Colonoscopy

Abstract

Colonoscopy is the most commonly performed endoscopic procedure in the United States and is the preferred method to screen for colorectal cancer. Polypectomy during colonoscopy has been shown to decrease the incidence of colorectal cancer and associated mortality. However, colonoscopy is not a perfect tool and several aspects of this procedure continue to be the focus of active research to improve the quality as well as patient outcomes. In this review, we summarize the published literature in 2015 to 2016 regarding the different facets of colonoscopy as it relates to colorectal cancer screening and prevention. Adequate bowel preparation is a critical component of colonoscopy. The quality benchmark for bowel preparation is that it should be adequate enough to detect lesions >5 mm in size. Several bowel preparation scales have been reported in the literature, and a systematic review assessed the validity and reliability of these scales.1Parmar R. Martel M. Rostom A. et al.Validated scales for colon cleansing: a systematic review.Am J Gastroenterol. 2016; 111 (quiz 205): 197-204Google Scholar The authors reported that the Boston Bowel Preparation Scale (BBPS) was the most thoroughly validated and should be used in the clinical setting. Increasing BBPS scores were associated with polyp detection, less repeat colonoscopies, shorter insertion/withdrawal times, with substantial to excellent inter- and intra-observer reliability. Calderwood et al2Calderwood A.H. Thompson K.D. Schroy 3rd, P.C. et al.Good is better than excellent: bowel preparation quality and adenoma detection rates.Gastrointest Endosc. 2015; 81: 691-699.e1Google Scholar evaluated the association between the quality of bowel preparation by the BBPS and polyp detection rate and adenoma detection rate (ADR) in 2 large cohorts. The polyp detection rate associated with a total BBPS score of 6, 7, and 8 were higher than those associated with a BBPS of 9 in both cohorts. This trend was also observed for the detection rate of adenomas and advanced adenomas. Although the exact reasons for these findings are unclear, it is possible that excellent bowel preparation may lead to overconfidence on part of the endoscopist, resulting in less meticulous examination of the colon during withdrawal. Another possibility is that the cleaning process to achieve excellent bowel preparation may distract the focus of the endoscopist from inspecting for polyps. Therefore, based on the results of this study, it appears that striving to achieve the highest levels of bowel cleanliness may not improve clinically important endpoints such as ADR or polyp detection rates. On the other hand, a recent study showed that there is a significantly higher miss rate of adenomas >5 mm in colon segments with a BBPS score of 1 compared with a score of 2 (10.7%) or 3 (10.3%), whereas there was no difference in the miss rate between segments with a score of 2 versus 3.3Clark B.T. Protiva P. Nagar A. et al.Quantification of adequate bowel preparation for screening or surveillance colonoscopy in men.Gastroenterology. 2016; 150 (quiz e14-15): 396-405Google Scholar Multiple studies have shown the superiority of split-dose bowel preparation compared with day-before regimens. This was further confirmed in a meta-analysis of 47 trials showing that split-dose bowel preparation resulted in significantly better colon cleansing than day-before preparation (odds ratio [OR], 2.51) across all types of colonic preparations.4Martel M. Barkun A.N. Menard C. et al.Split-dose preparations are superior to day-before bowel cleansing regimens: a meta-analysis.Gastroenterology. 2015; 149: 79-88Google Scholar Further studies are needed to compare split-dose regimens with same-day bowel preparation. Compliance to bowel preparation regimen is a pre-requisite for achieving good quality cleansing. A meta-analysis of 9 studies confirmed that consumption of a low residue diet showed favorable results compared with a clear liquid diet with regard to higher odds of tolerability (OR, 1.92) and willingness to repeat the preparation (OR, 1.86) without negatively affecting the quality of bowel preparation or increasing adverse effects.5Nguyen D.L. Jamal M.M. Nguyen E.T. et al.Low-residue versus clear liquid diet before colonoscopy: a meta-analysis of randomized, controlled trials.Gastrointest Endosc. 