1 2011 Vol: 8(10):554-564. DOI: 10.1038/nrgastro.2011.141

Colonoscopy: basic principles and novel techniques

Colonoscopy is considered the 'gold standard' for detection and removal of premalignant lesions in the colon. However, studies suggest that colonoscopy is less protective for right-sided than for left-sided colorectal cancer. Optimizing the effectiveness of colonoscopy is a continuous process, and during the past decade several important quality indicators have been defined that can be used to measure the performance of colonoscopy and to identify areas for quality improvement. The quality of bowel preparation can be enhanced by split-dose regimens, which are superior to single-dose regimens. Cecal intubation rates should approximate 95% and can be optimized by good technique. In selected patients, specific devices can be used to facilitate cecal intubation. Adenoma detection rates should be monitored and exceed a minimum of 25% in men and 15% in women. To this aim, optimal withdrawal technique and adequate time for inspection are of utmost importance. Of all advanced imaging techniques, chromoendoscopy is the only technique with proven benefit for adenoma detection. Finally, the technique of polypectomy affects the number of complications as well as the success of completely removing a lesion. In this Review, we provide an overview of both standard and novel colonoscopy techniques and their impact on quality indicators.

Mentions
Figures
Figure 1: Representation of the magnetic endoscopic imaging system.a | During colonoscopy, the left monitor displays the normal endoscopic view. The right and the middle monitor display a three-dimensional configuration of the colonoscopic shaft, providing information about the anatomical position of the colonoscope. b | The colonoscope is displayed in anteroposterior and lateral view. Figure 2: Advanced imaging of the colon.a,c,e | Example images of high-resolution white-light endoscopy and corresponding images with b | chromoendoscopy, d | narrow band imaging and f | autofluorescence imaging. During chromoendoscopy, the superficial structure of the lesion is enhanced with dyes. Narrow band imaging highlights the mucosal pit pattern and microvasculature resulting in more clearly demarcated and sometimes darker lesions. In autofluorescence imaging, adenomas become purple, whereas normal colonic mucosa appear green. Figure 3: Cap-assisted colonoscopy.a | A small cap (diameter 15 mm) is attached to the tip of the colonoscope, which b | potentially improves visualization of the colonic mucosa behind folds and flexures. Figure 4: Paris endoscopy classification for superficial lesions.An international group of endoscopists, surgeons and pathologists proposed an endoscopic classification system for superficial lesions of the esophagus, stomach and colon.78 Superficial lesions are divided into three main categories—protruding, nonprotuding and nonexcavated, and excavated—and then subdivided into further groups. The combined patterns of excavation and depression are termed type III + IIc (most of the surface is excavated) or IIc + III (most of the surface is depressed). Combined elevated and depressed lesions are termed IIc + IIa (most of the surface is depressed) or IIa + IIc (central depression in a globally elevated lesion). Figure 5: Endoscopic mucosal resection.a,b | Normal saline with a drop of methylene blue is injected beneath the lesion creating a submucosal fluid cushion. c | The added methylene blue in the injection solution clearly demarcates the borders of the polyp. d–f | Snare polypectomy enables removal of the polyp.
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References
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    • . . . Colonoscopy is an invasive procedure with a potential risk of complications, such as perforation or bleeding (Box 1).1, 2, 3, 4, 5, 6, 7 Every patient should receive verbal and written information about the procedure, the risk of complications and possible alternatives . . .
    • . . . Complications occur in approximately 2 per 1,000 colonoscopies and this risk increases when a biopsy or polypectomy is performed during the procedure (Box 1).1, 2, 3, 4, 5, 6, 7 Complications can occur either immediately during the procedure or several days later . . .
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    • . . . Colonoscopy is an invasive procedure with a potential risk of complications, such as perforation or bleeding (Box 1).1, 2, 3, 4, 5, 6, 7 Every patient should receive verbal and written information about the procedure, the risk of complications and possible alternatives . . .
    • . . . Complications occur in approximately 2 per 1,000 colonoscopies and this risk increases when a biopsy or polypectomy is performed during the procedure (Box 1).1, 2, 3, 4, 5, 6, 7 Complications can occur either immediately during the procedure or several days later . . .
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    • . . . Colonoscopy is an invasive procedure with a potential risk of complications, such as perforation or bleeding (Box 1).1, 2, 3, 4, 5, 6, 7 Every patient should receive verbal and written information about the procedure, the risk of complications and possible alternatives . . .
    • . . . Complications occur in approximately 2 per 1,000 colonoscopies and this risk increases when a biopsy or polypectomy is performed during the procedure (Box 1).1, 2, 3, 4, 5, 6, 7 Complications can occur either immediately during the procedure or several days later . . .
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    • . . . Colonoscopy is an invasive procedure with a potential risk of complications, such as perforation or bleeding (Box 1).1, 2, 3, 4, 5, 6, 7 Every patient should receive verbal and written information about the procedure, the risk of complications and possible alternatives . . .
    • . . . Complications occur in approximately 2 per 1,000 colonoscopies and this risk increases when a biopsy or polypectomy is performed during the procedure (Box 1).1, 2, 3, 4, 5, 6, 7 Complications can occur either immediately during the procedure or several days later . . .
  5. Regula, J. et al. Colonoscopy in colorectal-cancer screening for detection of advanced neoplasia. N. Engl. J. Med. 355, 1863-1872 , .
    • . . . Colonoscopy is an invasive procedure with a potential risk of complications, such as perforation or bleeding (Box 1).1, 2, 3, 4, 5, 6, 7 Every patient should receive verbal and written information about the procedure, the risk of complications and possible alternatives . . .
    • . . . Complications occur in approximately 2 per 1,000 colonoscopies and this risk increases when a biopsy or polypectomy is performed during the procedure (Box 1).1, 2, 3, 4, 5, 6, 7 Complications can occur either immediately during the procedure or several days later . . .
  6. Sieg, A., Hachmoeller-Eisenbach, U. & Eisenbach, T. Prospective evaluation of complications in outpatient GI endoscopy: a survey among German gastroenterologists. Gastrointest. Endosc. 53, 620-627 , .
    • . . . Colonoscopy is an invasive procedure with a potential risk of complications, such as perforation or bleeding (Box 1).1, 2, 3, 4, 5, 6, 7 Every patient should receive verbal and written information about the procedure, the risk of complications and possible alternatives . . .
    • . . . Complications occur in approximately 2 per 1,000 colonoscopies and this risk increases when a biopsy or polypectomy is performed during the procedure (Box 1).1, 2, 3, 4, 5, 6, 7 Complications can occur either immediately during the procedure or several days later . . .
  7. Viiala, C. H., Zimmerman, M., Cullen, D. J. & Hoffman, N. E. Complication rates of colonoscopy in an Australian teaching hospital environment. Intern. Med. J. 33, 355-359 , .
    • . . . Colonoscopy is an invasive procedure with a potential risk of complications, such as perforation or bleeding (Box 1).1, 2, 3, 4, 5, 6, 7 Every patient should receive verbal and written information about the procedure, the risk of complications and possible alternatives . . .
    • . . . Complications occur in approximately 2 per 1,000 colonoscopies and this risk increases when a biopsy or polypectomy is performed during the procedure (Box 1).1, 2, 3, 4, 5, 6, 7 Complications can occur either immediately during the procedure or several days later . . .
