Index Colonoscopy Research Articles

Sa2008 – Risk of Metachronous Sessile Serrated Adenomas in Patients with Sessile Serrated Adenomas on Index Colonoscopy

Sa2008 – Risk of Metachronous Sessile Serrated Adenomas in Patients with Sessile Serrated Adenomas on Index Colonoscopy

Post-colonoscopy colorectal cancer in Belgium: characteristics and influencing factors.

Background and study aims Post-colonoscopy colorectal cancer (PCCRC) is an important quality parameter of colonoscopy. Most studies have shown that the risk for colorectal cancer is reduced after an index colonoscopy for screening or diagnostic purposes with or without polypectomy. In this study, we aimed to quantify and describe PCCRC in Belgium, including the possible relationships with patient, physician, and colonoscopy characteristics. Patients and methods Reimbursement data on colorectal related medical procedures from the Intermutualistic Agency (IMA-AIM) were linked with data on clinical and pathological staging of colorectal cancer (CRC) available at the Belgian Cancer Registry (BCR) over a period covering 9 years (2002 – 2010). Results In total, 63 518 colorectal cancers were identified in 61 616 patients between 2002 and 2010. We calculated a mean PCCRC rate of 7.6 %. PCCRC was significantly higher in older people and correlated significantly with polyp detection rate and the number of resections and procedures performed per year per physician. Conditional observed survival, given still alive 3 years since first colonoscopy, for PCCRC was worse than for CRC. Older patients and patients with invasive carcinomas had a worse outcome. Conclusions Although no quality register exists in Belgium, we were able to demonstrate that PCCRC in Belgium is directly related to the experience of the physician performing the procedure. In the absence of a quality register, utilization of population-based data sources proved to be a valuable tool to identify quality parameters.

A systematic review and cost analysis of repeat colonoscopies due to inadequate bowel cleansing in five European countries

ABSTRACTBackground: Colonoscopies are carried out for a range of reasons including for the detection of colon cancer and investigation of abdominal and bowel related symptoms. Inadequate preparation can increase the burden of repeat procedures.Methods: A systematic review aimed to identify the rate of repeat colonoscopies due to inadequate bowel preparation in France, Germany, Italy, Spain and the United Kingdom. The information obtained populated a decision analytic model to estimate the cost implications of inadequate bowel cleansing in the same five countries. The model explored scenarios by comparing one and two-litre polyethylene glycol-based bowel preparation.Results: The systematic review identified 14 eligible studies reporting on the proportion of patients with inadequate bowel cleansing indicated for a repeat procedure. Data were available for Italy (27.5%-35.9%), Spain (63%) and the UK (24.5%) only. The decision analytic model demonstrates that improving the proportion of adequate bowel cleansing at first colonoscopy is likely to generate cost savings.Conclusions: Based on the available evidence, increasing the proportion of people who have adequate bowel cleansing at index colonoscopy will likely have financial benefits in Italy, Spain and the UK. A paucity of data, for France and Germany, limits the robustness of conclusions in these countries.

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

Most post-colonoscopy interval colorectal cancers are proximal; serrated polyps are often precursors to these cancers and are considered difficult to detect. We assessed the safety, feasibility, and economic effect of chromocolonoscopy on detection of proximal serrated neoplasia. We did an open-label, multicentre, randomised, controlled non-inferiority trial including patients from Bowel Screening Wales centres. Participants who tested positive for faecal occult blood and who were eligible for and considered fit to have colonoscopy (patients with known cases of polyposis syndromes, Lynch syndrome, and chronic inflammatory disease were excluded) were randomly assigned (1:1; with the use of minimisation, stratified by centre with an 80:20 random element) to either standard white light colonoscopy (standard group) or chromocolonoscopy (indigo carmine dye [0·2%]; chromocolonoscopy group) using a secure, internet-based, computerised, randomisation system that used centralised, dynamic allocation. Participants were followed up for 1 year and data from index colonoscopies and associated clearance procedures were analysed. All proximal polyps were reviewed by an expert pathologist panel. The main outcome on which power was based was time taken to perform the colonoscopy procedure, defined as from the time when the scope was inserted to withdrawal from the anus, assessed in the per-protocol population. The non-inferiority margin was 15 min. This trial is complete and is registered with ClinicalTrials.gov, number NCT01972451. Between Nov 20, 2014, and June 16, 2016, 741 (72%) of 1031 patients screened were eligible and consented: 360 were randomly assigned to white light colonoscopy and 381 to chromocolonoscopy. In the chromocolonoscopy group, the procedure took a mean of 36·8 min (SD 15·0), compared with a mean of 30·6 min (13·7) in the standard group (mean difference 6·3 min [95% CI 4·2-8·4] longer with chromocolonoscopy than in the standard group). The mean difference was within the prespecified non-inferiority margin. Detection rates for proximal serrated lesions were significantly higher in the chromocolonoscopy group than in the control group (45 [12%] of 381 patients vs 23 [6%] of 360 patients; odds ratio 1·96 [95% CI 1·16-3·32]; p=0·012). Serious adverse events (four cases of postpolypectomy bleeding [two in each group], and one case of anxiety and hyperventilation [in the chromocolonoscopy group]), colonoscopy quality measures, comfort scores, and sedation were similar between groups. Chromocolonoscopy is feasible within a population-based colorectal cancer screening programme, is safe, and has significantly increased detection of proximal serrated neoplasia and other polyp types compared with standard colonoscopy. Larger randomised trials of chromocolonoscopy, powered for improved detection of significant serrated polyps and for longer-term follow-up to investigate the effect on reduction of interval cancers within screening populations, are warranted. Health and Care Research Wales (RfPPB-1021).