2016; 83: 499-507.e1Google Scholar Therefore, a low residue diet may be allowed on the day before colonoscopy to improve compliance. A significant increase in the involvement of anesthesia services for colonoscopy over the past decade has been reported. Wernli et al6Wernli K.J. Brenner A.T. Rutter C.M. et al.risks associated with anesthesia services during colonoscopy.Gastroenterology. 2016; 150 (quiz e18): 888-894Google Scholar conducted a prospective cohort study that quantified the difference in adverse events from colonoscopy among 3,168,228 unique colonoscopies performed with and without anesthesia services using an administrative claims database. Nationwide, a total of 34.4% of colonoscopies were conducted with anesthesia services with significant regional variation. Multivariable logistic regression models were adjusted for relevant variables to estimate the association between the use of anesthesia services and any adverse outcome and specific adverse events. The use of anesthesia services was associated with a 13% higher risk of any adverse event within 30 days. In addition, use of anesthesia services was also associated with a higher risk of perforation, hemorrhage, abdominal pain, adverse events related to anesthesia, and stroke. The risk of perforation associated with anesthesia services was increased only in patients undergoing polypectomy (OR, 1.26). Interestingly, regional differences in anesthesia-related adverse outcomes were noted with the greatest increase in risk in regions with a low prevalence of use of anesthesia services. Plausible explanations for these adverse outcomes related to anesthesia services include direct effects related to anesthetic agents and increased colonic-wall tension related to absence of patient feedback. In contrast, results of a recent systematic review and meta-analysis compared sedation-related cardiopulmonary adverse events associated with the use of propofol versus non-propofol agents for endoscopic procedures and showed that propofol sedation had similar risks of cardiopulmonary adverse events compared with non-propofol agents (hypoxia: pooled OR, 0.82; hypotension, OR, 0.92).7Wadhwa V. Issa D. Garg S. et al.Similar risk of cardiopulmonary adverse events between propofol and traditional anesthesia for gastrointestinal endoscopy: a systematic review and meta-analysis.Clin Gastroenterol Hepatol. 2016; http://dx.doi.org/10.1016/j.cgh.2016.07.013Google Scholar The use of propofol in non-advanced endoscopic procedures, including colonoscopy, was associated with a 39% reduction in adverse event rates (OR, 0.61). Future research needs to clarify the role of anesthesia services using propofol during routine colonoscopy and its association with adverse events. Recent changes to the standards for basic anesthesia monitoring require the use of capnography in all procedures using moderate sedation. The basic premise of the use of capnography, which measures the CO2 concentration, is the real-time evaluation of alterations in ventilation status such as hypoventilation and hypercapnea that precede changes on pulse oximetry. A randomized blinded controlled trial by Mehta et al8Mehta P.P. Kochhar G. Albeldawi M. et al.Capnographic monitoring in routine EGD and colonoscopy with moderate sedation: a prospective, randomized, controlled trial.Am J Gastroenterol. 2016; 111: 395-404Google Scholar studied the impact of routine capnographic monitoring in the detection of hypoxemia in healthy patients (American Society of Anesthesiologists class I and II) undergoing colonoscopy and upper endoscopy under moderate sedation. There was no difference in the rates of hypoxemia (defined as Sao2 <90% for 10 seconds) between the 2 groups in patients undergoing colonoscopy (P = .79). Similarly, another prospective cohort study showed that addition of capnography in a low-risk screening colonoscopy population did not improve patient safety or satisfaction and in fact increased the overall cost of the procedure.9Barnett S. Hung A. Tsao R. et al.Capnographic monitoring of moderate sedation during low-risk screening colonoscopy does not improve safety or patient satisfaction: a prospective cohort study.Am J Gastroenterol. 