Colon Polyp Surveillance: Separating the Wheat From the Chaff.

One goal of colorectal cancer (CRC) screening is to prevent CRC incidence by removing precancerous colonic polyps, which are detected in up to 50% of screening examinations. Yet, the lifetime risk of CRC is 3.9%-4.3%, so it is clear that most of these individuals with polyps would not develop CRC in their lifetime. It is, therefore, a challenge to determine which individuals with polyps will benefit from follow-up, and at what intervals. There is some evidence that individuals with advanced polyps, based on size and histology, benefit from intensive surveillance. However, a large proportion of individuals will have small polyps without advanced histologic features (ie, "nonadvanced"), where the benefits of surveillance are uncertain and controversial. Demand for surveillance will further increase as more polyps are detected due to increased screening uptake, recent United States recommendations to expand screening to younger individuals, and emergence of polyp detection technology. We review the current understanding and clinical implications of the natural history, biology, and outcomes associated with various categories of colon polyps based on size, histology, and number. Our aims are to highlight key knowledge gaps, specifically focusing on certain categories of polyps that may not be associated with future CRC risk, and to provide insights to inform research priorities and potential management strategies. Optimization of CRC prevention programs based on updated knowledge about the future risks associated with various colon polyps is essential to ensure cost-effective screening and surveillance, wise use of resources, and inform efforts to personalize recommendations.

Multitarget Stool RNA Test for Colorectal Cancer Screening.

Importance: Noninvasive tests for colorectal cancer screening must include sensitive detection of colorectal cancer and precancerous lesions. These tests must be validated for the intended-use population, which includes average-risk individuals 45 years or older. Objective: To evaluate the sensitivity and specificity of a noninvasive, multitarget stool RNA (mt-sRNA) test (ColoSense) test compared with results from a colonoscopy. Design, Setting, and Participants: This phase 3 clinical trial (CRC-PREVENT) was a blinded, prospective, cross-sectional study to support a premarket approval application for a class III medical device. A total of 8920 participants were identified online using social media platforms and enrolled from June 2021 to June 2022 using a decentralized nurse call center. All participants completed the mt-sRNA test, which incorporated a commercially available fecal immunochemical test (FIT), concentration of 8 RNA transcripts, and participant-reported smoking status. Stool samples were collected prior to participants completing a colonoscopy at their local endoscopy center. The mt-sRNA test results (positive or negative) were compared with index lesions observed on colonoscopy. Over the course of 12 months, individuals 45 years and older were enrolled in the clinical trial using the decentralized recruitment strategy. Participants were enrolled from 49 US states and obtained colonoscopies at more than 3800 different endoscopy centers. Main Outcomes and Measures: The primary outcomes included the sensitivity of the mt-sRNA test for detecting colorectal cancer and advanced adenomas and the specificity for no lesions on colonoscopy. Results: The mean (range) age of participants was 55 (45-90) years, with 4% self-identified as Asian, 11% as Black, and 7% as Hispanic. Of the 8920 eligible participants, 36 (0.40%) had colorectal cancer and 606 (6.8%) had advanced adenomas. The mt-sRNA test sensitivity for detecting colorectal cancer was 94%, sensitivity for detecting advanced adenomas was 46%, and specificity for no lesions on colonoscopy was 88%. The mt-sRNA test showed significant improvement in sensitivity for colorectal cancer (94% vs 78%; McNemar P = .01) and advanced adenomas (46% vs 29%; McNemar P < .001) compared with results of the FIT. Conclusions and Relevance: In individuals 45 years and older, the mt-sRNA test showed high sensitivity for colorectal neoplasia (colorectal cancer and advanced adenoma) with significant improvement in sensitivity relative to the FIT. Specificity for no lesions on colonoscopy was comparable to existing molecular diagnostic tests. Trial Registration: ClinicalTrials.gov Identifier: NCT04739722.

Longitudinal assessment of colonoscopy adverse events in the prospective Cooperative Studies Program no. 380 colorectal cancer screening and surveillance cohort.