  8. Spiegel, B. M. et al. Development and validation of a novel patient educational booklet to enhance colonoscopy preparation. Am. J. Gastroenterol. 106, 875-883 , .
  9. Froehlich, F., Wietlisbach, V., Gonvers, J. J., Burnand, B. & Vader, J. P. Impact of colonic cleansing on quality and diagnostic yield of colonoscopy: the European Panel of Appropriateness of Gastrointestinal Endoscopy European multicenter study. Gastrointest. Endosc. 61, 378-384 , .
    • . . . Inadequate bowel preparation is associated with reduced adenoma detection rates, incomplete colonoscopy and increased costs.9, 10, 11 The quality of preparation should be assessed during endoscopy and documented in the procedure report . . .
  10. Harewood, G. C., Sharma, V. K. & de Garmo, P. Impact of colonoscopy preparation quality on detection of suspected colonic neoplasia. Gastrointest. Endosc. 58, 76-79 , .
    • . . . Inadequate bowel preparation is associated with reduced adenoma detection rates, incomplete colonoscopy and increased costs.9, 10, 11 The quality of preparation should be assessed during endoscopy and documented in the procedure report . . .
  11. Rex, D. K., Imperiale, T. F., Latinovich, D. R. & Bratcher, L. L. Impact of bowel preparation on efficiency and cost of colonoscopy. Am. J. Gastroenterol. 97, 1696-1700 , .
    • . . . Inadequate bowel preparation is associated with reduced adenoma detection rates, incomplete colonoscopy and increased costs.9, 10, 11 The quality of preparation should be assessed during endoscopy and documented in the procedure report . . .
  12. National Health Service Bowel Cancer Screening Programme Endoscopy Quality Assurance Group. Quality assurance guidelines for colonoscopy publication no.6. National Health Service [online], , .
  13. Aronchick, C. A. Bowel preparation scale. Gastrointest. Endosc. 60, 1037-1038 , .
    • . . . To assess the preparation quality in a validated and standardized format, several bowel preparation scales (such as the Ottawa, Boston and Aronchick scales) are available.13, 14, 15 Although these scales have been shown to be a reliable tool for assessing the quality of preparation, their use in clinical practice is not yet recommended by formal guidelines. . . .
  14. Lai, E. J., Calderwood, A. H., Doros, G., Fix, O. K. & Jacobson, B. C. The Boston bowel preparation scale: a valid and reliable instrument for colonoscopy-oriented research. Gastrointest. Endosc. 69, 620-625 , .
    • . . . To assess the preparation quality in a validated and standardized format, several bowel preparation scales (such as the Ottawa, Boston and Aronchick scales) are available.13, 14, 15 Although these scales have been shown to be a reliable tool for assessing the quality of preparation, their use in clinical practice is not yet recommended by formal guidelines. . . .
  15. Rostom, A. & Jolicoeur, E. Validation of a new scale for the assessment of bowel preparation quality. Gastrointest. Endosc. 59, 482-486 , .
    • . . . To assess the preparation quality in a validated and standardized format, several bowel preparation scales (such as the Ottawa, Boston and Aronchick scales) are available.13, 14, 15 Although these scales have been shown to be a reliable tool for assessing the quality of preparation, their use in clinical practice is not yet recommended by formal guidelines. . . .
  16. Belsey, J., Epstein, O. & Heresbach, D. Systematic review: oral bowel preparation for colonoscopy. Aliment. Pharmacol. Ther. 25, 373-384 , .
    • . . . Polyethylene glycol (PEG) solutions are widely used because they are safe and effective.16 Nevertheless, the high volume of PEG solutions (usually 3–4 l) is challenging for the patient to consume and is often poorly tolerated . . .
    • . . . Another frequently used preparation agent is sodium phosphate.16 A systematic review comparing sodium phosphate and PEG reported no differences concerning colon cleansing results, but sodium phosphate was better tolerated.16 A 2011 randomized study compared three bowel cleansing agents—sodium phosphate, sodium picosulfate and PEG—and showed preparation quality with sodium phosphate was worst for morning procedures, while all agents were equally effective for afternoon procedures.20 . . .
  17. Corporaal, S., Kleibeuker, J. H. & Koornstra, J. J. Low-volume PEG plus ascorbic acid versus high-volume PEG as bowel preparation for colonoscopy. Scand. J. Gastroenterol. 45, 1380-1386 , .
    • . . . These low-volume PEG regimens are generally better tolerated than the high-volume PEG regimens, with comparable cleansing results.17, 18, 19 . . .
  18. Marmo, R. et al. Effective bowel cleansing before colonoscopy: a randomized study of split-dosage versus non-split dosage regimens of high-volume versus low-volume polyethylene glycol solutions. Gastrointest. Endosc. 72, 313-320 , .
    • . . . These low-volume PEG regimens are generally better tolerated than the high-volume PEG regimens, with comparable cleansing results.17, 18, 19 . . .
  19. Ell, C. et al. Randomized trial of low-volume PEG solution versus standard PEG + electrolytes for bowel cleansing before colonoscopy. Am. J. Gastroenterol. 103, 883-893 , .
  20. Lawrance, I. C., Willert, R. P. & Murray, K. Bowel cleansing for colonoscopy: prospective randomized assessment of efficacy and of induced mucosal abnormality with three preparation agents. Endoscopy 43, 412-418 , .
  21. Kilgore, T. W. et al. Bowel preparation with split-dose polyethylene glycol before colonoscopy: a meta-analysis of randomized controlled trials. Gastrointest. Endosc. 73, 1240-1245 , .
  22. Singh, H. et al. Propofol for sedation during colonoscopy. Cochrane Database Syst. Rev. 2008, Issue 4. Art. No.: CD006268. doi: 10.1002/14651858.CD006268.pub2 , .
    • . . . A meta-analysis showed that, when compared with traditional sedation, propofol leads to increased patient satisfaction and faster discharge times without an increase in adverse effects.22 No differences were observed in other clinically important outcomes, such as cecal intubation rates and procedure times . . .
  23. Rex, D. K. et al. Endoscopist-directed administration of propofol: a worldwide safety experience. Gastroenterology 137, 1229-1237 , .
    • . . . However, because of the assumed increased risk of respiratory depression, propofol is often administered by an anesthetist or dedicated nurse resulting in substantially higher treatment costs.23 In addition, little or no sedation only has two other considerable advantages in comparison with deep sedation . . .
  24. Shah, S. G., Saunders, B. P., Brooker, J. C. & Williams, C. B. Magnetic imaging of colonoscopy: an audit of looping, accuracy and ancillary maneuvers. Gastrointest. Endosc. 52, 1-8 , .
    • . . . First, dynamic position changes are an important technique during colonoscopy and sometimes the key to cecal intubation, and is much easier to achieve with a conscious and cooperating patient.24 Second, conscious patients report pain, which can indicate loop formation . . .
    • . . . Abdominal pressure is commonly applied to reduce loop formation in the sigmoid and transverse colon and is effective in helping the tip of the colonoscope pass the hepatic flexure.24 Rex et al.35 demonstrated that applying abdominal pressure was the most important noninstrumental technique in achieving cecal intubation in patients referred because of prior incomplete colonoscopy . . .
    • . . . In a study by Shah and colleagues,24 position changes were effective 66% of the time (95 of 144 maneuvers), which was defined as improvement of the luminal view or a definite advancement of the colonoscope.24 Nevertheless, no randomized studies have been performed to determine the exact role of external abdominal pressure and position changes on cecal intubation rates. . . .