2016; 111: 388-394Google Scholar Routine capnography monitoring does not seem to add any benefit to standard monitoring in low-risk patients undergoing colonoscopy. Future studies should focus on clarifying the role of capnography in subpopulations most likely to benefit from this intervention. There have been several studies showing that water-aided colonoscopy affords the advantage of less patient discomfort and less need for sedation. Water immersion (WI) and water exchange (WE) are the two methods of water-aided colonoscopy. These methods have not been compared in a rigorous fashion. Cadoni et al10Cadoni S. Sanna S. Gallittu P. et al.A randomized, controlled trial comparing real-time insertion pain during colonoscopy confirmed water exchange to be superior to water immersion in enhancing patient comfort.Gastrointest Endosc. 2015; 81: 557-566Google Scholar compared air insufflation (AI), WI, and WE in a randomized controlled study on patients undergoing unsedated colonoscopy with the option of on-demand sedation. Real-time pain on a 10-point VAS was reported to be the lowest in the WE group (2.5 for WE vs 3.5 for WI and 4.1 for AI; P < .0005). The proportion of patients completing unsedated colonoscopy was the highest with WE (74% for WE vs 62% for WI and 65% for AI). Carbon dioxide (CO2) insufflation has been shown to cause less intra- and post-procedural pain compared with AI and has been recommended. Direct comparisons between CO2 insufflation and water-aided methods are lacking. A large study compared AI, CO2 insufflation, WI, and WE (with air and CO2 on withdrawal).11Cadoni S. Falt P. Gallittu P. et al.water exchange is the least painful colonoscope insertion technique and increases completion of unsedated colonoscopy.Clin Gastroenterol Hepatol. 2015; 13: 1972-1980.e1-3Google Scholar Mean insertion pain scores were the lowest and the proportion of patients completing unsedated colonoscopy were the highest in the WE group. Therefore, even compared with CO2 insufflation, WE seems to be superior for completing a less painful or unsedated colonoscopy. Abdominal pain and bloating after colonoscopy is not uncommon and can persist for 1 to 2 days resulting in visits to the emergency department and absence from work. Based on data from a study by Cadoni et al12Cadoni S. Falt P. Gallittu P. et al.Impact of carbon dioxide insufflation and water exchange on postcolonoscopy outcomes in patients receiving on-demand sedation: a randomized controlled trial.Gastrointest Endosc. 2016; 85: 210-218Google Scholar using WE during insertion with CO2 insufflation on withdrawal may be the optimal method to minimize the discomfort associated with colonoscopy, especially when performed in unsedated patients or with on-demand sedation. Colonoscopy is started with the patient in the left lateral position. In a randomized controlled trial, Vergis et al13Vergis N. McGrath A.K. Stoddart C.H. et al.Right Or Left in COLonoscopy (ROLCOL)? A randomized controlled trial of right- versus left-sided starting position in colonoscopy.Am J Gastroenterol. 2015; 110: 1576-1581Google Scholar challenged this conventional starting position by comparing it with the right lateral starting position. Cecal intubation was quicker by 3 minutes 33 seconds, and patient comfort was higher when colonoscopy began with patients in the right lateral position. The greatest benefit was seen in women and those with a previous history of surgery. These results need further validation in larger multicenter trials and could lead to a simple and inexpensive change in colonoscopy practice for improving efficiency and patient satisfaction. Looping of the colonoscope is the bane of the insertion phase of colonoscopy, causing pain, increasing procedure time as well as the risk of adverse events such as perforation and splenic injury. Abdominal pressure is routinely used to prevent looping and an abdominal compression device (ColoWrap) has been developed for this purpose. In a randomized, sham-controlled trial, Crockett et al14Crockett S.D. Cirri H.O. Kelapure R. et al.Use of an abdominal compression device in colonoscopy: a randomized, sham-controlled trial.Clin Gastroenterol Hepatol. 