BACKGROUND AND AIMS: Data are limited regarding colonoscopy risk during long-term, programmatic colorectal cancer screening and follow-up. We aimed to describe adverse events during follow-up in a colonoscopy screening program after the baseline examination and examine factors associated with increased risk. METHODS: Cooperative Studies Program no. 380 includes 3121 asymptomatic veterans aged 50 to 75 years who underwent screening colonoscopy between 1994 and 1997. Periprocedure adverse events requiring significant intervention were defined as major events (other events were minor) and were tracked during follow-up for at least 10 years. Multivariable odds ratios (ORs) were calculated for factors associated with risk of follow-up adverse events. RESULTS: Of 3727 follow-up examinations in 1983 participants, adverse events occurred in 105 examinations (2.8%) in 93 individuals, including 22 major and 87 minor events (examinations may have had >1 event). Incidence of major events (per 1000 examinations) remained relatively stable over time, with 6.1 events at examination 2, 4.8 at examination 3, and 7.2 at examination 4. Examinations with major events included 1 perforation, 3 GI bleeds requiring intervention, and 17 cardiopulmonary events. History of prior colonoscopic adverse events was associated with increased risk of events (major or minor) during follow-up (OR, 2.7; 95% confidence interval, 1.6-4.6). CONCLUSIONS: Long-term programmatic screening and surveillance was safe, as major events were rare during follow-up. However, serious cardiopulmonary events were the most common major events. These results highlight the need for detailed assessments of comorbid conditions during routine clinical practice, which could help inform individual decisions regarding the utility of ongoing colonoscopy follow-up.

Early-Age Onset Colorectal Neoplasia in Average-Risk Individuals Undergoing Screening Colonoscopy: A Systematic Review and Meta-Analysis.

BACKGROUND & AIMS: Incidence and mortality associated with early-age onset colorectal cancer (EAO-CRC) is increasing, prompting professional society recommendations to lower the screening age in average-risk individuals. The yield of screening individuals younger than 50 years is not known. METHODS: A systematic review of 3 databases from inception through July 2020 was performed in all languages that reported colonoscopy findings in average-risk individuals younger than 50 years. The primary outcomes were EAO colorectal neoplasia (CRN) and advanced colorectal neoplasia (aCRN) prevalence. Subgroup analyses were performed based on sex, geographic location, time period, and age, including comparison with those aged 50-59 years. Generalized linear mixed model with random intercept logistic regression and fixed subgroup effects were performed. RESULTS: Of 10,123 unique articles, 17 studies published between 2002 and 2020, including 51,811 average-risk individuals from 4 continents, were included. The pooled rate of EAO-CRN was 13.7% (95% confidence interval [CI], 0.112%-0.168%) and EAO-aCRN was 2.2% (95% CI, 0.016%-0.031%). Prevalence of CRC was 0.05% (95% CI, 0.00029%-0.0008%). Rates of EAO-CRN were higher in men compared with women (relative risk, 1.71%; 95% CI, 1.49%-1.98%), and highest in the United States (15.6%; 95% CI, 12.2%-19.7%) compared with Europe (14.9%; 95% CI, 6.9%-29.3%), East Asia (13.4%; 95% CI, 10.3%-17.2%), and the Middle East (9.8%; 95% CI, 7.8%-12.2%) (P = .04) The rate of EAO-CRN in age groups 45-49 years and 50-59 years was 17.8% (95% CI, 14.5%-21.6%) and 24.8% (95% CI, 19.5%-30.8%), respectively (P = .04). The rate of EAO-aCRN in age group 45-49 years was 3.6% (95% CI, 1.9%-6.7%) and 4.2% (95% CI, 3.2%-5.7%), respectively (P = .69). CONCLUSIONS: The rate of aCRN in individuals aged 45-49 years was similar to the rate observed in individual aged 50-59 years, suggesting that expanding screening to this population could yield a similar impact on colorectal cancer risk reduction.

Increased Risk of Colorectal Cancer Tied to Advanced Colorectal Polyps: An Untapped Opportunity to Screen First-Degree Relatives and Decrease Cancer Burden.

Advanced adenomas represent a subset of colorectal polyps that are known to confer an increased risk of colorectal neoplasia to the affected individual and their first-degree relatives (FDRs). Accordingly, professional guidelines suggest earlier and more intensive screening for FDRs of those with advanced adenomas similar to FDRs of those with colorectal cancer (CRC). Although the risk to family members is less clear among patients with advanced serrated polyps, they are often considered in the same category. Unfortunately, there is a growing concern that patients, endoscopists, and primary care providers are unaware of the familial risk associated with these polyps, leaving a wide gap in screening these high-risk individuals. Herein, we propose a standardized language around advanced colorectal polyps and present a detailed review of the literature on associated familial risk. We outline the challenges to implementing the current screening recommendations and suggest approaches to overcome these limitations, including a proposed new colonoscopy quality metric to capture communication of familial CRC risk. Improving screening in these high-risk groups has the potential to substantially reduce the burden of CRC.

