Advanced Colon Polypectomy

Abstract

In the United States colorectal cancer (CRC) is the second leading cause of death from cancer.1Winawer S.J. Zauber A.G. Ho M.N. et al.Prevention of colorectal cancer by colonoscopic polypectomy: the National Polyp Study Workgroup.N Engl J Med. 1993; 329: 1977-1981Crossref PubMed Scopus (3830) Google Scholar, 2Citarda F. Tomaselli G. Capocaccia R. et al.Efficacy in standard clinical practice of colonoscopic polypectomy in reducing colorectal cancer incidence.Gut. 2001; 48: 812-815Crossref PubMed Scopus (611) Google Scholar Removal of colon adenomas is associated with a reduction in the incidence of CRC.1Winawer S.J. Zauber A.G. Ho M.N. et al.Prevention of colorectal cancer by colonoscopic polypectomy: the National Polyp Study Workgroup.N Engl J Med. 1993; 329: 1977-1981Crossref PubMed Scopus (3830) Google Scholar, 3Thiis-Evensen E. Hoff G.S. Sauar J. et al.Population-based surveillance by colonoscopy: effect on the incidence of colorectal cancer: Telemark Polyp Study I.Scand J Gastroenterol. 1999; 34: 414-420Crossref PubMed Scopus (406) Google Scholar Thus, CRC largely could be prevented by the detection and removal of adenomatous polyps.4Levin B. Lieberman D.A. McFarland B. et al.Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology.CA Cancer J Clin. 2008; 58: 130-160Crossref PubMed Scopus (1361) Google Scholar There are several methods to remove polyps by using either surgical or endoscopic methods.5Rex D.K. Colonoscopy.Gastrointest Endosc Clin N Am. 2000; 10: 135-160PubMed Google Scholar, 6Shirai M. Nakamura T. Matsuura A. et al.Safer colonoscopic polypectomy with local submucosal injection of hypertonic saline-epinephrine solution.Am J Gastroenterol. 1994; 89: 334-338PubMed Google Scholar Standard polyp removal methods include the use of biopsy forceps and various types of electrocautery snares.5Rex D.K. Colonoscopy.Gastrointest Endosc Clin N Am. 2000; 10: 135-160PubMed Google Scholar, 6Shirai M. Nakamura T. Matsuura A. et al.Safer colonoscopic polypectomy with local submucosal injection of hypertonic saline-epinephrine solution.Am J Gastroenterol. 1994; 89: 334-338PubMed Google Scholar Advanced polypectomy techniques are used to remove large, flat, atypical, or colon polyps located in difficult anatomic positions.7Ahmad N.A. Kochman M.L. Long W.B. et al.Efficacy, safety, and clinical outcomes of endoscopic mucosal resection: a study of 101 cases.Gastrointest Endosc. 2002; 55: 390-396Abstract Full Text Full Text PDF PubMed Scopus (332) Google Scholar, 8Conio M. Repici A. Demarquay J.F. et al.EMR of large sessile colorectal polyps.Gastrointest Endosc. 2004; 60: 234-241Abstract Full Text Full Text PDF PubMed Scopus (187) Google Scholar, 9Zlatanic J. Waye J.D. Kim P.S. et al.Large sessile colonic adenomas: use of argon plasma coagulator to supplement piecemeal snare polypectomy.Gastrointest Endosc. 1999; 49: 731-735Abstract Full Text Full Text PDF PubMed Scopus (176) Google Scholar Multimodal or advanced imaging techniques such as chromoendoscopy and virtual chromoendoscopy might be helpful in the characterization of polyps.10Hurlstone D.P. Cross S.S. Adam I. et al.Endoscopic morphological anticipation of submucosal invasion in flat and depressed colorectal lesions: clinical implications and subtype analysis of the Kudo type V pit pattern using high-magnification-chromoscopic colonoscopy.Colorectal Dis. 2004; 6: 369-375Crossref PubMed Scopus (71) Google Scholar, 11Machida H. Sano Y. Hamamoto Y. et al.Narrow-band imaging in the diagnosis of colorectal mucosal lesions: a pilot study.Endoscopy. 2004; 36: 1094-1098Crossref PubMed Scopus (455) Google Scholar Minor and major complications occur in about 10% of advanced polypectomies.12Watabe H. Yamaji Y. Okamoto M. et al.Risk assessment for delayed hemorrhagic complication of colonic polypectomy: polyp-related factors and patient-related factors.Gastrointest Endosc. 