2016; 14: 850-857.e3Google Scholar found no benefit of the ColoWrap in cecal intubation time, frequency of manual pressure, or position changes. However, in a subset analysis of patients with body mass index between 30 and 40 kg/m2, the cecal intubation time was significantly lower in the ColoWrap group (4.69 minutes vs 6.10 minutes in the sham group; P = .03). Magnetic endoscopic imaging (MEI) is another device that can help avoid looping by showing the three-dimensional real-time configuration of the colonoscope. A meta-analysis showed that the adjunctive use of MEI improved cecal intubation rates and lowered cecal intubation times as well as pain scores compared with standard colonoscopy.15Mark-Christensen A. Brandsborg S. Iversen L.H. Magnetic endoscopic imaging as an adjuvant to elective colonoscopy: a systematic review and meta-analysis of randomized controlled trials.Endoscopy. 2015; 47: 251-261Google Scholar However, this equipment requires capital investment and its utility in routine clinical practice may be limited. It could, however, have a role as a teaching tool for trainees to understand the dynamics of colonoscope insertion and optimize the learning curves. ADR is an important quality metric of colonoscopy and efforts to improve this outcome continues to be an area of active research. Performance targets of ≥30% ADR in males and ≥20% in females have been recommended as benchmarks.16Rex D.K. Schoenfeld P.S. Cohen J. et al.Quality indicators for colonoscopy.Gastrointest Endosc. 2015; 81: 31-53Google Scholar However, wide variability has been reported in the ADR of endoscopists, and withdrawal time has been cited as one of the reasons for this variability, albeit with conflicting data. Shaukat et al17Shaukat A. Rector T.S. Church T.R. et al.Longer withdrawal time is associated with a reduced incidence of interval cancer after screening colonoscopy.Gastroenterology. 2015; 149: 952-957Google Scholar evaluated the relationship between withdrawal time, ADR, and the incidence of interval cancer in >75,000 colonoscopies performed by 51 gastroenterologists. The mean withdrawal time was 8.3 minutes (range, 3.9-14.4 minutes). Longer mean withdrawal times were associated with higher ADR, with a 3.6% increase in ADR/minute increase in withdrawal time. Furthermore, physicians’ mean annual withdrawal times were found to be inversely associated with interval cancer incidence over a 410,687 person-years follow-up period. The adjusted incidence rate ratio (IRR) for withdrawal times <6 minutes compared with ≥6 minutes was 2.3 (P < .0001). This is the first study showing that when the mean withdrawal time was shorter, the incidence of interval cancer was significantly increased. Along similar lines, another study showed that the average withdrawal time over 6 minutes and >20% detection rate of adenoma and serrated polyps were associated with a reduced risk of interval cancer (OR, 0.12 and 0.17, respectively).18Hilsden R.J. Dube C. Heitman S.J. et al.The association of colonoscopy quality indicators with the detection of screen-relevant lesions, adverse events, and postcolonoscopy cancers in an asymptomatic Canadian colorectal cancer screening population.Gastrointest Endosc. 2015; 82: 887-894Google Scholar Withdrawal time was also associated with the detection of adenoma and serrated polyps. Although it is difficult to explain the exact mechanism of these findings, longer withdrawal time is probably a surrogate marker of a higher-quality mucosal inspection technique that results in higher ADR. It is recommended that withdrawal time should be measured and documented in all colonoscopy examinations, with the performance target being an average withdrawal time ≥6 minutes in screening colonoscopies with a negative result.16Rex D.K. Schoenfeld P.S. Cohen J. et al.Quality indicators for colonoscopy.Gastrointest Endosc. 2015; 81: 31-53Google Scholar The importance of this was highlighted in another study.19Vavricka S.R. Sulz M.C. Degen L. et al.Monitoring colonoscopy withdrawal time significantly improves the adenoma detection rate and the performance of endoscopists.Endoscopy. 