular (Type D). Outcomes were ascertained prospectively at 30 days from index procedures.

RESULTS

A total of 637 patients with native papillae were included. Compared to Type I papillae, Type II and Type IIIb papillae were associated with PEP, with adjusted odds ratios (AOR) of 7.28 (95% confidence intervals, CI, 1.84-28.74) and 4.25 (95% CI 1.26-14.32), respectively. Type II and IIIb papillae were associated with significantly longer cannulation times by 5.37 (95% CI 2.39-8.35) and 4.01 (95% CI 1.72-6.30) minutes, respectively. Type IIIb papillae were associated with lower deep cannulation success (AOR 0.17, 95% CI 0.06-0.48).

CONCLUSION

Papillary morphology is an important factor influencing both ERCP success and outcomes. Understanding this is key for managing intraprocedural approaches and minimizing adverse events.

PROSPECTIVE REGISTRY REGISTRATION

Clinicaltrials.gov identifier NCT04259580.

Associations between endoscopist feedback and improvements in colonoscopy quality indicators: a systematic review and meta-analysis

BACKGROUND AND AIMS

Colonoscopy quality indicators such as adenoma detection rate (ADR) are surrogates for the effectiveness of screening-related colonoscopy. It is unclear whether endoscopist feedback on these indicators improves performance. We performed a meta-analysis to determine whether associations exist between endoscopist feedback and colonoscopy performance.

METHODS

We conducted a search through May 2019 for studies reporting on endoscopist feedback and associations with ADR or other colonoscopy quality indicators. Pooled rate ratios (RRs) and weighted mean differences were calculated using DerSimonian and Laird random effects models. Subgroup, sensitivity, and meta-regression analyses were performed to assess for potential methodological or clinical factors associated with outcomes.

RESULTS

From 1326 initial studies, 12 studies were included in the meta-analysis for ADR, representing 33,184 colonoscopies. Endoscopist feedback was associated with an improvement in ADR (RR, 1.21; 95% confidence interval [CI], 1.09-1.34). Low performers derived a greater benefit from feedback (RR, 1.62; 95% CI, 1.18-2.23) compared with moderate performers (RR, 1.19; 95% CI, 1.11-1.29), whereas high performers did not derive a significant benefit (RR, 1.06; 95% CI, 0.99-1.13). Feedback was not associated with increases in withdrawal time (weighted mean difference, +0.43 minutes; 95% CI, -0.50 to +1.36 minutes) or improvements in cecal intubation rate (RR, 1.00; 95% CI, 0.99-1.01).

CONCLUSION

Endoscopist feedback is associated with modest improvements in ADR. The implementation of routine endoscopist audit and feedback should be considered alongside other quality improvement interventions in institutions dedicated to the provision of high-quality screening-related colonoscopy.

Development of a Model for Predicting Early Discontinuation of Adjuvant Chemotherapy in Stage III Colon Cancer

PURPOSE

To develop a tool that can be used to predict early discontinuation of adjuvant chemotherapy among patients with stage III colon cancer.

PATIENTS AND METHODS

Through record linkage of Alberta administrative and tumor registry databases, we identified a cohort of individuals age ≥ 18 years who were diagnosed with stage III colon cancer and who received adjuvant chemotherapy in Alberta between 2004 and 2015. Early discontinuation was defined as receipt of < 5 months of a planned 6-month course of chemotherapy. By a systematic review of the literature and a survey of medical oncologists, the following candidate variables were identified: age (years), number of comorbidities (0, 1, ≥ 2), cancer stage (IIIC v IIIA-B), type of chemotherapy (fluorouracil, leucovorin, and oxaliplatin; capecitabine and oxaliplatin; or monotherapy), time from surgery to chemotherapy initiation (weeks), type of treatment facility (academic or community), and distance from home to treatment center (kilometers). Models developed using penalized logistic regression and the random forest algorithm were compared. Model performance was assessed using the C-statistic, Brier score, and a calibration plot. Internal validation was performed using the bootstrap method.

RESULTS

From an initial 3,115 patients identified, 1,378 were deemed eligible for inclusion. Of these patients, 474 patients (34.4%) failed to complete at least 5 months of chemotherapy. Although well calibrated, the penalized logistic regression model had poor discrimination (optimism-adjusted C-statistic, 0.63; 95% CI, 0.60 to 0.67). In contrast, the random forest model achieved adequate discrimination (optimism-adjusted C-statistic, 0.80; 95% CI, 0.79 to 0.82). Although the degree of calibration of the random forest was acceptable, it was slightly worse than that of the penalized logistic regression model.