  25. Bretthauer, M. et al. NORCCAP (Norwegian colorectal cancer prevention): a randomised trial to assess the safety and efficacy of carbon dioxide versus air insufflation in colonoscopy. Gut 50, 604-607 , .
    • . . . Several randomized trials have shown that using carbon dioxide instead of oxygen for insufflation substantially reduces abdominal pain and discomfort in patients undergoing colonoscopy.25, 26, 27 We believe, use of carbon dioxide insufflation is, therefore, recommended for daily colonoscopic practice. . . .
  26. Sumanac, K. et al. Minimizing postcolonoscopy abdominal pain by using CO2 insufflation: a prospective, randomized, double blind, controlled trial evaluating a new commercially available CO2 delivery system. Gastrointest. Endosc. 56, 190-194 , .
    • . . . Several randomized trials have shown that using carbon dioxide instead of oxygen for insufflation substantially reduces abdominal pain and discomfort in patients undergoing colonoscopy.25, 26, 27 We believe, use of carbon dioxide insufflation is, therefore, recommended for daily colonoscopic practice. . . .
  27. Church, J. & Delaney, C. Randomized, controlled trial of carbon dioxide insufflation during colonoscopy. Dis. Colon Rectum 46, 322-326 , .
    • . . . Several randomized trials have shown that using carbon dioxide instead of oxygen for insufflation substantially reduces abdominal pain and discomfort in patients undergoing colonoscopy.25, 26, 27 We believe, use of carbon dioxide insufflation is, therefore, recommended for daily colonoscopic practice. . . .
  28. Baxter, N. N. et al. Association of colonoscopy and death from colorectal cancer. Ann. Intern. Med. 150, 1-8 , .
    • . . . Accumulating evidence suggests that colonoscopy is more protective for left-sided than for right-sided cancer.28, 29, 30 Among others, a possible explanation for this finding is that polyps in the right colon are not visualized, either because they are nonpolypoid, because of inadequate bowel preperation or because this part of the colon is not visualized at all . . .
  29. Brenner, H. et al. Protection from right- and left-sided colorectal neoplasms after colonoscopy: population-based study. J. Natl Cancer Inst. 102, 89-95 , .
    • . . . Accumulating evidence suggests that colonoscopy is more protective for left-sided than for right-sided cancer.28, 29, 30 Among others, a possible explanation for this finding is that polyps in the right colon are not visualized, either because they are nonpolypoid, because of inadequate bowel preperation or because this part of the colon is not visualized at all . . .
  30. Singh, H. et al. The reduction in colorectal cancer mortality after colonoscopy varies by site of the cancer. Gastroenterology 139, 1128-1137 , .
    • . . . Accumulating evidence suggests that colonoscopy is more protective for left-sided than for right-sided cancer.28, 29, 30 Among others, a possible explanation for this finding is that polyps in the right colon are not visualized, either because they are nonpolypoid, because of inadequate bowel preperation or because this part of the colon is not visualized at all . . .
  31. Neerincx, M. et al. Colonic work-up after incomplete colonoscopy: significant new findings during follow-up. Endoscopy 42, 730-735 , .
    • . . . In a population-based cohort study of patients who underwent a previously incomplete colonoscopy, advanced neoplasia was detected in the nonvisualized part of the colon during follow-up examination in 4.3% of patients.31 Worryingly, studies have demonstrated that only the minority of patients with an incomplete colonoscopy do undergo a complete colonic evaluation within 12–18 months after the initial colonoscopy.31, 32 . . .
    • . . . Variable cecal intubation rates are reported in the literature, ranging from 75.4% to 97.7%, depending on the clinical setting and the indication for colonoscopy.33, 34 Reasons for incomplete colonoscopy are a dolichocolon, discomfort of the patient, obstructing tumors, insufficient bowel preparation, diverticulosis, stenosis and severe inflammation.31 In addition, a large population-based study demonstrated that advanced age, female sex and prior abdominal or pelvic surgery were statistically significant independent predictive factors associated with an incomplete colonoscopy.33 Several techniques are available that can facilitate cecal intubation and these are discussed below. . . .
  32. Rizek, R. et al. Rates of complete colonic evaluation after incomplete colonoscopy and their associated factors: a population-based study. Med. Care 47, 48-52 , .
  33. Shah, H. A., Paszat, L. F., Saskin, R., Stukel, T. A. & Rabeneck, L. Factors associated with incomplete colonoscopy: a population-based study. Gastroenterology 132, 2297-2303 , .
    • . . . Variable cecal intubation rates are reported in the literature, ranging from 75.4% to 97.7%, depending on the clinical setting and the indication for colonoscopy.33, 34 Reasons for incomplete colonoscopy are a dolichocolon, discomfort of the patient, obstructing tumors, insufficient bowel preparation, diverticulosis, stenosis and severe inflammation.31 In addition, a large population-based study demonstrated that advanced age, female sex and prior abdominal or pelvic surgery were statistically significant independent predictive factors associated with an incomplete colonoscopy.33 Several techniques are available that can facilitate cecal intubation and these are discussed below. . . .
    • . . . Variable cecal intubation rates are reported in the literature, ranging from 75.4% to 97.7%, depending on the clinical setting and the indication for colonoscopy.33, 34 Reasons for incomplete colonoscopy are a dolichocolon, discomfort of the patient, obstructing tumors, insufficient bowel preparation, diverticulosis, stenosis and severe inflammation.31 In addition, a large population-based study demonstrated that advanced age, female sex and prior abdominal or pelvic surgery were statistically significant independent predictive factors associated with an incomplete . . .
  34. Lieberman, D. A. et al. Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380. N. Engl. J. Med. 343, 162-168 , .
    • . . . Variable cecal intubation rates are reported in the literature, ranging from 75.4% to 97.7%, depending on the clinical setting and the indication for colonoscopy.33, 34 Reasons for incomplete colonoscopy are a dolichocolon, discomfort of the patient, obstructing tumors, insufficient bowel preparation, diverticulosis, stenosis and severe inflammation.31 In addition, a large population-based study demonstrated that advanced age, female sex and prior abdominal or pelvic surgery were statistically significant independent predictive factors associated with an incomplete colonoscopy.33 Several techniques are available that can facilitate cecal intubation and these are discussed below. . . .
  35. Rex, D. K., Chen, S. C. & Overhiser, A. J. Colonoscopy technique in consecutive patients referred for prior incomplete colonoscopy. Clin. Gastroenterol. Hepatol. 5, 879-883 , .
    • . . . Abdominal pressure is commonly applied to reduce loop formation in the sigmoid and transverse colon and is effective in helping the tip of the colonoscope pass the hepatic flexure.24 Rex et al.35 demonstrated that applying abdominal pressure was the most important noninstrumental technique in achieving cecal intubation in patients referred because of prior incomplete colonoscopy . . .
  36. Shumaker, D. A., Zaman, A. & Katon, R. M. A randomized controlled trial in a training institution comparing a pediatric variable stiffness colonoscope, a pediatric colonoscope, and an adult colonoscope. Gastrointest. Endosc. 55, 172-179 , .
    • . . . Concerning cecal intubation rates and procedure times, two randomized studies in nonselected patients failed to show any advantage of pediatric colonoscope use in adults in comparison with standard adult colonoscope.36, 37 However, in women with previous hysterectomy, higher cecal intubation rates were obtained with a pediatric colonoscope (96.1% versus 71.4%, P <0.001).38 Furthermore, for nonadvancing procedures, it can be useful to change to a pediatric colonoscope to achieve cecal intubation.37, 38 . . .
