Colorectal polyps are the precursors for most colorectal cancers (CRCs). Some colorectal polyps accumulate enough mutations to develop high-grade dysplasia and eventual invasion of dysplastic elements into the submucosa (1). The invasion of dysplastic elements into the submucosa constitutes the clinical definition of CRC (Figure 1).Figure 1.: Cancer depth and AJCC classification.The term malignant polyp specifically refers to a colorectal lesion with cancer invading the submucosa but not extending into the muscularis propria. These lesions are classified as pT1 in the TNM classification system (2). A synonymous and more modern term is submucosally invasive lesion. We will use the nomenclature of submucosal invasion throughout this document interchangeably when referring to a malignant polyp. The prevalence of cancer in colorectal polyps ranges from 0.2% to 5% (3–5). Malignant polyps represent the earliest form of clinically relevant CRC in most patients because neoplastic invasion of the submucosa allows for possible lymphatic and vascular metastasis. The risk of metastasis depends on several endoscopic and histologic features. The clinical issue most often raised by malignant polyps is whether a patient with an endoscopically resected colorectal lesion with submucosal invasion requires surgical resection of the colorectal segment from which the lesion was removed. Some malignant polyps can be managed endoscopically because the risk of residual cancer in the bowel wall and/or adjacent lymph nodes is very low. Other endoscopically resected malignant polyps are best managed by surgical resection because endoscopic resection alone is accompanied by a very high risk of residual cancer and/or lymph node metastases. Optimal selection of patients with malignant polyps for endoscopic surveillance vs surgical treatment is important to minimize both the risk of residual cancer and the risk of surgery (6,7). The purpose of this document is to guide endoscopists on how to assess lesions for endoscopic features associated with cancer, discuss how these factors guide endoscopic management, and to outline the factors that frame whether to advise surgery after a malignant polyp has been endoscopically resected. The approach in the document is formulated around several specific key questions with relevant data from the literature that inform the recommendations. Specifically, we will discuss 6 key questions that address the following 3 tasks: endoscopic recognition of colorectal polyps with deep submucosal invasion that should be referred directly to surgery; optimal endoscopic resection techniques and specimen handling when an increased risk of superficial submucosally invasive polyp is identified; and weighing the risks and benefits of surgery when an endoscopically removed polyp is found to have submucosal invasion. Another document by the US Multi-Society Task Force (Kaltenbach, unpublished data) discusses optimal resection techniques for large and malignant polyps. This document excludes management of polyps associated with inflammatory bowel disease. Methods Literature Review The English language medical literature was searched using MEDLINE, EMBASE, and Cochrane Database of Systematic reviews from January 1980 to December 31, 2018. A combination of key words and Medical Subject Headings were used and are summarized in Appendix 1, https://links.lww.com/AJG/B748. Review articles, meta-analyses, and editorials were reviewed for additional references. Grading of Evidence The US Multi-Society Task Force on Colorectal Cancer (USMSTF) consists of gastroenterologists with expertise in colorectal neoplasia (ie, CRC and precursor lesions, such as polyps). The American College of Gastroenterology, the American Gastroenterological Association, and the American Society for Gastrointestinal Endoscopy are represented. Summary tables and a draft document were circulated to members of the USMSTF and final guidelines were developed by consensus during several joint teleconferences. The document underwent committee review and governing board approval by all 3 societies. The USMSTF grades the quality of evidence and strength of recommendations using an adaptation of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach (8). The GRADE process categorizes the quality of the evidence as high, moderate, low, or very low (Table 1). This categorization is based on an assessment of the study design (eg, randomized controlled trial or observational study), study limitations, inconsistency of results, indirectness of evidence, imprecision, and publication bias. The USMSTF members conduct literature searches to identify published articles that address the key issues discussed within these recommendations. These publications are supplemented both by review of citations from the identified articles, as well as other key references elicited from the subject matter experts on the Task Force. The GRADE process involves the collection of