CONCLUSION

Internal validation of our random forest model suggests that it may have clinical utility. Additional research regarding its external validation and clinical impact is needed.

Association Between Time to Colonoscopy After Positive Fecal Testing and Colorectal Cancer Outcomes: A Systematic Review

BACKGROUND & AIMS

Colonoscopy is required following a positive fecal screening test for colorectal cancer (CRC). It remains unclear to what extent time to colonoscopy is associated with CRC-related outcomes. We performed a systematic review to elucidate this relationship.

METHODS

An electronic search was performed through April 2020 for studies reporting associations between time from positive fecal testing to colonoscopy and outcomes including CRC incidence (primary outcome), CRC stage at diagnosis, and/or CRC-specific mortality. Our primary objective was to quantify these relationships following positive fecal immunochemical testing (FIT). Two authors independently performed screening, abstraction, and risk of bias assessments.

RESULTS

From 1,612 initial studies, 8 were included in the systematic review, with 5 reporting outcomes for FIT. Although meta-analysis was not possible, consistent trends between longer time delays and worse outcomes were apparent in all studies. Colonoscopy performed beyond 9 months from positive FIT compared to within 1 month was significantly associated with a higher incidence of CRC, with adjusted odds ratios (AORs) of 1.75 and 1.48 in the two largest studies. These studies also reported significant associations between colonoscopy performed beyond 9 months and higher incidence of advanced stage CRC (stage III or IV) at diagnosis, with AORs of 2.79 and 1.55, respectively.

CONCLUSIONS

Colonoscopy for positive FIT should not be delayed beyond 9 months. Given the additional time required for urgent referrals and surgical planning for CRC, colonoscopy should ideally be performed well in advance of 9 months following a positive FIT.

Educational interventions are associated with improvements in colonoscopy quality indicators: a systematic review and meta-analysis

Background and study aims  The quality of screening-related colonoscopy depends on several physician- and patient-related factors. Adenoma detection rate (ADR) varies considerably between endoscopists. Educational interventions aim to improve endoscopists' ADRs, but their overall impact is uncertain. We aimed to assess whether there is an association between educational interventions and colonoscopy quality indicators. Methods  A comprehensive search was performed through August 2019 for studies reporting any associations between educational interventions and any colonoscopy quality indicators. Our primary outcome of interest was ADR. Two authors assessed eligibility criteria and extracted data independently. Risk of bias was also assessed for included studies. Pooled rate ratios (RR) with 95 % confidence intervals (CI) were reported using DerSimonian and Laird random effects models. Results  From 2,253 initial studies, eight were included in the meta-analysis for ADR, representing 86,008 colonoscopies. Educational interventions were associated with improvements in overall ADR (RR 1.29, 95 % CI 1.25 to 1.42, 95 % prediction interval 1.09 to 1.53) and proximal ADR (RR 1.39, 95 % CI 1.29 to 1.48), with borderline increases in withdrawal time, ([WT], mean difference 0.29 minutes, 95 % CI - 0.12 to 0.70 minutes). Educational interventions did not affect cecal intubation rate ([CIR], RR 1.01, 95 % CI 1.00 to 1.01). Heterogeneity was considerable across many of the analyses. Conclusions  Educational interventions are associated with significant improvements in ADR, in particular, proximal ADR, and are not associated with improvements in WT or CIR. Educational interventions should be considered an important option in quality improvement programs aiming to optimize the performance of screening-related colonoscopy.

The incidence of young-onset colorectal cancer in Canada continues to increase

BACKGROUND

Despite decreases in the overall incidence of colorectal cancer (CRC) in Canada, a concerning increase has been observed among younger adults in recent years. The aim of this study was to update age-specific incidence trends of CRC from 1971 to 2017 in Canada.

METHODS

Data was obtained from the National Cancer Incidence Reporting System and the Canadian Cancer Registry. Age-specific annual percent changes in the incidence of CRC was estimated using NCI's Joinpoint Regression Program.

RESULTS

The incidence of CRC among adults over age 50 has continued to decrease, while the incidence among adults under the age of 50 has continued to rise. The largest increases have occurred among 20-29 and 30-39 age groups for colon and rectal cancers, respectively.

CONCLUSION

The incidence of CRC among young adults, particularly those under 40, continues to increase among men and women in Canada. Studies examining potential risk factors for young-onset CRC are required.

