Colonoscopy Withdrawal Time Research Articles

Adenoma miss rates associated with a 3-minute versus 6-minute colonoscopy withdrawal time: a prospective, randomized trial

The 6-minute withdrawal time for colonoscopy, widely considered the standard of care, is controversial. The skill and technique of endoscopists may be as important as, or more important than, withdrawal time for adenoma detection. It is unclear whether a shorter withdrawal time with good technique yields an acceptable lesion detection rate. Our objective was to evaluate a 3-minute versus a 6-minute withdrawal time by using segmental tandem colonoscopy. We performed a prospective, randomized trial by using 4 expert endoscopists. Patients were randomized to a 3-minute or a 6-minute initial withdrawal, each followed by a tandem second 6-minute withdrawal. All polyps were removed. The primary outcomes were adenoma miss rates (AMRs), adenomas per colonoscopy (APC) rates, and adenoma detection rates (ADRs). A total of 99 and 101 patients were enrolled in the 3-minute and 6-minute withdrawal groups, respectively. The AMR was significantly higher in the 3-minute withdrawal group (48.0% vs 22.9%; P= .0001). After controlling for endoscopist, patient age and/or sex, Boston Bowel Preparation Scale score, and size and/or location and/or morphology of adenoma, the AMR remained significantly higher in the 3-minute withdrawal group (odds ratio, 2.78; 95% confidence interval, 1.35-5.15; P= .0001). The ADR was similar between both groups (39.2% vs 40.6%; P= .84). However, the mean APC rate was significantly lower in the 3-minute withdrawal group (0.55 vs 0.80; P= .0001). The AMR was significantly higher, and the APC rate was significantly lower in the 3-minute withdrawal group versus the 6-minute withdrawal group. Despite expert technique, a shorter withdrawal time is associated with an unacceptably high AMR and low APC rate. (Clinical trial registration number: NCT01802008.).

Multitarget stool DNA test: clinical performance and impact on yield and quality of colonoscopy for colorectal cancer screening

Multitarget stool DNA (MT-sDNA) testing is now approved by the U.S. Food and Drug Administration for average-risk colorectal cancer screening. Trials leading to its approval used blinded colonoscopy as the reference standard. In the postapproval screen setting, the clinical performance and impact of MT-sDNA testing on unblinded colonoscopy has not been described. We measured the impact that knowledge of a positive MT-sDNA test result has on colonoscopy yield and quality. The unblinded group comprised all patients with positive MT-sDNA results on screening from September 1, 2014 to September 30, 2015 at a single tertiary center. Off-label test patients were excluded. The blinded group included all MT-sDNA-positive participants in a preapproval screening study from the same center. Detailed colonoscopy findings and withdrawal times were recorded. There were 172 MT-sDNA-positive patients in the unblinded group and 72 in the blinded group. Moretotal adenomatous/sessile serrated polyps (70% vs 53%, P= .013) and advanced neoplasms (28% vs 21%, P= .27) were detected in unblinded than in blinded groups. Median numbers of polyps detected were 2 (IQR, 1-4) and 1 (IQR, 0-2) in unblinded and blinded groups, respectively (P= .0007). Among polyps detected, flat or slightly raised lesions in the right side of the colon were proportionately more frequent with unblinded (40%) than with blinded examinations (9%) (P= .0017). Median withdrawal time was 19 minutes (IQR, 13-29) in the unblinded group compared with 13 minutes (IQR, 10-20) in the blinded group (P= .0001). Knowledge of a positive MT-sDNA result appears to have a beneficial impact on the diagnostic yield and quality of subsequent colonoscopy.

