Demographic and pathological characteristics of serrated polyps of colorectum

CT Colonography for Colorectal Cancer Prevention and Detection: Integration Into Clinical Practice, From the AJR Special Series on Screening

CT colonography (CTC) is a CT examination, performed with low dose and typically without IV contrast media, optimized to detect colorectal polyps and cancer. Despite extensive supporting data, CTC has had variable acceptance and use over the past two decades, particularly for a main indication of colorectal cancer screening. CTC is now at an inflection point after the approval in 2025 by CMS for reimbursement of CTC performed for colorectal cancer screening. Widespread use of CTC for CRC screening could help increase screening adherence rates and prevent cancer incidence. Nonetheless, radiologists must incorporate emerging knowledge regarding polyps' natural history and recognition of sessile serrated lesions, to leverage the screening efficiencies of CTC-based screening. The purposes of this article are to describe the current status of CRC in the United States and United Kingdom with consideration of historical reasons that have limited the test's use along with recent events that may portend a marked change in the test's acceptance; to highlight the challenges and potential solutions toward successful widespread CTC implementation; and to present new concepts in CTC and CRC screening relevant to radiologists.

The Comparison of Diagnostic Ability between Blue Laser/Light Imaging and Narrowband Imaging for Sessile Serrated Lesions with or without Dysplasia

Objectives

Diagnostic ability of sessile serrated lesions (SSL) and SSL with dysplasia (SSLD) using blue laser/light imaging (BLI) has not been well examined. We analyzed the diagnostic accuracy of BLI for SSL and SSLD using several endoscopic findings compared to those of narrow band imaging (NBI).

Materials and Methods

This was a subgroup analysis of prospective studies. 476 suspiciously serrated lesions of ≥2 mm on the proximal colon showing serrated change with magnified NBI or BLI in our institution between 2014 and 2021 were examined histopathologically. After propensity score matching, we evaluated the diagnostic ability of SSL and SSLD of the NBI and BLI groups regarding various endoscopic findings. For WLI findings, granule, depression, and reddish were examined for diagnosing SSLD. For NBI/BLI findings, expanded crypt opening (ECO) or thick and branched vessels (TBV) were examined for diagnosing SSL. Network vessels (NV) and white dendritic change (WDC) defined originally were examined for diagnosing SSLD.

Results

Among matched 176 lesions, the sensitivity of lesions with either ECO or TBV for SSL in the NBI/BLI group was 97.5%/98.5% (p = 0.668). Those with either WDC or NV for diagnosing SSLD in the groups were 81.0%/88.9% (p = 0.667). Regarding the rates of endoscopic findings among 30 SSLD and 290 SSL, there were significant differences in WDC (66.4% vs. 8.6%, p < 0.001), NV (55.3% vs. 1.4%, p < 0.001), and either WDC or NV (86.8% vs. 9.0%, p < 0.001).

Conclusions

The diagnostic ability of BLI for SSL and SSLD was not different from NBI. NV and WDC were useful for diagnosing SSLD.

Analysis of Predictors and Risk Factors of Postpolypectomy Syndrome

BACKGROUND AND AIMS

Postpolypectomy syndrome (PPS) is a relevant adverse event that can appear after polypectomy. Several publications mention postpolypectomy syndrome using different criteria to define it. The aim of this study is to detect potential risk factors and predictors for developing PPS and to define the main criteria of PPS.

METHODS

In this retrospective monocentric study, 475 out of 966 patients who underwent colonoscopy with polypectomy from October 2015 to June 2020 were included. The main criterion of PPS is defined as the development of postinterventional abdominal pain lasting more than six hours.

RESULTS

A total of 9.7% of the patients developed PPS, which was defined as local abdominal pain around the polypectomy area after six hours. A total of 8.6% of the study population had abdominal pain within six hours postintervention. A total of 3.7% had an isolated triad of fever, leukocytosis, and increased CRP in the absence of abdominal pain. Increased CRP combined with an elevated temperature over 37.5 °C seems to be a positive predictor for developing PPS. Four independent risk factors could be detected: serrated polyp morphology, polypoid configurated adenomas, polyp localization in the cecum, and the absence of intraepithelial neoplasia.

