Polypectomy, Endoscopic Mucosal Resection, and Tattooing in the Colon
Sarah K. McGill, MD
Theodore W. James, MD
Ian S. Grimm, MD
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Colonoscopy and removal of neoplasms prevents colorectal cancer. Techniques employed for resection include (1) cold snare polypectomy, (2) hot snare polypectomy, and (3) endoscopic mucosal resection. Recent research has provided a sound basis for choosing one method of polyp resection over another, based on polyp size and morphology. Endoscopic tattooing indelibly marks a lesion, facilitating localization for surgical resection or endoscopic surveillance.
Carefully assess the size, shape, and probable histology of a polyp prior to resection. Estimate the polyp’s size by comparing it to a device placed adjacent to the lesion, such as a standard snare catheter (2 mm), an open biopsy forceps (7 mm), or an opened snare of known diameter.
Polyp morphology can be described using the Paris classification: sessile polyps have a broad base (Paris 1s), pedunculated polyps have a narrow stalk consisting of normal tissue (Paris 1p), and nonpolypoid neoplasms are either slightly elevated but <2.5 mm in height (0-IIa), completely flat (0-IIb), or slightly depressed (0-IIc).
Study the color, surface pit pattern, and vascular pattern of a polyp to predict its most likely histology and the likelihood that it contains an invasive cancer. Advanced imaging techniques such as narrow band imaging (NBI) or i-Scan may help. The NBI International Colorectal Endoscopic (NICE) Classification is a simple and effective tool for visual prediction of polyp histology (Table 22.1
TABLE 22.1 NICE Classification of Polyps
Same or lighter than background
Browner relative to background (verify that color arises from vessels)
Brown to dark brown relative to background; sometimes patchy whiter areas
None, or isolated lacy vessels may be present coursing across the lesion
Brown vessels surrounding white structures
Has area(s) of disrupted or missing vessels
Dark or white spots of uniform size, or homogeneous absence of pattern
Oval, tubular, or branched white structures surrounded by brown vessels
Amorphous or absent surface pattern
Most likely pathology
Hyperplastic or sessile serrated polyp
Deep submucosal invasive cancer
1. The lesion has features suggestive of invasive carcinoma including ulceration, fixation, hard consistency, NICE 3 features. A nonlifting sign following submucosal injection is a relative contraindication; polyps that have been previously subjected to endoscopic therapy will often not lift well, but this should not be taken as a sign of invasive cancer.
2. Inability to complete the resection at the initial colonoscopy. Partial resection of a polyp should not be performed; the resulting submucosal fibrosis can complicate subsequent attempts at resection. Patients found to have large polyps during a screening examination may need to be rescheduled for a repeat procedure when adequate time and an experienced team are available to complete the resection in a single session.
3. Complete resection is not likely to be achieved. Polyps over 4 cm and those involving the ileocecal valve, appendiceal orifice, or anorectal junction are often very challenging, and may require referral to an expert in endoscopic resection techniques.
4. Unaddressed coagulation disorder.
5. Poor bowel preparation.
6. Poor general medical condition of the patient; excessive anesthetic risk.
7. Lack of the necessary staffing, training, and equipment needed to manage potential adverse events.
Colonoscopic polypectomy is routinely performed on an outpatient basis following standard bowel preparation. Include polypectomy as part of the typical consent for colonoscopy. Consider asking patients to discontinue aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and anticoagulants, especially when they are known in advance to have a large polyp requiring resection.
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