Clinical Predictors of Colonic Sessile Serrated Adenomas Include Obesity, Smoking, and Cancers Outside of GI System

Introduction: Sessile serrated adenomas (SSAs) are precursors to colorectal cancer (CRC). Here we aimed to identify factors which may predict an increased likelihood of the presence of SSAs during colonoscopy. Methods: We collected retrospective data for all patients diagnosed with SSAs in our institution during year 2014 to include patient history, clinical characteristics, and factors related to colonoscopy. Results: SSAs were found in 2.1% (119 patients) of all colonoscopies. Average age at the time of SSA detection was 59 years; 53% cases were in females; 7% had family history of colonic polyps and 11% of colon cancer. The majority (77%) of patients with SSA were overweight/ obese (BMI>25), with BMI 29.68±6.78 (average±SD). A minority of patients with SSAs took aspirin (24%), NSAIDs (12%) or statins (23%); 21% of them had cardiovascular co-morbidity, 17% had diabetes and 32% had known cancers outside of gastrointestinal system. Majority (53%) of patients with SSA were tobacco smokers. The colonoscope withdrawal time was 21±11 minutes and 60% cases had bowel prep good or better. The SSAs were located in the right colon in 43%; 13% SSAs were found in both right and left colon. One third (29%) SSA cases were performed with participation of fellow in training. Conclusion: We conclude that obesity, smoking, and presence of cancers outside of gastrointestinal system are features that that may lead to a higher suspicion for SSAs. Intake of agents known to reduce incidence of colorectal neoplasia, such as of ASA or NSAIDS, is infrequent among newly diagnosed SSA cases. Unlike previous reports of predominant prevalence of SSAs in the right colon and in female, we report that SSAs are equally present in males and distributed with equal frequency throughout GI tract. Finally, case performance with fellow, which are usually associated with prolonged examination, did not predict increased detection of SSAs. Describing clinical features of SSAs which may increase the suspicion for these higher risk polyps can be validated in prospective studies.

A review of withdrawal time of colonoscopy

A review of withdrawal time of colonoscopy

PTU-027 Colonoscopy Withdrawal Time in Non-Screening Colonoscopies. 6 Minutes or Not?

Introduction Several studies have shown that, in screening colonoscopies, ADR is significantly related to endoscopists with a colonoscopy withdrawal time (CWT). 1 A CWT of more than than 6 minutes is recommended. Studies have also demonstrated that if the endoscopists aware of being monitored they might increase their CWT (the Hawthorne effect). The bowel cancer screening program actively monitors the CWT of endoscopists to ensure that all colonoscopies are of adequate quality but non-screening colonoscopies are not routinely monitored in the same way. Methods We prospectively looked at 19 endoscopists’ practice of colonoscopy of 210 procedures. This included 10 gastroenterologists and 9 non-gastroenterologists. We calculated their withdrawal time by looking at time duration between caecal and rectal retroflexion images. Exclusion criteria included procedures that were incomplete, poor preparation, screening patients, patients in whom polyps were found and planned therapeutic procedures. In order to avoid ‘Hawthorne effect’, endoscopists were unaware that they were being monitored. Subsequent to that we did a statistical analysis to see if withdrawal time correlated with adenoma detection rate. The ADR was available from the unit’s annual endoscopy audit. Results CWT was less than 6 minutes in 20% of procedures. The mean CWT varied greatly among endoscopists. The mean CWT was significantly longer where the endoscopist was a gastroenterologist rather than a non-gastroenterologist (p = 0.0003). All of the endoscopists that had a mean CWT less than 6 minutes were part of the non-gastroenterologist group. Although we found ADR levels lower in mean CWT of less than 6 minutes and a positive correlation, this however did not reach statistical significance(p = 0.62). Conclusion In our study we found in majority of the non-screening colonoscopies, withdrawal time was more than the recommended 6 minutes. Statistically significant correlation between ADR and withdrawal in non-screening colonoscopies may be achieved by participating in large multi-centred studies. Reference 1 Lee TJ, Blanks RG, Rees CJ, Wright KC, Nickerson C, Moss SM, Chilton A, Goddard AF, Patnick J, McNally RJ, Rutter MD. Longer mean colonoscopy withdrawal time is associated with increased adenoma detection: evidence from the Bowel cancer screening programme in England. Endoscopy 2013; 45 (1):20–6. Disclosure of Interest None Declared

PWE-110 Post Endoscopy Missed Colorectal Cancer at A Local DGH - Implication for Practice