Lower Annual Rate of Progression of Short-Segment vs Long-Segment Barrett's Esophagus to Esophageal Adenocarcinoma.

BACKGROUND & AIMS: European guidelines recommend different surveillance intervals of non-dysplastic Barrett's esophagus (NDBE) based on segment length, as opposed to guidelines in the United States, which do recommend surveillance intervals based on BE length. We studied rates of progression of NDBE to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) in patients with short-segment BE using the definition of BE in the latest guidelines (length ≥1 cm). METHODS: We collected demographic, clinical, endoscopy, and histopathology data from 1883 patients with endoscopic evidence of NDBE (mean age, 57.3 years; 83.5% male; 88.1% Caucasians) seen at 7 tertiary referral centers. Patients were followed for a median 6.4 years. Cases of dysplasia or EAC detected within 1 year of index endoscopy were considered prevalent and were excluded. Unadjusted rates of progression to HGD or EAC were compared between patients with short (≥1 and <3) and long (≥3) BE lengths using log-rank tests. A subgroup analysis was performed on patients with a documented Prague C&M classification. We used a multivariable proportional hazards model to evaluate the association between BE length and progression. Adjusted hazards ratios were calculated after adjusting for variables associated with progression. RESULTS: We found 822 patients to have a short-segment BE (SSBE) and 1061 to have long segment BE (LSBE). We found patients with SSBE to have a significantly lower annual rate of progression to EAC (0.07%) than of patients with LSBE (0.25%) (P = .001). For the combined endpoint of HGD or EAC, annual progression rates were significantly lower among patients with SSBE (0.29%) compared to compared to LSBE (0.91%) (P < .001). This effect persisted in multivariable analysis (hazard ratio, 0.32; 95% CI, 0.18-0.57; P < .001). CONCLUSION: We analyzed progression of BE (length ≥1 cm) to HGD or EAC in a large cohort of patients seen at multiple centers and followed for a median 6.4 years. We found a lower annual rate of progression of SSBE to EAC (0.07%/year) than of LSBE (0.25%/year). We propose lengthening current surveillance intervals for patients with SSBE.

Increasing prevalence of high-grade dysplasia and adenocarcinoma on index endoscopy in Barrett's esophagus over the past 2 decades: data from a multicenter U.S. consortium.

INTRODUCTION: Data on time trends of dysplasia and esophageal adenocarcinoma (EAC) in Barrett's esophagus (BE) during the index endoscopy (ie, prevalent cases) are limited. Our aim was to determine the prevalence patterns of BE-associated dysplasia on index endoscopy over the past 25 years. METHODS: The Barrett's Esophagus Study is a multicenter outcome project of a large cohort of patients with BE. Proportions of patients with index endoscopy findings of no dysplasia (NDBE), low-grade dysplasia (LGD), high-grade dysplasia (HGD), and EAC were extracted per year of index endoscopy, and 5-yearly patient cohorts were tabulated over years 1990 to 2010+ (2010-current). Prevalent dysplasia and endoscopic findings were trended over the past 25 years using percentage dysplasia (LGD, HGD, EAC, and HGD/EAC) to assess changes in detection of BE-associated dysplasia over the last 25 years. Statistical analysis was done using SAS version 9.4 software (SAS, Cary, NC). RESULTS: A total of 3643 patients were included in the analysis with index endoscopy showing NDBE in 2513 (70.1%), LGD in 412 (11.5%), HGD in 193 (5.4%), and EAC in 181 (5.1%). Over time, there was an increase in the mean age of patients with BE (51.7 ± 29 years vs 62.6 ± 11.3 years) and the proportion of males (84% vs 92.6%) diagnosed with BE but a decrease in the mean BE length (4.4±4.3 cm vs 2.9±3.0 cm) as time progressed (1990-1994 to 2010-2016 time periods). The presence of LGD on index endoscopy remained stable over 1990 to 2016. However, a significant increase (148% in HGD and 112% in EAC) in the diagnosis of HGD, EAC, and HGD/EAC was noted on index endoscopy over the last 25 years (P < .001). There was also a significant increase in the detection of visible lesions on index endoscopy (1990-1994, 5.1%; to 2005-2009, 6.3%; and 2010+, 16.3%) during the same period. CONCLUSION: Our results suggest that the prevalence of HGD and EAC has significantly increased over the past 25 years despite a decrease in BE length during the same period. This increase parallels an increase in the detection of visible lesions, suggesting that a careful examination at the index examination is crucial.

