Detection Rate Of Colon Polyps Research Articles

Bowel preparation efficacy and safety of compound polyethylene glycol electrolyte powder combined with linaclotide for colonoscopy: A randomized controlled trial.

Adequate bowel preparation is essential for colonoscopy, which is important for detecting colon polyps and preventing colorectal cancer. Linaclotide is approved for irritable bowel syndrome with predominant constipation (IBS-C) symptoms. The main objective of this study was to explore the quality of bowel preparation by low-volume compound polyethylene glycol (PEG) combined with linaclotide. A total of 266 patients who underwent colonoscopy in Shangrao People's Hospital from June 2021 to June 2022 were randomized to 1 of 3 split PEG regimens: 4LPEG, 2LPEG, and 2LPEG + L (linaclotide). The primary end point was adequate bowel preparation (Boston Bowel Preparation Scale [BBPS] total score of ≥6, with each of three colonic segments subscores ≥2). Secondary outcomes were polyp detection rates and the incidence of adverse reactions. Over 12 months, 266 subjects were randomized into 2LPEG (n = 12), 4LPEG (n = 112), or 2LPEG + L (n = 142). There were no significant differences between the 4LPEG and 2LPEG + L groups in achieving adequate bowel preparation (P > 0.05). The mean BBPS score of the total colon, left hemi-colon, right hemi-colon, and transverse in the 2LPEG + L group was higher than that in the 2LPEG group (P < 0.001). Patient's sleeping quality and the incidence of adverse reactions of 2LPEG + L group were compatible with 2LPEG group, but it was significantly lower than that in 4LPEG group. There was no statistically significant difference in the detection rate of colon polyps between each group. The quality of bowel preparation of the compound polyethylene glycol electrolyte powder combined with linaclotide is approximately the same as that of 4LPEG, and it can reduce the adverse reactions in the process of bowel preparation, and its intestinal cleansing effect is also better than that of 2LPEG.

Quantitative immunochemical fecal occult blood test in health check-up population

Objective To assess the application of quantitative immunochemical fecal occult blood test (qFIT) in screening of gastrointestinal diseases for health check-up population. Methods Total 19 633 health check-up subjects, who received qFIT in AiKang Guobin Physical Examination Center from January 2018 to June 2019 qFIT, were enroll in the study. The positive rate of subjects who received qFIT were analyzed. Gastrointestinal endoscopy were used to diagnose gastrointestinal lesions. The application of qFIT in screening gastrointestinal diseases, especially colorectal cancer and precancerous lesions was evaluated. Results Total 718 (3.66%) subjects were positive for qFIT, among whom 103 (42.3%) underwent gastrointestinal endoscopic examinations. Finally, 33 (42.3%) cases of colon adenoma, 9 (11.5%) cases of peptic ulcer, and 4 (3.1%) cases of colorectal cancer were detected; and other conditions including gastroenteritis and hemorrhoids were were also diagnosed. There were 87 cases whose qFIT were negative performed colon endoscopy, 5 (5.7%) cases of colon adenoma, no colorectal cancer were detected. The mean value of qFIT for colon cancer was higher than that for polyps (3 569±1 085)μg/L vs. (823±106) μg/L, P=0.01]. The detection rate of colon polyps in qFIT positive subjects was higher than that in qFIT negative subjects [32%(33/103) vs.5.7% (5/87)], and the detective rate of colon cancer in qFIT positive subjects was higher than that in qFIT negative subjects [3.9%(4/103) vs.0(0/87)]. Conclusion Quantitative immunochemical fecal occult blood test can improve the detection rate of colorectal cancer and precancerous lesions in screening of gastrointestinal diseases. Key words: Occult blood; Feces; Colonic neoplasms; Healthy examination

Clinical significance of colorectal polyp detection on colonoscopy insertion.

Colorectal lesions are generally evaluated during the withdrawal phase of colonoscopy. Minimising the risk of missed lesions is crucial to determine an appropriate future surveillance colonoscopy interval. This study aimed to evaluate the clinical significance of detecting sigmoid colon lesions during the insertion phase. This retrospective study included 172 consecutive patients undergoing colonoscopy between October 2017 and April 2018. The total number of detected polyps, mean polyps per procedure, mean polyps per positive procedure, and histological and clinical characteristics of detected lesions were recorded. The primary endpoint was the difference in sigmoid colon polyp detection rates during insertion and withdrawal. A total of 172 colonoscopies were performed for each patient and 322 lesions were detected. Sixty-two (19%) polyps were detected during insertion, 312 (97%) during withdrawal, and 52 (16%) during both insertion and withdrawal. Although all polyps except for those in the sigmoid colon could be detected during withdrawal, 10 of 87 (11%) polyps in the sigmoid colon could only be detected during insertion. In this study, attempts to detect polyps, even in the insertion phase, showed the clinical significance to decrease the risk of missed adenomatous polyps in the sigmoid colon.