Introduction Colonoscopy is the “gold standard” approach to investigating symptoms in relation to the colon. However, recent literature has shown that colonoscopy as a diagnostic test for colorectal cancer is far from perfect with a cancer missed rate of 8.6% in the UK. We aim to identify the rate of colorectal cancers diagnosed following a negative flexible sigmoidoscopy and/or colonoscopy and to explore contributing factors. Methods This is a retrospective case analysis investigating all patients who received a diagnosis of colorectal cancer over a five-year period (2010–2015). We used our local clinical databases in identifying those patients who had negative flexible sigmoidoscopy and/ or colonoscopies but subsequently received a diagnosis of colorectal cancer. Results 368 (Females 156; males 167; average age 76.71) patients were included in the initial sample. Of those 45 were excluded as an initial endoscope examination was not carried out and the cancers were identified by other means. Of 368 patients who were diagnosed with colorectal cancer, 35 (10.83%) had a previously normal endoscopic examination (19 flexible sigmoidoscopy; 16 colonoscopy) Conclusion This research has shown that despite being the gold standard, colonoscopy as a diagnostic test for colorectal cancer is still far from perfect. In keeping with current research there appears to be a missed rate in detection of colorectal cancers, polyps and adenomas. Factors contributing to missed lesions are thought to be the presence of >2 lesions, lesions present in the left side of the colon, withdrawal time where longer withdrawal time was associated with higher lesion detection rate. Furthermore the smaller the lesion the lower the detection rate on colonoscopy (missed rate: 6% in adenomas >1 cm; 27% in adenomas References 1 Rex DK, Cutler CS, Lemmel GT, Rahmani EY, Clark DW, Helper DJ, Lehman GA, Mark DG. Colonoscopic miss rates of adenomas determined by back-to-back colonoscopies. Gastroenterology 1997; 112 (1):24–8. 2 Barclay RL, Vicari JJ, Doughty AS, Johanson JF, Greenlaw RL. Colonoscopic withdrawal times and adenoma detection during screening colonoscopy. New England Journal of Medicine 2006; 355 :2533–2541. Disclosure of Interest None Declared

Optimizing Colonoscopy Quality: From Bowel Preparation to Surveillance.

Colonoscopy is a powerful screening method for colorectal cancer. However, colonoscopy performance is highly variable and quality indicators are needed to ensure delivery of high-quality healthcare. A multi-society task force has recently identified three priority quality indicators in colonoscopy: adenoma detection rate, cecal intubation rate, and adherence to surveillance guidelines. The best-studied quality indicator is the adenoma detection rate, which is inversely correlated to the risk of interval colorectal cancer. Other important quality determinants include colonoscopy withdrawal time and the bowel preparation quality. It is important to note that these quality metrics are interrelated and optimization at every level is necessary for any high-quality colorectal cancer screening and prevention program.

The Impact of Colonoscopy Quality Control Table on Adenoma Detection Rates.

Objective. This study aims to investigate the effects of reporting colonoscopy findings and the regular review of outcomes on adenoma detection rates. Methods. Patients who underwent colonoscopy from August 2013 to February 2014 were selected as the intervention group. The preintervention group included patients who underwent colonoscopy from January 2013 to July 2013, in which the procedure sheet for this group of patients was not accomplished. The primary outcome was adenoma detection rate (ADR), and secondary outcomes included the success rate of intubation and withdrawal time. Results. This study included 2,467 cases: 1,302 cases in the intervention group and 1,165 cases in the preintervention group. There was no significant difference in demographic characteristics between the two groups. In the intervention group, withdrawal time of colonoscopy was longer (P < 0.01), and the success rate of intubation (92.5% versus 89.1%, P < 0.05) and detection rate of polyps (32.6% versus 27.6%, P < 0.05) and adenomas (20.0% versus 16.1%, P < 0.05) were higher. Significantly high detection rates for proximal adenomas, flat adenomas, and adenomas with a diameter <5 mm were observed in the intervention group (all P < 0.01). Conclusion. The reporting and review of procedure details help to improve quality indicators of colonoscopy.