Quality of endoscopy reporting at index colonoscopy significantly impacts outcome of subsequent EMR in patients with > 20 mm colon polyps.

Background and study aims Endoscopic mucosal resection (EMR) is safe and cost-effective in management of patients with colon polyps. However, very little is known about the actions of the referring endoscopist following identification of these lesions at index colonoscopy, and the impact of those actions on the outcome of subsequent referral for EMR. The aim of this study was to identify practices at index colonoscopy that lead to failure of subsequent EMR. Patients and methods Two hundred and eighty-nine consecutive patients with biopsy-proven non-malignant colon polyps (> 20 mm) referred for EMR were analyzed to identify practices that could be improved from the time of identifying the lesion at index colonoscopy until completion of therapy. Results EMR was abandoned at colonoscopy at the EMR center in 71 of 289 patients (24.6 %). Reasons for abandoning EMR included diagnosis of invasive carcinoma (n = 9; 12.7 %), tethered lesions (n = 21; 29.6 %) from prior endoscopic interventions, and overly large (n = 22; 31 %) and inaccessible lesions (n = 17; 24 %) for complete and safe resection whose details were not recorded in the referring endoscopy report, or polyposis syndromes (n = 2; 2.8 %) that were not recognized. Conclusions In our practice, one in four EMR attempts were abandoned as a result of inadequate diagnosis or management by the referring endoscopist, which could be improved by education on optical diagnosis of polyps, comprehensive documentation of the procedure and avoidance of interventions that preclude resection.

Statins reduce the progression of non-advanced adenomas to colorectal cancer: a postcolonoscopy study in 187 897 patients

Background and aimsPostcolonoscopy colorectal cancer (PCCRC) accounts for up to 9% of all CRCs. Statins have been shown to be associated with a lower CRC risk. We aimed to investigate...

A Review of the Management of Sporadic Colorectal Adenomas in Young People: Is Surveillance Wasted on the Young?

The national incidence of colorectal cancer is increasing in people younger than 50years old. Although diagnostic colonoscopy is detecting more sporadic adenomas in young adults, there are no guidelines for post-polypectomy surveillance. The aim of this review was to survey the medical literature on the prevalence of sporadic adenomas in young adults, subsequent risk of metachronous neoplasia, and lastly to provide several concluding recommendations for clinical practice. We found that the prevalence of sporadic adenomas in young adults is greater than initially estimated and dependent upon factors such as colonoscopy indication and age. The incidence of metachronous colorectal neoplasia following polypectomy is unclear but does not appear to be greater than that of older adults. Risk factors for metachronous neoplasia include findings on index colonoscopy, male gender, smoking status, and certain medical comorbidities. Upon finding a colorectal adenoma in a young person, we suggest that a detailed family history be obtained to confirm that it is truly sporadic. Testing adenomas for evidence of Lynch syndrome is low yield. Strategies to inform surveillance intervals may include an assessment of risk factors for metachronous neoplasia, although surveillance intervals shorter than those recommended in current guidelines are not warranted. Future research should focus on obtaining long-term, prospective data on the incidence of metachronous neoplasia in diverse patient populations.

Effect of Cotinine-Verified Change in Smoking Status on Risk of Metachronous Colorectal Neoplasia After Polypectomy