2016; 48: 256-262Google Scholar When endoscopists were unaware that their withdrawal times were being monitored, the median was 4.5 minutes, and this increased to 7.3 minutes when they were made aware of being monitored. This increment in withdrawal time also resulted in a significant increase in the ADR from 21% to 36% (P < .001). This positive impact of monitoring also known as the Hawthorne effect is a simple method of improving ADR. A major reason for missing polyps is the difficulty in completely examining the proximal aspects of the haustral folds. Cap-assisted colonoscopy is a simple technique in which a transparent cap is attached to the tip of the colonoscope, which helps to depress the haustral folds, thereby improving the visualization of their proximal aspects. Several studies have evaluated its impact on ADR with conflicting results, and the largest study from the United States was published by Pohl et al.20Pohl H. Bensen S.P. Toor A. et al.Cap-assisted colonoscopy and detection of Adenomatous Polyps (CAP) study: a randomized trial.Endoscopy. 2015; 47: 891-897Google Scholar A total of 1113 patients were randomized to cap-assisted colonoscopy or standard colonoscopy by 10 endoscopists. There was no difference in the ADR (42% vs 40%; P = .45) or the mean number of adenomas per patient (0.89 vs 0.82; P = .43). ADR with cap was higher by up to 20% for some endoscopists and lower by up to 15% for others. Interestingly, the endoscopists who preferred cap-assisted colonoscopy achieved a higher ADR and advanced ADRs with cap-assisted colonoscopy compared with endoscopists who preferred standard colonoscopy. Based on this study, cap-assisted colonoscopy may be a helpful technique to improve the ADR for some endoscopists but its positive impact on ADR cannot be generalized. Other devices such as the EndoRings and balloon colonoscope have also been evaluated for improving ADR. Both have shown lower adenoma miss rates compared with standard colonoscopy in multicenter, randomized tandem studies.21Dik V.K. Gralnek I.M. Segol O. et al.Multicenter, randomized, tandem evaluation of EndoRings colonoscopy–results of the CLEVER study.Endoscopy. 2015; 47: 1151-1158Google Scholar, 22Halpern Z. Gross S.A. Gralnek I.M. et al.Comparison of adenoma detection and miss rates between a novel balloon colonoscope and standard colonoscopy: a randomized tandem study.Endoscopy. 2015; 47: 301Google Scholar Larger studies will be needed to confirm these findings and whether the extra expense involved with using these devices can be justified. Inadequate luminal distension during withdrawal may also lead to missing adenomas. Sequentially changing the position of patients from left lateral to supine and then to right lateral can help in improving the luminal distension of the ascending, transverse, and left colon, respectively. In a large, multicenter, randomized controlled study, this dynamic position change during withdrawal was compared with complete examination in the left lateral position.23Lee S.W. Chang J.H. Ji J.S. et al.Effect of dynamic position changes on adenoma detection during colonoscope withdrawal: a randomized controlled multicenter trial.Am J Gastroenterol. 2016; 111: 63-69Google Scholar A significantly higher ADR was seen in the position change group (42% vs 33%; P = .002) as well as higher adenoma per patient (0.90 vs 0.67; P = .01). This increase in the number of adenomas detected was seen in the transverse and left colon and for endoscopists with a relatively low detection rate. Dynamic position change represents a simple and inexpensive means for improving the ADR especially if difficulty is encountered in adequate luminal distension. Up to a third of colon cancers can arise from the serrated neoplasia pathway. Therefore, detection and resection of premalignant serrated polyps is recognized as an important component of colorectal cancer screening and prevention. The clinical importance of serrated polyps as a marker of neoplasia was highlighted in a meta-analysis of 9 studies that showed the presence of proximal serrated polyps and large serrated polyps was associated with an increased risk of synchronous advanced neoplasia (OR, 2.77 and 4.10, respectively).24Gao Q. Tsoi K.K. Hirai H.W. et al.Serrated polyps and the risk of synchronous colorectal advanced neoplasia: a systematic review and meta-analysis.Am J Gastroenterol. 