CONCLUSIONS

Four independent risk factors for developing PPS were detected. The combination of increased CRP levels with elevated temperature seems to be a predictor for this pathology. As expected, the increasing use of cold snare polypectomies will reduce the incidence of this syndrome. Key summary: Our monocentric study on 966 patients detected four independent risk factors for developing PPS: pedunculated polyp, resected polyps in the cecum, absence of IEN, and serrated polyp morphology. The combination of increased CRP levels with elevated temperature seems to be a predictor for this pathology.

Lansoprazole inhibits the development of sessile serrated lesions by inducing G1 arrest via Skp2/p27 signaling pathway

BACKGROUND

Although the serrated-neoplasia pathway reportedly accounts for 15-30% of colorectal cancer (CRC), no studies on chemoprevention of sessile serrated lesions (SSLs) have been reported. We searched for effective compounds comprehensively from a large series of compounds by employing Connectivity Map (CMAP) analysis of SSL-specific gene expression profiles coupled with in vitro screening using SSL patient-derived organoids (PDOs), and validated their efficacy using a xenograft mouse model of SSL.

METHODS

We generated SSL-specific gene signatures based on DNA microarray data, and applied them to CMAP analysis with 1309 FDA-approved compounds to select candidate compounds. We evaluated their inhibitory effects on SSL-PDOs using a cell viability assay. SSL-PDOs were orthotopically transplanted into NOG mice for in vivo evaluation. The signal transduction pathway was evaluated by gene expression profile and protein expression analysis.

RESULTS

We identified 221 compounds by employing CMAP analysis of SSL-specific signatures, which should cancel the gene signatures, and narrowed them down to 17 compounds. Cell viability assay using SSL-PDOs identified lansoprazole as having the lowest IC50 value (47 µM) among 17 compounds. When SSL-PDO was orthotopically transplanted into murine intestinal tract, the tumor grew gradually. Administration of lansoprazole to mice inhibited the growth of SSL xenograft whereas the tumor in control mice treated with vehicle alone grew gradually over time. The Ki67 index in xenograft lesions from the lansoprazole group was significantly lower compared with the control group. Cell cycle analysis of SSL-PDOs treated with lansoprazole exhibited a significant increase in G1 phase cell population. Microarray and protein analysis revealed that lansoprazole downregulated Skp2 expression and upregulated p27 expression in SSL-PDOs.

CONCLUSIONS

Our data strongly suggest that lansoprazole is the most effective chemopreventive agent against SSL, and that lansoprazole induces G1 cell cycle arrest by downregulating Skp2 and upregulating p27 in SSL cells.

Risk of Metachronous Neoplasia with High-Risk Adenoma and Synchronous Sessile Serrated Adenoma: A Systematic Review and Meta-Analysis

Background: Sessile serrated adenomas are important precursors to colorectal cancers and account for 30% of colorectal cancers. The United States Multi-Society Task Force recommends that patients with sessile serrated adenomas undergo surveillance similar to tubular adenomas. However, the risk of metachronous neoplasia when the high-risk adenoma co-exists with sessile serrated adenomas is poorly defined. Objective: To examine the risk of metachronous neoplasia in the presence of high-risk adenoma and synchronous sessile serrated adenomas compared with isolated high-risk adenoma. Data sources: PubMed, Embase, Scopus, Cochrane Library. Study selection: A literature search for studies evaluating the risk of metachronous neoplasia in patients with high-risk adenoma alone and those with synchronous high-risk adenoma and sessile serrated adenomas during surveillance colonoscopy was conducted on online databases. Main outcome measures: The primary outcome of interest was the presence of metachronous neoplasia. Results: Of the 1164 records reviewed, six (four retrospective and two prospective) studies met inclusion criteria with 2490 patients (1607 males, mean age 59.98 ± 3.23 years). Average follow-up was 47.5 ± 12.5 months. There were 2068 patients with high-risk adenoma on index colonoscopy and 422 patients with high-risk adenoma and synchronous sessile serrated adenomas. Pooled estimates showed a significantly elevated risk for metachronous neoplasia in patients with high-risk adenoma and synchronous sessile serrated adenomas (pooled odds ratio 2.21; 95% confidence intervals 1.65-2.96; p < 0.01). There was low heterogeneity (I² = 11%) among the studies. Sensitivity analysis of the prospective studies alone also showed elevated risk of metachronous neoplasm (pooled odds ratio 2.56; 95%, confidence intervals 1.05-6.23; p = 0.04). Limitations: Inclusion of a small number of retrospective studies. Conclusions: The presence of high-risk adenomas and synchronous sessile serrated adenomas is associated with an increased risk of metachronous neoplasia. Therefore, shorter surveillance intervals may be considered in patients with high-risk adenoma and synchronous sessile serrated adenomas compared to those with high-risk adenoma alone.

