Colorectal Malignant Polyps: Characterization and Endoscopic Resection Technique.

Advanced Colon Polypectomy

Most colorectal cancers evolve from colorectal adenomatous polyps in a pathway known as the adenoma to carcinoma sequence. Early detection and removal of colorectal adenomas can prevent the development of...

Endoscopic Management of Large Sessile Colonic Polyps: Getting the Low Down From Down Under

Malignant colorectal polyp refers to the polyp in which the neoplastic lesion invades into but not beyond the submucosa. The morphological features and surface patterns of the malignant polyps are examined by the white-light and image-enhanced endoscopy, which help to predict the depth of invasion of neoplastic lesions. The deep submucosal invasion is associated with a high risk of residual cancer and lymph node metastasis. The image-enhanced endoscopy is useful in identifying the malignant polyp amenable for endoscopic resection or require formal oncological surgery. After the endoscopic resection of the polyp, the thorough histopathological assessment is required to determine the possibility of residual tumor, recurrence, and lymph node involvement. The presence of high-risk features (deep submucosal invasion, poor differentiation, lymphovascular invasion, <1 mm resection margin, piecemeal resection, and tumor budding) indicates a need for surgical resection with lymph node clearance. In low-risk cases, the endoscopic resection is considered adequate and further surveillance is advised. The final decision about the endoscopic resection versus surgical resection of malignant polyp needs to be individualized and should be based not only on polyp related characteristics but also on comorbidities, local resources, expertise availability, and patient’s preference.

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 An invasion depth of ≥1 mm submucosal is associated with a risk of residual in the bowel wall or lymph nodes after endoscopic resection and is generally an for surgical Kikuchi Classification of Depth of Submucosal Invasion. In et al proposed a classification system for depth of cancer invasion in polyps. The classification is in Figure This system is most for pedunculated polyps. within pedunculated polyps are classified as levels In dysplastic elements are to the mucosa. have submucosal invasion but are based on the invasive in the and of the pedunculated polyp. 1 cancer invasion into the submucosa, but is to the of the pedunculated polyp. 2 cancer the of the pedunculated polyp in 3, cancer the 4 cancer invading the submucosa the but not the muscularis propria of the pedunculated polyp. malignant lesions that by definition have submucosal invasion are classified as 4. endoscopists pedunculated polyps through the it the clinical of the classification in assessment of malignant polyps resected and endoscopic features in a colorectal polyp predict deep submucosal When deep submucosal cancer is how should and pedunculated polyps be We that both pedunculated and polyps with the following features be considered to have deep submucosal invasion: NICE classification type 3 or Kudo classification of type V and Strong evidence lesions with these features should be biopsied (in the of surface in or the and referred to surgery. polyps with features of deep submucosal invasion should undergo endoscopic Weak evidence and lesions Endoscopic features of deep submucosal invasion are highly et al a of the NICE 3 features for prediction of deep submucosal invasion using and a of 5 expert endoscopists, and that presence of any 1 of the 3 deep submucosal invasive carcinoma or surface and (13). type VN pit pattern in the Kudo classification deep submucosal invasion. A observational study by the Endoscopic resection study patients with large mm) polyps and found invasion of the deep submucosa in of of polyps with pit pattern type V to in lesions with other pit In their study lesions, pit pattern V was the associated with submucosal invasive cancer and cancer with and A of studies of Kudo pit a of colorectal lesions from 4 studies that the of lesions in pit pattern by pathology results, and a sensitivity of and specificity of When lesions with NICE 3 or Kudo VN features are should be to the of surface if not in or the and the patient to surgery. NICE 3 and Kudo VN features are often associated with surface and In 1 the risk of deep submucosal invasion in lesions that were LST-NG with was and for lesions of size 10–19 mm, 20–29 mm, and mm, respectively (35). The nonlifting sign for sessile polyps is also associated with deep submucosal invasion with of However, lesions may also not lift because of submucosal fibrosis from prior biopsy, cautery, or (0–Ip) lesions polyps with features of deep submucosal invasion are candidates for endoscopic resection, as the features may be pedunculated lesions should be resected en bloc through the and the polyp and by An accurate histologic is key to accurate staging and management (see Figure an for recognition and management of malignant for approach to malignant polyp assessment and endoscopic features predict risk of superficial submucosal invasion in a sessile is the optimal endoscopic of resection for sessile and pedunculated malignant polyps with superficial submucosal LST-NG morphology with sessile or and LST-G with a nodule predict a higher risk of submucosally invasive cancer. Weak evidence We that such lesions be considered for en bloc endoscopic resection, of resection, when and based on In the case of LST-G with a at the nodular should be considered for en bloc resection. pedunculated polyps, even if should be resected en Weak evidence In a lesion, if endoscopic features of deep submucosal invasion are the is to the polyp for other morphologic features that predict an increased risk of superficial submucosal invasion. should be to the lesion en bloc for pathologic assessment if the morphologic features discussed are with depressed (0–IIc) morphology are often associated with invasive cancer even when small One study found that of lesions, of lesions submucosal the morphology of mm lesions, et al that with lesions with and morphology were associated with submucosal invasive cancer. The also that lesions with a a high specificity and for submucosal invasive cancers but low sensitivity In Paris classification and morphology, the were to the prediction of or submucosal invasive cancer as endoscopic features of submucosally invasive cancer, such as a depressed or or an of surface pit such that nongranular and nongranular lesions a higher risk of submucosal invasive cancer and Type lesions in the JNET classification have a higher risk of superficial submucosal invasion, where en bloc resection should be if JNET can be without optical magnification on of the JNET classification are and studies lesion size alone have enough to predict risk of submucosal invasion, but with other endoscopic features (see these factors may studies have that risk of submucosal invasion is higher with lesions In their et al lesions and invasive carcinoma was found in The of submucosal invasion was in lesions mm, to an of 10 in lesions mm in size to polyps mm in which no cancer was et al also found a between in lesion size and risk of reviewed invasive carcinoma and of the invasive were >20 mm in size Some of the largest lesions in the colon are the LST-G. These lesions have a low risk of submucosal invasion, which allows to grow laterally for large et al published a of that were removed with that LST-NG were more to be present in the right colon and have submucosal invasion with LST-G.