Previous assessments of colorectal neoplasia (CRN) recurrence after polypectomy used self-report to determine smoking status. We evaluated the association between change in smoking status and metachronous CRN risk after polypectomy using cotinine level in urine to determine tobacco exposure. We performed a retrospective study of participants in the Kangbuk Samsung Health Study in Korea who underwent a screening colonoscopy examination and measurement of cotinine in urine samples. Our analysis included 4762 patients who had 1 or more adenomas detected in an index colonoscopy performed between January 2010 and December 2014, and underwent a surveillance colonoscopy, 6 or more months later, until December2017. Patients were classified into 4 groups based on the change in cotinine-verified smoking status from index to follow-up colonoscopy (mean interval, 3.2 ± 1.3 y), as follows: remained nonsmokers (n= 2962; group 1), smokers changed to nonsmokers (n= 600; group 2), nonsmokers changed to smokers (n= 138; group 3), and remained smokers (n= 1062; group 4). After adjustment for confounding factors, group 4 had a significantly higher risk of metachronous CRN than group 1 (hazard ratio [HR], 1.54; 95% CI, 1.36-1.73) and group 2 (HR, 1.63; 95% CI, 1.39-1.99). Group 4 also had a higher risk of metachronous advanced CRN than group 1 (HR, 2.84; 95% CI, 1.79-4.53) and group 2 (HR, 2.10; 95% CI, 1.13-3.89). Group 3 had a higher risk of metachronous CRN than group 1 (HR, 1.50; 95% CI, 1.14-1.97) and group 2 (HR, 1.62; 95% CI, 1.20-2.20). In a retrospective study of individuals with at least 1 adenoma, we found that cotinine-verified changes in smoking status between index and follow-up colonoscopy are associated with a risk of metachronous CRN. Helping patients quit smoking is important for effective prevention of colorectal cancer.

Differential risk of disease progression between isolated anastomotic ulcers and mild ileal recurrence after ileocolonic resection in patients with Crohn’s disease

It is standard of care to perform ileocolonoscopy within a year of ileocolonic resection for Crohn's disease (CD) and to guide management decisions based on the Rutgeert score (RS). The modified RS subdivides i2 into lesions confined to the anastomosis (i2a) or >5 aphthous lesions in the neoterminal ileum (i2b). There is uncertainty, however, if i2a lesions incur an increased risk of disease recurrence. The primary aim of this study was to compare the rates of endoscopic progression between i2a and i2b when compared with i0-i1. This was a retrospective, single-center study including patients with CD who had an ileocolonoscopy≤12 months after ileocolonic resection with primary anastomosis and who had >1 year of documented clinical follow-up after the index endoscopic evaluation. All consecutive eligible patients between 2004 and 2014 were included in the study. Demographic, disease, and treatment data were collected. Patients with i3 or i4 at index colonoscopy were excluded from further analyses. Outcomes included endoscopic progression and recurrent surgery. For patients with RS of i0 to i2, endoscopic progression was predefined as progression of the RS in subsequent colonoscopies to i3 or i4. Recurrent surgical interventions were defined as re-resection or stricturoplasty of the previous ileocolonic anastomosis. Two hundred seven CD patients (median age, 36 years [interquartile range, 26-48]) had an ileocolonoscopy≤12 months after ileocolonic resection. At index colonoscopy, 95 patients (45.9%) had an RS of i0, 31 (14.9%) i1, 40 (19.3%) i2a, 25 (12.1%) i2b, 10 (4.8%) i3, and 6 (2.9%) i4. One hundred ninety-one patients had an RS of i0 to i2 and were included in the analyses for recurrent surgery. One hundred forty-nine patients had a second endoscopic evaluation and were included in the analysis for the primary outcome of endoscopic disease progression. Kaplan-Meier analyses were performed and found the hazard ratio (HR) of endoscopic progression to be significantly higher with i2b lesions when compared with i0 or i1 (HR, 6.22; 95% confidence interval [CI], 2.38-16.2; P= .0008). Patients with i2a did not have significantly higher rates of endoscopic progression when compared with i0 or i1 (HR, 2.30; 95% CI, .80-6.66; P= .12). Likewise, patients with i2b lesions had higher risk of needing recurrent surgery when compared with i0 or i1 (HR, 3.64; 95% CI, 1.10-12.1; P= .034), whereas patients with i2a lesions were not found to have a significantly elevated risk of recurrent surgery (HR, 1.43; 95% CI, .35-5.77; P= .62). Endoscopic lesions limited to the ileocolonic anastomosis (RS i2a) in patients with CD undergoing colonoscopy within 1 year of their resection were not associated with a significantly higher rate of progression to more severe disease, whereas those in the neoileum (RS i2b) were. Prospective studies are needed to confirm these findings.