Sessile serrated lesions: Clinicopathological characteristics, endoscopic diagnosis, and management

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

Efficacy of specimen pasting after cold snare polypectomy for pathological evaluation of horizontal margins

Background and study aims  Several studies have reported that pathological horizontal margin evaluation cannot be diagnosed in cold snare polypectomy (CSP) specimens. We conducted a prospective randomized controlled trial to determine the efficacy of pasting CSP specimens on paper for pathological horizontal margins. Patients and methods  This was a single-center, prospective study conducted at Osaka Saiseikai Nakatsu Hospital. In this study, the indications for CSP were adenomas ≤ 10 mm. Colorectal polyps resected by CSP were randomized to the pasting and non-pasting groups after exclusion of fragmented specimens, and the extended CSP specimens pasted on paper were formalin-fixed in the pasting group. The primary endpoint was rate of unclear horizontal margins after CSP. Results  A total of 216 CSP specimens were analyzed. The rate of unclear horizontal margins was significantly lower in the pasting group than in the non-pasting group (15.1 % vs 33.6 %, P  = 0.002). CSP specimen pasting significantly reduced the rate of unclear horizontal margins. On multivariate analysis, non-pasting group (odds ratio [OR], 2.69; 95 % confidence interval [CI], 1.38-5.41; P  = 0.003) and right colon (OR, 1.98; 95 %CI, 1.01-4.01; P  = 0.047) were independent risk factors for unclear horizontal margins in CSP specimens. Conclusions  Pasting the extended specimen is important for accurate pathological examination after CSP.

A comparison of 9-min colonoscopy withdrawal time and 6-min colonoscopy withdrawal time: A systematic review and meta-analysis

INTRODUCTION

The optimal colonoscopy withdrawal time is still a controversial topic. While several studies demonstrate that longer withdrawal time improves adenoma detection rate, others have contradicted these findings.

METHODS

Three independent reviewers performed a comprehensive review of all original articles published from inception to January 2021 and included studies reporting comparison of the two cohorts-(i) ≥ 6 but less than 9 min of colonoscopy withdrawal time (CWT) and (ii) ≥ 9 min of CWT. The outcome measures were the following: (i) adenoma detection rate (ADR), (ii) advanced ADR, and (iii) sessile serrated adenoma detection rate (SDR). The meta-analysis was performed, and the statistics were two-tailed.

RESULTS

A total of seven studies met the inclusion criteria after a thorough search of the literature was completed. The analysis revealed that ≥ 9 min of CWT had significantly higher odds of adenoma detection as compared with 6-9 min of CWT (odds ratio [OR] 1.54, 95% confidence interval [CI] 1.30-1.82; I²  = 93.7). Additionally, a significantly higher odds of sessile serrated adenoma detection (OR 1.68, 95% CI 1.28-2.22; I²  = 0) and a trend towards higher odds of advanced adenoma detection (OR 1.38, 95% CI 0.98-1.95, I²  = 90) were seen with CWT of at least 9 min when compared with 6-9 min of CWT.

CONCLUSION

This systematic review and meta-analysis analysis provides further evidence that at least 9 min of CWT cohort had significantly higher ADR and SDR as compared with the at least 6 min but less than 9 min of cohort.