2015; 110 (quiz 510): 501-509Google Scholar Therefore, detection of these high-risk serrated polyps should alert the endoscopist to be vigilant in performing a meticulous inspection because of the high chances of detecting another advanced lesion. CT colonography has been recommended as one of the screening modalities for colorectal cancer. In a post hoc analysis of data from a randomized controlled trial comparing colonoscopy with CT colonography for population screening, the authors showed a significantly lower detection of patients with ≥1 high-risk sessile serrated polyp (4.3% vs 0.8%; OR, 5.5; P < .001) with the latter.25JE I.J. Tutein Nolthenius C.J. Kuipers E.J. et al.CT-colonography vs. colonoscopy for detection of high-risk sessile serrated polyps.Am J Gastroenterol. 2016; 111: 516-522Google Scholar A possible explanation is the small size, inconspicuous and flat morphology of serrated polyps, making their detection difficult with CT colonography. These results have implications for the value of CT colonography as a primary colorectal cancer screening modality. The second-generation colon capsule (PillCam COLON 2, Given Imaging, Yoqneam, Israel) has been developed with improvements over the previous iteration. It has motion detection and variable frame speed, taking photos at 4 frames per second when stationary and 35 frames per second when moving, and an increased angle of view from 152° to 172°. In a large, multicenter study, capsule colonoscopy identified individuals with one or more adenomas ≥6 mm with 88% sensitivity and 82% specificity and those with one or more adenomas ≥10 mm with 92% sensitivity and 95% specificity.26Rex D.K. Adler S.N. Aisenberg J. et al.Accuracy of capsule colonoscopy in detecting colorectal polyps in a screening population.Gastroenterology. 2015; 148: 948-957.e2Google Scholar Sessile serrated polyp detection was suboptimal with a false-negative rate of 26%. The authors concluded that colon capsule may be appropriate for those who cannot undergo a colonoscopy or had an incomplete colonoscopy. Real-time diminutive polyp histology characterization continues to be the focus of intense research given its potential for significant cost savings. The American Society for Gastrointestinal Endoscopy published the Preservation and Incorporation of Valuable Endoscopic Innovations (PIVI) document, which sets out the thresholds for endoscopic technologies before they are deemed appropriate to be incorporated into clinical practice.27Rex D.K. Kahi C. O'Brien M. et al.The American Society for Gastrointestinal Endoscopy PIVI (Preservation and Incorporation of Valuable Endoscopic Innovations) on real-time endoscopic assessment of the histology of diminutive colorectal polyps.Gastrointest Endosc. 2011; 73: 419-422Google Scholar A meta-analysis has shown that these PIVI thresholds have been met, at least with narrow-band imaging (NBI), with experts in advanced imaging technology, and when the characterization is made with high confidence.28Committee A.T. Abu Dayyeh B.K. Thosani N. et al.ASGE Technology Committee systematic review and meta-analysis assessing the ASGE PIVI thresholds for adopting real-time endoscopic assessment of the histology of diminutive colorectal polyps.Gastrointest Endosc. 2015; 81: 502.e1-502.e16Google Scholar However, several challenges remain for the widespread implementation of real-time histology. One of these is training and testing the competency of endoscopists who have had limited experience with these novel imaging technologies. Patel et al29Patel S.G. Schoenfeld P. Kim H.M. et al.Real-time characterization of diminutive colorectal polyp histology using narrow-band imaging: implications for the resect and discard strategy.Gastroenterology. 2016; 150: 406-418Google Scholar showed that with a standardized training protocol, academic gastroenterologists, without previous experience in NBI, met the PIVI thresholds for surveillance interval (91%) and the negative predictive value for adenomatous histology in rectosigmoid polyps (95%). Another study from Europe showed that gastroenterologists in community practice who underwent a rigorous training session as well as a periodic audit of their performance were also able to achieve both the PIVI thresholds with NBI.30Paggi S. Rondonotti E. Amato A. et al.Narrow-band imaging in the prediction of surveillance intervals after polypectomy in community practice.Endoscopy. 