Magnitude, Risk Factors, and Factors Associated With Adenoma Miss Rate of Tandem Colonoscopy: A Systematic Review and Meta-analysis

We performed a systematic review and meta-analysis to comprehensively estimate adenoma miss rate (AMR) and advanced AMR (AAMR) and explore associated factors. We searched the PubMed, Web of Science, and Ovid EMBASE databases for studies published through April 2018 on tandem colonoscopies, with AMR and AAMR as the primary outcomes. We performed meta-regression analyses to identify risk factors and factors associated with outcome. Primary outcomes were AMR and AAMR and secondary outcomes were AMR and AAMR for different locations, sizes, pathologies, morphologies, and populations. In a meta-analysis of 43 publications and more than 15,000 tandem colonoscopies, we calculated miss rates of 26% for adenomas (95% confidence interval [CI] 23%-30%), 9% for advanced adenomas (95% CI 4%-16%), and 27% for serrated polyps (95% CI 16%-40%). Miss rates were high for proximal advanced adenomas (14%; 95% CI 5%-26%), serrated polyps (27%; 95% CI 16%-40%), flat adenomas (34%; 95% CI 24%-45%), and in patients at high risk for colorectal cancer (33%; 95% CI 26%-41%). Miss rates could be decreased by adequate bowel preparation and auxiliary techniques (P= .06; P= .04, and P= .01, respectively). The adenoma detection rate (ADR), adenomas per index colonoscopy, and adenomas per positive index colonoscopy (APPC) were independently associated with AMR (P= .02, P= .01, and P= .008, respectively), whereas APPC was the only factor independently associated with AAMR (P= .006). An APPC value greater than 1.8 was more effective in monitoring AMR (31% vs 15% for AMR P < .0001) than an ADR value of at least 34% (27% vs 17% for AMR; P= .008). The AAMR of colonoscopies with an APPC value below 1.7 was 35%, vs 2% for colonoscopies with an APPC value of at least 1.7 (P= .0005). In a systematic review and meta-analysis, we found that adenomas and advanced adenomas are missed (based on AMR and AAMR) more frequently than previously believed. In addition to ADR, APPC deserves consideration as a complementary indicator of colonoscopy quality, if it is validated in additional studies.

Receipt of Colonoscopy Following Diagnosis of Advanced Adenomas: An Analysis within Integrated Healthcare Delivery Systems.

To reduce colorectal cancer incidence and mortality, experts recommend surveillance colonoscopy 3 years after advanced adenoma removal. Little is known about adherence to that interval. We describe patterns of and factors associated with subsequent colonoscopy among persons with ≥3 adenomas and/or ≥1 adenoma with villous/tubulovillous histology in four U.S. integrated healthcare delivery systems. We report Kaplan-Meier estimators of the cumulative percentage of patients undergoing colonoscopy 6 months to 3.5 years after an index colonoscopy with high-risk findings. Combining data from three healthcare systems, we used multivariable logistic regression with inverse probability of censoring weights to estimate ORs and 95% confidence intervals (CI) for associations between patient characteristics and receipt of subsequent colonoscopy. Among 6,909 persons with advanced adenomas, the percent receiving a subsequent colonoscopy 6 months to 3.5 years later ranged from 18.3% (95% CI: 11.7%-27.8%) to 59.5% (95% CI: 53.8%-65.2%) across healthcare systems. Differences remained significant in the multivariable model. Patients with ≥3 adenomas were more likely than those with 1 to 2 villous/tubulovillous adenomas to undergo subsequent colonoscopy. Subsequent colonoscopy was also more common for patients ages 60-74 and less common for patients ages 80 to 89 compared with those ages 50 to 54 years at their index colonoscopy. Sex, race/ethnicity, and comorbidity index score were generally not associated with subsequent colonoscopy receipt. Colonoscopy within the recommended interval following advanced adenoma was underutilized and varied by healthcare system, age, and number of adenomas. Strategies to improve adherence to surveillance colonoscopy following advanced adenomas are needed.

The impact of colonoscopy indication on polyp detection rate.

BackgroundAdenoma/polyp detection rates are considered to be among the most important quality indicators of colonoscopy and are key measures of a quality procedure. However, they are designed for use in the screening setting and are not amenable to other colonoscopy indications. Little is known about their significance in other colonoscopy indications. We aimed to evaluate the impact of the various indications on polyp detection rate (PDR).MethodsThis was a retrospective, single-center study. Electronic reports of index colonoscopy procedures with adequate bowel preparation over a 10-year period were reviewed. Patients were divided into 7 groups based on the study indication. PDR was determined for each group and was compared to that of a control group, the screening indication group. Adjustment was made for potential confounders such as age, sex, and procedural setting.ResultsA total of 13,054 patients were considered suitable for the study. PDR was greatest in the positive fecal occult blood test group, with a value of 33.1% (P<0.01). Overall, the remaining groups showed similar PDRs compared with screening (22.1% vs. 20.4%; P=0.15). This trend persisted in a multivariate analysis, which showed the odds ratio in the positive fecal occult blood test group to be significantly higher, with a value of 1.955 (1.759-2.172, P<0.001) compared with the screening group.ConclusionPDR was highest for the positive fecal occult blood test indication, but was not affected significantly by most indications. Further randomized studies are warranted to confirm these findings and help calculate recommended thresholds for “overall” PDR.

Structured Approach for Evaluating Strategies for Cancer Ascertainment Using Large-Scale Electronic Health Record Data.

