Advanced Polypectomy and Resection Techniques

doi:10.1016/j.giec.2014.11.005

Gastrointestinal Endoscopy Clinics of North America

Volume 25, Issue 2, April 2015, Pages 303-333

https://doi.org/10.1016/j.giec.2014.11.005 Get rights and content

Section snippets

Key points

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Endoscopic mucosal resection (EMR) is a safe, cost-effective and curative intervention for most advanced mucosal neoplasms of the colon.
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Lesion morphology can be used to stratify for the risk of submucosal invasion (SMI).
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En bloc EMR is usually limited to lesions less than or equal to 20 mm. Larger lesions are best treated by piecemeal EMR or, if early invasive disease is suspected, endoscopic submucosal dissection (ESD).
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Real-time macroscopic assessment of lesion type and risk of SMI may be

Indications/contraindications and limitations

Accepted indications and contraindications for advanced endoscopic resection in the colon are summarized in Box 1. In general, all patients found to have colonic AMN should be considered for endoscopic therapy with an experienced clinician. Modeling using the (CR) Physiologic and operative severity score for the enumeration of mortality and morbidity (POSSUM) and the Association of Coloproctology of Great Britain and Ireland score (ACPGBI) scores applied to a large prospective multicenter AMN

Technique/procedure

Patient assessment and preparation

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Candidates for advanced endoscopic resection should fully consent to the procedure and its alternatives.
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A comprehensive medical history and medication list is essential. Newer generation anticoagulants and antiplatelets are increasingly used. These agents are highly potent, have a rapid onset of action, and physicians should be aware of the risks and recommendations regarding cessation and resumption of these medications in the extreme environment of advanced endoscopic resection (Table 1).32,

Submucosal Injectate

The submucosal injection solution is composed of 3 main elements: the colloid solution, diluted epinephrine, and an inert dye (indigo carmine or methylene blue).

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The colloid fluid creates a cushion between the mucosa and muscularis propria (MP), thus reducing the risk of deep tissue entrapment in the snare, transmural thermal injury, and perforation. Normal saline (NS) is commonly used; however, in a randomized trial, the inexpensive colloid plasma volume expander succinylated gelatin

Lesion Assessment

Endoscopic assessment before lesion resection is essential. This assessment entails an overview evaluation of lesion morphology, followed by targeted interrogation of any suspicious areas. A thorough assessment can identify lesions with significant scarring or inaccessibility and may also identify lesions with possible SMI, which may dictate a change in the endoscopic approach or referral for surgical treatment.

Core injection principles

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An adequately performed injection is vital to successful resection. The injection should elevate the lesion into the lumen and toward the colonoscope, improving access.
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Excessive injection should be avoided because this may hinder adequate visualization and create excessive tension within the cushion, which makes snare capture of adequate tissue challenging. For large piecemeal EMR, we recommend an inject-and-resect technique with 1 to 3 resections per injection.
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Inadequate injection may be

Endoscopic submucosal dissection

The ESD technique uses the principal of creating a submucosal cushion, using an injection catheter, in similar fashion to EMR, which is followed by controlled dissection within the submucosal plane beneath the lesion, permitting en bloc resection.18, 27, 53

A variety of endoscopic knives are available for ESD and the choice of a specific knife is usually a personal one. Few comparative studies are available, although certain knives may be advantageous in particular situations.54, 55 The

Hybrid techniques

The hybrid ESD and EMR technique uses circumferential mucosal incision followed by en bloc snare resection of the lesion. This technique may lead to improved R0 resection rates for EMR with shorter procedure time than ESD.57, 58 Further study in the human colon is necessary to define its role. One limitation is the risk of MP entrapment with large lesions in the mobile intra-abdominal colon.

Anorectum

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The unique lymphovascular supply and innervation of the distal rectum and anus requires a modified approach.⁶
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Lymphovascular drainage from the distal rectum enters directly into the systemic circulation, bypassing the reticuloendothelial system operating with conventional portal drainage. Significant bacteremia is a risk with major resection. Prophylactic intravenous antibiotics for large or extensive (>30–40 mm) resections should be considered.⁵⁹
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Sensory nerve supply distal to the dentate line

Endoscopic tattooing

Endoscopic tattooing in the colon serves 3 main purposes:

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Tumor localization during laparoscopic surgery.
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Localization of difficult-to-detect lesions (ie, medial wall ascending colon, transverse colon, lengthy left colon) referred for EMR.
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Localization of the post-EMR scar for surveillance purposes.

The 2 most commonly used tattooing agents are Endomark (India ink; PMT/Permark Inc, Chanhassen, MN) and Spot (sterile carbon particle suspension; GI Supply Inc, Camp Hill, PA). Both are sterilized,

Complications and their management

Advanced resection in the colon is associated with an increased risk of complications. These complications may include bleeding, nonspecific postprocedural pain, serositis, perforation, and recurrent/residual tissue. Careful evaluation of the mucosal defect, early recognition of the endoscopic and clinical signs, and prompt treatment are crucial for successful prevention and management.

Postoperative care

Patients undergoing advanced endoscopic resections require close monitoring following the procedure. Patient discomfort and developing clinical signs of complications should be recognized and treated early. We suggest a 2-stage evaluation scheme (Fig. 17).

Follow-up

A repeat colonoscopy (surveillance colonoscopy 1 [SC1]) is recommended at 4 to 6 months after the index procedure to assess the scar area for any residual/recurrent tissue. The optimal timing of this procedure is not precisely known and it may be possible for those with only low-grade dysplasia to have SC1 at 12 months. The scar is carefully interrogated using both high-definition white light and NBI. Residual/recurrent tissue is treated with hot snare resection or cold avulsion followed by

Treatment of T1 Cancers

Optimal treatment of early (T1) CRC remains an active area of debate and research. Low-risk T1 cancers (SMI <1 mm, no LVI, well-differentiated tumor) may be suitable for endoscopic therapy alone. En bloc resection is a prerequisite and, if that is the case, then the risk of recurrence and lymph node metastasis is low.¹⁹ High-risk T1 lesions (SMI >1 mm, LVI, or poor tumor differentiation) traditionally require surgery because the risk of LNM in those that can be endoscopically resected may reach

Summary

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EMR is safe and effective for noninvasive AMN because no risk of LNM exists.
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AMN with SMI is associated with a risk of LNM that may be stratified into high and low risk. Low-risk lesions may be managed endoscopically, whereas high-risk lesions mandate consideration of surgery.
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En bloc EMR is usually limited to lesions less than or equal to 20 mm. Larger lesions that are deemed to be endoscopically manageable are best treated by piecemeal EMR.
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Colonic ESD seems to confer little if any long-term