Serrated lesions: A challenging enemy

The serrated pathway accounts for 30%-35% of colorectal cancer (CRC). Unlike hyperplastic polyps, both sessile serrated lesions (SSLs) and traditional serrated adenomas are premalignant lesions, yet SSLs are considered to be the principal serrated precursor of CRCs. Serrated lesions represent a challenge in detection, classification, and removal–contributing to post-colonoscopy cancer. Therefore, it is of the utmost importance to characterize these lesions properly to ensure complete removal. A retrospective cohort study developed a diagnostic scoring system for SSLs to facilitate their detection endoscopically and subsequent removal. From the study, it can be ascertained that both indistinct border and mucus cap are essential in both recognizing and diagnosing serrated lesions. The proximal colon poses technical challenges for some endoscopists, which is why high-quality colonoscopy plays such an important role. The indistinct border of some SSLs poses another challenge due to difficult complete resection. Overall, it is imperative that gastroenterologists use the key features of mucus cap, indistinct borders, and size of at least five millimeters along with a high-quality colonoscopy and a good bowel preparation to improve the SSL detection rate.

S100P Expression via DNA Hypomethylation Promotes Cell Growth in the Sessile Serrated Adenoma/Polyp-Cancer Sequence

BACKGROUND/AIMS

Sessile serrated adenomas/polyps (SSA/Ps) are a putative precursor lesion of colon cancer. Although the relevance of DNA hypermethylation in the SSA/P-cancer sequence is well documented, the role of DNA hypomethylation is unknown. We investigated the biological relevance of DNA hypomethylation in the SSA/P-cancer sequence by using 3-dimensional organoids of SSA/P.

METHODS

We first analyzed hypomethylated genes using datasets from our previous DNA methylation array analysis on 7 SSA/P and 2 cancer in SSA/P specimens. Expression levels of hypomethylated genes in SSA/P specimens were determined by RT-PCR and immunohistochemistry. We established 3-dimensional SSA/P organoids and performed knockdown experiments using a lentiviral shRNA vector. DNA hypomethylation at CpG sites of the gene was quantitated by MassARRAY analysis.

RESULTS

The mean number of hypomethylated genes in SSA/P and cancer in SSA/P was 41.6 ± 27.5 and 214 ± 19.8, respectively, showing a stepwise increment in hypomethylation during the SSA/P-cancer sequence. S100P, S100α2, PKP3, and MUC2 were most commonly hypomethylated in SSA/P specimens. The mRNA and protein expression levels of S100P, S100α2, and MUC2 were significantly elevated in SSA/P compared with normal colon tissues, as revealed by RT-PCR and immunohistochemistry, respectively. Among these, mRNA and protein levels were highest for S100P. Knockdown of the S100P gene using a lentiviral shRNA vector in 3-dimensional SSA/P organoids inhibited cell growth by >50% (p < 0.01). The mean diameter of SSA/P organoids with S100P gene knockdown was significantly smaller compared with control organoids. MassARRAY analysis of DNA hypomethylation in the S100P gene revealed significant hypomethylation at specific CpG sites in intron 1, exon 1, and the 5'-flanking promoter region.

CONCLUSION

These results suggest that DNA hypomethylation, including S100P hypomethylation, is supposedly associated with the SSA/P-cancer sequence. S100P overexpression via DNA hypomethylation plays an important role in promoting cell growth in the SSA/P-cancer sequence.

Differential diagnosis of appendiceal serrated lesions and polyps and low-grade appendiceal mucinous neoplasm: analysis of 88 cases

PURPOSE

To identify clinicopathological features for the differential diagnosis of appendiceal serrated lesions and polyps (SPs) and low-grade appendiceal mucinous neoplasm (LAMN) for the purpose of avoiding over-diagnosis.

METHODS

Clinical data and pathological features of 66 patients with SPs diagnosed at the Aerospace Center Hospital between January 2013 and January 2021 were collected and compared to 22 cases of LAMN.