Comparison of colon polyp detection rate with full-spectrum endoscopy versus forward-viewing colonoscopy

Comparison of colon polyp detection rate with full-spectrum endoscopy versus forward-viewing colonoscopy

Timed colonoscopy withdrawal, a mandatory quality measure in the era of national screening?

A minimum recommended withdrawal time for screening colonoscopy is recommended for by both the US Multi-Society Task Force on Colorectal Cancer and European Society of Gastrointestinal Endoscopy. To characterize the relationship between endoscopists withdrawal time at colonoscopy and polyp detection in a symptomatic cohort of patients as compared to previously untimed withdrawal. Three experienced medical endoscopists prospectively performed 1079 colonoscopies during a 24-month period in an Irish hospital. Mean withdrawal time and individual polyp detection rate were noted. Introduction of mandatory withdrawal time which was monitored and documented was associated with higher polyp detection rate (33 versus 21%, p < 0.005) as compared to previously untimed withdrawal. Our findings support a monitored colonoscopy withdrawal time of at least 6min, which correlates with higher colon polyp detection rates in a symptomatic cohort.

Clinical application of simethicone emulsion on bowel preparation for colonoscopy

Objective To assess the clinical effects of simethicone emulsion combined with polyethylene glycol on bowel preparation for colonoscopy. Methods Two hundred out-patients, who underwent colonoscopy, were randomly divided into the study group and the control group. The study group was given simethicone in addition with polyethylene glycol, and the control group was given polyethylene glycol only. The differences on bowel preparation scores, air bubble reduction rate, colon lens sharpness, ileocecal region arrival time, colon polyp detection rate, the number of colon poly detection, and adverse event rate between the two groups were compared. Results The air bubble reduction rate, colon lens sharpness score and ileocecal region arrival time of the study group was 1(0-3) score, 1.0(0-2) score, and 9 (5-21) min, respectively, which was 2 (1-3) score, 1.5 (0-2) score and 12 (6-22) min, respectively in the control group. Differences between the two groups were statistically significant(Z=-9.490, P=0.000; Z=-6.768, P=0.000; Z=-5.521, P=0.000). For the bowel preparation score, colonoscopy polyp detection rate, the detection rate of colon polyp of diameter less than 5 mm, and number of colonoscopy polyp detection, there was no statistical difference between the two groups (P>0.05). No adverse events were observed in the both two groups. Conclusion The bowel preparation using simethicone combined with polyethylene glycol could effectively decrease the number of air bubble, enhance colon lens sharpness and shorten operation time, which contributes significant improvement for colonoscopy quality. Key words: Colonoscopy; Bowel preparation; Simethicone; Polyethylene glycol

Paired comparison of procedural sequence in same-day bidirectional endoscopy with moderate sedation and carbon dioxide insufflation: A prospective observational study.

Background/Aims:Same-day bidirectional endoscopy (BDE) is a commonly performed procedure, but the optimal sequence of the procedure with carbon dioxide insufflation is not well established. In this study, we investigated the optimal sequence for same-day BDE without polypectomy under moderate sedation and carbon dioxide insufflation in terms of sedation doses and colonoscopy performance.Patients and Methods:We performed a prospective observational study of 63 asymptomatic patients who were admitted for physical check-ups. A colonoscopy-esophagogastroduodenoscopy (EGD) examination was performed first and then an EGD-colonoscopy examination was performed within 1.5 years.Results:The total procedure time, procedure complexity, bowel preparation quality, cecal intubation time, colon polyp detection rate, and adverse events were similar between the two study groups. The total doses of fentanyl and midazolam were significantly higher for the colonoscopy-EGD group than that for the EGD-colonoscopy group (70.8 ± 9.6 μg vs. 56.6 ± 9.2 μg and 6.1 ± 1.3 mg vs. 4.6 ± 1.1 mg, P < 0.0001 and P < 0.0001, respectively). The recovery time to discharge was significantly longer for the colonoscopy-EGD group compared to the EGD-colonoscopy group (38.5 ± 3.9 min vs. 31.9 ± 3.2 min, P < 0.001, respectively).Conclusions:EGD-colonoscopy is the optimal sequence for same-day BDE. In this order, the procedures are better tolerated, the sedation doses are reduced, and the recovery time is shorter.