Audit of colonoscopy practice in Lagos University Teaching Hospital

Introduction: Recent procurement of new endoscopies and accessories led to the reactivation of diagnostic and therapeutic colonoscopy services at our center. A preliminary audit is deemed necessary after a 2-year period of open access colonoscopy. Objective: To assess the pattern of indications, diagnostic yield, and selected key performance indicators in the practice of colonoscopy at our tertiary hospital. Patients and Methods: The endoscopy reports of all patients that underwent colonoscopy from January 2012 to April 2014 were reviewed. The demographic data, indications, and endoscopic findings were recorded. Information on cecal intubation, colonoscopy withdrawal time, polyp detection, adverse events, and bowel preparation quality were also extracted and analyzed. Results: Colonoscopy was performed in 149 patients. They were 81 males and 68 females, aged between 18 and 101 years with a mean of 46.9 ± 22.7 years. 126 (84.5%) patients had a colonoscopy for symptomatic conditions while 5 (4%) were for screening. Bowel preparation was assessed to be excellent in 81 (54.4%), adequate in 42 (28.2%), and inadequate in 26 (17.4%) patients, respectively. The cecal intubation rate (CIR) was 80.2%, polyp detection rate 7.4%, average colonoscopy withdrawal time was 6 min 53 s, overall diagnostic yield 55.9% and there were no adverse events. Tumors were seen in 19 patients (10.1%); 13 were located in the rectum, three in the sigmoid and three in the descending colon. Conclusion: The audit revealed that our CIR could be improved by a more effective bowel preparation, increased expertise, and procedure volume of endoscopists. Tumors of the colorectum were detected in 10.1% of patients.

Determinants of Bowel Preparation Quality and Its Association With Adenoma Detection

The predictors of poor bowel preparation in colorectal cancer screening participants have not been adequately studied, and the association between the quality of bowel preparation and adenoma detection has not been firmly established. This study examined the determinants of poor bowel preparation, and evaluated its relationship with adenoma detection.We included subjects aged between 50 and 70 years who received colonoscopy between 2008 and 2014 in a colorectal cancer screening program in Hong Kong. The quality of the bowel preparation was assessed by colonoscopists, and the factors associated with poor bowel cleansing were evaluated by a binary logistic regression analysis. A multivariate regression model was constructed to evaluate if poor bowel preparation was associated with detection of colorectal neoplasia.From 5470 screening participants (average age 57.7 years, SD 4.9), 1891 (34.6%) had poor or fair bowel preparation. The average cecal intubation time was 7.0 minutes (SD 5.4; range 1.22–36.9 minutes) and the average colonoscopy withdrawal time was 10.8 minutes (SD 6.9; range 6.0–107.0 minutes). Among all, 26.5% had colorectal neoplasia and 5.5% had advanced neoplasia. Older age (≥60 years; adjusted odds ratio [AOR] = 1.19–1.38, P = 0.02–0.04), male sex (AOR = 1.38, 95% confidence interval [CI] 1.19–1.60, P < 0.001), and current smoking (AOR = 1.41, 95% CI 1.14–1.75, P = 0.002) were significantly associated with poor/fair bowel preparation. Poorer cleansing resulted in significantly lower detection rate of neoplasia (AOR = 0.35–0.62) and advanced neoplasia (AOR = 0.36–0.50) irrespective of polyp size.Steps to improve proper procedures of bowel preparation are warranted, especially among subjects at risk of poor bowel preparation. Strategies should be implemented to improve bowel cleansing, which is now demonstrated as a definite quality indicator.

Procedure Delays and Time of Day Are Not Associated With Reductions in Quality of Screening Colonoscopies.