RESULTS

SPs, compared with LAMN, are likely to be associated with acute inflammation (SPs 53.0% vs. LAMN 18.2%), and may be located in the appendix partly, although with smaller diameter (average 9.6 vs. 27.2 mm); epithelial structures of serrated (100% vs. 22.7%) and filiform villous (47.0% vs. 18.2%) were often found in SPs. SPs occasionally show attenuated or flattened morphology (16.7% vs. 100%) and undulating or scalloped (7.6% vs. 40.9%) structures, and can also be accompanied by diverticulum (18.2% vs. 18.2%) and acellular mucin in the appendiceal wall (16.7% vs. 54.5%), which causes confusion with LAMN. The key point of the differential diagnosis is to observe whether the muscularis mucosa exists (loss, 0% vs. 100%) and fibrosis of the appendiceal wall (0% vs. 100%). SMA immunohistochemistry can assist in the diagnosis. Calcification is also indicative of LAMN.

CONCLUSIONS

The epithelial structure of SPs can appear flattened and focally scalloped, and can be accompanied by mucin in the appendiceal wall, which may appear as complex lesions, easily over-diagnosed as LAMN. Key differential diagnostic features are identifying the structure of lamina propria, determining whether the muscularis mucosa exists, and whether the appendiceal wall is fibrotic.

Features associated with high-risk sessile serrated polyps at index and follow-up colonoscopy

BACKGROUND AND AIM

Clinically significant serrated polyps are precursors of colorectal cancers, with features considered high risk including size ≥10 mm, dysplasia, and presence of synchronous conventional adenoma. While these features have been described in cohorts undergoing screening colonoscopy, there is little information regarding the prevalence and patient characteristics associated with high-risk sessile serrated polyps (SSPs) in those undergoing surveillance colonoscopy.

METHODS

Polyp pathology at the index and first follow-up colonoscopy performed between 2004 and 2019 were examined in patients enrolled in a surveillance program because of an index finding of adenoma and/or SSP. Demographics and pathology features for SSP were compared between the colonoscopies.

RESULTS

Of 6297 patients undergoing index colonoscopy, 2035 underwent follow-up colonoscopy after 3.3 years (interquartile range 2.1-4.8 years). The proportion with SSP decreased from 7.6% at index to 5.0% at follow-up (P < 0.001); however, the proportion of SSPs that were considered high risk was not different between the colonoscopies (62.8% vs 62.4%). Female gender was associated with the presence of high-risk SSP at index colonoscopy (odds ratio [OR] 1.62, 95% confidence interval [CI] 1.28-2.06), while age ≥75 years (OR 3.38, 95% CI 1.67-6.81) and previous high-risk SSP (OR 9.40, 95% CI 4.23-20.88) were independently associated with high-risk SSP at follow-up.

CONCLUSIONS

The prevalence of SSP falls by one-third at first follow-up colonoscopy although the proportion of SSP with high-risk features remains the same. While females were more likely to have a high-risk SSP at the index colonoscopy, those at greatest risk for high-risk SSP at follow-up colonoscopy were age >75 years and an index high-risk SSP.

TXI: Texture and Color Enhancement Imaging for Endoscopic Image Enhancement

Recognition of lesions with subtle morphological and/or color changes during white light imaging (WLI) endoscopy remains a challenge. Often the endoscopic image suffers from nonuniform illumination across the image due to curvature in the lumen and the direction of the illumination light of the endoscope. We propose an image enhancement technology to resolve the drawbacks above called texture and color enhancement imaging (TXI). TXI is designed to enhance three image factors in WLI (texture, brightness, and color) in order to clearly define subtle tissue differences. In our proposed method, retinex-based enhancement is employed in the chain of endoscopic image processing. Retinex-based enhancement is combined with color enhancement to greatly accentuate color tone differences of mucosal surfaces. We apply TXI to animal endoscopic images and evaluate the performance of TXI compared with conventional endoscopic enhancement technologies, conventionally used techniques for real-world image processing, and newly proposed techniques for surgical endoscopic image augmentation. Our experimental results show that TXI can enhance brightness selectively in dark areas of an endoscopic image and can enhance subtle tissue differences such as slight morphological or color changes while simultaneously preventing over-enhancement. These experimental results demonstrate the potential of the proposed TXI algorithm as a future clinical tool for detecting gastrointestinal lesions having difficult-to-recognize tissue differences.