Association Between Endoscopist Annual Procedure Volume and Colonoscopy Quality: Systematic Review and Meta-analysis

BACKGROUND & AIMS

In addition to monitoring adverse events (AEs) and post-colonoscopy colorectal cancers (PCCRC), indicators for assessing colonoscopy quality include adenoma detection rate (ADR) and cecal intubation rate (CIR). It is unclear whether there is an association between annual colonoscopy volume and ADR, CIR, AEs, or PCCRC.

METHODS

We searched publication databases through March 2019 for studies assessing the relationship between annual colonoscopy volume and outcomes, including ADR, CIR, AEs, or PCCRC. Pooled odds ratios (ORs) were calculated using DerSimonian and Laird random effects models. Sensitivity analyses were performed to assess for potential methodological or clinical factors associated with outcomes.

RESULTS

We performed a systematic review of 9235 initial citations, generating 27 retained studies comprising 11,276,244 colonoscopies. There was no association between procedural volume and ADR (OR, 1.00; 95% CI, 0.98-1.02 per additional 100 annual procedures). CIR improved with each additional 100 annual procedures (OR, 1.17; 95% CI, 1.08-1.28). There was a non-significant trend toward decreased overall AEs per additional 100 annual procedures (OR, 0.95; 95% CI, 0.90-1.00). There was considerable heterogeneity among most analyses.

CONCLUSIONS

In a systematic review and meta-analysis, we found higher annual colonoscopy volumes to correlate with higher CIR, but not with ADR or PCCRC. Trends toward fewer AEs were associated with higher annual colonoscopy volumes. There are few data available from endoscopists who perform fewer than 100 annual colonoscopies. Studies are needed on extremes in performance volumes to more clearly elucidate associations between colonoscopy volumes and outcomes.

Development of a definition and rules for causal attribution of post-colonoscopy bleeding

Background

Post-colonoscopy bleeding (PCB) is an important colonoscopy quality indicator that is recommended to be routinely collected by colorectal cancer screening programs and endoscopy quality improvement programs. We created a standardized and reliable definition of PCB and set of rules for attributing the relatedness of PCB to a colonoscopy.

Methods

PCB events were identified from colonoscopies performed at the Forzani & MacPhail Colon Cancer Screening Centre. Existing definitions and relatedness rules for PCB were reviewed by the authors and a draft definition and set of rules was created. The definition and rules were revised after initial testing was performed using a set of 15 bleeding events. Information available for each event included the original endoscopy report and data abstracted from the emergency or inpatient record by a trained research assistant. A validation set of 32 bleeding events were then reviewed to assess their interrater reliability by having three endoscopists and one research assistant complete independent reviews and three endoscopists complete a consensus review. The Kappa statistic was used to measure interrater reliability.

Results

The panel classified 28 of 32 events as meeting the definition of PCB and rated 7, 8 and 6 events as definitely, probably and possibly related to the colonoscopy, respectively. The Kappa for the definition of PCB for the three independent reviews was 0.82 (substantial agreement). The Kappa for the attribution of the PCB to the colonoscopy by the three endosocopists was 0.74 (substantial agreement). The research assistant had a high agreement with the panel for both the definition (100% agreement) and application of the causal criteria (kappa 0.95).

Conclusions

A standardized definition of PCB and attribution rules achieved high interrater reliability by endoscopists and a non-endoscopist and provides a template of required data for event adjudication by screening and quality improvement programs.

Prophylactic Endoscopic Clipping Does Not Prevent Delayed Postpolypectomy Bleeding in Routine Clinical Practice: A Propensity Score-Matched Cohort Study

INTRODUCTION

Delayed postpolypectomy bleeding (DPPB) is a relatively common adverse event. Evidence is conflicting on the efficacy of prophylactic clipping to prevent DPPB, and real-world effectiveness data are lacking. We aimed to determine the effectiveness of prophylactic clipping in preventing DPPB in a large screening-related cohort.

METHODS

We manually reviewed records of patients who underwent polypectomy from 2008 to 2014 at a screening facility. Endoscopist-, patient- and polyp-related data were collected. The primary outcome was DPPB within 30 days. All unplanned healthcare visits were reviewed; DPPB cases were adjudicated by committee using a criterion-based lexicon. Multivariable logistic regression was performed, yielding adjusted odds ratios (AORs) for the association between clipping and DPPB. Secondary analyses were performed on procedures where one polyp was removed, in addition to propensity score-matched and subgroup analyses.