There have been conflicting results from studies to determine whether factors unrelated to endoscopist skill, such as fatigue, affect the quality of screening colonoscopy. We studied the effects of human and system factors on screening colonoscopy withdrawal time and likelihood of detecting an adenoma in a large cohort of patients. We performed a retrospective analysis of operation and quality improvement data in colonoscopies performed at single academic medical center from November 2012 through February 2014. We collected data from the Northwestern Medicine Enterprise Data Warehouse on endoscopy procedure reports, patient demographics, and pathology reports of all patients undergoing endoscopy. We identified all screening colonoscopies during the study period and determined whether an adenoma was identified in each screening colonoscopy procedure. Our study included data from 7004 screening colonoscopies of patients 50-75 years old performed by endoscopists who performed at least 100 screening colonoscopies during the study period (n = 18). Approximately 27% of procedures began on time; the median colonoscope insertion time was 5.9 minutes (interquartile range, 4.0-8.6). In multivariable logistic regression analysis adjusting for covariates and endoscopist-level clustering, adenoma detection was not associated with procedure delay (P = .48), hour of day (P = .40), or performing the second of 2 colonoscopy blocks in 1 day (P = .88). Adenoma detection was associated with insertion time overall (P = .006), but there was no consistent directional relationship across insertion quintiles. Procedure delays and measured factors associated with fatigue, including time of day and multiple procedure blocks, do not reduce the odds of detecting an adenoma. Adenoma detection varies widely among providers, so efforts to improve adenoma detection should focus mainly on optimizing physician skill.

Screening Colonoscopy Withdrawal Time and Proximal Serrated Polyp Detection Rate: Analysis of a Large, Single, High-Volume Center Using Natural Language Processing: ACG Fellows-In-Training Award

Screening Colonoscopy Withdrawal Time and Proximal Serrated Polyp Detection Rate: Analysis of a Large, Single, High-Volume Center Using Natural Language Processing: ACG Fellows-In-Training Award

Demonstrating that colonoscopy is high quality.

Colonoscopy is the gold standard investigation for examining the lower GI tract [1]. It plays a fundamental role in investigation of symptomatic individuals and in screening for colorectal cancer (CRC) [2,3]. Colonoscopy must be high quality in order to maximize its benefit [4]. Poor-quality colonoscopy is associated with increased interval cancer rates [4]. High-quality colonoscopy involves a complete procedure that provides comprehensive inspection of colonic mucosa [5]. There are a number of markers of colonoscopy quality, [2,6,7] with cecal intubation rate (CIR) historically being the most widely reported [8]. Cecal intubation was previously confirmed by written documentation of the cecal landmarks; however, photo-documentation of the cecum is now the accepted method of confirming colonoscopy completion. The European Society of Gastrointestinal Endoscopy (ESGE) guidelines recommend that such photo-documentation includes images of both the ileocecal valve and the cecum with views of the appendiceal orifice [9]. CIR is variable and many measures have been used to improve it [10–12]. The United Kingdom has engaged in a comprehensive quality improvement program with significant improvements [10,13]. Other countries have demonstrated similar results [14]. Although CIR is an important marker of completion of a procedure, other markers of quality include adenoma detection rate (ADR), bowel preparation, rectal examination and rectal retroflexion, colonoscopy withdrawal time (CWT), polyp retrieval, and complication rates [15–21]. Furthermore, comfort scores, tattooing of suspected malignant lesions in the colon, and taking diagnostic biopsies for unexplained diarrhea are seen as quality markers in addition to the rate of postcolonoscopy colorectal cancer [22–25]. Clinician performance in each of these areas is variable, but those who perform well tend to do so across all measures [22]. Among all measures, the most important marker of colonoscopy quality is adenoma detection rate [15–17]. ADR has clearly been shown to correlate with interval cancers [4]. Patients scoped by colonoscopists with high ADRs have lower interval cancer rates [4]. Furthermore, patients scoped by colonoscopists with higher ADRs have lower CRC mortality rates [16]. Polyp detection rate (PDR) can be used as a surrogate marker of ADR [26]. The paper, “Meticulous cecal image documentation at colonoscopy is associated with improved polyp detection,” published in this edition of Endoscopy International Open, explores the link between polyp detection rates and the quality of cecal photo-documentation. The paper reports a correlation between good-quality cecal photodocumentation and higher PDRs, including rightsided polyp detection (although some of these were hyperplastic polyps). Right-sided lesions are of particular interest and it may be that failure to detect them is one reason that screening programs are not adequately preventing right-sided colorectal cancer [27,28]. The reason for the correlation between PDR and image quality may be that colonoscopists who take time to capture convincing cecal images are generally more careful in their withdrawal examination. Another explanation may be that these “meticulous” colonoscopists have better control over the endoscope, which leads to better mucosal visualization. Longer mean CWTs are associated with increased adenoma detection, and are more relevant than total procedure times, as the majority of mucosal visualisation occurs on withdrawal of the colonoscope [19,29]. Although there was no statistically significant difference in procedure duration between “meticulous” and “non-meticulous” endoscopists in this study, the