Cancer ascertainment using large-scale electronic health records is a challenge. Our aim was to propose and apply a structured approach for evaluating multiple candidate approaches for cancer ascertainment using colorectal cancer (CRC) ascertainment within the US Department of Veterans Affairs (VA) as a use case. The proposed approach for evaluating cancer ascertainment strategies includes assessment of individual strategy performance, comparison of agreement across strategies, and review of discordant diagnoses. We applied this approach to compare three strategies for CRC ascertainment within the VA: administrative claims data consisting of International Classification of Diseases, Ninth Revision (ICD9) diagnosis codes; the VA Central Cancer Registry (VACCR); and the newly accessible Oncology Domain, consisting of cases abstracted by local cancer registrars. The study sample consisted of 1,839,043 veterans with index colonoscopy performed from 1999 to 2014. Strategy-specific performance was estimated based on manual record review of 100 candidate CRC cases and 100 colonoscopy controls. Strategies were further compared using Cohen's κ and focused review of discordant CRC diagnoses. A total of 92,197 individuals met at least one CRC definition. All three strategies had high sensitivity and specificity for incident CRC. However, the ICD9-based strategy demonstrated poor positive predictive value (58%). VACCR and Oncology Domain had almost perfect agreement with each other (κ, 0.87) but only moderate agreement with ICD9-based diagnoses (κ, 0.51 and 0.57, respectively). Among discordant cases reviewed, 15% of ICD9-positive but VACCR- or Oncology Domain-negative cases had incident CRC. Evaluating novel strategies for identifying cancer requires a structured approach, including validation against manual record review, agreement among candidate strategies, and focused review of discordant findings. Without careful assessment of ascertainment methods, analyses may be subject to bias and limited in clinical impact.

Assessing the Impact of Metformin Use on Colonic Polyp Behavior

Introduction: Colorectal cancer (CRC) is the third most common cancer worldwide. Age-appropriate CRC screening with colonoscopy provides two benefits: (1) early cancer detection; and (2) resection of premalignant colonic polyps. The principle of cancer chemoprophylaxis has been proposed as a possible synergistic approach to endoscopic colon cancer prevention. Patients with diabetes mellitus (DM) are at increased risk of CRC, compared to non-diabetics. Metformin, one of the most commonly used therapeutic agents used to treat type 2 DM has previously been studied as a potential chemoprophylactic agent against CRC, however, the results have been mixed. We investigate the impact of metformin use on the behavior of colonic polyp generation in a veteran population. Methods: We performed a retrospective observational study. Included were average-risk patients with at least two documented screening colonoscopies between 1997 and 2013 at the Veterans Affairs New York Harbor Healthcare System. Exclusion criteria were: family history of CRC; personal history of IBD; personal or family history of polyposis syndromes. Patient demographics (age, sex, race, ethnicity, body mass index) and colon polyp-specific data (number, histology, largest size) were collected via chart review. Comparative statistics were performed. Results: 1,344 patients were included in our analyses (190 had prescription for metformin prior to their index colonoscopy, 1,154 were non-users). Mean follow-up was 6.9 vs. 7.2 years, respectively. Baseline demographic characteristics are summarized in Table 1. At index colonoscopy, metformin users had fewer adenomatous polyps compared to non-users 1.16 vs. 1.68 (p = 0.0046). In follow-up, however, metformin users had a statistically significant a higher per-annum rate of adenoma generation 0.36 vs. 0.25 as well as higher per-annum rates of high-risk adenoma generation (defined as villous histology, high-grade dysplasia, and/or size > 1 cm). Conclusion: While metformin appeared to be protective against adenomatous polyps at time of index colonoscopy, metformin users demonstrated higher rates of per-annum adenoma generation, including high-risk adenomas. There were no differences in sessile serrated polyp generation at baseline or in follow-up. The effect of metformin use on colon polyp behavior should be further investigated with specific aim of assessing impact of timing of drug exposure on colon cancer chemoprophylaxis.248_A Figure 1 No Caption available.248_B Figure 2 No Caption available.