Clinical Practice Guideline on Screening for Colorectal Cancer in Individuals With a Family History of Nonhereditary Colorectal Cancer or Adenoma: The Canadian Association of Gastroenterology Banff Consensus.

BACKGROUND & AIMS: A family history (FH) of colorectal cancer (CRC) increases the risk of developing CRC. These consensus recommendations developed by the Canadian Association of Gastroenterology and endorsed by the American Gastroenterological Association, aim to provide guidance on screening these high-risk individuals. METHODS: Multiple parallel systematic review streams, informed by 10 literature searches, assembled evidence on 5 principal questions around the effect of an FH of CRC or adenomas on the risk of CRC, the age to initiate screening, and the optimal tests and testing intervals. The GRADE (Grading of Recommendation Assessment, Development and Evaluation) approach was used to develop the recommendations. RESULTS: Based on the evidence, the Consensus Group was able to strongly recommend CRC screening for all individuals with an FH of CRC or documented adenoma. However, because most of the evidence was very-low quality, the majority of the remaining statements were conditional ("we suggest"). Colonoscopy is suggested (recommended in individuals with ≥2 first-degree relatives [FDRs]), with fecal immunochemical test as an alternative. The elevated risk associated with an FH of ≥1 FDRs with CRC or documented advanced adenoma suggests initiating screening at a younger age (eg, 40-50 years or 10 years younger than age of diagnosis of FDR). In addition, a shorter interval of every 5 years between screening tests was suggested for individuals with ≥2 FDRs, and every 5-10 years for those with FH of 1 FDR with CRC or documented advanced adenoma compared to average-risk individuals. Choosing screening parameters for an individual patient should consider the age of the affected FDR and local resources. It is suggested that individuals with an FH of ≥1 second-degree relatives only, or of nonadvanced adenoma or polyp of unknown histology, be screened according to average-risk guidelines. CONCLUSIONS: The increased risk of CRC associated with an FH of CRC or advanced adenoma warrants more intense screening for CRC. Well-designed prospective studies are needed in order to make definitive evidence-based recommendations about the age to commence screening and appropriate interval between screening tests.

Screening Women Aged 50-59 for CRC Using Fecal Occult Blood Test Produces Outcomes Similar to Men Undergoing Screening Colonoscopy.

BACKGROUND: Average-risk women aged 50-59 years have a lower incidence and mortality of colorectal cancer relative to age-matched men, calling into question the benefit of screening colonoscopy in this age group. AIMS: We aimed to determine whether FOBT is an effective initial screening test in 50-59-year-old women. METHODS: We conducted a cross-sectional study using a computerized endoscopic report generator. We identified 320,906 individuals who had average-risk screening colonoscopy and 32,369 who had colonoscopy for positive FOBT. The primary outcome was the positive predictive value (PPV) of FOBT for large polyp(s) greater than 9 mm, as a surrogate for advanced neoplasia. RESULTS: Among patients aged 50-59 years undergoing screening colonoscopy, men were more likely than women to have large polyps (6.3 vs 4.2%, p < 0.0001). Black women undergoing screening colonoscopy had higher rates of large polyps compared to non-Black women. The PPV in FOBT-positive men aged 50-54 (11.5%) and 55-59 (14.4%) was higher than in women aged 50-54 (6.1%) and 55-59 (5.4%). Despite this lower PPV, women aged 50-54 with a positive FOBT had a similar rate of large polyps as 50-54-year-old men undergoing screening colonoscopy (6.1 vs 6.3%, p = 0.626). CONCLUSIONS: CRC screening with FOBT identifies 50-59-year-old men and women with a higher risk of large polyps. Since younger women have a lower risk of large polyps than men, screening with FOBT in 50-59-year-old non-Black women could be an effective screening strategy, with outcomes similar to the use of screening colonoscopy in 50-59-year-old men.