literature, analysis, summary, and a separate review of the quality of evidence and strength of recommendations. The USMSTF members employed a modified, qualitative approach for this assessment based on exhaustive and critical review of evidence, without a traditional meta-analysis. The GRADE process separates evaluation of the quality of the evidence to support a recommendation from the strength of that recommendation. This is done in recognition of the fact that, although the quality of the evidence impacts the strength of the recommendation, other factors can influence a recommendation, such as side effects, patient preferences, values, and cost. Strong recommendations mean that most informed patients would choose the recommended management and that clinicians can structure their interactions with patients accordingly. Weak recommendations mean that patients' choices will vary per their values and preferences, and clinicians must ensure that patient care is in keeping with their values and preferences. Weaker recommendations are indicated by phrases such as “we suggest,” and stronger recommendations are stated as “we recommend.”Table 1.: Grading of Recommendations Assessment, Development and Evaluation Ratings of EvidenceDefinitions Definition of Malignant Polyp The term malignant polyp refers to a colorectal polyp including flat lesions with neoplastic invasion of the submucosa without extension into the muscularis propria (2,9). Another term for such lesions is submucosally invasive polyps. The Vienna classification system is a consensus between Western and Japanese pathologists for classifying gastrointestinal epithelial neoplasia into 5 categories (Table 2) (10). According to this classification, malignant polyps would fall under category 5.2 (submucosal carcinoma and beyond).Table 2.: Vienna Classification of Gastrointestinal Epithelial NeoplasiaMalignant colorectal polyps are classified as pT1 in the 8th edition of the American Joint Committee on Cancer (AJCC) staging system (Figure 1) (2). This clinical definition of CRC excludes lesions with high-grade dysplasia, in which dysplastic changes are solely confined to the epithelium, lamina propria, or muscularis mucosa. Such lesions are classified as “Tis” in the AJCC staging system and National Comprehensive Cancer Network guidelines (2,9). Pathologists sometimes use the term cancer or carcinoma in situ or intramucosal carcinoma to describe such lesions. However, the use of terms such as carcinoma or cancer in describing lesions confined to the mucosa may cause undue alarm to endoscopists, surgeons, patients, or primary care providers, and can lead to unnecessary surgery. Although lesions confined to the mucosa, lamina propria, and the muscularis mucosa, are precancerous, they should not be confused with invasive colon cancer. The recommended management of adenomas with high-grade dysplasia should be endoscopic resection alone, because these lesions have no risk of residual neoplasia in the bowel wall or lymph nodes after complete endoscopic resection. We encourage endoscopists to discuss appropriate terminology with their pathologists and for pathologists to avoid the terms carcinoma and cancer in describing lesions confined to the mucosa, in order to reduce errors in understanding and clinical management. Endoscopic and Histologic Classification Systems Used in This Document The optimal management of malignant polyps in modern colonoscopy is based on the endoscopic diagnosis. Before endoscopic resection, every colorectal lesion detected at colonoscopy should undergo complete assessment of the lesion morphology, surface, and vessel pattern. A skilled assessment, often accompanied by dye-based chromoendoscopy or electronic-based image enhancement, will identify lesions with endoscopic features that are specific for deep submucosal invasion of cancer (see below). Deep submucosal invasion of a colorectal lesion is defined as ≥1 mm (1000 μm) of submucosal invasion, and is associated with a high risk of residual cancer after endoscopic resection, specifically a high risk of lymph node metastases (11). When endoscopic features of deep submucosal invasion are present, areas exhibiting these features should be biopsied and the patient scheduled for staging studies in anticipation of surgical resection. Absent the endoscopic features of deep submucosal invasion, most colorectal lesions are candidates for endoscopic resection. There are no endoscopic signs with high sensitivity or specificity for superficial (<1 mm) invasion, however, there are certain endoscopic features associated with a higher risk of superficial submucosal invasion, including large size (≥2 cm), depressed or sessile morphology in nongranular lateral spreading tumors (LST-NG), and discrete nodules in granular lateral spreading tumors (LST-G) (see below). Some lesions with these features should be considered for en bloc endoscopic resection because en bloc resection optimizes the pathologic