Duodenal sessile serrated adenoma/polyp with characteristic endoscopic and pathologic features

Sessile serrated adenomas/polyps (SSA/Ps), recently called sessile serrated lesions, have a neoplastic pathway in the large intestine and are treated as lesions with malignant potential. There are a few reports of traditional serrated adenomas in the duodenum but no reports of duodenal SSA/Ps. A 66-year-old man underwent screening upper gastrointestinal endoscopy and was found to have a white elevated lesion in the second portion of the duodenum. Magnifying blue laser imaging showed various sized villous-like structures with dilated crypt openings in the white surface mucosa, similar to a SSA/P. Based on these images, a duodenal adenoma was suspected at the time of endoscopic resection. Pathological findings of the resected specimen showed a saw-tooth structure corresponding to basal crypt dilatation and branching with mucus and positive immunostaining for MUC6 and MUC2, similar to a colonic SSA/P. MUC5AC did not stain the glandular crypt cells. KRAS mutation was detected. Immunohistochemical expression of Annexin A10 was clearly identified in the lesion. Although not all of molecular biological features were satisfied, these findings were similar to a colonic SSA/P which has malignant potential. This is the first report of a duodenal SSA/P which should be considered when evaluating elevated duodenal lesions.

Adenoma and polyp detection rates during insertion versus withdrawal phase of colonoscopy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Colonoscopy is the preferred modality for colorectal cancer screening because it has both diagnostic and therapeutic capabilities. Current consensus states that colonoscopy should be performed with initial rapid passage of the instrument to the cecum, followed by thorough evaluation for and removal of all polyps during a deliberate slow withdrawal. Reports have suggested that polyps that are seen but not removed during insertion are sometimes quite difficult to find during withdrawal.

METHODS

We performed a comprehensive literature search of several major databases (from inception to March 2020) to identify randomized controlled trials comparing inspection and polypectomy during the insertion phase as opposed to the traditional practice of inspection and polypectomy performed entirely during the withdrawal phase. We examined differences in terms of adenoma detection rate (ADR), polyps detected per patient (PDPP), cecal intubation time (CIT), withdrawal time, and total procedure time.

RESULTS

Seven randomized controlled trials, including 3834 patients, were included in our final analysis. The insertion/withdrawal cohort had 1951 patients and the withdrawal-only cohort 1883 patients. Pooled odds of adenoma detection in the insertion/withdrawal cohort was .99 (P = .8). ADR was 47.2% in the insertion/withdrawal cohort and 48.6% in the withdrawal-only cohort. Although total procedure and withdrawal times were shorter in the insertion/withdrawal cohort, PDPP in both cohorts were not statistically significant (1.4 vs 1.5, P = .7).

CONCLUSIONS

Additional inspection and polypectomy during the insertion and withdrawal phases of colonoscopy offer no additional benefit in terms of ADR or PDPP.

From Mixed Hyperplastic/Adenomatous Polyp to Sessile Serrated Lesion: A Long and Winding Road for Long and Winding Crypts

CONTEXT.—

During the past 3 decades, numerous articles in the literature have offered terminology, diagnostic criteria, and consensus recommendations regarding the entity currently referred to by the World Health Organization as sessile serrated lesion. Given the many names and various, variably reproducible diagnostic criteria ascribed to sessile serrated lesion, confusion persists for many pathologists and gastroenterologists regarding the diagnosis. This distinction is important, as sessile serrated lesion can progress to malignancy, unlike its main differential diagnosis, hyperplastic polyp. Research studies have shed light on the characteristic architecture and morphology, immunohistochemical patterns, and molecular alterations of sessile serrated lesion, and multiple consensus meetings around the globe have developed their criteria and nomenclature, often clashing or mixing terms.

OBJECTIVE.—

To provide a narrative review from the entity's early description to our current understanding.

DATA SOURCES.—

The existing scientific and clinical literature, published texts, medical society recommendations, and specialty consensus guidelines.

CONCLUSIONS.—

The current World Health Organization criteria are a distillation of this scientific process, but terminology is still a point of contention worldwide.