  37. Saifuddin, T., Trivedi, M., King, P. D., Madsen, R. & Marshall, J. B. Usefulness of a pediatric colonoscope for colonoscopy in adults. Gastrointest. Endosc. 51, 314-317 , .
    • . . . Concerning cecal intubation rates and procedure times, two randomized studies in nonselected patients failed to show any advantage of pediatric colonoscope use in adults in comparison with standard adult colonoscope.36, 37 However, in women with previous hysterectomy, higher cecal intubation rates were obtained with a pediatric colonoscope (96.1% versus 71.4%, P <0.001).38 Furthermore, for nonadvancing procedures, it can be useful to change to a pediatric colonoscope to achieve cecal intubation.37, 38 . . .
  38. Marshall, J. B., Perez, R. A. & Madsen, R. W. Usefulness of a pediatric colonoscope for routine colonoscopy in women who have undergone hysterectomy. Gastrointest. Endosc. 55, 838-841 , .
  39. Othman, M. O., Bradley, A. G., Choudhary, A., Hoffman, R. M. & Roy, P. K. Variable stiffness colonoscope versus regular adult colonoscope: meta-analysis of randomized controlled trials. Endoscopy 41, 17-24 , .
    • . . . A 2009 meta-analysis of randomized trials compared the efficacy of pediatric and adult VSCs with regular adult colonoscopes.39 Use of adult or pediatric VSC resulted in higher cecal intubation rates than regular adult colonoscopes (odds ratio 2.08; 95% CI 1.29–3.36) . . .
    • . . . Furthermore, the VSC was associated with reduced abdominal pain scores and a decreased need for sedation during colonoscopy.39 A subgroup analysis on solely adult colonoscopes showed statistically significant higher cecal intubation rates with the VSC than with the standard colonoscope (odds ratio 3.20; 95% CI 1.45–7.10), supporting an independent effect of the variable stiffness mode. . . .
  40. Shah, S. G., Brooker, J. C., Williams, C. B., Thapar, C. & Saunders, B. P. Effect of magnetic endoscope imaging on colonoscopy performance: a randomised controlled trial. Lancet 356, 1718-1722 , .
    • . . . Two randomized controlled trials of the MEI device showed improved performance of endoscopists, both in terms of patient tolerance and cecal intubation rates, and in particular when little or no sedation was used.40, 41 In our opinion, MEI should, therefore, be considered, particularly in procedures when little or no sedation is used and in a training setting. . . .
  41. Shah, S. G. et al. Effect of magnetic endoscope imaging on patient tolerance and sedation requirements during colonoscopy: a randomized controlled trial. Gastrointest. Endosc. 55, 832-837 , .
    • . . . Two randomized controlled trials of the MEI device showed improved performance of endoscopists, both in terms of patient tolerance and cecal intubation rates, and in particular when little or no sedation was used.40, 41 In our opinion, MEI should, therefore, be considered, particularly in procedures when little or no sedation is used and in a training setting. . . .
  42. Wehrmann, T., Lechowicz, I., Martchenko, K. & Riphaus, A. Routine colonoscopy with a standard gastroscope. A randomized comparative trial in a western population. Int. J. Colorectal Dis. 23, 443-446 , .
    • . . . However, two randomized studies in nonselected patients showed no additional value of using an upper endoscope with regard to cecal intubation rates.42, 43 . . .
  43. Park, C. H. et al. Sedation-free colonoscopy using an upper endoscope is tolerable and effective in patients with low body mass index: a prospective randomized study. Am. J. Gastroenterol. 101, 2504-2510 , .
  44. Keswani, R. N. Single-balloon colonoscopy versus repeat standard colonoscopy for previous incomplete colonoscopy: a randomized, controlled trial. Gastrointest. Endosc. 73, 507-512 , .
    • . . . The first randomized prospective study comparing cecal intubation rates for a single-balloon enteroscope plus overtube with standard colonoscopes in 30 patients who had a prior incomplete colonoscopy was published in 2011.44 Cecal intubation was more successful with the balloon enteroscope than with standard equipment (92.9% versus 50%, P = 0.016). . . .
  45. Rex, D. K., Khashab, M., Raju, G. S., Pasricha, J. & Kozarek, R. Insertability and safety of a shape-locking device for colonoscopy. Am. J. Gastroenterol. 100, 817-820 , .
  46. Van Rijn, J. C. et al. Polyp miss rate determined by tandem colonoscopy: a systematic review. Am. J. Gastroenterol. 101, 343-350 , .
    • . . . Although colonoscopy is considered the 'gold standard' for polyp detection, a systematic review of back-to-back colonoscopies demonstrated a miss rate of 2.1% for polyps >10 mm, 13% for polyps 5–10 mm and 26% for polyps <5 mm.46 Kaminski et al.47 published a landmark study in 2010 demonstrating an association between colonoscopy-related quality indicators and the risk of interval CRCs . . .
  47. Kaminski, M. F. et al. Quality indicators for colonoscopy and the risk of interval cancer. N. Engl. J. Med. 362, 1795-1803 , .
    • . . . Although colonoscopy is considered the 'gold standard' for polyp detection, a systematic review of back-to-back colonoscopies demonstrated a miss rate of 2.1% for polyps >10 mm, 13% for polyps 5–10 mm and 26% for polyps <5 mm.46 Kaminski et al.47 published a landmark study in 2010 demonstrating an association between colonoscopy-related quality indicators and the risk of interval CRCs . . .
  48. Rex, D. K. et al. Quality indicators for colonoscopy. Gastrointest. Endosc. 63, S16-S28 , .
  49. Lee, R. H. et al. Quality of colonoscopy withdrawal technique and variability in adenoma detection rates (with videos). Gastrointest. Endosc. 74, 128-134 , .
    • . . . Lee and colleagues49 divided 11 endoscopists into three groups based on their adenoma detection rate (low, <20%; moderate, 20–42%; high >42%) . . .
  50. East, J. E. et al. Dynamic patient position changes during colonoscope withdrawal increase adenoma detection: a randomized, crossover trial. Gastrointest. Endosc. 73, 456-463 , .
    • . . . In addition, East and colleagues50 reported that dynamic position changes during withdrawal provides better luminal distension with a marked improvement in detection of adenomas as a result . . .
  51. Lee, J. M. et al. Effects of hyosine N.-butyl bromide on the detection of polyps during colonoscopy. Hepatogastroenterology 57, 90-94 , .
  52. East, J. E. et al. A comparative study of standard vs. high definition colonoscopy for adenoma and hyperplastic polyp detection with optimized withdrawal technique. Aliment. Pharmacol. Ther. 28, 768-776 , .
    • . . . Five studies have been published comparing high-definition white-light colonoscopy with standard white-light colonoscopy.52, 53, 54, 55, 56 Only one large retrospective, nonrandomized cohort study showed a higher adenoma detection rate using high-definition white-light colonoscopy (28.8% versus 24.3%, P = 0.012),56 whereas the other four studies (two randomized and two cohort studies) demonstrated no statistically significant difference in adenoma detection rates between the two approaches.52, 53, 54, 55 . . .