assessment of any lesion, particularly with regard to the depth of invasion. These points emphasize that optimal management of potentially malignant lesions includes careful endoscopic evaluation and estimation of the degree of invasiveness before resection. Once resection has occurred and cancer is identified by pathology, then the more traditionally discussed issues of whether to proceed with surgery must be addressed. The post-resection management of submucosally invasive lesions optimally utilizes a multidisciplinary approach, with input from the pathologist, surgeon, and sometimes an oncologist and/or radiation oncologist. However, the endoscopist often plays the central role in informed decision-making, frequently serving as the point of contact for the patient and their family. Endoscopic Surface Pattern Classifications Endoscopic assessment of colorectal polyps and lesions to predict the histologic class (ie, adenoma vs serrated class) and determine the presence of features associated with deep submucosal invasion are important skills for the modern colonoscopist. Endoscopic assessment can be assisted by illumination with wavelengths that enhance blood vessels and delineate surface features (eg, narrow band imaging [NBI]; Olympus, Center Valley, PA and Fujinon Blue Light Imaging; Fujinon, Valhalla, NY) or by post-processing techniques that enhance these elements (eg, Fujinon Linked Color Imaging and Pentax iscan; Pentax Medical, Montvale, NJ). Optical magnification can assist with characterization, if available. Classification systems associating endoscopically visualized surface features with specific histology facilitate prediction of histology by the endoscopist. The descriptions of the polyp and endoscopic classification systems used in the document are provided below. Narrow Band Imaging International Colorectal Endoscopic Classification. In 2009, the Colon Tumor NBI Interest Group proposed the NBI International Colorectal Endoscopic (NICE) classification system, which has been validated in subsequent studies as an accurate system to classify polyps as type 1 (serrated class: either hyperplastic or sessile serrated polyp) or type 2 (conventional adenoma) (12). Lesions with disruption of the surface pattern and vessel structure are type 3, which is specific (although not sensitive) for deep submucosal invasive cancer (13). The NICE classification system can be used with or without magnification, and does not require use of dye spray (14,15) (Table 3 and Figure 2).Table 3.: Narrow Band Imaging International Colorectal Endoscopic ClassificationFigure 2.: NICE classification Kudo pit pattern classification.Japanese Narrow Band Imaging Expert Team Classification (Modified Narrow Band Imaging International Colorectal Endoscopic Classification). One limitation of the NICE classification is that it is difficult to distinguish among low-grade dysplasia, high-grade dysplasia, and superficial submucosal invasion in type 2 lesions. To address this limitation, the Japanese Narrow Band Imaging Expert Team (JNET) published a new NBI colorectal magnification classification in 2014 (16), which requires magnification endoscopy. JNET maintains NICE types 1 and 3 but divides NICE type 2 into JNET 2a and 2b, with 2b features associated with high-grade dysplasia and superficial submucosal invasion. The classification system is presented in Table 4 and Figure 3.Table 4.: Japanese Narrow Band Imaging Expert Team ClassificationFigure 3.: JNET classification.Kudo Pit Pattern Classification. Used extensively in the East, the Kudo pit pattern classification system has been adopted in the Western world as well (17–20). It requires magnification colonoscopy with dye spray (although many Western endoscopists use it without dye spray), and allows for evaluation of malignant polyps through characterization of the pits, which are openings for crypts (21–23). As described by Kudo and colleagues (18), pits are classified into 6 patterns: type I, II, IIIL, IIIS, IV and V. Type I pits appear as roundish pits; type II pits appear as stellar or papillary pits; type III-s pits are small roundish, tubular pits (smaller than type I), and type III-L are roundish and tubular pits (larger than type I); type IV pits appear as branch-like or gyrus-like pits and type V pits appear as nonstructured pits. Pit pattern type V is further classified as VN (nonstructural) and VI (irregular). Type I and II are characteristic of normal, serrated or inflammatory polyps, whereas pit pattern classes III–V are considered to indicate dysplastic and malignant changes. The classification system is presented in Table 5 and Figure 2.Table 5.: Kudo's Classification of Polyp Pit Pattern (18)Other Classification Systems. Using magnification endoscopy and NBI, there are several colorectal NBI magnifying classifications, such as the Hiroshima classification (24), Sano classification (25), Showa classification (26), and Jikei classification (27) used