Hyperplastic Polyps on Colonoscopy - Not so Benign After All

Introduction: Hyperplastic polyps (HP) are the commonest colon polyps detected at colonoscopy. Small HPs are considered low risk colon lesions. Colorectal cancer screening and surveillance guidelines recommend an average risk colonoscopy screening interval of 10 years in individuals with <10mm rectosigmoid HPs, and offer no recommendation for < 10 mm HPs proximal to the sigmoid. We compared the risk of adenomas and serrated polyps between subjects with a normal baseline colonoscopy versus those with HPs (< 10 mm) within or proximal to the rectosigmoid colon. Methods: We obtained colonoscopy (CS) and pathology reports from patients undergoing >2 screening and surveillance colonoscopies between 2004-2014. We excluded inpatients, or patients with age 75 years, a family or personal history of CRC, IBD, colorectal surgery, or baseline colonoscopy with any adenoma, SSP, or HP >9mm. We compared the risk of metachronous polyps by baseline CS findings: normal, 1 HP, & ≥ 2 HPs. The risk of metachronous lesions is presented as odd ratios and 95% confidence interval (CI). Results: 1,798 patients were included. At index colonoscopy, 83% of patients had a normal exam, 11% had 1 < 1 cm HP and 6% had between 2 and 9 2HPs (56 mos [39.7,72.5]) vs 1 HP (62.4 mos [49.5,80.1]) vs those with a normal exam (63.7 mos [52.9,84.5]) (p<0.001). Patients with one or more HPs on index colonoscopy had an increased risk of metachronous HPs and SSPs throughout the colon (Table 1). When limited to patients with HPs in the rectosigmoid, the follow-up interval for colonoscopy was 54.2 mos [38.2,71.4] for patients with >2 HP, 61.9 mos [50.0,80.8] for patients with 1 HP, and 63.8 mos [52.9,84.5] (p<0.001) for patients with a normal exam. Patients with rectosigmoid HPs were not at an increased risk for metachronous SSPs or adenomas. Conclusion: Patients with <9mm HPs proximal to the sigmoid colon have an increased risk of metachronous HPs and SSPs. Patients with rectosigmoid HPs do not appear to have an increased risk carry the same predictive risk.274_A Figure 1. OR: odds ratio; CI: confidence interval; SSP: sessile serrated polyp a: lesions detected throughout the colon including sigmoid *Adjusted for age, indication for baseline scope and time between scopes Separate multivariable logistic regression models were built to look at each outcome. For each model, the finding of interest was modeled as the outcome with age, indication for baseline colonoscopy, findings at baseline colonoscopy (none vs. 1 HP vs. 2+ HPs) and time between colonoscopies as the independent variables274_B Figure 2. OR: odds ratio; CI: confidence interval; SSP: sessile serrated polyp a: lesions detected throughout the colon including sigmoid *Adjusted for age, indication for baseline scope and time between scopes Separate multivariable logistic regression models were built to look at each outcome. For each model, the finding of interest was modeled as the outcome with age, indication for baseline colonoscopy, findings at baseline colonoscopy (none vs. 1 HP in recto-sigmoid vs. 2+ HPs in recto-sigmoid) and time between colonoscopies as the independent variables

Tailoring Surveillance Colonoscopy in Patients With Advanced Adenomas

Introduction: Patients with advanced adenomas (AA) consume considerable colonoscopy resources. Understanding their risk of subsequent colorectal cancer (CRC) and their comorbidity might improve use of surveillance colonoscopy (SC) by directing it to those with high subsequent CRC risk &/or low comorbidity and away from those with low CRC risk &/or high comorbidity. In this study, we derived a prediction rule that stratifies risk for non-CRC mortality (NCM) following removal of AA. Methods: We identified Veterans whose VA-based index colonoscopy (IC) (2002-2009) revealed ≥ 1 AA (adenoma ≥1 cm, villous histology or high-grade dysplasia). Excluded were those with CRC < 6 months of the IC and those with CRC prior to IC. Through 2015, we obtained subsequent CRC incidence, all-cause mortality (ACM), and CRC-specific mortality (CSM) from VA electronic sources, linked VA-Medicare data, and non-VA facilities. Comorbidity was measured with the Charlson comorbidity index (CCI). The National Death Index provided cause of death, while CRC incidence was obtained from VA oncology data. Logistic regression identified factors independently associated with NCM. We applied points to each factor based on its odds ratio (OR), calculated NCM risk at each point total, collapsed point totals into risk strata for which we calculated risk of NCM, CSM and CRC incidence. Results: 2,943 Veterans had AA (mean age [SD] 63.1 [8.6] years, 98% men, 74% White), of whom 2,080 had ≥ 1 SC. Mean [SD} follow-up was 7.5 [2.9] years, mean CCI was 1.4 [1.8]; 42% used tobacco. CRC incidence was 1.4%, CSM was 0.4%, ACM was 31.3% and NCM was 30.9%. Independently associated with NCM was age, CCI, APACHE score, several individual comorbidities and recent hospitalization (c-statistic=0.75, [CI, 0.73-0.77]; GOF test P-value=0.92). Risk scores (0-11) identified three risk groups for NCM: Low (score 0-2), intermediate (3-5), and high (≥ 6) with respective risks of 14.0%, 33.7%, and 64.3% and respective sample proportions of 40.3%, 43.1% and 16.6%. Foregoing SC in the high-risk group would reduce colonoscopy resources by nearly 17%, and would have missed 4 (10%) of 40 incident CRCs and 1 (8.5%) of 12 CRC deaths. Conclusion: Among Veterans with AA, patient-specific information may be used to tailor SC based on risk for NCM. While this prediction rule requires validation, this type of work combined with factors predicting subsequent risk for CSM may improve the clinical utility and efficiency of SC in this high-risk group.