2006; 64: 73-78Abstract Full Text Full Text PDF PubMed Scopus (202) Google Scholar, 13Webb W.A. McDaniel L. Jones L. Experience with 1000 colonoscopic polypectomies.Ann Surg. 1985; 5: 626-632Crossref Scopus (98) Google Scholar, 14Silvis S.E. Nebel O. Rogers G. et al.Endoscopic complications: results of the 1974 American Society for Gastrointestinal Endoscopy survey.JAMA. 1976; 235: 928-930Crossref PubMed Scopus (613) Google Scholar Therefore, any physician attempting advanced polypectomy techniques should be an experienced colonoscopist and have adequate training in interventional endoscopy. The objective of this practical review is to present the principles, theory, and technique of advanced colon polypectomy. The patient should undergo a detailed preoperative history and physical examination and be informed by the physician about the benefits and risks of colonoscopic polypectomy. The informed consent should not only include the information about the endoscopic risks but also those risks associated with sedation. Routine preoperative laboratory blood testing is not indicated before polypectomy, unless there is clinical evidence or suspicion of a blood dyscrasia or patients are being treated with coumarin oral anticoagulants or heparin and its derivatives. Even though colon polypectomy is considered a high-risk endoscopic procedure, the limited data available do not show any increased risk of bleeding after polypectomy in patients taking NSAIDs, aspirin, or clopidogrel.15Zuckerman M.J. Hirota W.K. Adler D.G. et al.ASGE guideline: the management of low-molecular-weight heparin and nonaspirin antiplatelet agents for endoscopic procedures.Gastrointest Endosc. 2005; 61: 189-194Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar Thus, we do not routinely stop these medications before polypectomy. However, if an endoscopic mucosal resection (EMR) or removal of a large polyp is planned electively, we ask the patient to stop aspirin or clopidogrel (not both) 1 week before the procedure. The American Society of Gastrointestinal Endoscopy guidelines are very useful to guide the endoscopist in the management of anticoagulants such as warfarin or heparin and their derivatives during the periendoscopic period.15Zuckerman M.J. Hirota W.K. Adler D.G. et al.ASGE guideline: the management of low-molecular-weight heparin and nonaspirin antiplatelet agents for endoscopic procedures.Gastrointest Endosc. 2005; 61: 189-194Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar Colon polyps are classified on the basis of endoscopic and histologic criteria.16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 17Bond J.H. Colon polyps and cancer.Endoscopy. 2001; 33: 46-54Crossref PubMed Scopus (31) Google Scholar, 18Mönkemüller K.E. Fry L.C. Jones B.H. et al.Histological quality of polyps resected using the cold versus hot biopsy technique.Endoscopy. 2004; 36: 432-436Crossref PubMed Scopus (38) Google Scholar There is an ongoing debate on how to best define a polyp endoscopically.19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar The name polyp derives from the Greek language, means “many-footed,” and is used to characterize the protrusions of an octopus. In medicine the term polyp is used to characterize any growth of tissue of any size and height that protrudes from the epithelial lining.16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 17Bond J.H. Colon polyps and cancer.Endoscopy. 2001; 33: 46-54Crossref PubMed Scopus (31) Google Scholar, 18Mönkemüller K.E. Fry L.C. Jones B.H. et al.Histological quality of polyps resected using the cold versus hot biopsy technique.Endoscopy. 2004; 36: 432-436Crossref PubMed Scopus (38) Google Scholar, 19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar Polyps with a stalk, stem, pedicle, or peduncle are currently named pedunculated polyps, and those without a pedicle are categorized as sessile polyps.17Bond J.H. Colon polyps and cancer.Endoscopy. 2001; 33: 46-54Crossref PubMed Scopus (31) Google Scholar The third type of colon polyp is the flat lesion19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar (Table 1). Most flat polyps are adenomas.16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar Flat adenomas have special biologic and genetic characteristics that make them more aggressive.16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar Even if small, these lesions can harbor advanced neoplasia or even carcinoma.3Thiis-Evensen E. Hoff G.S. Sauar J. et al.Population-based surveillance by colonoscopy: effect on the incidence of colorectal cancer: Telemark Polyp Study I.Scand J Gastroenterol. 1999; 34: 414-420Crossref PubMed Scopus (406) Google Scholar, 4Levin B. Lieberman D.A. McFarland B. et al.Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology.CA Cancer J Clin. 2008; 58: 130-160Crossref PubMed Scopus (1361) Google Scholar, 5Rex D.K. Colonoscopy.Gastrointest Endosc Clin N Am. 2000; 10: 135-160PubMed Google Scholar, 16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar Thus, removal of these lesions should be performed by using mucosectomy techniques.Table 1Comparison of the Standard and New Polyp ClassificationsPolyp morphologyStandardParis-JapaneseaAdapted from both the Kyoto and Paris workshops (see references 16, 19).PedunculatedPedunculatedProtruding polypoid, pedunculated, type ISessilebAlways mention whether the polyp has a depression or ulceration.Sessile-LSTProtruding polypoid, sessile, type IFlat-LSTSuperficial, polypoid lesion Pedunculated (0-Ip) Sessile (0-Is) Mixed (0-Isp)Superficial, non-polypoid lesion Slightly elevated (0-IIa) Completely flat (0-IIb) Slightly depressed (0-IIc)Superficial, mixed types Elevated and depressed (0-IIa + IIc) Depressed and elevated (0-IIc + IIa) Sessile and depressed (0-Is + IIc)NOTE. The Paris-Japanese classification defines a protruding polypoid lesion as a lesion that is elevated >2.5 mm above the surrounding mucosa; superficial or non-polypoid lesions should be elevated <2.5 mm or be depressed <2.5 mm. A type 0 lesion is defined as a superficial, sessile, polypoid, flat/depressed, or excavated lesion. A type I lesion is defined as a protruding polypoid lesion.Abbreviations: LST, laterally spreading tumor or carpet-shaped polyp; p, pedunculated; s, sessile; a, elevated; b, flat; c, depressed.a Adapted from both the Kyoto and Paris workshops (see references 16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar).b Always mention whether the polyp has a depression or ulceration. Open table in a new tab NOTE. The Paris-Japanese classification defines a protruding polypoid lesion as a lesion that is elevated >2.5 mm above the surrounding mucosa; superficial or non-polypoid lesions should be elevated <2.5 mm or be depressed <2.5 mm. A type 0 lesion is defined as a superficial, sessile, polypoid, flat/depressed, or excavated lesion. A type I lesion is defined as a protruding polypoid lesion. Abbreviations: LST, laterally spreading tumor or carpet-shaped polyp; p, pedunculated; s, sessile; a, elevated; b, flat; c, depressed. Although this simple description of colon polyps is the most practical and most commonly used, there is a strong debate on whether it is useful to further subcategorize polyps on the basis of their gross appearance and/or by using advanced endoscopic imaging techniques.16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar In some of these classifications some experts refer to colonic polyps as colonic superficial neoplastic lesions, avoiding the term polyp at all.16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar Other experts propose to divide colonic neoplastic lesions into polypoid and non-polypoid.16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar The major problem with these newer classifications is that they have not been prospectively validated. Furthermore, the terms remain unclear, because there is no exact definition as to what constitutes protruded or polypoid, and many non-polypoid lesions either develop into polypoid lesions or have a polypoid appearance from the beginning.16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 19Kudo S. Lambert R. Allen J.I. et al.Non-polypoid neoplastic lesions of the colorectal mucosa.Gastrointest Endosc. 2008; 68: 3-47Abstract Full Text Full Text PDF Scopus (396) Google Scholar In addition, these classifications rely on the operative specimen, because for a protruded lesion to be called as such, “the height of the lesion should be more than double the thickness of the adjacent mucosa.”16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar This description is not possible with current endoscopic technology. Thus, we believe that the classification of polyps should remain practical and simple, and thus we prefer to categorize polyps on the basis of the gross endoscopic appearance, which divides polyps into protruded (pedunculated and sessile) and flat. For polyps with a pedicle, the major issue of interest is whether the stalk is thick or thin, and for sessile and flat polyps, the major aspects are whether these are laterally spreading (carpet-shaped) or have a central depression or ulceration. Certainly, the size and location of the polyp