mainly in Asian countries. The BASIC system (for FUJI Blue Light Imaging) (28), is similar to the NICE classification. Irregular and thickened microvessels, when using NBI, is another way to assess for risk of submucosal invasion with Sano class III A and B, being highly sensitive and specific for estimating depth of submucosal invasion (29). However, several of these systems are not commonly used in the United States. Endoscopic Morphologic Classification Systems Paris Classification. Proposed in 2002 at the Paris collaborative meeting (30), the Paris classification is an endoscopic classification of superficial colorectal lesion morphology, whereby a lesion is superficial when its endoscopic appearance suggests that the depth of penetration in the digestive wall is not more than into the submucosa, that is, there is no infiltration of the muscularis propria. The Paris classification describes 3 major superficial morphologies with subtypes. Lesions are classified as polyps (type 0–I), which include both pedunculated (0–Ip) and sessile (0–Is) morphologies; or flat lesions (type 0–II), which consist of slightly elevated (0–IIa), flat (0–IIb), and slightly depressed (0–IIc) morphologies. Lesions with the third major morphology, excavated (0–III), are rarely seen in the colon. The classification system is presented in Figure 4. We present differences in management and outcomes based on morphologies in the key questions, where applicable. It is important to acknowledge that interobserver agreement of the Paris classification among expert endoscopist is modest (31).Figure 4.: Paris classification of polyp morphology.Laterally Spreading Tumor (Lesion). Okamoto et al (32) described polyps in the colorectum that are > 10 mm, flat (0–II), or sessile (0–Is) shape, and extend laterally (in contrast to vertically) along the colonic wall, as LSTs or lateral spreading lesions. These lesions are further classified into 2 distinct phenotypes, LST-G, which has a nodular surface, and LST-NG, which have a smooth surface (Figures 5 and 6). LST-G can be subtyped by the nodular surface and are comprised of lesions with homogeneous even-sized nodules and lesions with nodules of mixed sizes known as mixed LST-G. LST-NG have a smooth surface and are comprised of the flat elevated and pseudodepressed subtypes.Figure 5.: Granular laterally spreading tumors (LST-G). (A, B) Nodular surface. (C, D) mixed nodular morphology.Figure 6.: Nongranular laterally spreading tumors (LST-NG). (A, B) Smooth surface. (C, D) Pseudodepressed.The morphologic sub-classifications of LSTs facilitate the endoscopic removal plan, as they inform about the risks of submucosal invasion and submucosal fibrosis. For example, LST-G with even-sized nodules tend to grow laterally to very large diameters with a low risk of developing submucosal invasion (<2%) or significant fibrosis regardless of size (33), whereas LST-G with mixed-sized nodules have a higher risk of submucosal invasion (7.1% for lesions <20 mm and 38% for those >20 mm) (34), with the point of invasion usually located under the largest nodule. In such lesions, it is preferable to remove the largest nodule (and any nodule suspicious to harbor more advanced pathology) in one piece when feasible, in order to optimize histologic assessment. LST-NG have a high risk of submucosal invasion: 27.8% and 41.4% in nongranular pseudodepressed LSTs 10–19 mm and 20–29 mm, respectively, and 6.4% and 10.4% in nongranular flat elevated LSTs 10–19 mm and 20–29 mm, respectively (35). In such lesions, the points of invasion are typically multifocal. In addition, LST-NG lesions often have submucosal fibrosis that can make their removal with simple snare resection or even standard endoscopic mucosal resection (EMR) more technically challenging. Nonlifting Sign. The nonlifting sign for sessile polyps was described by Uno et al, (36) whereby fluid injected under the polyp fails to lift it. The nonlifting sign may be due to deep submucosal invasion (37) in lesions without prior endoscopic manipulation or attempted resection. The nonlifting sign may also be the result of fibrosis from prior biopsy, cautery, or tattoo, in which case it does not reflect deep submucosal invasion and is not a contraindication to endoscopic resection (38). Histologic Classification Systems for Depth of Cancer Invasion Kikuchi and Kitajima Classification Systems for Depth of Submucosal Invasion. Accurate measurement of the depth of invasion in malignant polyps generally requires specific handling of the pathology specimen, that is, pinning the cut surface of the specimen to a stiff material before immersion into formalin. Pinning the specimen enables the cut sections to be properly oriented for evaluation by the pathologist (ie, at right angles to the plane of the resection). For sessile malignant polyps, the Kikuchi classification describes the depth of invasion by dividing the submucosa into three levels (SM1–3). SM1, 2, and 3 denote invasion