Sa1435 Is There an Easy Way to Check the Detection Rate of Colon Polyps?: A Simple Colonoscopy Reporting System

Sa1435 Is There an Easy Way to Check the Detection Rate of Colon Polyps?: A Simple Colonoscopy Reporting System

Simple colonoscopy reporting system checking the detection rate of colon polyps.

To present a simple colonoscopy reporting system that can be checked easily the detection rate of colon polyps. A simple colonoscopy reporting system Kosin Gastroenterology (KG quality reporting system) was developed. The polyp detection rate (PDR), adenoma detection rate (ADR), serrated polyp detection rate (SDR), and advanced adenoma detection rate (AADR) are easily calculated to use this system. In our gastroenterology center, the PDR, ADR, SDR, and AADR test results from each gastroenterologist were updated, every month. Between June 2014, when the program was started, and December 2014, the overall PDR and ADR in our center were 62.5% and 41.4%, respectively. And the overall SDR and AADR were 7.5% and 12.1%, respectively. We envision that KG quality reporting system can be applied to develop a comprehensive system to check colon polyp detection rates in other gastroenterology centers.

167 Temporal Trends in the Detection of Right-Sided Colon Polyps: Summary Data of Large GI Practices

167 Temporal Trends in the Detection of Right-Sided Colon Polyps: Summary Data of Large GI Practices Nalini M. Guda*, Neil Gupta, Dominic Klyve, John I. Allen, Thomas M. Deas, Lin Huang, Scott R. Ketover, Kyle P. Etzkorn, Kumar G. Gutta, Steven Morris, Prateek Sharma, Lyndon V. Hernandez GI Associates, Milwaukee, WI; Yale University, New Haven, CT; Central Washington University, Ellensburg, WA; Atlanta Gastroenterology Associates, Atlanta, GA; Gastroenterology Associates, Fort Worth, TX; Boorland-Groover Clinic, Jacksonville, FL; Minnesota Gastroneterology, Minneapolis, MN; Digestive Health Specialists, Tacoma, WA; GI Associatesof N. Texas, Fort Worth, TX; Gastroenterology, University of Kansas Medical Center, Kansas City, KS; Gastroenterology, Loyola Medicine, Chicago, IL Although overall colorectal cancer incidence and mortality has decreased in those undergoing colonoscopy, there is still a concern regarding efficacy of colonoscopy in detection of right-sided colonic lesions and prevention of colon cancers on the right side. Quality measures in colonoscopy have traditionally looked at detecting adenomatous polyps from throughout the colon. Data regarding polyp detection and cancer prevention in the left vs. right side are sparse. Aim: To assess the temporal trends in polyp detection (right vs. left-sided) Methods: Data from the Gastroenterology Practice Management Group (GPMG) which comprises of large GI practices in the country were analyzed. All the participating groups did not have electronic records (EHR) and data collection was not consistent. There were seven groups that had contributed de-identified from January of 2009 to October of 2013. Locations of polyps, time trends for polyp detection and in particular detection of right-sided polyps were analyzed(proximal). Left-sided polyps included those distal to hepatic flexure and those proximal to hepatic flexure were considered right sided for the purpose of this analysis(distal). Statistical and time-series analysis of quarterly detection rates was conducted for individual sites and for the entire group. Special attention was paid to determine temporal trends p values refer to the probability of seeing changes in detection rates in random data. Results: During the five-year period summary there was an overall increase in colon polyp detection rates from 39% in 2009 to 47% in 2013. Based on polyp location there was no significant increase in left colon polyp detection rate the average annual increase was 0.6% (p Z 0.214). However, the right colon detection rate during the same time period increased by 2.1% per annum, and almost entirely accounted for the increase in detection rates (p! 0.001)(See graph and table). Conclusions: 1. There was an overall increase in polyp detection rates based on a registry from major GI practices in the country. 2. Majority of the increased detection appear to be accounted for by right-sided colonic polyps.3. Increased awareness, improvement in technology, quality improvement programs likely have contributed to the increase. None of these practice groups have any financial incentives attached to polyp detection rates.4. This is summary level data and hence there are limitations regarding demographics, pathology of the polyps detected, and indications for colonoscopy as predictive factors for polyp detection.