Bowel Preparation, Colonoscopy Withdrawal Time and Adenoma Detection Rate: A Prospective Study of Screening Colonoscopies

There are few studies on the determinants of poor bowel preparation among colorectal cancer screening participants, and current evidence on the association between bowel preparation and adenoma detection was inconclusive. We evaluated the independent factors associated with poor bowel preparation and its impact on adenoma detection. We included asymptomatic subjects aged between 50-70 years who self-referred for colorectal cancer screening and received colonoscopy between 2008 and 2012 in Hong Kong. The quality of the bowel preparation was assessed by colonoscopists, and the factors associated with poor bowel cleansing were evaluated by binary logistic regression analyses. A multivariate regression model was constructed to evaluate if poor bowel preparation was associated with detection of colorectal neoplasia. From 5,470 screening participants with an average age of 57.7 years (SD 4.9), up to 34.6% had poor or fair bowel preparation. The level of poor or fair bowel preparation was as high as 34.6%. After controlling for sociodemographic and clinical factors, older age (≥ 60 years; adjusted odds ratio [AOR]=1.19 to 1.38, P = .017-0.038), male gender (AOR=1.38, 95% C.I. 1.19-1.60, P < .001), and smokers (AOR=1.41, 95% C.I. 1.14-1.75, P = .002) were significantly associated with poor or fair bowel preparation. Poorer cleansing led to longer caecal intubation time and colonoscopy withdrawal time, yet resulted in significantly lower detection rates of colorectal neoplasia (AOR=0.35 to 0.62) and colorectal advanced neoplasia (AOR=0.39 to 0.50) irrespective of their diameter (< 5mm or ≥ 5mm). Steps to improve proper procedures of bowel preparation are warranted, especially among subjects at risk of poor bowel preparation. These include more intensive preparation protocols and measures to improve patient understanding of bowel preparation as parts of continuous quality-improvement programmes. This study supports bowel preparation as a definite quality indicator.

Sa1639 Impact of Bowel Preparation Quality on Detection of Non-Polypoid Colorectal Neoplasms and Their Prevalence in Average-Risk Screening Colonoscopy

family history, colonoscopy history, or withdrawal time of colonoscopy; prior history of invasive CRC, inflammatory bowel disease, or familial adenomatous polyposis. Patients who had undergone colonoscopy performed by a colonoscopist who had experience with!30 colonoscopies during the study period were also excluded. Colonoscopists who participated in the study were divided into following 3 groups, based on median withdrawal time of negative colonoscopy:!6 min (group A); 6-9 min (group B); and R10 min (group C). We analyzed the relationship between the withdrawal time group and adenoma detection rate using multiple logistic regression. The odds ratios were adjusted according to age, sex, past history of CRC, family history of CRC, past history of colonoscopy, and whether or not a distal attachment was used. Results: The final analysis included 4988 patients. Compared with group A, the odds ratios for detection of any adenoma or cancer by colonoscopists in group B, and group C were 1.53 (95% confidence interval [CI], 1.15-2.04) and 1.95 (95% CI, 1.45-2.63), respectively. For detection of advanced neoplasia, the respective odds ratios were 1.61 (95% CI, 0.95-2.73) and 1.97 (95% CI, 1.15-3.37). Conclusions: The results of this study suggest that a colonoscopy withdrawal time of over 6 min would be a useful quality indicator of colonoscopy in the Japanese setting. Relationship between colonoscopist groups and adenoma detection rates

Sa1638 Colonoscopy Withdrawal Time and Adenoma Detection Rate: a Japanese Multicenter Analysis

Several studies in Western countries have yielded conflicting results regarding whether colonoscopy withdrawal time should be used as a quality indicator of colonoscopy. In Japan, limited evidence exists on the relationship between colonoscopy withdrawal time and adenoma detection rate. We have previously reported on the clinical impact of the frequency of colonoscopy follow-up for colorectal cancer (CRC) prevention in a Japanese multicenter study. The objective of the present study was to review the circumstances surrounding quality issues in the previous study, and to clarify the clinical impact of colonoscopy withdrawal time in the Japanese setting.