Family history of colorectal cancer in first-degree relatives and metachronous colorectal adenoma.

OBJECTIVES: Little is known about the relationship between having a first-degree relative (FDR) with colorectal cancer (CRC) and risk for metachronous colorectal adenoma (CRA) following polypectomy. METHODS: We pooled data from seven prospective studies of 7697 patients with previously resected CRAs to quantify the relationship between having a FDR with CRC and risk for metachronous adenoma. RESULTS: Compared with having no family history of CRC, a positive family history in any FDR was significantly associated with increased odds of developing any metachronous CRA (OR = 1.14; 95% CI = 1.01-1.29). Higher odds of CRA were observed among individuals with an affected mother (OR = 1.27; 95% CI = 1.05-1.53) or sibling (OR = 1.34; 95% CI = 1.11-1.62) as compared with those without, whereas no association was shown for individuals with an affected father. Odds of having a metachronous CRA increased with number of affected FDRs, with ORs (95% CIs) of 1.07 (0.93-1.23) for one relative and 1.39 (1.02-1.91) for two or more. Younger age of diagnosis of a sibling was associated with higher odds of metachronous CRA, with ORs (95% CIs) of 1.66 (1.08-2.56) for diagnosis at <54 years; 1.34 (0.89-2.03) for 55-64 years; and 1.10 (0.70-1.72) for >65 years (p-trend = 0.008). Although limited by sample size, results for advanced metachronous CRA were similar to those for any metachronous CRA. CONCLUSIONS: A family history of CRC is related to a modestly increased odds of metachronous CRA. Future research should explore whether having a FDR with CRC, particularly at a young age, should have a role in risk stratification for surveillance colonoscopy.

Quality of Colonoscopy Performed in Rural Practice: Experience From the Clinical Outcomes Research Initiative and the Oregon Rural Practice-Based Research Network.

PURPOSE: Colon cancer screening is effective. To complete screening in 80% of individuals over age 50 years by 2018 will require adequate colonoscopy capacity throughout the country, including rural areas, where colonoscopy providers may have less specialized training. Our aim was to study the quality of colonoscopy in rural settings. METHODS: The Clinical Outcomes Research Initiative (CORI) and the Oregon Rural Practice-based Research Network (ORPRN) collaborated to recruit Oregon rural practices to submit colonoscopy reports to CORI's National Endoscopic Database (NED). Ten ORPRN sites were compared to non-ORPRN rural (n = 11) and nonrural (n = 43) sites between January 2009 and October 2011. Established colonoscopy quality measures were calculated for all sites. RESULTS: No ORPRN physicians were gastroenterologists compared with 82% of nonrural physicians. ORPRN practices reached the cecum in 87.4% of exams compared with 89.3% of rural sites (P = .0002) and 90.9% of nonrural sites (P < .0001). Resected polyps were less likely to be retrieved (84.7% vs 91.6%; P < .0001) and sent to pathology (77.1% vs 91.3%; P < .0001) at ORPRN practices compared to nonrural sites. The overall polyp detection (39.0% vs 40.3%) was similar (P = .217) between ORPRN and nonrural practices. Of exams with polyps, the rate for largest polyp on exam 6-9 mm was 20.8% at ORPRN sites, compared to 26.8% at nonrural sites (P < .0001), and for polyps >9mm 16.6% vs 18.7% (P = .106). CONCLUSION: ORPRN sites performed well on most colonoscopy quality measures, suggesting that high-quality colonoscopy can be performed in rural settings.

Inadequate Boston Bowel Preparation Scale scores predict the risk of missed neoplasia on the next colonoscopy.