Detection of Polyps Including Adenomas in the Ascending Colon by Cap-assisted Chromocolonoscopy with Indigo Carmine.

Adenomatous polyps are precursors of colorectal cancer, and their removal is important because it could potentially reduce the incidence and mortality of colorectal cancer. These concepts have formed the basis for the removal of adenomatous polyps after detection.1 Nonpolypoid adenomas, which are at an increased risk of developing into colorectal cancer, are difficult to detect during routine colonoscopy, and small adenomas may be missed during colonoscopy.2 Cap-assisted colonoscopy and chromocolonoscopy have emerged as techniques with the potential to improve the detection of colon polyps. Cap-assisted colonoscopy uses a transparent plastic hood attached to the tip of the colonoscope to flatten the semilunar folds and improve mucosal exposure.3 A systemic research and meta-analysis of 12 studies that have examined the usefulness of cap-assisted colonoscopy for polyp detection found that cap-assisted colonoscopy was associated with improved detection of colorectal polyps.3 Chromocolonoscopy is a colonoscopic examination performed using the indigo carmine spray technique. Togashi et al.4 described that chromocolonoscopy increased the detection of neoplastic polyps and flat adenomas, particularly diminutive polyps, but did not increase the detection of advanced lesions.4 Hashimoto et al.5 showed that the adenomatous polyp detection rate of chromocolonoscopy was not better than that of standard colonoscopy. Thus, whether chromocolonoscopy using indigo carmine increases the detection of colorectal polyps remains controversial.4,5 Additional indigo carmine spraying during cap-assisted colonoscopy is expected to improve the detection rate of colon polyps, especially adenomatous polyps. Therefore, this study aimed to evaluate the usefulness of cap-assisted chromocolonoscopy in the proximal colon for routine colonoscopic examinations.6 Hood cap-assisted colonoscopic examination was first performed, followed by hood cap-assisted chromocolonoscopy with 0.2% indigo carmine, from the cecum to the hepatic flexure. The total number and characteristics of polyps were compared before and after spraying indigo carmine. Cap-assisted chromocolonoscopy was performed in 86 consecutive patients. Before indigo carmine spraying, a mean of 0.56 polyps per patient and 0.29 adenomas per patient (52% of the polyps) were found. After spraying of the dye, a mean of 0.62 polyps and 0.22 adenomas (36% of these additional polyps) were found additionally. Most (85%) of these additional polyps found after spraying were small (<0.5 cm). In total, a mean of 1.17 polyps and 0.51 adenomas (44% of total polyps) were found before and after spraying of the dye. In this study, hood cap-assisted chromocolonoscopy using indigo carmine showed a higher detection rate of polyps (especially, small polyps <0.5 cm) and adenomas in the ascending colon than cap-assisted colonoscopy without spraying of the dye. It is unclear whether cap-assisted chromocolonoscopy can increase the detection rate of polyps and adenomas compared with chromocolonoscopy without cap. This study has some limitations. It was a single-institution analysis, and a limited number of patients were included. Because only one laterally spreading tumor and one polyp >1 cm were observed in this study, the detection rate of laterally spreading tumors or large polyps could not be analyzed. The clinical significance of these small adenomas that can be found only after spraying a contrast agent needs to be further investigated.2

A Korean experience of the use of Boston bowel preparation scale: a valid and reliable instrument for colonoscopy-oriented research.

Background/Aims:Few bowel preparation scales have been validated. The Boston Bowel Preparation Scale (BBPS) is a novel bowel preparation scale in western countries. We validated the BBPS in Korean patients and assessed the relationship between the colon polyp detection rate and BBPS score.Patients and Methods:This study was a prospective, single-center trial. The BBPS is a 10-point scale that assesses bowel preparation after the completion of all cleansing maneuvers. We assessed three segment scores (the right side, transverse section, and left side) and total BBPS scores during screening colonoscopy. In addition, we compared the BBPS scores with clinically meaningful outcomes such as the polyp detection rate and colonoscope withdrawal times.Results:We enrolled 482 screening colonoscopies between January 2011 and January 2012. The mean (± standard deviation [SD]) BBPS score was 8.1 ± 1.1. Higher BBPS scores (≥8 vs <8) were associated with a higher polyp detection rate (44.9% vs. 33.0%, P = 0.042). The BBPS scores were inversely correlated with colonoscope withdrawal times (r = −0.167, P < 0.001).Conclusions:The BBPS is a valid and reliable measure for assessing bowel preparation during colonoscopy in Korean patients. The polyp detection rate is higher in patients with higher BBPS scores than in those with lower BBPS scores during a colonoscopic procedure.