RESULTS

In total, 8,366 colonoscopies involving polypectomy were analyzed, yielding 95 DPPB events. Prophylactic clipping was not associated with reduced DPPB (AOR 1.27; 0.83-1.96). These findings were similar in the single-polyp cohort (n = 3,369, AOR 1.07; 0.50-2.31). In patients with one proximal polyp ≥20 mm removed, there was a nonsignificant AOR with clipping of 0.55 (0.10-2.66). Clipping was not associated with a protective benefit in the propensity score-matched or other subgroup analyses.

DISCUSSION

In this large cohort study, prophylactic clipping was not associated with lower DPPB rates. Endoscopists should not routinely use prophylactic clipping in most patients. Additional effectiveness and cost-effectiveness studies are required in patients with proximal lesions ≥20 mm, in whom there may be a role for prophylactic clipping.

Low Incidence of Aerodigestive Cancers in Patients With Negative Results From Colonoscopies, Regardless of Findings From Multitarget Stool DNA Tests

BACKGROUND & AIMS

We aimed to compare the incidence of aerodigestive cancers in persons with negative results from colonoscopies and positive vs negative results from multitarget stool DNA tests for colorectal cancer and vs expected incidence.

METHODS

We performed a retrospective cohort study of 1216 subjects with comprehensive patient records and/or cancer registry data from 3 medical centers in North America. Subjects had no neoplasia or only nonadvanced adenomas, based on screening colonoscopy, and either negative results (concordant with colonoscopy, n = 1011) or positive results (discordant colonoscopy, n = 205) from the multitarget stool DNA test. Outcomes included aerodigestive cancers in discordant vs concordant groups and comparison of observed aerodigestive cancer incidence between the groups and compared with expected incidence for the population, based on the Surveillance, Epidemiology, and End Results (SEER) data.

RESULTS

Median follow-up times were comparable between subjects in the discordant (5.3 y; interquartile range, 3.5-5.8 y) and concordant (5.4 y; interquartile range, 3.7-5.8 y) groups. Aerodigestive cancers developed in 5 subjects in the discordant group vs 11 subjects in the concordant group (crude risk ratio, 2.3; 95% CI, 0.8-6.6; adjusted risk ratio, 2.2; 95% CI, 0.8-6.2; P = .151). The incidence of aerodigestive cancer was lower in the concordant group than the expected incidence based on SEER data (risk ratio, 0.4; 95% CI, 0.2-0.6; P = .0008). The incidence of aerodigestive cancer was not significantly greater in the population in the discordant group than the expected incidence based on SEER data (risk ratio, 0.8; 95% CI, 0.3-1.9; P = .599).

CONCLUSIONS

In a retrospective study with a median follow-up time of 5.4 years, incident aerodigestive cancers were uncommon among subjects with negative findings from colonoscopies, regardless of discordant or concordant results from multitarget stool DNA tests. Patients with negative results from high-quality colonoscopies therefore should not undergo further testing.

A20 VITAMIN D SUPPLEMENTATION REDUCES THE OCCURRENCE OF COLORECTAL POLYPS IN HIGH-LATITUDE LOCATIONS

Background

There is suggestive evidence for the role of vitamin D in the development of colorectal cancer (CRC). Furthermore, previous studies have observed associations with vitamin D supplementation and lower incidence of CRC. Due to high latitudes in Canada, many Canadians are vitamin D deficient throughout winter

Aims

In this analysis, we aimed to examine the association between either vitamin D supplement use or meeting the reccommended daily intake of vitamin D, and either any colorectal polyp, or a known precursor of CRC: high-risk adenomatous polyps (HRAPs).

Methods

The study population was drawn from the biorepository at the Forzani & MacPhail Colon Cancer Screening Centre (CCSC) in Calgary. Data were obtained from the Diet History Questionnaire (DHQ) I or II, the Health and Lifestyle Questionnaire (HLQ), and through post-colonoscopy reports completed by the endoscopist. Multivariable logistic regression models were used to examine the association between intake of supplemental vitamin D and presence of HRAPs. Models were adjusted for age, sex, BMI, fiber intake, alcohol consumption, and smoking status.