Adenoma Detection Rates in Patients in the 40-49 Year Age Group Across Different Ethnicities: Presidential Poster Award

Introduction: Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the third leading cause of cancer related deaths in United States. Recent guidelines from the American Cancer Society (ACS) recommend starting CRC screening at 45 years in average-risk patient population in United States. Previous studies have shown an increase in incidence of CRC in African Americans less than 50 years of age. Despite this, there is limited evidence about prevalence of adenomatous polyps in this age group. We aimed to examine the prevalence of adenomas in 40 to 49 years old patients without any family history (FH) of CRC or polyps across different races. Methods: A retrospective cross sectional study was performed using our electronic endoscopy database. Study subjects included all 40 to 49-year-old patients without any FH of CRC undergoing their index colonoscopy at our tertiary care academic institution from January 1, 2010 to September 30, 2017. Exclusion criteria included patients who underwent colonoscopy for overt gastrointestinal bleeding, inflammatory bowel disease, patients who had previous colonoscopies, a history of familial adenomatous polyposis, hereditary non polyposis CRC. Results: A total of 1856 patients were included in the study. Of these 53.6 % were Caucasian, 26.9% African Americans, and 19.4 % were Hispanics. Mean age of these patients was 44.7 yrs (S.D 2.6) and 57.6 % were males. Adenoma detection rate (ADR) was 22.1 % in Caucasians, 16.0 % in African Americans, 23.3% in Hispanics (Table 1). On multivariate analysis while adjusting for possible confounding factors, African Americans had lower ADR as compared to Caucasians (adjusted Odds Ratio: 0.6, 95% CI: 0.4-0.8, P-value=0.001). Conclusion: The ADR across all races in the 40-49 year age group is lower than the previously recommended ADR in patients with average risk undergoing their screening colonoscopy at 50 years of age (i.e. 25%). With the advent of new guidelines from the ACS, new benchmarks for quality indicators in colonoscopy regarding ADR will be needed. The lower ADR in African Americans suggests that further studies are needed to look for factors beyond the traditional adenoma-carcinoma pathway to understand the increasing incidence of CRC in African Americans in the younger age group.478 Figure 1 No Caption available.

Increased Risk of Endoscopic Disease Progression With Rutgeertsʼ i2a and i2b Recurrence: Implications for Disease Prevention

Introduction: It is standard of care to perform ileocolonoscopy within a year of ileo-colonic resection for CD and to guide management decisions based on the Rutgeerts' score (RS). i2 lesions correlate with increased rates of clinical recurrence of CD when compared to i0 or i1. The modified RS subdivides i2 into lesions confined to the anastomosis (i2a) or over 5 aphthous lesions in the neo-terminal ileum (i2b). There is uncertainty if i2a lesions incur an increased risk of disease recurrence. The aim of this study was to compare the endoscopic progression (EP) of i2a and i2b when compared to i0 and i1. Methods: This was a retrospective single center study including CD patients who had an ileocolonoscopy ≤12 months after ileo-colonic resection and who had >1 year of follow up. Demographic, disease and treatment data were collected. Endoscopic recurrence was determined from the endoscopy report and separately rereviewed based on the images obtained. Discrepancies were resolved by a third investigator. Patients with i3 or i4 RS recurrence at baseline were excluded. For patients with RS i0-i2 (including i2a, i2b), endoscopic progression (EP) was pre-defined as progression of the RS in subsequent colonoscopies to i3 or i4. Results: 180 CD patients (median 37.7 years old (range 14-74)) with a median follow up of 52 months (range 12-145) were included in this study. 91% of patients had either stricturing or penetrating disease prior to surgery and 12% of patients in the cohort had repeat surgery or endoscopic dilation during the follow up period. At index colonoscopy, 79 patients (43.8%) had a RS i0, 29 (16 %) i1, 34 (18.8%) i2a, 25 (13.9%) i2b, 9 (5%) i3 and 4 (2.2%) i4. EP was observed in 3 patients (3.4%) with i0, 2 patients (6%) with i1, 6 patients (17.6%) with i2a and 10 patients (40%) with i2b. Odds of EP were significantly higher with i2a and i2b lesions when compared to i0 or i1 (OR=3.64, 95%CI [1.01,12.94] and OR=11.3 95%CI [11.3,38.1] respectively) Fig 1. Patients with i2b had numerically higher rates of EP when compared to i2a, but this did not reach statistical significance (OR=3.1 95%CI [0.9,10]).694 Figure 1. Comparison of endoscopic progression between i2a, i2b and i0+i1Conclusion: This large study of CD patients demonstrated that both i2a and i2b have a significant risk of progression of disease compared to i0 or i1. We recommend escalation of medical therapy in these patients. Prospective trials to validate these findings are needed.