Efficacy of Hood-cap Assisted Colonoscopy; Comparison with Conventional Colonoscopy

Background/Aims: A few studies showed that hood-cap assisted colonoscopy (CAC) had improved cecal intubation rate and cecal intubation time but did not help in finding colon polyps in comparison with conventional colonoscopy (CC). However, other studies have shown different results. Therefore, we investigated the efficacy of CAC for the cecal intubation time and polyp detection rate. Methods: Patients for colonoscopy in Busan St. Mary’s Medical Center were enrolled to this randomized controlled trial between July 2010 and September 2010. The evaluated outcomes were polyp detection rate, adenoma detection rate, and cecal intubation time in all patients, in difficult cases (history of previous abdominal or pelvic surgery, obesity, old age), and in the expert and non-expert groups. Results: A total of 260 patients enrolled in this study were randomly allocated to the CAC group (n=130), or CC group (n=130). The overall cecal intubation time was shorter in the CAC group (5.7±3.4 min vs. 7.8±5.7 min, P<0.001). The polyp detection rate was higher in the CAC group (58.4% vs. 43%, P=0.008). The cecal intubation time in the expert and non-expert groups were shorter in the CAC group (expert: 4.1±2.2 min vs. 5.5±2.0 min, P=0.001; non-expert: 6.7±3.7 min vs. 9.4±5.9 min, P=0.001). Conclusions: The use of CAC improved the detection rate of colon polyps and shortened the cecal intubation time for both the expert and non-expert groups. (Intest Res 2012;10: 280-288) 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

Participation by experienced endoscopy nurses increases the detection rate of colon polyps during a screening colonoscopy: a multicenter, prospective, randomized study

No reported prospective, randomized study has evaluated the impact of an endoscopy nurse participating as a second observer during colonoscopy. To determine whether the participation of an endoscopy nurse enhanced the polyp detection rate (PDR) and adenoma detection rate (ADR) during screening colonoscopy. Multicenter, prospective, randomized study. Academic hospitals. A total of 844 consecutive patients undergoing screening colonoscopy. Single observation by colonoscopist or dual observation by colonoscopist and endoscopy nurse during colonoscope withdrawal. PDR and ADR. No significant difference in patient demographic data, adequacy of bowel preparation, or mean withdrawal time was observed between the 2 groups. In total, 1153 polyps, including 762 adenomas, were detected in 791 patients. Seven nonpolypoid, depressed neoplastic lesions (0-IIc or combined types) were only detected in the dual observation group. A multivariate analysis revealed that experienced (≥ 2 years) endoscopy nurse participation significantly increased the PDR and ADR compared with those in the single observation group by a colonoscopist alone (adjusted odds ratio [OR] 1.58 [95% CI, 1.07-2.32]; adjusted OR 1.47 [95% CI, 1.01-2.12], respectively). Additionally, the PDR was significantly higher in the dual-observation group with fellows (<500 colonoscopies) and an experienced endoscopy nurse versus that in the single observation group (adjusted OR 2.07 [95% CI, 1.15-3.74]). There was no significant benefit of experienced nurse participation in the subgroup with experienced colonoscopists. Absence of colonoscopist blinding. Experienced endoscopy nurse participation increased the PDR and ADR during screening colonoscopy. However, the benefit of participation by experienced nurses appears to be exclusively with inexperienced colonoscopists.

W1480: Narrow Band Imaging for Detection of Non-Polypoid Colorectal Neoplasms; A Prospective Study

Non-polypoid (flat and depressed) colorectal neoplasms (NP-CRNs), especially depressed in shape, are more difficult to detect by conventional white light colonoscopy (WLC) or computed tomography colonography, because the subtle findings can be difficult to distinguish from those of normal mucosa. Narrow band imaging (NBI) has been reported to highlight the mucosal capillaries of neoplastic lesions and thus increase detection rate of colon polyps, however, the detection rate of NP-CRNs, especially depressed in shape, has never been assessed.