will also dictate whether and how an endoscopic resection is performed. Magnification and standard chromoendoscopy techniques such as indigo carmine or methylene blue might improve visualization of colon polyps by enhancing the mucosal detail (pit pattern), allowing a better demarcation of its margins and allowing a detailed view of the vessels beneath the mucosa, also referred to as the submucosal capillary network.10Hurlstone D.P. Cross S.S. Adam I. et al.Endoscopic morphological anticipation of submucosal invasion in flat and depressed colorectal lesions: clinical implications and subtype analysis of the Kudo type V pit pattern using high-magnification-chromoscopic colonoscopy.Colorectal Dis. 2004; 6: 369-375Crossref PubMed Scopus (71) Google Scholar, 11Machida H. Sano Y. Hamamoto Y. et al.Narrow-band imaging in the diagnosis of colorectal mucosal lesions: a pilot study.Endoscopy. 2004; 36: 1094-1098Crossref PubMed Scopus (455) Google Scholar, 20Fu K.I. Sano Y. Kato S. et al.Chromoendoscopy using indigo carmine dye spraying with magnifying observation is the most reliable method for differential diagnosis between non-neoplastic and neoplastic colorectal lesions: a prospective study.Endoscopy. 2004; 36: 1089-1093Crossref PubMed Scopus (166) Google Scholar Both the pit pattern and the submucosal capillary network are disarranged in the presence of neoplasia.11Machida H. Sano Y. Hamamoto Y. et al.Narrow-band imaging in the diagnosis of colorectal mucosal lesions: a pilot study.Endoscopy. 2004; 36: 1094-1098Crossref PubMed Scopus (455) Google Scholar, 20Fu K.I. Sano Y. Kato S. et al.Chromoendoscopy using indigo carmine dye spraying with magnifying observation is the most reliable method for differential diagnosis between non-neoplastic and neoplastic colorectal lesions: a prospective study.Endoscopy. 2004; 36: 1089-1093Crossref PubMed Scopus (166) Google Scholar Currently, however, there are no data showing any benefit from the use of complex pit and submucosal capillary pattern classifications on the decision-making process of colon polypectomy. Although the pit pattern evaluation can aid in the differentiation of hyperplastic from adenomatous polyps, most experts would agree that any polyp larger than 10 mm should be resected, specifically if these are located in the proximal colon.21Lapalus M.G. Helbert T. Napoleon B. et al.Does chromoendoscopy with structure enhancement improve the colonoscopic adenoma detection rate?.Endoscopy. 2006; 38: 444-448Crossref PubMed Scopus (105) Google Scholar In addition, many experts question the value of leaving a polyp larger than 10 mm in situ solely on the basis of the pit pattern.21Lapalus M.G. Helbert T. Napoleon B. et al.Does chromoendoscopy with structure enhancement improve the colonoscopic adenoma detection rate?.Endoscopy. 2006; 38: 444-448Crossref PubMed Scopus (105) Google Scholar, 22Bianco M.A. Rotondano G. Marmo R. et al.Predictive value of magnification chromoendoscopy for diagnosing invasive neoplasia in nonpolypoid colorectal lesions and stratifying patients for endoscopic resection or surgery.Endoscopy. 2006; 38: 470-476Crossref PubMed Scopus (56) Google Scholar Although some endoscopists are satisfied with diagnostic accuracies of 84.1%–89.3% for chromoendoscopy in the classification of polyps, these rates are substandard when the decision to remove or leave a polyp in situ has to be taken.20Fu K.I. Sano Y. Kato S. et al.Chromoendoscopy using indigo carmine dye spraying with magnifying observation is the most reliable method for differential diagnosis between non-neoplastic and neoplastic colorectal lesions: a prospective study.Endoscopy. 2004; 36: 1089-1093Crossref PubMed Scopus (166) Google Scholar Furthermore, the predictive value of pit pattern for non-neoplastic colon lesions has been called into question, because there are tendencies to overstage or understage the lesions.21Lapalus M.G. Helbert T. Napoleon B. et al.Does chromoendoscopy with structure enhancement improve the colonoscopic adenoma detection rate?.Endoscopy. 2006; 38: 444-448Crossref PubMed Scopus (105) Google Scholar, 22Bianco M.A. Rotondano G. Marmo R. et al.Predictive value of magnification chromoendoscopy for diagnosing invasive neoplasia in nonpolypoid colorectal lesions and stratifying patients for endoscopic resection or surgery.Endoscopy. 