Relationship between serrated polyps and synchronous and metachronous advanced neoplasia: A retrospective study

OBJECTIVE

Serrated polyps (SP) are regarded as precursor lesions of colorectal cancer (CRC). We conducted this single-center study aiming to investigate the relationship between SP and synchronous and metachronous advanced neoplasia in the Chinese population.

METHODS

The data for this retrospective study were collected from the Endoscopy Center and Department of Gastroenterology of Renji Hospital, School of Medicine, Shanghai Jiao Tong University between May 2012 and May 2019. Altogether 2205 patients were pathologically confirmed with colorectal SP.

RESULTS

The detection rate of SP among all polyps has gradually increased since 2014 and reached 8.74% by 2019. Among all the SP cases, 1540 (69.84%) were confirmed as having hyperplasic polyps (HP), 486 (22.04%) were having sessile serrated lesions (SSL), and 171 (7.76%) had traditional serrated adenomas (TSA). Compared with HP (2.14%), SSL and TSA were larger and more likely to be accompanied by synchronous and metachronous advanced neoplasia (6.79% and 6.08%). We next found that large SP (diameter ≥10 mm) (odds ratio [OR] 2.52, 95% confidence interval [CI] 1.40-4.55, P = 0.002) and SSL with high-grade intraepithelial neoplasia (OR 13.85, 95% CI 3.28-58.56, P < 0.001) were associated with an increased risk of synchronous advanced neoplasia. However, we failed to find a relationship between SP and metachronous advanced neoplasia because few patients had developed metachronous advanced neoplasia.

CONCLUSION

Large SP and SSL with high-grade intraepithelial neoplasia are associated with synchronous advanced neoplasia and require timely surveillance.

Usefulness of the Japan narrow-band imaging expert team classification system for the diagnosis of sessile serrated lesion with dysplasia/carcinoma

BACKGROUND

Sessile serrated lesion (SSL) is a colorectal polyp that has malignant potential. However, the dysplastic components within an SSL can be difficult to diagnose with conventional endoscopy, because most SSLs with dysplasia/carcinoma have subtle mucosal features. Many studies have indicated that narrow-band imaging (NBI) observations of colorectal polyps are very useful, accurate predictors of histology. We aimed to verify the usefulness of the Japan NBI Expert Team (JNET) classification system for the diagnosis of SSLs with dysplasia/carcinoma.

METHODS

We examined 709 endoscopically or surgically resected lesions that were pathologically diagnosed as SSL, including 647 with no dysplasia, 37 with low-grade dysplasia, 15 with high-grade dysplasia, and 10 with submucosal invasive carcinoma. We retrospectively evaluated their clinicopathologic characteristics and conventional endoscopic and magnifying NBI endoscopic findings using the JNET system.

RESULTS

Cases in all groups were more frequently located in the proximal colon. Submucosal invasive carcinomas were significantly larger than no dysplasia and low-grade dysplasia lesions. Almost all studied lesions (96.3%) were covered with a mucus cap. Five hundred and eighty (81.8%) lesions exhibited dark spots inside the crypts, which are NBI findings' characteristic of SSL. As for the JNET classification of magnifying NBI endoscopic findings, all 709 lesions showed Type 1. Six hundred and eighteen (95.5%) SSLs with no dysplasia lesions exhibited Type 1 only, whereas 52 (83.9%) SSLs with dysplasia/carcinoma had a combination of Type 1 and Type 2A, 2B, or 3, corresponding to SSL and dysplasia/carcinoma, respectively. The JNET classification had high sensitivity (83.9%), specificity (95.5%), and overall diagnostic accuracy (94.5%) for diagnosing SSLs with dysplasia/carcinoma.

CONCLUSIONS

Use of magnifying NBI endoscopy with the JNET classification might be useful for diagnosing SSLs with dysplasia/carcinoma. This increased awareness may also improve the recognition of SSLs with dysplasia/carcinoma.

Macroscopic and microscopic morphology and molecular profiling to distinguish heterogeneous traditional serrated adenomas of the colorectum

OBJECTIVES

Serrated lesions of the colorectum often have complex histological morphology, and some groups include subtypes with different molecular biology. This study aimed to characterize serrated lesions with heterogeneous histology that was dominated by a traditional serrated adenoma (TSA) component.