Results

Individuals between the age of 50 and 74 years (n= 1,409) were included. When examining the association between any supplemental vitamin D use and HRAPs, a protective effect was observed with an ORadj of 0.57 (95% CI: 0.33–0.96). Similarly, meeting the recommended daily intake (RDI) of vitamin D (600 IU) was protective against HRAPs with an ORadj of 0.78 (95% CI: 0.62–0.99).

Conclusions

This study suggests that adequate vitamin D supplementation can reduce the risk of HRAPs. These results could be used to inform public health recommendations for vitamin D intake with hopes of reducing the risk of HRAPs.

Funding Agencies

None

A147 ENDOSCOPIST FEEDBACK IS ASSOCIATED WITH IMPROVEMENTS IN COLONOSCOPY QUALITY INDICATORS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

Colonoscopy quality indicators such as adenoma detection rate (ADR) are surrogates for the effectiveness of screening-related colonoscopy. Endosocpist feedback may be associated with improvements in ADR and other quality indicators.

Aims

To conduct a systematic review and meta-analysis to determine whether an association exists between endoscopist feedback and improvements in colonoscopy quality indicators.

Methods

An electronic and manual search was conducted through May 2019 for studies reporting on endoscopist feedback and associations with ADR or other colonoscopy quality indicators. Studies primarily assessing the effect of audit and feedback on trainees and studies that included interventions other then feedback were excluded from the analysis. Pooled rate ratios (RR) and weighted mean differences (WMD) were calculated using DerSimonian and Laird random effects models. Subgroup, sensitivity and meta-regression analyses were performed to assess for potential methodological or clinical factors associated with outcomes.

Results

Of 1,326 initial studies, 12 studies were included in the meta-analysis for ADR, representing 33,184 colonoscopies. Endoscopist feedback was associated with an improvement in ADR (RR 1.21, 95% confidence interval, CI, 1.09 to 1.34). Low performers derived a greater benefit from feedback (RR 1.62, 95% CI 1.18 to 2.23) compared to moderate performers (RR 1.19, 95% CI 1.11 to 1.29), while high performers did not derive a significant benefit (RR 1.06, 95% CI 0.99 to 1.13). Feedback was not associated with increases in withdrawal time (WMD +0.43 minutes, 95% CI -0.50 to +1.36 minutes) or improvements in cecal intubation rate (RR 1.00, 95% CI 0.99 to 1.01).

Conclusions

Endoscopist feedback is associated with modest improvements in ADR. Routine audit and feedback may be a feasible strategy to optimize outcomes in screening colonoscopy.

Funding Agencies

None

A2 THE BOWEL CLEANSING NATIONAL INITIATIVE (BCLEAN): PREDICTORS OF INADEQUATE BOWEL PREPARATION

Background

Adequate bowel cleansing before colonoscopy is, in theory, a simple concept but the high rate of inadequate or incomplete bowel cleanliness and its consequences have been the subject of many studies, guidelines, and meta- analyses. The complexity resides in all the pre-endoscopic factors surrounding preparation intake that may? influence quality of the bowel preparation.

Aims

To identify preendoscopic variables associated with inadequate bowel preparation

Methods

In this randomized trial conducted in adult outpatients in 10 Canadian hospitals, all early morning (AM) colonoscopies were scheduled between 7h30AM and 10h30AM and patients were randomized to PEG low volume or high- volume split-dose or high- volume day before. Later colonoscopies (PM) were scheduled between 10h30AM and 16h30PM and patients were randomized to PEG low-volume or high- volume split-dose or low- volume same day. A secondary random allocation assigned patients to a clear fluid or low residue diet. Inadequate bowel preparation was identified on the Boston Bowel Preparation Scale with a total score &lt;6 with any of the 3 colonic segments subscores &lt;2). All preendoscopic variables such as patients related factors, diet and type of bowel preparation were evaluated between groups with chi-square, Fisher’s exact or t-test where appropriate. All variables found to be significantly associated with a clean preparation on univariable analysis at the P=0.15 level were used to construct a multivariable model. Because of stratified randomization by time with possible resulting differing confounders, AM and PM patients were analysed separately.

Results

Over 29 months, 1726 patients were stratified in the AM group and 1750 patients in the PM group. 16.9% had inadequate bowel preparation in the AM group and 9.8% in the PM group. Pre-endoscopic variables associated with an inadequate bowel cleanliness in AM colonoscopy were a non screening indication (OR 1.36, 95%CI 1.04–1.78), a Charlson score&gt;0 (OR 1.36, 95% 1.03–1.80) and a low residue diet (OR 1.53, 95%CI 1.17–2.01). Amongst PM colonoscopies, variables associated with an inadequate bowel cleanliness were increased age (OR 1.03, 95% 1.01–1.04), a non screening indication (OR 1.90 95%CI 1.35–2.70); a Charlson score&gt;0 (OR 1.63, 95%CI 1.15–2.32), and a low residue diet (OR 1.41, 95%CI 1.01; 1.98).