2006; 38: 470-476Crossref PubMed Scopus (56) Google Scholar, 23Hurlstone D.P. Cross S.S. Drew K. et al.An evaluation of colorectal endoscopic mucosal resection using high-magnification chromoscopic colonoscopy: a prospective study of 1000 colonoscopies.Endoscopy. 2004; 36: 491-498Crossref PubMed Scopus (95) Google Scholar Virtual chromoendoscopy methods such as narrow band imaging (NBI) and Fujinon intelligent chromoendoscopy also enhance the surface characterization of colonic polyps, while avoiding the use of dyes and the utensils needed to spray them on the mucosa.24Pohl J. May A. Rabenstein T. et al.Computed virtual chromoendoscopy: a new tool for enhancing tissue surface structures.Endoscopy. 2007; 39: 80-83Crossref PubMed Scopus (130) Google Scholar, 25Pohl J. Nguyen-Tat M. Pech O. et al.Computed virtual chromoendoscopy for classification of small colorectal lesions: a prospective comparative study.Am J Gastroenterol. 2008; 103: 562-569Crossref PubMed Scopus (131) Google Scholar, 26Tischendorf J.J. Wasmuth H.E. Koch A. et al.Value of magnifying chromoendoscopy and narrow band imaging (NBI) in classifying colorectal polyps: a prospective controlled study.Endoscopy. 2007; 39: 1092-1096Crossref PubMed Scopus (201) Google Scholar Nonetheless, large, well-done prospective studies have not shown major advantages on the detection rates of colon polyps when using these virtual techniques.27Kaltenbach T. Friedland S. Soetikno R. A randomised tandem colonoscopy trial of narrow band imaging versus white light examination to compare neoplasia miss rates.Gut. 2008; 57: 1406-1412Crossref PubMed Scopus (143) Google Scholar Nonetheless, standard and virtual chromoendoscopy methods are useful to define the margins of large sessile or laterally spreading polyps (LSP).16Paris workshop participants: the Paris endoscopic classification of superficial neoplastic lesions: esophagus, stomach and colon.Gastrointest Endosc. 2002; 58 (Anonymous): 3-43Google Scholar, 24Pohl J. May A. Rabenstein T. et al.Computed virtual chromoendoscopy: a new tool for enhancing tissue surface structures.Endoscopy. 2007; 39: 80-83Crossref PubMed Scopus (130) Google Scholar We prefer to also mark the borders of large sessile or LSP by applying bursts of argon plasma coagulation (APC) to their margins. This approach is very useful if piecemeal technique is being used, because frequently bleeding during polypectomy will either mix with the dye or interfere with NBI, making the use of standard and virtual chromoendoscopy useless. Colon polyps can be categorized as easy and difficult to resect on the basis of their size (large, >15 mm), shape (thick pedicle, broad sessile, laterally spreading or carpet-shape, flat-depressed), type (villous), number (>3), and location (cecum, on top, or behind the folds) (Table 2) (Figure 1, Figure 2, Figure 3).5Rex D.K. Colonoscopy.Gastrointest Endosc Clin N Am. 2000; 10: 135-160PubMed Google Scholar, 17Bond J.H. Colon polyps and cancer.Endoscopy. 2001; 33: 46-54Crossref PubMed Scopus (31) Google Scholar, 28Dobrowolski S. Dobosz M. Babicki A. et al.Prophylactic submucosal saline-adrenaline injection in colonoscopic polypectomy: prospective randomized study.Surg Endosc. 2004; 18: 990-993Crossref PubMed Scopus (94) Google Scholar, 29Heldwein W. Dollhopf M. Rösch T. et al.The Munich Polypectomy Study (MUPS): prospective analysis of complications and risk factors in 4000 colonic snare polypectomies.Endoscopy. 2005; 37: 1116-1122Crossref PubMed Scopus (287) Google Scholar Resection of difficult polyps falls into the category of advanced polypectomy. The rate of significant complications increases with difficult polyps.29Heldwein W. Dollhopf M. Rösch T. et al.The Munich Polypectomy Study (MUPS): prospective analysis of complications and risk factors in 4000 colonic snare polypectomies.Endoscopy. 2005; 37: 1116-1122Crossref PubMed Scopus (287) Google Scholar, 30Macrae F. Tan K. Williams C. Towards safer colonoscopy: a report on the complications of 5000 diagnostic or therapeutic colonoscopies.Gut. 1983; 24: 376-383Crossref PubMed Scopus (431) Google Scholar, 31Iishi H. Tatsuta M. Kitamura S. et al.Endoscopic resection of large sessile colorectal polyps using a submucosal saline injection technique.Hepatogastroenterology. 1997; 44: 698-702PubMed Google Scholar, 32Nelson D. Block D. Bosco J. et al.ASGE technology status evaluation report: endoscopic mucosal resection.Gastrointest Endosc. 