of cancer into the first one-third, second one-third, and the deepest one-third of the submucosa, respectively (39). The Kikuchi classification system is presented in Figure 7. The difficulty in implementing the Kikuchi system is that the entire submucosa is not typically present in endoscopic resection specimens. For that reason, the Kikuchi system has been largely replaced by measuring the depth of submucosal invasion with an optical micrometer. An invasion depth of < 1 mm is called “superficial submucosal invasion” and is associated with a very low risk of lymph node metastasis (0%–4%), provided that other adverse histologic features are absent. An invasion depth of ≥1 mm (“deep submucosal invasion”) is associated with a substantial risk of residual disease in the bowel wall or lymph nodes after endoscopic resection (10%–18%) (11), and is generally an indication for adjuvant surgical resection.Figure 7.: Kikuchi classification.Haggitt Classification of Depth of Submucosal Invasion. In 1985, Haggitt et al (40) proposed a classification system for depth of cancer invasion in polyps. The Haggitt classification is shown in Figure 8. This system is most useful for pedunculated polyps. Neoplasia within pedunculated polyps are classified as levels 0–4. In level 0, dysplastic elements are limited to the mucosa. Levels 1–4 have submucosal invasion but are based on the invasive portion in the head, neck, and stalk of the pedunculated polyp. Level 1 denotes cancer invasion into the submucosa, but is limited to the head of the pedunculated polyp. Level 2 denotes cancer cells reaching the neck of the pedunculated polyp and, in level 3, cancer cells invade the stalk. Level 4 indicates cancer cells invading the submucosa below the stalk, but not the muscularis propria of the pedunculated polyp. All malignant nonpedunculated lesions that by definition have submucosal invasion are classified as Haggitt level 4. Because endoscopists transect pedunculated polyps through the stalk, it limits the clinical relevance of the Haggitt classification in assessment of malignant polyps resected endoscopically.Figure 8.: Haggitt classification.Key Questions, Recommendations, and Discussion Question 1a: Which endoscopic features in a colorectal polyp predict deep submucosal cancer? Question 1b: When deep submucosal cancer is suspected, how should nonpedunculated and pedunculated polyps be managed? Recommendation 1a. We recommend that both pedunculated and nonpedunculated polyps with the following features be considered to have deep submucosal invasion: NICE classification type 3 or Kudo classification of type V (VN and VI). Strong recommendation; high-quality evidence Recommendation 1b. Nonpedunculated lesions with these features should be biopsied (in the area of surface feature disruption), tattooed (unless in or near the cecum), and referred to surgery. Pedunculated polyps with features of deep submucosal invasion should undergo endoscopic polypectomy. Weak recommendation; low-quality evidence Discussion Nonpedunculated (0–Is and 0–II) lesions Endoscopic features of deep submucosal invasion are highly specific. Hayashi et al (13) performed a validation of the NICE 3 features for prediction of deep submucosal invasion using 80 images and a panel of 5 expert endoscopists, and reported that presence of any 1 of the 3 deep submucosal invasive carcinoma (color, vessels, or surface pattern) had 94% accuracy and 96% negative predictive value (13). Similarly, type VN pit pattern in the Kudo classification indicates deep submucosal invasion. A 2011 prospective multicenter, observational study by the Australian Colonic Endoscopic resection study group evaluated 479 patients with large (≥20 mm) polyps and found invasion of the deep submucosa in 56% (14 of 25) of polyps with pit pattern type V compared to only 4%–5% in lesions with other pit patterns (41). In their follow-up study (42) evaluating 2693 lesions, Kudos pit pattern V was the strongest factor associated with overt submucosal invasive cancer (odds ratio [OR], 1.42; 95% confidence interval [CI], 8.57–23.4) and predicted cancer with 97% specificity, 40% sensitivity, and 93% diagnostic accuracy. A meta-analysis of 20 studies evaluating diagnostic accuracy of Kudo pit pattern, performed a sub-group analysis of 1623 colorectal lesions from 4 studies that reported the number of lesions in each pit pattern by pathology results, and reported a pooled sensitivity of 90.4% (95% CI, 79.7–95.7) and pooled specificity of 88.4% (95% CI, 82.9–92.3) (23). When nonpedunculated lesions with NICE 3 or Kudo VN features are encountered, biopsy should be directed to the region of surface feature disruption, tattooed if not in or near the cecum, and the patient directed to surgery. NICE 3 and Kudo VN features are often associated with surface ulceration and irregularity. In 1 series, the risk of deep submucosal invasion in 181 lesions that were LST-NG with depression/ulceration was 12.5%, 32.4%, and 