  53. Pellise, M. et al. Impact of wide-angle, high-definition endoscopy in the diagnosis of colorectal neoplasia: a randomized controlled trial. Gastroenterology 135, 1062-1068 , .
    • . . . Five studies have been published comparing high-definition white-light colonoscopy with standard white-light colonoscopy.52, 53, 54, 55, 56 Only one large retrospective, nonrandomized cohort study showed a higher adenoma detection rate using high-definition white-light colonoscopy (28.8% versus 24.3%, P = 0.012),56 whereas the other four studies (two randomized and two cohort studies) demonstrated no statistically significant difference in adenoma detection rates between the two approaches. . . .
  54. Burke, C. A., Choure, A. G., Sanaka, M. R. & Lopez, R. A comparison of high-definition versus conventional colonoscopes for polyp detection. Dig. Dis. Sci. 55, 1716-1720 , .
    • . . . Five studies have been published comparing high-definition white-light colonoscopy with standard white-light colonoscopy.52, 53, 54, 55, 56 Only one large retrospective, nonrandomized cohort study showed a higher adenoma detection rate using high-definition white-light colonoscopy (28.8% versus 24.3%, P = 0.012),56 whereas the other four studies (two randomized and two cohort studies) demonstrated no statistically significant difference in adenoma detection rates between the two approaches.52, . . .
  55. Tribonias, G. et al. Comparison of standard vs high-definition, wide-angle colonoscopy for polyp detection: a randomized controlled trial. Colorectal Dis. 12, e260-e266 , .
    • . . . Five studies have been published comparing high-definition white-light colonoscopy with standard white-light colonoscopy.52, 53, 54, 55, 56 Only one large retrospective, nonrandomized cohort study showed a higher adenoma detection rate using high-definition white-light colonoscopy (28.8% versus 24.3%, P = 0.012),56 whereas the other four studies (two randomized and two cohort studies) demonstrated no statistically significant difference in adenoma detection rates between the two approaches.52, 53, 54, 55 . . .
    • . . . Five studies have been published comparing high-definition white-light colonoscopy with standard white-light colonoscopy.52, 53, 54, 55, 56 Only one large retrospective, nonrandomized cohort study showed a higher adenoma detection rate using high-definition white-light colonoscopy (28.8% versus 24.3%, P = 0.012),56 whereas the other four studies (two randomized and two cohort studies) demonstrated no statistically significant difference in adenoma detection rates between the two approaches.52, 53, . . .
  56. Buchner, A. M. et al. High-definition colonoscopy detects colorectal polyps at a higher rate than standard white-light colonoscopy. Clin. Gastroenterol. Hepatol. 8, 364-370 , .
    • . . . Five studies have been published comparing high-definition white-light colonoscopy with standard white-light colonoscopy.52, 53, 54, 55, 56 Only one large retrospective, nonrandomized cohort study showed a higher adenoma detection rate using high-definition white-light colonoscopy (28.8% versus 24.3%, P = 0.012),56 whereas the other four studies (two randomized and two cohort studies) demonstrated no statistically significant difference in adenoma detection rates between the two approaches.52, 53, 54, 55 . . .
  57. Ignjatovic, A. et al. What is the most reliable imaging modality for small colonic polyp characterization? Study of white-light, autofluorescence, and narrow-band imaging. Endoscopy 43, 94-99 , .
    • . . . These techniques can facilitate the on-site prediction of histology (differentiation), a topic that will not be discussed in this manuscript and that is discussed in detail elsewhere.57, 58 Of these techniques, chromoendoscopy, electronic image enhancement—narrow band imaging (NBI, Olympus, Tokyo, Japan), i-Scan (Pentax, Tokyo Japan) and Fuji intelligent chromoendoscopy (FICE, Fujifilm, Tokyo, Japan)—and autofluorescence imaging have been studied most extensively and are discussed below . . .
  58. van den Broek, F. J. et al. Combining autofluorescence imaging and narrow-band imaging for the differentiation of adenomas from non-neoplastic colonic polyps among experienced and non-experienced endoscopists. Am. J. Gastroenterol. 104, 1498-1507 , .
    • . . . These techniques can facilitate the on-site prediction of histology (differentiation), a topic that will not be discussed in this manuscript and that is discussed in detail elsewhere.57, 58 Of these techniques, chromoendoscopy, electronic image enhancement—narrow band imaging (NBI, Olympus, Tokyo, Japan), i-Scan (Pentax, Tokyo Japan) and Fuji intelligent chromoendoscopy (FICE, Fujifilm, Tokyo, Japan)—and autofluorescence imaging have been studied most extensively and are discussed below . . .
  59. Kiesslich, R., von, B. M., Hahn, M., Hermann, G. & Jung, M. Chromoendoscopy with indigocarmine improves the detection of adenomatous and nonadenomatous lesions in the colon. Endoscopy 33, 1001-1006 , .
    • . . . Panchromoendoscopy has been shown to increase the detection of adenomatous lesions in patients with sporadic adenomas, as well as in patients with Lynch syndrome.59, 60, 61 The implementation in daily practice is, however, hampered, as chromoendoscopy is labor intensive, time consuming and switching back and forth between the conventional and chromoendoscopy image is not possible . . .
  60. Pohl, J. et al. Pancolonic chromoendoscopy with indigo carmine versus standard colonoscopy for detection of neoplastic lesions: a randomised two-centre trial. Gut 60, 485-490 , .
    • . . . Panchromoendoscopy has been shown to increase the detection of adenomatous lesions in patients with sporadic adenomas, as well as in patients with Lynch syndrome.59, 60, 61 The implementation in daily practice is, however, hampered, as chromoendoscopy is labor intensive, time consuming and switching back and forth between the conventional and chromoendoscopy image is not possible . . .
  61. Lecomte, T. et al. Chromoendoscopic colonoscopy for detecting preneoplastic lesions in hereditary nonpolyposis colorectal cancer syndrome. Clin. Gastroenterol. Hepatol. 3, 897-902 , .
    • . . . Panchromoendoscopy has been shown to increase the detection of adenomatous lesions in patients with sporadic adenomas, as well as in patients with Lynch syndrome.59, 60, 61 The implementation in daily practice is, however, hampered, as chromoendoscopy is labor intensive, time consuming and switching back and forth between the conventional and chromoendoscopy image is not possible . . .
  62. East, J. E. et al. Narrow band imaging for colonoscopic surveillance in hereditary non-polyposis colorectal cancer. Gut 57, 65-70 , .
    • . . . Although improved adenoma detection rates in high-risk patients have been observed,62 a systematic review did not demonstrate an additional benefit of NBI on adenoma detection.63 . . .
  63. van den Broek, F. J., Reitsma, J. B., Curvers, W. L., Fockens, P. & Dekker, E. Systematic review of narrow-band imaging for the detection and differentiation of neoplastic and nonneoplastic lesions in the colon (with videos). Gastrointest. Endosc. 69, 124-135 , .
  64. Hoffman, A. et al. High definition colonoscopy combined with i-Scan is superior in the detection of colorectal neoplasias compared with standard video colonoscopy: a prospective randomized controlled trial. Endoscopy 42, 827-833 , .
    • . . . One randomized study has compared high-definition colonoscopy in combination with i-Scan versus standard video colonoscopy.64 High-definition colonoscopy in combination with i-Scan detected significantly more patients with at least one neoplasia compared with standard video colonoscopy (38% versus 13%, P <0.001).64 However, due to the remarkable low neoplasia detection rate of only 13% in the reference group, the additional value of i-Scan might have been overestimated and thus further data are needed . . .