2015; 47: 808-814Google Scholar Contrary to these results, the DISCARD 2 study from the United Kingdom, which involved 28 endoscopists in 6 hospitals, concluded that NBI optical diagnosis cannot currently be recommended for implementation in routine clinical practice as the performance fell short of the recommended thresholds.31Rees C.J. Rajasekhar P.T. Wilson A. et al.Narrow band imaging optical diagnosis of small colorectal polyps in routine clinical practice: the Detect Inspect Characterise Resect and Discard 2 (DISCARD 2) study.Gut. 2016; http://dx.doi.org/10.1136/gutjnl-2015-310584Google Scholar A recent advancement in endoscopic technology is the development of push-button optical magnification, which enables a 65× magnification when the tip of the colonoscope is brought close to the mucosa (near focus). Comparing this near focus to standard focus NBI, Kaltenbach et al32Kaltenbach T. Rastogi A. Rouse R.V. et al.Real-time optical diagnosis for diminutive colorectal polyps using narrow-band imaging: the VALID randomised clinical trial.Gut. 2015; 64: 1569-1577Google Scholar showed that endoscopists were more likely to make a high-confidence optical diagnosis of diminutive polyps with the former. Sessile serrated adenoma/polyp (SSA/P) continues to be a challenge not only for detection and histologic assessment but also for optical diagnosis. The NICE classification did not differentiate between the different types of serrated polyps. Researchers from Amsterdam developed the WASP classification to differentiate sessile serrated adenoma/polyps from hyperplastic and adenomatous polyps.33JE I.J. Bastiaansen B.A. van Leerdam M.E. et al.Development and validation of the WASP classification system for optical diagnosis of adenomas, hyperplastic polyps and sessile serrated adenomas/polyps.Gut. 2016; 65: 963-970Google Scholar The presence of 2 of 4 features was sufficient for the diagnosis and included a clouded surface, indistinct borders, irregular shape, and dark spots inside crypts. This was integrated with the NICE classification and the accuracy after training for a high-confidence diagnosis was 0.84. The NPV for neoplastic histology (adenomas and SSA/P) was 0.91. The safety and effectiveness of EMR of large-colon polyps has been demonstrated in multiple studies. A recent systematic review and meta-analysis reporting on outcomes among 6442 patients with 6779 large-colon polyps provided several important estimates.34Hassan C. Repici A. Sharma P. et al.Efficacy and safety of endoscopic resection of large colorectal polyps: a systematic review and meta-analysis.Gut. 2016; 65: 806-820Google Scholar The technical success rate for endoscopic management was 90.3% and the pooled rates for patients undergoing surgery because of non-curative endoscopic resection and adverse events were 8% and 1%, respectively. Low adverse event rates were reported in this analysis (perforation rate 1.5%, bleeding rate 6.5%, and mortality rate 0.08%). This study also reported an overall endoscopic recurrence rate of 13.8% (95% confidence interval [CI], 12.9-14.7). This important issue was also addressed in a prospective observational study (n = 1000) that reported recurrence rates at 4 months (early) and 16 months (late) after EMR of large colon polyps.35Moss A. Williams S.J. Hourigan L.F. et al.Long-term adenoma recurrence following wide-field endoscopic mucosal resection (WF-EMR) for advanced colonic mucosal neoplasia is infrequent: results and risk factors in 1000 cases from the Australian Colonic EMR (ACE) study.Gut. 2015; 64: 57-65Google Scholar Early and late recurrences were reported in 16% and 4% of cases, respectively, and most of these recurrences were successfully treated using endoscopic techniques. Consistent with their previous study,36Moss A. Bourke M.J. Williams S.J. et al.Endoscopic mucosal resection outcomes and prediction of submucosal cancer from advanced colonic mucosal neoplasia.Gastroenterology. 2011; 140: 1909-1918Google Scholar the authors again demonstrated that lesion size, use of argon plasma coagulation, and bleeding during EMR were all predictors of early recurrence. The Australian group also reported outcomes after EMR of large SSA/Ps.37Pellise M. Burgess N.G