Effect of 6-minute colonoscopy withdrawal time policy on polyp detection rate in a community hospital.

In 2002, a U.S. Multi-Society Task Force on colorectal cancer recommended a 6-minute or more withdrawal time as an indicator of a quality colonoscopy. In 2006, found a correlation between longer withdrawal time and an increased rate in the detection of adenomas. In January 2008, the endoscopy department at our institution adopted the Multi-Society Task Force recommendation. The aim of our study was to evaluate the effect of a minimal 6-minute withdrawal time policy at our institution on polyp detection rate. All colonoscopies performed for screening indications from April 2007 to September 2008 were reviewed retrospectively. Group I (pre-policy) was compared with Group II (post-policy). Data collected included age, gender, indication, polyp detection rate, size, and withdrawal time. Unpaired t tests evaluated pre- and postprocedure results. Fisher's exact tests were used to compare detection rates between withdrawal time less than 6 minutes and more than 6 minutes. Mann-Whitney U Tests were performed to analyze the significance between the number of polyps detected for withdrawal time less than 6 minutes versus more than 6 minutes. A total of 1,342 colonoscopies were available for analysis in Group I and 1,316 in Group II. Polyp detection rate was 46.6% in Group I versus 48.2% in Group II (p = .39), a non-statistically significant difference; however, there was a trend toward identifying small- and medium-sized polyps in Group II. Small polyps can carry a risk of severe dysplasia (). Data were then analyzed for withdrawal time. The polyp detection rate was 20.9 in procedures that took less than 6 minutes versus 48.3 in those that took more than 6 minutes (p ≤ .01). In this study, a 6-minute or more withdrawal time increased the polyp detection rate by 133% for all polyp sizes, especially small and medium. Small polyps (5 mm or less) should be removed and not ignored. A 6-minute or more withdrawal time should be mandatory in those patients without a previous colon resection.

Assessing Multiple Variables in Adenoma Detection: An Interim Analysis

Introduction: To examine the impact of key variables such as anatomic abnormalities, patient age, and prep quality on colonoscopy withdrawal time and adenoma detection rate for screening exams. Methods: Approximately 2,000 paper and electronic records of colonoscopies from October 2012-October 2013 in an outpatient endoscopy center were manually reviewed. Screening colonoscopies on asymptomatic patients were included. Patients with recent endoscopy (>1 year), personal history of inflammatory bowel disease, familial adenomatous polyposis, or Lynch syndrome were excluded. Personal or family history of polyps was not exclusive. Variables including patient age, gender, number of polyps, polyp location, histology, withdrawl time (WT), prep and view quality, sedation dose, and performing endoscopist were recorded as continuous or categorical where appropriate. Data were analyzed using Microsoft Excel 2010 with Analysis ToolPak®. Chi-squared analysis, Student t test, linear regression, and ANOVA were applied to assess significance where appropriate. Results: One thousand-eight patients treated by 9 endoscopists met criteria for review. The mean age was 61.4±9.6 years; 53.3% patients were male and 47.7% were female. The mean WT was 13.4 minutes for all endoscopists (range: 9.7-18.4 minutes). The ADR was 37.8% among all endoscopists (range: 7-48%). Six hundred forty-eight (64.3%) patients were found to have polyps of any kind. Three hundred eighty-two (59.0%) of those patients had adenomatous polyps, and those with adenomas had 1.9 on average (SD 1.43). The presence of diverticulae, adhesions, or other noticeable anatomical abnormalities increased WT by 1.07 minutes (p=0.02), but did not affect ADR (p=0.34). Quality of bowel prep had no relationship with ADR (Chi-squared 0.18; DF 3; p=0.97), but was associated with a longer WT (12.8 minutes for excellent vs 16.8 minutes for fair or poor; p<0.01). Older age was associated with increased presence of adenomas (p<0.01). There was a trend toward longer WT with older age that did not reach statistical significance (p=0.23). Conclusion: Diverticulosis and other anatomic abnormalities tended to increase the time needed to adequately survey the colon. The quality of bowel prep may increase the time needed for adequate exam, but did not alter ADR in this series. Age was not independently associated with longer WTs. By increasing WT over the minimum accepted time, the ADR in this series is 37.8%, well over standard accepted rates of 25%. Disclosure - Dr. Randall - serves as a consultant to UCB, Bristol-Meyers Squibb, Takeda, Janssen, Salix, Abbvie, Amergen, Ironwood, Forest, Romark, Vecta, EnteraHealth, Boston Scientific, and Furiex. Dr. Taboada - nothing to disclose. Dr. Vizuete - nothing to disclose. Dr. Wendorf - nothing to disclose. Dr. Ayyar - nothing to disclose. Dr. Constantine - nothing to disclose.