Surgery for non-malignant colorectal polyps is rarely performed and is considered if endoscopic removal is not feasible or unsuccessful, especially since the development of enhanced endoscopic mucosal resection (EMR) techniques and the advancements in endoscopic submucosal dissection (ESD). We aimed to evaluate the trend of surgery and endoscopic resection in patients with non-malignant colorectal polyps from 2014 to 2024. We conducted a retrospective cohort study in the United States using the TriNetX research network to identify patients with non-malignant colorectal polyps who underwent surgery. After excluding patients with colorectal cancer and other surgical indications, we assessed the yearly incidence of colorectal surgery from 2014 to 2024 using CPT and ICD10 codes for partial colectomy &/or proctectomy. Furthermore, we assessed EMR and ESD rates in this population from 2014 to 2024. A total of 1,693,869 adult patients had non-malignant colorectal polyps from 2014 to 2024, among which 5750 (0.3%) underwent surgery and, while 112,029 (6.6%) underwent endoscopic resection techniques (ERT) with either EMR or ESD. From 2014 to 2024, the incidence of colorectal surgery for patients with colorectal polyps declined from 4.1 to 3.0 per 1000 cases, whereas the utilization of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) demonstrated a significant upward trend, increasing from 52.8 to 64.3 per 1000 cases over the same period. Over the past 10 years, there has been a modest decline in surgery rates for nonmalignant colorectal polyps, coinciding with increasing rates of EMRs and ESDs. Future studies are needed to understand reason for these trends and interventions to enhance the uptake of organ sparing polyp resection.

Endoscopic Resection Is As Effective As Surgical Resection in Managing Malignant Colorectal Polyps - Analysis of Data From a National Cancer Registry

Post-polypectomy surveillance colonoscopy (SC) plays an integral role in efforts to reduce colorectal cancer risk, but its effectiveness is invariably dependent on patient compliance. This study aimed to evaluate patient adherence to SC after endoscopic resection (ER) of polyps ≥ 20 mm and identify potential barriers associated with loss to follow-up. This was a single-center retrospective study evaluating adherence to SC after ER of polyps ≥ 20 mm between April 2018 to December 2021. Adherence to SC was defined as the proportion of patients who underwent follow-up colonoscopy. Multivariate logistic regression was performed to identify factors associated with loss to follow-up. A total of 959 patients (mean age 67 years; 47.9% women) underwent endoscopic resection of colorectal polyps ≥ 20 mm (mean size 33.2 ± 13.7 mm). Nearly half of the patients (n = 478; 49.8%) were lost to follow-up. On multivariate analysis, factors associated with a higher likelihood of SC non-adherence were: lack of a primary care physician (odds ratio [OR] 1.7;95% confidence interval [CI] 1.3- 2.3; P < 0.05), American Society of Anesthesiologists grade 3 or 4 (OR 1.4; 95% CI 1.1-1.9; P < 0.05), residence > 60 miles from the endoscopy suite (OR 1.6; 95% CI 1.2-2.3; P = 0.02), being referred by a physician outside of our healthcare system (OR 1.4; 95% CI 1.1-1.8; P = 0.01), and lack of written follow-up recommendations on the colonoscopy report (OR 3.6; 95% CI 1.4-10.2; P = 0.01). Nearly half of patients undergoing ER of colorectal polyps ≥ 20 mm are lost to follow-up. We identified several patient- and healthcare-related factors as barriers to SC adherence. Strategies to address these issues and targeting of high-risk populations are urgently needed to enhance SC programs.

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How to Manage the Large Nonpedunculated Colorectal Polyp

Large nonpedunculated colorectal polyps ≥ 20 mm (LNPCPs) comprise 1% of all colorectal lesions. LNPCPs are more likely to contain advanced histology such as high-grade dysplasia and submucosal invasive cancer (SMIC). Endoscopic resection is the first-line approach for management of these lesions. Endoscopic resection options include endoscopic mucosal resection (EMR), cold-snare EMR (EMR), endoscopic submucosal dissection (ESD) and endoscopic full-thickness resection (EFTR). This review aimed to critically evaluate current endoscopic resection techniques. Evidence-based selective resection algorithms should inform the most appropriate endoscopic resection technique. Most LNPCPs are removed by conventional EMR but there has been a trend toward C-EMR for endoscopic resection of LNPCPs. More high-quality trials are required to better define the limitations of C-EMR. Advances in our understanding of ESD technique, has clarified its role within the colorectum. More recently, the development of a full thickness resection device (FTRD) has allowed the curative endoscopic resection of select lesions. Endoscopic resection should be regarded as the principle approach for all LNPCPs. Underpinned by high-quality research, endoscopic resection has become more nuanced, leading to improved patient outcomes.

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