Excellent Cecal Cleansing with Split Dose of Phosphosoda and 30 mg of Bisacodyl – A Retrospective Study Using Cecal Photograph as a Reflector of the Quality of Colon Cleansing

Purpose: Poor colon preparation was noted be 18% during an audit of the quality of colonoscopy preparation using polyethylene glycol based (PEG) solution in 2002. Since then, a series of changes have been made to our colon preparation protocol, which reduced the poor preparation rate to 8% & currently to 1%. Cecum appears to be the last to get cleaned out and is often obscured by stools despite excellent cleansing of the rest of the colon. Hence, 300 cecal photographs were graded to assess colon cleansing with different regimens by a single observer to avoid interobserver reporting bias. We also analysed the relationship between the quality of cecal image & colon polyp detection rate. Methods: 100 consecutive colonoscopies in each group were compared. Group A: 1 gallon of polyethylene glycol (PEG) the evening before procedure. Group B: 1.5 ounces phosphosoda (P) the evening before & 1.5 ounces on the day of procedure. Group C: Group B regimen + 10 mg of bisacodyl at noon and the evening before and on the day of procedure (P + BIS). Assessment: The cecal photograph was graded on a scale of 1–3: 1 = stool obscured the mucosa; 2 = 50–100% of mucosa visualized; specs of stool; 3 = Entire (100%) of the mucosa visualized (excellent prep); no stool. Endpoints: Mean colon cleansing (MCC) score & polyp detection for each preparation. Results:Excellent visualization of cecum (Grade 3) – Clean with 100% mucosal visualization: 57% in the split dose of P + 30 mg BIS, 20% in the PEG, & 24% in the split dose of FP (P < 0.001). MCC Score: 2.47 ± 0.69 in the split dose of P + 30 mg of BIS, 1.98 ± 0.71 in the split dose of P, & 1.92 ± 0.6 9 in the PEG respectively, P < .0001. The MCC score was higher in the P+BIS group in men (P < .0001); females (P= 0.04); age < 65 yrs (P < 0.0001) & ≥65 yrs (P < 0.0001). Polyp detection: In the P+BIS group, there was a correlation between the quality of cecal image and polyp detection (P= 0.04). Conclusion: Using the cecal photograph as a reflector of the quality of colon cleansing, the split dose of phosphosoda & 30 mg bisacodyl proved to be superior to other regimens.[figure1]Figure

Does Narrow Band Imaging (NBI) Colonoscopy Increase the Detection Rate of Colon Polyps? - A Pilot Feasibility Study

Does Narrow Band Imaging (NBI) Colonoscopy Increase the Detection Rate of Colon Polyps? - A Pilot Feasibility Study

Impact of endoscopist withdrawal speed on polyp yield: implications for optimal colonoscopy withdrawal time

In 2002, a U.S. Multi-Society Task Force on Colorectal Cancer recommended that the withdrawal phase for colonoscopy should average at least 6-10 min. This was based on 10 consecutive colonoscopies by two endoscopists with different adenoma miss rates. To characterize the relationship between endoscopist withdrawal time and polyp detection at colonoscopy, and to determine the withdrawal time that corresponds to the median polyp detection rate. Procedural data from out-patient colonoscopies performed at the Mayo Clinic, Rochester during 2003 were reviewed. Endoscopists were characterized by their mean withdrawal time for a negative procedure and individual polyp detection rate. A total of 10 955 colonoscopies performed by 43 endoscopists were analysed. Median withdrawal time was 6.3 min (range: 4.2-11.9); polyp detection rate was 44.0% (all polyps), 29.8% (< or = 5 mm), 5.9% (6-9 mm), 6.7% (10-19 mm), 2.1% (> or = 20 mm). Longer withdrawal time was associated with higher polyp detection rate (r = 0.76; P < 0.0001); this relationship weakened for larger polyps (r = 0.19 for polyps 6-9 mm, r = 0.28 for polyps 10-19 mm, r = 0.02 for polyps > or = 20 mm). Overall median polyp detection rate corresponded to a withdrawal time of 6.7 min. Our findings support a colonoscopy withdrawal time of at least 7 min, which correlates with higher colon polyp detection rates.