Colonic Polyp Detection Rates Before and After Documentation of Colonoscopic Withdrawal Time

Colonic Polyp Detection Rates Before and After Documentation of Colonoscopic Withdrawal Time

229 A Prospective, Randomized Trial of Adenoma Miss Rates At Colonoscopy Associated With 3-Minute vs. 6-Minute Withdrawal Time

Introduction: A minimum withdrawal time for screening colonoscopy of 6 minutes has been proposed, based on an observational study. The 6-minute withdrawal time remains controversial and has not been compared in a standardized fashion to alternate withdrawal times. Aim: To perform a prospective, randomized trial to compare adenoma miss rates (AMR) associated with withdrawal times of 6 minutes vs. 3 minutes. Methods: Consecutive patients undergoing colonoscopy at Stanford University and Palo Alto Veterans Administration Hospital were randomized to undergo either a 3-minute or 6-minute withdrawal (1st pass), followed immediately by a tandem 6-minute withdrawal (2nd pass). AMR was defined as the number of adenomas detected on the 2nd pass divided by total number of adenomas found. A chi-square statistic was used to directly compare AMR. A z-statistic was used to determine effect of polyp size/location on AMR. A mixed-effects logistic regression model was then created to compare AMR, controlling for endoscopist, size/location of adenoma, and patient. Finally, a Cochrane-Armitage test for trend was used to evaluate the trend of adenoma detection associated with increasing withdrawal time. Results: 200 subjects were enrolled (99 in the 3-minute group, 101 in the 6-minute group). Demographics and indications for colonoscopy were similar between the two groups (Table 1). AMR was significantly higher in the 3-minute withdrawal group compared to the 6-minute withdrawal group (48.5% vs 21.8%; p≤0.0001). Adenomas were significantly more likely to be missed in the 3-minute withdrawal group in all 3 locations of the colon (right, transverse and left colon). AMR was higher in the 3-minute withdrawal group among adenomas that were ≤5mm; there was no significant difference in AMR for adenomas that were 6-9mm or ≥10mm. After controlling for endoscopist, size/location of the polyp/adenoma, and the patient, AMR remained significantly higher in the 3-minute withdrawal group compared to the 6-minute withdrawal group (OR 2.92, 95% CI=1.54-5.55) (Table 1). Adenoma detection rate (ADR) was similar between both 3 and 6 minute withdrawal groups (38.4% vs 40.6%, p=0.75); however, this study was not powered to detect differences in ADR. There was a significant trend towards higher total number of adenomas detected as withdrawal time increased (52 at 3 minutes, 87 at 6 minutes, 101 at 9 minutes, and 111 at 12 minutes; p<0.001) (Figure 1). Conclusions: A 3-minute withdrawal time leads to an unacceptably high AMR. A 6minute withdrawal time is more appropriate for colorectal cancer screening. Location did not affect AMR; however, adenomas that were ≤5mm were more likely to be missed in the 3-minute withdrawal group. Further research into the optimal withdrawal time, including evaluation of withdrawal times longer than 6 minutes, is warranted.