  65. Aminalai, A. et al. Live image processing does not increase adenoma detection rate during colonoscopy: a randomized comparison between FICE and conventional imaging (Berlin Colonoscopy Project 5, BECOP-5). Am. J. Gastroenterol. 105, 2383-2388 , .
    • . . . Three randomized studies comparing the FICE system with standard colonoscopy showed no improvement in adenoma detection.65, 66, 67 . . .
  66. Chung, S. J. et al. Efficacy of computed virtual chromoendoscopy on colorectal cancer screening: a prospective, randomized, back-to-back trial of Fuji Intelligent Color Enhancement versus conventional colonoscopy to compare adenoma miss rates. Gastrointest. Endosc. 72, 136-142 , .
    • . . . Three randomized studies comparing the FICE system with standard colonoscopy showed no improvement in adenoma detection.65, 66, 67 . . .
  67. Pohl, J. et al. Computed virtual chromoendoscopy versus standard colonoscopy with targeted indigocarmine chromoscopy: a randomised multicentre trial. Gut 58, 73-78 , .
  68. Ramsoekh, D. et al. A back-to-back comparison of white light video endoscopy with autofluorescence endoscopy for adenoma detection in high-risk subjects. Gut 59, 785-793 , .
    • . . . Two randomized studies comparing autofluorescence imaging with conventional white-light endoscopy for detection of adenomas have reported conflicting results.68, 69 Ramsoekh et al.68 reported a marked improvement in the detection of adenomas in high-risk patients with the Onco-LIFE® system (Xillix Technologies Corporation, Richmond, BC, Canada), whereas van den Broek and colleagues69 demonstrated comparable adenoma detection rates in a randomized study in nonselected patients with the Lucera® system (Olympus, Tokyo, Japan). . . .
    • . . . Two randomized studies comparing autofluorescence imaging with conventional white-light endoscopy for detection of adenomas have reported conflicting results.68, 69 Ramsoekh et al . . .
  69. van den Broek, F. J. et al. Clinical evaluation of endoscopic trimodal imaging for the detection and differentiation of colonic polyps. Clin. Gastroenterol. Hepatol. 7, 288-295 , .
    • . . . Two randomized studies comparing autofluorescence imaging with conventional white-light endoscopy for detection of adenomas have reported conflicting results.68, 69 Ramsoekh et al.68 reported a marked improvement in the detection of adenomas in high-risk patients with the Onco-LIFE® system (Xillix Technologies Corporation, Richmond, BC, Canada), whereas van den Broek and colleagues69 demonstrated comparable adenoma detection rates in a randomized study in nonselected patients with the Lucera® system (Olympus, Tokyo, Japan). . . .
  70. Kondo, S. et al. A randomized controlled trial evaluating the usefulness of a transparent hood attached to the tip of the colonoscope. Am. J. Gastroenterol. 102, 75-81 , .
    • . . . Kondo et al.70 demonstrated a significantly higher polyp detection rate for cap-assisted colonoscopy than during standard colonoscopy (49.3% versus 39.1%; P = 0.04) . . .
    • . . . Randomized studies comparing cap-assisted colonoscopy with standard colonoscopy showed no difference in cecal intubation rates.70, 71, 72, 73, 74 . . .
  71. Lee, Y. T. et al. Efficacy of cap-assisted colonoscopy in comparison with regular colonoscopy: a randomized controlled trial. Am. J. Gastroenterol. 104, 41-46 , .
    • . . . However, Lee and co-workers71 reported a lower polyp detection rate (30.5% versus 37.5%; P = 0.02) during cap-assisted colonoscopy than standard colonoscopy . . .
    • . . . Randomized studies comparing cap-assisted colonoscopy with standard colonoscopy showed no difference in cecal intubation rates.70, 71, 72, 73, 74 . . .
  72. Morgan, J., Thomas, K., Lee-Robichaud, H. & Nelson, R. L. Transparent cap colonoscopy versus standard colonoscopy for investigation of gastrointestinal tract conditions. Cochrane Database Syst. Rev. Issue 2. Art. No.: CD008211. doi: 10.1002/14651858.CD008211.pub2. , .
    • . . . Randomized studies comparing cap-assisted colonoscopy with standard colonoscopy showed no difference in cecal intubation rates.70, 71, 72, 73, 74 . . .
  73. Hewett, D. G. & Rex, D. K. Cap-fitted colonoscopy: a randomized, tandem colonoscopy study of adenoma miss rates. Gastrointest. Endosc. 72, 775-781 , .
    • . . . Randomized studies comparing cap-assisted colonoscopy with standard colonoscopy showed no difference in cecal intubation rates.70, 71, 72, 73, 74 . . .
  74. Tee, H. P. et al. Prospective randomized controlled trial evaluating cap-assisted colonoscopy vs standard colonoscopy. World J. Gastroenterol. 16, 3905-3910 , .
  75. DeMarco, D. C. et al. Impact of experience with a retrograde-viewing device on adenoma detection rates and withdrawal times during colonoscopy: the Third Eye Retroscope study group. Gastrointest. Endosc. 71, 542-550 , .
    • . . . The additional use of the retroscope increased the number of detected adenomas by 11% and 16% in the two different studies.75, 76 In 2011, the first randomized tandem colonoscopy trial was published . . .
  76. Waye, J. D. et al. A retrograde-viewing device improves detection of adenomas in the colon: a prospective efficacy evaluation (with videos). Gastrointest. Endosc. 71, 551-556 , .
    • . . . The additional use of the retroscope increased the number of detected adenomas by 11% and 16% in the two different studies.75, 76 In 2011, the first randomized tandem colonoscopy trial was published . . .
  77. Leufkens, A. M. et al. Effect of a retrograde-viewing device on adenoma detection rate during colonoscopy: the TERRACE study. Gastrointest. Endosc. 73, 480-489 , .
    • . . . In total, 448 patients were randomly assigned to undergo standard colonoscopy followed by TER or TER followed by standard colonoscopy.77 The relative risk of missing adenomas per patient with standard colonoscopy compared with TER was 1.92 (28% versus 15%, P = 0.029), suggesting that TER decreases the adenoma miss rate. . . .
  78. Endoscopy Classification Review Group. Update on the Paris classification of superficial neoplastic lesions in the digestive tract. Endoscopy 37, 570-578 , .
  79. Winawer, S. J. et al. Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup. N. Engl. J. Med. 329, 1977-1981 , .
    • . . . Data from the National Polyp Trial suggested that colonoscopy and polypectomy prevented 76–90% of incident cancers.79 Concerning the polypectomy technique, several issues need discussion . . .
  80. Iqbal, C. W. et al. Surgical management and outcomes of 165 colonoscopic perforations from a single institution. Arch. Surg. 143, 701-706 , .
    • . . . Complications after a colonoscopy are rare, but are associated with a high morbidity.80 Second, a polypectomy should eradicate a polyp completely to prevent local recurrence, as highlighted by two studies demonstrating that a quarter of all interval cancers after colonoscopy might have developed from residual tissue after polypectomy.81, 82 Third, retrieval of polyps for histological assessment is necessary to exclude invasive carcinoma and to determine the surveillance interval . . .
  81. Pabby, A. et al. Analysis of colorectal cancer occurrence during surveillance colonoscopy in the dietary Polyp Prevention Trial. Gastrointest. Endosc. 61, 385-391 , .