Conclusions

In this large randomized trial, amongst patients undergoing an AM colonoscopy, pre- endoscopic factors associated with an inadequate bowel preparation were a non screening indication, comorbidities and a low residue diet. Amongst PM colonoscopy patients, in addition to these variables, an increased age was also associated with an inadequate bowel preparation.

Funding Agencies

received arm-length funding from Pendopharm Inc.

A141 ENDOSCOPIST PROCEDURAL VOLUME AND COLONOSCOPY OUTCOMES: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

In addition to monitoring adverse events (AEs) and post-colonoscopy colorectal cancers (PCCRC), several indicators are used to assess the overall quality of colonoscopy performance, including adenoma detection rate (ADR) and cecal intubation rate (CIR). It is unclear whether there is an association between an endoscopist’s annual colonoscopy volumes and ADR, CIR, AEs or PCCRC.

Aims

We performed a systematic review and meta-analysis to determine whether there is an association between annual colonoscopy volume and colonoscopy quality indicators, or between annual volume and colonoscopy outcomes.

Methods

A comprehensive electronic search was performed through March of 2019 for any studies assessing the potential association between annual colonoscopy volume and outcomes, or quality indicators, including ADR, CIR, AEs or PCCRC. Pooled odds ratios (OR) were calculated using DerSimonian and Laird random effects models. Subgroup and sensitivity analyses were also performed to assess for any potential methodological or clinical factors associated with outcomes. These included dividing procedural volume into total procedures or screening procedures performed.

Results

Out of an initial 9,235 studies, 27 were included in our systematic review, representing 11,276,244 colonoscopies performed by over 530 endoscopists. There was no association between procedural volume and ADR (OR 1.00, 95% confidence intervals, CI, 0.98 to 1.02 per additional 100 annual total colonoscopy procedures performed by an endoscopist). CIR was improved with each additional 100 annual colonoscopy procedures (OR 1.17, 95% CI 1.08 to 1.28). There was a trend toward decreased overall adverse events per additional 100 annual procedures that did not meet significance (OR 0.95, 95% CI 0.90 to 1.00), although there was a decreased incidence of colonic perforations with increasing colonoscopy volume. Figure 1 - Forest plots demonstrating the odds of A) detecting an adenoma, B) intubating the cecum, and C) incurring an overall or specific adverse event, per additional 100 annual procedures, for total and screening procedures.

Conclusions

In this meta-analysis, higher annual colonoscopy volumes correlated with higher CIR, but not with ADR or PCCRC. Trends toward lower AE rates were also demonstrated with higher volumes. All studies included in this review examined endoscopists performing above respective recommended minimum volume thresholds for their health region. Thus, data are lacking on endoscopists performing very low numbers or very high numbers of colonoscopies annually. Future studies should focus on measuring colonoscopy quality metrics and outcomes among these extreme performers to more clearly determine associations between annual volume and colonoscopy outcomes.

Funding Agencies

Alberta Health Services Digestive Health Strategic Care Network

Prognostic factors of adjuvant chemotherapy discontinuation among stage III colon cancer patients: A survey of medical oncologists and a systematic review and meta-analysis

Background

Factors that are prognostic of early discontinuation of adjuvant chemotherapy among stage III colon cancer patients have yet to be described. To address this gap, a survey of medical oncologists and a systematic review and meta‐analysis were conducted.

Methods

A survey was distributed in March 2019 to medical oncologists who treat colon cancer within Alberta, Canada. Clinicians were asked to rank the prognostic importance of a set of variables using a Likert scale and agreement was quantified using a weighted Cohen's kappa. In addition, we systematically searched four databases up to July 2019. Meta‐analyses were conducted using a random‐effects model.