83.3% for lesions of size 10–19 mm, 20–29 mm, and ≥30 mm, respectively (35). The nonlifting sign for sessile polyps is also associated with deep submucosal invasion (37), with positive predictive value of approximately 80%.38 However, lesions may also not lift because of submucosal fibrosis from prior biopsy, cautery, or tattoo (43). Pedunculated (0–Ip) lesions Pedunculated polyps with features of deep submucosal invasion are candidates for endoscopic resection, as the overall histological features may still be favorable (44). All pedunculated lesions should be resected en bloc through the stalk and bivalved though the polyp head and stalk by pathology. An accurate histologic diagnosis is key to accurate staging and management (see question 2). Figure 9 provides an algorithm for recognition and management of malignant polypsFigure 9.: Algorithm for approach to malignant polyp assessment and management.Question 2a. Which endoscopic features predict risk of superficial submucosal invasion in a sessile polyp? Question 2b. What is the optimal endoscopic method of resection for sessile and pedunculated malignant polyps with superficial submucosal invasion? Recommendation 2a. LST-NG morphology with sessile shape or depression, and LST-G with a dominant nodule predict a higher risk of submucosally invasive cancer. Weak recommendation; moderate-quality evidence Recommendation 2b. We recommend that such lesions be considered for en bloc endoscopic resection, instead of piecemeal resection, when feasible and based on local expertise. In the case of LST-G with a dominant nodule, at least the nodular area should be considered for en bloc resection. All pedunculated polyps, even if large, should be resected en bloc. Weak recommendation; low-quality evidence Discussion In a nonpedunculated lesion, if endoscopic features of deep submucosal invasion are absent, the next step is to evaluate the polyp for other morphologic features that predict an increased risk of superficial submucosal invasion. Consideration should be given to resecting the lesion en bloc for precise pathologic assessment if the morphologic features discussed below are present. Polyps with depressed (0–IIc) morphology are often associated with invasive cancer even when small (45–49). One study found that of 3680 lesions, 61% of 0–IIc lesions had submucosal invasion.30 Assessing the morphology of 2277 ≥20 mm lesions, Burgess et al (42) reported that compared with 0–IIa, lesions with 0–Is (OR, 2.73; 95% CI, 1.64–4.55) and 0–IIa+0–Is (OR, 2.49; 95% CI, 1.52–4.08) morphology were associated with submucosal invasive cancer. The authors also reported that lesions with a 0–IIc component had a high specificity (95.9%) and diagnostic accuracy (90.3%) for submucosal invasive cancers but low sensitivity (21%). In combining Paris classification and gross morphology, the authors were able to improve the prediction of covert or occult submucosal invasive cancer (defined as lacking endoscopic features of submucosally invasive cancer, such as a depressed or ulcerated component, or an area of disrupted surface pit pattern), such that 0–Is nongranular and 0–IIa+Is nongranular lesions had a substantially higher risk of occult submucosal invasive cancer (OR, 22.5; 95% CI, 7.07–71.6 and OR, 14.4; 95% CI, 4.53–45.5, respectively). Type 2B lesions in the JNET classification have a higher risk of superficial submucosal invasion, where en bloc resection should be considered, if feasible. Whether JNET can be applied accurately without full optical magnification remains uncertain. Studies on diagnostic accuracy of the JNET classification are ongoing, and early studies show promise (16). Neither lesion size nor location alone have enough discriminant value to reliably predict risk of submucosal invasion, but combined with other endoscopic features (see above), these factors may warrant consideration. Multiple studies have demonstrated that risk of submucosal invasion is higher with lesions ≥20 mm. In their 1997 study, Nusko et al (50) examined 11,188 adenomatous lesions and invasive carcinoma was found in 1313 (11.7%). The odds of submucosal invasion was 4.27 (95% CI, 3.06–5.96) in lesions >16 mm, rising to an OR of 10 (95% CI, 6.97–14.56) in lesions >35 mm in size compared to polyps ≤5 mm in which no cancer was detected. Consolo et al (51) also found a correlation between increase in lesion size and risk of malignancy. They reviewed 1354 polypectomies, 28 (2.1%) had invasive carcinoma and 71% of the invasive carcinomas were >20 mm in size (51). Some of the largest nonpedunculated lesions in the colon are the LST-G. These lesions have a low risk of submucosal invasion, which presumably allows them to grow laterally for large distances while remaining benign. Hurlstone et al (52) published a prospective series of 82 LST that were removed with EMR. They reported that LST-NG were more likely to be present in the right colon and have submucosal invasion compared with LST-G.