    • . . . Complications after a colonoscopy are rare, but are associated with a high morbidity.80 Second, a polypectomy should eradicate a polyp completely to prevent local recurrence, as highlighted by two studies demonstrating that a quarter of all interval cancers after colonoscopy might have developed from residual tissue after polypectomy.81, 82 Third, retrieval of polyps for histological assessment is necessary to exclude invasive carcinoma and to determine the surveillance interval . . .
  82. Farrar, W. D., Sawhney, M. S., Nelson, D. B., Lederle, F. A. & Bond, J. H. Colorectal cancers found after a complete colonoscopy. Clin. Gastroenterol. Hepatol. 4, 1259-1264 , .
    • . . . Complications after a colonoscopy are rare, but are associated with a high morbidity.80 Second, a polypectomy should eradicate a polyp completely to prevent local recurrence, as highlighted by two studies demonstrating that a quarter of all interval cancers after colonoscopy might have developed from residual tissue after polypectomy.81, 82 Third, retrieval of polyps for histological assessment is necessary to exclude invasive carcinoma and to determine the surveillance interval . . .
  83. Ignjatovic, A. et al. Optical diagnosis of small colorectal polyps at routine colonoscopy (Detect InSpect ChAracterise Resect and Discard; DISCARD trial): a prospective cohort study. Lancet Oncol. 10, 1171-1178 , .
    • . . . Interestingly, a 2009 study reported that for polyps <10 mm, in vivo optical diagnosis with either white light, NBI or chromoendoscopy seems to be an acceptable strategy to assess polyp histology and predict future surveillance intervals.83 Possibly, this technique could replace histology in future. . . .
  84. Efthymiou, M., Taylor, A. C., Desmond, P. V., Allen, P. B. & Chen, R. Y. Biopsy forceps is inadequate for the resection of diminutive polyps. Endoscopy 43, 312-316 , .
    • . . . A standardized polypectomy protocol is not available in the literature, but a few prospective and well-designed studies have been published and could make the choice for a specific polypectomy technique more evidence based.84, 85, 86 However, the relative lack of evidence urges the performance of more clinical research within this important field. . . .
    • . . . However, Efthymiou et al.84 reported a high incomplete resection rate of 61% with this technique . . .
  85. Moss, A. et al. Endoscopic mucosal resection outcomes and prediction of submucosal cancer from advanced colonic mucosal neoplasia. Gastroenterology 140, 1909-1918 , .
    • . . . A standardized polypectomy protocol is not available in the literature, but a few prospective and well-designed studies have been published and could make the choice for a specific polypectomy technique more evidence based.84, 85, 86 However, the relative lack of evidence urges the performance of more clinical research within this important field. . . .
    • . . . Flat and sessile lesions have a high risk (approximately 7%) of containing submucosal invasive cancer.85, 97 To avoid noncurative EMR procedures, these lesions should be identified beforehand . . .
    • . . . Lesions with a depressed component, with a nongranular surface, or with an advanced pit pattern have a markedly increased risk of containing adenocarcinoma.85, 98, 99 . . .
    • . . . Moss et al.85 published the first prospective, multicenter, intention-to-treat study evaluating the safety, efficacy and success predictors for EMR of large sessile colorectal polyps in 2011 . . .
  86. Saito, Y. et al. A prospective, multicenter study of 1111 colorectal endoscopic submucosal dissections (with video). Gastrointest. Endosc. 72, 1217-1225 , .
    • . . . A standardized polypectomy protocol is not available in the literature, but a few prospective and well-designed studies have been published and could make the choice for a specific polypectomy technique more evidence based.84, 85, 86 However, the relative lack of evidence urges the performance of more clinical research within this important field. . . .
    • . . . In Japan, several studies demonstrate high en bloc and curative resection rates with ESD.86, 108 In a prospective study including 1,111 colorectal tumors (with a mean size of 35 mm) in 1,090 patients, en bloc and curative resection rates were 88% and 89%, respectively.86 The mean procedure time was 116 min and perforations occurred in almost 5% of the cases . . .
  87. Singh, N., Harrison, M. & Rex, D. K. A survey of colonoscopic polypectomy practices among clinical gastroenterologists. Gastrointest. Endosc. 60, 414-418 , .
    • . . . Snare and forceps polypectomy, with ('hot') or without ('cold') electrocautery are the most widely used techniques to remove these polyps.87 In daily practice, most diminutive polyps are removed with cold biopsy forceps whereas small polyps are removed with either hot or cold snares.87 Regarding hot or cold snaring, most experts remove polyps ≤7 mm with cold snares as this method seems safe and effective.88 . . .
  88. Hewett, D. G. & Rex, D. K. Colonoscopy and diminutive polyps: hot or cold biopsy or snare? Do I send to pathology? Clin. Gastroenterol. Hepatol. 9, 102-105 , .
  89. Woods, A., Sanowski, R. A., Wadas, D. D., Manne, R. K. & Friess, S. W. Eradication of diminutive polyps: a prospective evaluation of bipolar coagulation versus conventional biopsy removal. Gastrointest. Endosc. 35, 536-540 , .
    • . . . Another study by Woods et al.89 used biopsies to confirm the completeness of CBP and demonstrated an incomplete resection rate of 29%. . . .
  90. Yoo, T. W. et al. Clinical significance of small colorectal adenoma less than 10 mm: the KASID study. Hepatogastroenterology 54, 418-421 , .
    • . . . Most experts are, therefore, recommending snares as a first-line technique for removal of diminutive and small polyps.88 Nevertheless, the study authors also emphasize that removal of tiny flat polyps is sometimes easier and more practical with CBP than with snares.88 Besides, whether incomplete resection of these lesions is clinically relevant is unknown, as the potential malignant character of diminutive lesions is low.90, 91 Hot forceps biopsy was previously an alternative to CPB, but seemed to be associated with an increased bleeding and perforation risk, making it no longer an appropriate treatment option.92, 93 . . .
  91. Lieberman, D., Moravec, M., Holub, J., Michaels, L. & Eisen, G. Polyp size and advanced histology in patients undergoing colonoscopy screening: implications for CT colonography. Gastroenterology 135, 1100-1105 , .
    • . . . Most experts are, therefore, recommending snares as a first-line technique for removal of diminutive and small polyps.88 Nevertheless, the study authors also emphasize that removal of tiny flat polyps is sometimes easier and more practical with CBP than with snares.88 Besides, whether incomplete resection of these lesions is clinically relevant is unknown, as the potential malignant character of diminutive lesions is low.90, 91 Hot forceps biopsy was previously an alternative to CPB, but seemed to be associated with an increased bleeding and perforation risk, making it no longer an appropriate treatment option.92, 93 . . .
  92. Wadas, D. D. & Sanowski, R. A. Complications of the hot biopsy forceps technique. Gastrointest. Endosc. 34, 32-37 , .
    • . . . Most experts are, therefore, recommending snares as a first-line technique for removal of diminutive and small polyps.88 Nevertheless, the study authors also emphasize that removal of tiny flat polyps is sometimes easier and more practical with CBP than with snares.88 Besides, whether incomplete resection of these lesions is clinically relevant is unknown, as the potential malignant character of diminutive lesions is low.90, 91 Hot forceps biopsy was previously an alternative to CPB, but seemed to be associated with an increased bleeding and perforation risk, making it no longer an appropriate treatment option.92, 93 . . .