2000; 52: 860-863Abstract Full Text Full Text PDF PubMed Scopus (24) Google Scholar Table 2 presents a list of “technical pearls” that can be useful when dealing with difficult polyps.5Rex D.K. Colonoscopy.Gastrointest Endosc Clin N Am. 2000; 10: 135-160PubMed Google Scholar, 17Bond J.H. Colon polyps and cancer.Endoscopy. 2001; 33: 46-54Crossref PubMed Scopus (31) Google Scholar, 33Mönkemüller K. Neumann H. Fry L.C. et al.Polypectomy techniques for difficult colon polyps.Dig Dis. 2008; 26: 342-346Crossref PubMed Scopus (21) Google ScholarTable 2Technical Pearls to Deal With Difficult PolypsDifficult polypsTechnical pearlsMorphologySessile >1 cmUse IAPOn top of folds, carpet-shaped (LST) or villousUse IAP and EMRSize<1.5 cmResect in toto (except cecum)Large (>3 cm)Use IAP and perform piecemeal polypectomyUse APC to eliminate remaining tissueBig headUse diluted epinephrine in headThick pedicleUse clips or loopsNumberMultipleSend to pathologist separately; resect when going in (if small) or when going out (if large)If more than 10, resect on separate occasions (≥1 colonoscopy)LocationRight colon and cecumDo not use hot biopsyTake air out before catching or snaring the polypBehind foldsInject distally firstDifficult endoscope positionChange position: 5 o'clock positionUse abdominal compressionHave assistant hold the endosocpeSuspicious appearing polyp or large, incompletely resectedMark the polyp site (eg, tattoo with India ink) Open table in a new tab Figure 2Adequate formation of the submucosal cushion after injection of epinephrine-saline mixture 1:10,000 (A). The polyp was resected in toto, leaving a nice mucosectomy site (B).View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 3Adequate mucosectomies of sessile polyps in the ascending colon. Whereas polyp in (A) was resected by using the piecemeal technique (C), the polyp in (B) could be resected in one piece because the submucosal cushion rose to form a broad “pseudostalk” that could be snared in one piece. Both mucosectomy sites do not show any evidence of residual neoplastic tissue (C, D). If there is a question of remaining tissue, APC can be applied to the borders. Occasionally, obtaining biopsies of the margins can also be used as objective evidence to evaluate for neoplastic tissue.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Anatomically, the most dangerous site to resect polyps is the cecum and ascending colon. Because of the thinness of the colon wall in this region, especially when air is insufflated, polypectomy is associated with a higher risk of perforation or transmural burn. Therefore, polyps located in the cecum and hepatic flexure should always be resected with additional caution. We recommend use of submucosal cushion for any sessile polyp larger than 10 mm present in these locations. Taking out the air will also decrease tension on the colon wall, allowing for a better ensnaring of the polyp and increasing the thickness of the underlying submucosal and muscular layers. When the polyp has been grasped, it is imperative to create a “tent.” By doing so, the electrosurgical current will tend to remain at the proximal base of the polyp, decreasing the pressure of the snare (and hence electrical current) against the colon wall. The approach to polyps located in tight corners should be individualized. Whereas polyps located in the rectosigmoid can be generally resected by using retroflexion of the scope, in other areas the help of an assistant to keep the scope in an adequate position while the endoscopist proceeds with the resection will be very helpful. Also, utilization of the locking devices on both the small and big wheels of the handle of the scope is useful to keep the scope in adequate position in such situations. Before catching and snaring a polyp, it is important to place the polyp in an adequate position (Figure 1). Occasionally, polyps located in the rectosigmoid junction or in a tortuous sigmoid can be difficult to remove because of their difficult localization, inability to achieve an adequate position (ie, 5–6 o'clock) or to place the snare around the lesion, despite torquing maneuvers. In these situations it might be useful to use a gastroscope, which has the opening of the accessory channel at the opposite position (ie, 7 o'clock). When removing polyps in the rect