Results

Of the 25 clinicians who were sent the survey, 14 responded. Overall, there was no agreement regarding which variables were prognostic of early discontinuation (weighted Cohen's kappa = 0.12; 95% CI = 0.05‐0.18). From an initial 3927 articles, 18 investigations were identified for inclusion in our review. Based upon evidence from both the survey and the systematic review, the following four variables were identified as being prognostic of early discontinuation: (a) comorbidity (OR_{2+ vs 0} = 1.53; 95% CI = 1.30‐1.79); (b) performance status (OR_{ECOG 2+ vs 0‐1} = 1.33; 95%CI = 1.07‐1.65); (c) T stage (OR_{T4 vs T1‐2} = 1.57; 95% CI = 0.99‐2.50); and (d) chemotherapy regimen (estimates not pooled due to heterogeneity). In addition to these factors, there was some suggestion that age, marital status/social support, muscle mass, N stage, and tumor grade had prognostic value.

Conclusions

Current evidence is heterogeneous and limited. Additional research is needed to confirm our findings and to explore additional prognostic factors.

Practice patterns and predictors of prophylactic endoscopic clip usage during polypectomy

Background and study aims  Prophylactic endoscopic clips are commonly placed during polypectomy to reduce risk of delayed bleeding, although evidence to support this practice is unclear. Our study aimed to: (1) identify variables associated with prophylactic clip use; (2) explore variability between endoscopists' clipping practices and (3) study temporal trends in prophylactic clip use. Patients and methods  This was a retrospective cohort study in a high-volume unit dedicated to screening-related colonoscopies. Colonoscopies involving polypectomy from 2008 to 2014 were reviewed. The primary outcome was prophylactic clipping status, both at the patient level and per polyp. Hierarchical regression models yielded adjusted odds ratios (AORs) to determine predictors of prophylactic clipping. Results  A total of 8,366 colonoscopies involving 19,129 polypectomies were included. Polyp size ≥ 20 mm was associated with higher clip usage (AOR 2.94; 95 % CI: 2.43, 3.54) compared to polyps < 10 mm. Right-sided polyps were more likely to be clipped (AOR 2.78; 95 % CI: 2.34, 3.30) relative to the rectum. Surgeons clipped less than gastroenterologists (OR 0.52; 95 % CI: 0.44, 0.63). From 2008 to 2014, the crude proportion of prophylactically clipped cases increased by 7.4 % (95 % CI: 7.1, 7.6) from 1.9 % to 9.3 %. Significant inter-endoscopist variability in clipping practices was observed, notably, for polyps < 10 mm. Conclusions  Prophylactic clip usage was correlated with established risk factors for delayed bleeding. Significantly increased clip usage over time was shown. Given that evidence does not clearly support prophylactic clipping, there is a need to educate practitioners and limit healthcare resource utilization.

National Trends in Colorectal Cancer Incidence Among Older and Younger Adults in Canada

IMPORTANCE

Recent evidence has shown that although the incidence of colorectal cancer (CRC) is decreasing among older adults, rates have increased in adults younger than 50 years. Given that younger adults are typically classified as at low risk for the disease, this epidemiologic shift is cause for concern.

OBJECTIVE

To analyze Canadian national cancer incidence registries to determine incidence trends for CRC among older and younger adults, updated to 2015.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study determined the incidence of CRC using data from the National Cancer Incidence Reporting System (1969-1992) and the Canadian Cancer Registry (1992-2015). All Canadians diagnosed with CRC from January 1, 1969, through December 31, 2015, were included in this study. Trends among men and women were examined separately and by age category (>50 vs <50 years). Birth cohort models were fit using 5-year groups starting in 1886, with 1936 as the reference cohort. Data were analyzed from May 13, 2018 to May 16, 2018.

MAIN OUTCOMES AND MEASURES

Annualized percentage changes and incidence rate ratios of CRC.

RESULTS

From 1971 to 2015, 688 515 incident cases (52.9% women) of CRC were identified. Although the incidence of CRC has decreased in older men and women, rates among younger men and women have increased since 2006 and 2010, respectively. For women younger than 50 years, incidence has increased with a mean annual percentage change of 4.45% since 2010; for men younger than 50 years, a mean annual percentage change of 3.47% from 2006 through 2015. There was an association between CRC incidence and birth cohort, with more recent cohorts being at greater risk than those born earlier. For men, the risk of colorectal cancer in the youngest cohort is more than double that of the reference (incidence rate ratio, 2.57; 95% CI, 1.32-5.02). Incidence rate ratios were not significant for women (IRR, 2.12; 95% CI, 0.95-4.70) but increased in successively younger cohorts.