  93. Nelson, A. M. Delayed hemorrhage following “hot biopsy” of a diminutive colonic polyp. Gastrointest. Endosc. 36, 418 , .
  94. Di Giorgio, P. et al. Detachable snare versus epinephrine injection in the prevention of postpolypectomy bleeding: a randomized and controlled study. Endoscopy 36, 860-863 , .
    • . . . Di Giorgio et al.94 randomly assigned 488 patients with pedunculated colorectal polyps to receive either placement of a detachable snare, injection with epinephrine or no intervention (control group) . . .
  95. Paspatis, G. A. et al. A prospective, randomized comparison of adrenaline injection in combination with detachable snare versus adrenaline injection alone in the prevention of postpolypectomy bleeding in large colonic polyps. Am. J. Gastroenterol. 101, 2805 , .
    • . . . Paspatis and colleagues95 demonstrated in 159 patients with pedunculated colonic polyps >2 cm that a combination of epinephrine and a detachable snare versus epinephrine alone significantly reduced the number of early bleeding episodes (1.2% versus 9.3%, P = 0.02) . . .
  96. Matsushita, M. et al. Ineffective use of a detachable snare for colonoscopic polypectomy of large polyps. Gastrointest. Endosc. 47, 496-499 , .
  97. Heresbach, D. et al. A national survey of endoscopic mucosal resection for superficial gastrointestinal neoplasia. Endoscopy 42, 806-813 , .
    • . . . Flat and sessile lesions have a high risk (approximately 7%) of containing submucosal invasive cancer.85, 97 To avoid noncurative EMR procedures, these lesions should be identified beforehand . . .
  98. Tanaka, S. et al. Clinicopathologic features and endoscopic treatment of superficially spreading colorectal neoplasms larger than 20 mm. Gastrointest. Endosc. 54, 62-66 , .
    • . . . Lesions with a depressed component, with a nongranular surface, or with an advanced pit pattern have a markedly increased risk of containing adenocarcinoma.85, 98, 99 . . .
  99. Uraoka, T. et al. Endoscopic indications for endoscopic mucosal resection of laterally spreading tumours in the colorectum. Gut 55, 1592-1597 , .
  100. Moss, A., Bourke, M. J. & Metz, A. J. A randomized, double-blind trial of succinylated gelatin submucosal injection for endoscopic resection of large sessile polyps of the colon. Am. J. Gastroenterol. 105, 2375-2382 , .
    • . . . To this aim, succinylated gelatin was compared with normal saline for sessile lesions >20 mm.100 Succinylated gelatin markedly reduced the number of resections and injections, lowered the injected volume and shortened the procedural time with no harmful adverse effects reported . . .
  101. Swan, M. P., Bourke, M. J., Alexander, S., Moss, A. & Williams, S. J. Large refractory colonic polyps: is it time to change our practice? A prospective study of the clinical and economic impact of a tertiary referral colonic mucosal resection and polypectomy service (with videos). Gastrointest. Endosc. 70, 1128-1136 , .
    • . . . EMR allows en bloc (one piece) resection of polyps as large as 15–20 mm.101 Larger resections are generally performed in a piecemeal fashion, but this procedure is associated with increased recurrence rates.102 The application of argon plasma coagulation to the margins of the polypectomy reduces adenoma recurrence and is, therefore, recommended for routine use after piecemeal EMR.103 . . .
  102. Mannath, J., Subramanian, V., Singh, R., Telakis, E. & Ragunath, K. Polyp recurrence after endoscopic mucosal resection of sessile and flat colonic adenomas. Dig. Dis. Sci. 56, 2389-2395 , .
    • . . . EMR allows en bloc (one piece) resection of polyps as large as 15–20 mm.101 Larger resections are generally performed in a piecemeal fashion, but this procedure is associated with increased recurrence rates.102 The application of argon plasma coagulation to the margins of the polypectomy reduces adenoma recurrence and is, therefore, recommended for routine use after piecemeal EMR.103 . . .
  103. Brooker, J. C. et al. Treatment with argon plasma coagulation reduces recurrence after piecemeal resection of large sessile colonic polyps: a randomized trial and recommendations. Gastrointest. Endosc. 55, 371-375 , .
  104. Onozato, Y. et al. Endoscopic submucosal dissection for early gastric cancers and large flat adenomas. Endoscopy 38, 980-986 , .
    • . . . Endoscopic submucosal dissection (ESD) was developed in Japan and was initially used to treat patients with early upper gastrointestinal tract cancers,104, 105 and was later also applied to large lesions in the colon.106 The technique involves removal of a lesion with an electrosurgical knife, enabling en bloc resection of polyps >20 mm . . .
  105. Imagawa, A. et al. Endoscopic submucosal dissection for early gastric cancer: results and degrees of technical difficulty as well as success. Endoscopy 38, 987-990 , .
    • . . . Endoscopic submucosal dissection (ESD) was developed in Japan and was initially used to treat patients with early upper gastrointestinal tract cancers,104, 105 and was later also applied to large lesions in the colon.106 The technique involves removal of a lesion with an electrosurgical knife, enabling en bloc resection of polyps >20 mm . . .
  106. Saito, Y. et al. Endoscopic treatment of large superficial colorectal tumors: a case series of 200 endoscopic submucosal dissections (with video). Gastrointest. Endosc. 66, 966-973 , .
    • . . . Endoscopic submucosal dissection (ESD) was developed in Japan and was initially used to treat patients with early upper gastrointestinal tract cancers,104, 105 and was later also applied to large lesions in the colon.106 The technique involves removal of a lesion with an electrosurgical knife, enabling en bloc resection of polyps >20 mm . . .
  107. Deprez, P. H. et al. Current practice with endoscopic submucosal dissection in Europe: position statement from a panel of experts. Endoscopy 42, 853-858 , .
  108. Niimi, K. et al. Long-term outcomes of endoscopic submucosal dissection for colorectal epithelial neoplasms. Endoscopy 42, 723-729 , .
    • . . . In Japan, several studies demonstrate high en bloc and curative resection rates with ESD.86, 108 In a prospective study including 1,111 colorectal tumors (with a mean size of 35 mm) in 1,090 patients, en bloc and curative resection rates were 88% and 89%, respectively.86 The mean procedure time was 116 min and perforations occurred in almost 5% of the cases . . .
    • . . . A perforation rate of 5% is notable in comparison with EMR (1.3%), but new endoscopic closure techniques could make ESD a more attractive procedure.109 Regarding long-term outcomes after ESD, a Japanese study showed a promising recurrence rate of only 2% during a follow-up time of 30 months.108 Interestingly, all recurrent tumors were initially treated in a piecemeal fashion, which highlights the importance of en bloc resections. . . .
  109. Voermans, R. P., Vergouwe, F., Breedveld, P., Fockens, P. & van Berge Henegouwen, M. I. Comparison of endoscopic closure modalities for standardized colonic perforations in a porcine colon model. Endoscopy 43, 217-222 , .
    • . . . A perforation rate of 5% is notable in comparison with EMR (1.3%), but new endoscopic closure techniques could make ESD a more attractive procedure.109 Regarding long-term outcomes after ESD, a Japanese study showed a promising recurrence rate of only 2% during a follow-up time of 30 months.108 Interestingly, all recurrent tumors were initially treated in a piecemeal fashion, which highlights the importance of en bloc resections. . . .
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