A Rare Care of Subcutaneous Emphysema After Colonoscopy with No Identifiable Mucosal Defect

We present an interesting case of subcutaneous emphysema after colonoscopy with near-obstructing mass noted at the hepatic flexure in an overall healthy 91-year-old female. Our patient was a healthy 91-year-old woman who presented with one week of right lower abdominal pain that started after a fall. CT scan of the abdomen revealed an indeterminate lesion at the cecum. A colonoscopy was performed for further evaluation and demonstrated a near obstructing lesion at the hepatic flexure that could not be traversed with the colonoscope. Biopsies were taken and the area was tattooed. After outpatient discharge following the colonoscopy, the patient re-presented to the emergency room with complaint of abdominal distention. While in the hospital she developed subcutaneous crepitus in the neck and face. Subsequent imaging revealed a large amount of subcutaneous air and findings consistent with pneumoperitoneum. She was hemodynamically stable, however given the concern for possible perforated viscus post-colonoscopy, the patient was urgently taken the operating room for an exploratory laparotomy and right-sided hemicolectomy. During surgery no full thickness tear of the colon was visualized. No defect was identified in colonic mucosa by pathology. It was only notable for adenocarcinoma. Subcutaneous face and neck emphysema is a rare complication after colonoscopy. The vast majority of cases of subcutaneous emphysema following colonoscopy in the literature are postulated to be secondary to colonic perforation and have been managed successfully with nonoperative treatment. Our case is unique in that our patient was taken to the operating room due to the obstructive lesion found, yet thorough examination of the colon intraoperatively and by pathology demonstrated no frank evidence of colonic perforation. Another interesting part of the case is the use of India ink tattooing of the obstructing lesion during the index colonoscopy to mark the lesion, which has also rarely been reported in the literature as a cause of occult perforation. Finally, the patient in our case could have been presenting with benign pneumoperitoneum found incidentally on imaging that were unrelated to her complaints of abdominal distension. While also uncommon in the literature, authors have recommended treating all cases of potentially benign pneumoperitoneum as perforations nonetheless, a practice that was followed in this patient's care. The patient recovered uneventfully.1576_A Figure 1. Stricture at hepatic flexure noted during colonoscopy1576_B Figure 2. Right eye crepitus1576_C Figure 3. Gross specimen

Is Adenoma Detection Rate Still the Quality Indicator for Screening Colonoscopy in Younger Patients?

Introduction: Recent guidelines from the American Cancer Society (ACS) recommend to start colon cancer screening at 45 years in average-risk patient population. Previously, it has been established that patients with family history (FH) of colorectal cancer (CRC) at any age should undergo screening at age 40 years. Despite these guidelines, data on the prevalence of adenomas in these patients is scant. We aimed to examine and compare the prevalence of adenomas in 40 to 49-year-old individuals undergoing colonoscopy because of FH of CRC of a first-degree relative (FDR) with CRC versus patients without any family history of CRC. Methods: A retrospective cross sectional study was performed using our electronic endoscopy database. Study subjects (cases) included all 40-49-year-old patients undergoing their index colonoscopy for diagnostic purposes (abdominal pain, diarrhea, weight loss, altered bowel habits, etc) at our center from January 2010 to September 2017. The control group consisted of all 40-49-year-old patients undergoing their index screening colonoscopy for a FDR with CRC. Exclusion criteria included patients who underwent colonoscopy for overt gastrointestinal bleeding, inflammatory bowel disease, patients who had previous colonoscopies, a history of familial adenomatous polyposis, hereditary non polyposis CRC. Results: A total of 2059 patients were included in the study. Mean age of these patients was 44.7 years, and 59.8% were males. Number of patients in the control group were 355, and number in study group was 1704. The adenoma detection rate (ADR) was 27.8% in the control group, and 19.7% (p=0.001) in the study group. The rate of neoplasia detected was 2.2% in patients with FH of CRC, and 1.3% in patients without FH of CRC (p=0.18). Conclusion: The ADR in average-risk 40-49 year old patients is less than the current recommended ADR in patients with average risk undergoing their screening colonoscopy at 50 years of age (i.e. 25%). However, the rate of neoplasia detected was comparable. This suggests that although early colonoscopy is beneficial in detecting CRC, but further studies are needed to look for factors beyond the traditional adenoma-carcinoma pathway in younger individuals. With the advent of the latest ACS guidelines, new quality benchmark for ADR will need to be established in average risk patients younger than 50 years of age undergoing screening colonoscopy. Future large multi-center prospective studies are needed to confirm this finding.225_A Figure 1 No Caption available.225_B Figure 2 No Caption available.