CONCLUSIONS AND RELEVANCE

This study found increasing incidence of colorectal cancer diagnoses among Canadian men and women younger than 50 years of age. This increase in incidence among a low-risk population calls for additional research on possible risk factors that may be affecting these younger cohorts. It appears that primary prevention should be the highest priority to reduce the number of younger adults developing CRC in the future.

Association Between Adjuvant Chemotherapy Duration and Survival Among Patients With Stage II and III Colon Cancer: A Systematic Review and Meta-analysis

IMPORTANCE

The results from the recent International Duration Evaluation of Adjuvant Therapy (IDEA) collaboration have led some clinicians to adopt shorter durations of adjuvant chemotherapy for patients with stage III colon cancer. The extent to which these findings are supported by other data is unknown.

OBJECTIVE

To conduct a systematic review and meta-analysis of randomized and observational studies investigating the association between the duration of adjuvant chemotherapy and survival among individuals diagnosed as having stage II and III colon cancer (PROSPERO protocol CRD42018108711]).

DATA SOURCES

Abstracts published in English between 2003 and 2018 within the MEDLINE, Embase, CENTRAL, and CINAHL databases were reviewed by 2 authors. Also searched were conference proceedings and the indexes of high-impact oncology journals.

STUDY SELECTION

Studies were excluded if they did not present original data; focused on animal populations, on cancers in sites other than the colon, or on patients with stage 0, I, or IV disease; did not examine a 5-flourouracil-based monotherapy or combination therapy; or did not evaluate the association between treatment duration and survival. The search identified 2341 articles, from which 2 randomized trials and 20 observational studies were included in the meta-analysis.

DATA EXTRACTION AND SYNTHESIS

This study followed the PRISMA and MOOSE reporting guidelines. The risk of bias was assessed by 2 authors using the Cochrane and Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tools. The results were synthesized using a random-effects model.

MAIN OUTCOMES AND MEASURES

The primary and secondary outcomes were overall survival and disease-free survival, respectively. It was hypothesized a priori that 3 months of chemotherapy would be as effective as 6 months of chemotherapy.

RESULTS

Twenty-two studies were included in the meta-analysis, representing 43 671 patients. The inclusion of patients with stage II disease or with rectal cancer was identified as a source of heterogeneity. After restricting the analysis to patients with stage III colon cancer, there was no association between the duration of chemotherapy and overall survival among studies involving FOLFOX (leucovorin calcium [folinic acid], fluorouracil, and oxaliplatin) or CAPOX (capecitabine plus oxaliplatin) regimens (hazard ratio [HR], 0.80; 95% CI, 0.58-1.09). Among studies focused exclusively on monotherapy, the standard 6-month regimen relative to a 3-month regimen was associated with improved survival (HR, 0.59; 95% CI, 0.52-0.68).

CONCLUSIONS AND RELEVANCE

Shortened durations of chemotherapy may reduce survival among patients with stage III colon cancer prescribed monotherapy but not a combination regimen.

Prediction of findings at screening colonoscopy using a machine learning algorithm based on complete blood counts (ColonFlag)

Adenomatous polyps are a common precursor lesion for colorectal cancer. ColonFlag is a machine- learning-based algorithm that uses basic patient information and complete blood cell counts (CBC) to identify individuals at elevated risk of colorectal cancer for intensified screening. The purpose of this study was to determine whether ColonFlag is also able to predict the presence of high risk adenomatous polyps at colonoscopy. This study was conducted at a large colon cancer screening center in Calgary, Alberta. The study population included asymptomatic individuals between the ages of 50 and 75 who underwent a screening colonoscopy between January 2013 and June 2015. All subjects had at least one CBC result within the year prior to colonoscopy. Based on age, sex, red blood cell parameters, inflammatory cells and platelets, the ColonFlag algorithm generated a score from 0 to 100. We compared the ability of the ColonFlag test result to discriminate between individuals who were found to have a high risk polyp and those with a normal colonoscopy. Among the 17,676 individuals who underwent a screening colonoscopy there were 1,014 found to have a high risk precancerous lesion (5.7%) and 60 were found to have colorectal cancer (0.3%). At a specificity of 95%, the odds ratio for a positive ColonFlag was 2.0 for those with an advanced precancerous lesion compared with those with a normal colonoscopy. The odds ratio did not vary according to patient subgroup, colorectal cancer location or stage. ColonFlag is a passive test that can use routine blood test results to help identify individuals at elevated risk for high risk precancerous polyps as well as frank colorectal cancer. These individuals may be targeted in an effort to achieve greater compliance with conventional screening tests.

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.