BACKGROUND AND AIMS: The risks of missed findings after inadequate bowel preparation are not fully characterized in a diverse cohort. We aimed to evaluate the likelihood of missed polyps after an inadequate preparation as assessed by using the Boston Bowel Preparation Scale (BBPS). METHODS: In this observational study of prospectively collected data within a large, national, endoscopic consortium, we identified patients aged 50 to 75 years who underwent average-risk screening colonoscopy (C1) followed by a second colonoscopy for any indication within 3 years (C2). We determined the polyp detection rates (PDRs) and advanced PDRs during C2 stratified by C1 BBPS scores. RESULTS: Among segment pairs without polyps at C1 (N = 601), those with inadequate C1 BBPS segment scores had a higher PDR at C2 (10%) compared with those with adequate bowel preparation at C1 (5%; P = .04). Among segment pairs with polyps at C1 (N = 154), segments with inadequate bowel preparation scores at C1 had higher advanced PDRs at C2 (20%) compared with those with adequate bowel preparation scores at C1 (4%; P = .03). In multivariable analysis, the presence of advanced polyps at C1 (adjusted odds ratio [OR] 3.5; 95% confidence intervals [CIs], 1.1-10.8) but not inadequate BBPS scores at C1 (adjusted OR 1.8; 95% CI, 0.6-5.1) was associated with a significantly increased risk of advanced polyps at C2. CONCLUSIONS: Inadequate BBPS segment scores generally are associated with higher rates of polyps and advanced polyps at subsequent colonoscopy within a short timeframe. The presence of advanced polyps as well as inadequate BBPS segment scores can inform the risk of missed polyps and help triage which patients warrant a timely repeat colonoscopy.

Risk stratification of individuals with low-risk colorectal adenomas using clinical characteristics: a pooled analysis.

OBJECTIVE: For individuals with 1-2 small (<1 cm) low-risk colorectal adenomas, international guidelines range from no surveillance to offering surveillance colonoscopy in 5-10 years. We hypothesised that the risks for metachronous advanced neoplasia (AN) among patients with low-risk adenomas differ based on clinical factors distinct from those currently used. DESIGN: We pooled data from seven prospective studies to assess the risk of metachronous AN. Two groups with 1-2 small adenomas were defined based on guidelines from the UK (n=4516) or the European Union (EU)/US (n=2477). RESULTS: Absolute risk of metachronous AN ranged from a low of 2.9% to a high of 12.2%, depending on specific risk factor and guideline used. For the UK group, the highest absolute risks for metachronous AN were found among individuals with a history of prior polyp (12.2%), villous histology (12.2%), age ≥70 years (10.9%), high-grade dysplasia (10.9%), any proximal adenoma (10.2%), distal and proximal adenoma (10.8%) or two adenomas (10.1%). For the EU/US group, the highest absolute risks for metachronous AN were among individuals with a history of prior polyp (11.5%) or the presence of both proximal and distal adenomas (11.0%). In multivariate analyses, strong associations for increasing age and history of prior polyps and odds of metachronous AN were observed, whereas more modest associations were shown for baseline proximal adenomas and those with villous features. CONCLUSIONS: Risks of metachronous AN among individuals with 1-2 small adenomas vary according to readily available clinical characteristics. These characteristics may be considered for recommending colonoscopy surveillance and require further investigation.

A prognostic model for advanced colorectal neoplasia recurrence.

PURPOSE: Following colonoscopic polypectomy, US Multisociety Task Force (USMSTF) guidelines stratify patients based on risk of subsequent advanced neoplasia (AN) using number, size, and histology of resected polyps, but have only moderate sensitivity and specificity. We hypothesized that a state-of-the-art statistical prediction model might improve identification of patients at high risk of future AN and address these challenges. METHODS: Data were pooled from seven prospective studies which had follow-up ascertainment of metachronous AN within 3-5 years of baseline polypectomy (combined n = 8,228). Pooled data were randomly split into training (n = 5,483) and validation (n = 2,745) sets. A prognostic model was developed using best practices. Two risk cut-points were identified in the training data which achieved a 10 percentage point improvement in sensitivity and specificity, respectively, over current USMSTF guidelines. Clinical benefit of USMSTF versus model-based risk stratification was then estimated using validation data. RESULTS: The final model included polyp location, prior polyp history, patient age, and number, size and histology of resected polyps. The first risk cut-point improved sensitivity but with loss of specificity. The second risk cut-point improved specificity without loss of sensitivity (specificity 46.2 % model vs. 42.1 % guidelines, p < 0.001; sensitivity 75.8 % model vs. 74.0 % guidelines, p = 0.64). Estimated AUC was 65 % (95 % CI: 62-69 %). CONCLUSION: This model-based approach allows flexibility in trading sensitivity and specificity, which can optimize colonoscopy over- versus underuse rates. Only modest improvements in prognostic power are possible using currently available clinical data. Research considering additional factors such as adenoma detection rate for risk prediction appears warranted.