METHODS

Representative lesions were selected based on both endoscopic and histological features. If a lesion had more than one component, each of the different structural parts was considered as a separate sample. DNA was extracted from 177 samples of 60 lesions and amplified to screen for BRAF and K/NRAS mutations.

RESULTS

Heterogeneous TSA samples were classified into four categories: sessile serrated lesion with TSA (SA-1); TSAs with microvesicular hyperplastic polyp (SA-2); TSAs with unclassified adenoma, characterized by tubulo-serrated histology (SA-3); and TSAs with conventional adenomas (SA-4). On endoscopy, SA-1 lesions had sessile-elevated morphology with the small reddish elevations; SA-2 lesions had a pedunculated appearance with a whitish mucosal component at the stalk; SA-3 lesions had a sessile-elevated component surrounded by flat spreading margins; and SA-4 lesions had mixed adenomatous morphology. Eighteen of the 19 category SA-1 and -2 lesions (95%) had BRAF mutations, and all of the SA-3 and -4 lesions had K/NRAS mutations.

CONCLUSIONS

Traditional serrated adenomas were classified into two phenotypes according to their molecular characteristics: microvesicular serrated subtypes with BRAF mutations (SA-1 and -2 lesions) and subtypes containing tubulo-serrated/conventional adenoma with K/NRAS mutations (SA-3 and -4 lesions). Each subtype had characteristic macroscopic and microscopic morphologies and was distinct on endoscopy.

Correlations of morphology and molecular alterations in traditional serrated adenoma

Traditional serrated adenoma was first reported by Longacre and Fenoglio-Presier in 1990. Their initial study described main features of this lesion, but the consensus diagnostic criteria were not widely adopted until recently. Traditional serrated adenoma presents with grossly protuberant configuration and pinecone-like appearance upon endoscopy. Histologically, it is characterized by ectopic crypt formation, slit-like serration, eosinophilic cytoplasm and pencillate nuclei. Although much is now known about the morphology and molecular changes, the mechanisms underlying the morphological alterations are still not fully understood. Furthermore, the origin of traditional serrated adenoma is not completely known. We review recent studies of the traditional serrated adenoma and provide an overview on current understanding of this rare entity.

Pathways of Colorectal Carcinogenesis

Colorectal cancer is a heterogeneous disease that develops via stepwise accumulation of well-characterized genetic and epigenetic alterations. We review the genetic changes associated with the development of precancerous colorectal adenomas and their progression to tumors, as well as the effects of defective DNA repair, chromosome instability, microsatellite instability, and alterations in the serrated pathway and DNA methylation. We provide insights into the different molecular subgroups of colorectal tumors that develop via each of these different mechanisms and their associations with patient outcomes.

Validation of serrated polyps (SPs) in Swedish pathology registers

Background

Little is known about the natural history of serrated polyps (SPs), partly due to the lack of large-scale epidemiologic data. In this study, we examined the validity of SP identification according to SNOMED (Systematised Nomenclature of Medicine) codes and free text from colorectal histopathology reports.

Methods

Through the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, we retrieved data on SPs from all pathology departments in Sweden in 2015–2017 by using SNOMED codes and free-text search in colorectal histopathology reports. Randomly selected individuals with a histopathology report of SPs were validated against patient charts using a structured, retrospective review.

Results

SPs were confirmed in 101/106 individuals with a histopathology report of SPs, yielding a positive predictive value (PPV) of 95% (95%CI = 89–98%). By year of diagnosis, the PPV was 89% (95%CI = 69–97%), 96% (95%CI = 81–99%) and 97% (95%CI = 89–99%) for individuals diagnosed before 2001 (n = 19), between 2001 and 2010 (n = 26) and after 2010 (n = 61), respectively. According to search method, the PPV for individuals identified by SNOMED codes was 100% (95%CI = 93–100%), and 93% (95%CI = 86–97%) using free-text search. Recorded location (colon vs. rectum) was correct in 94% of all SP histopathology reports (95%CI = 84–98%) identified by SNOMED codes. Individuals with SPs were classified into hyperplastic polyps (n = 34; 32%), traditional serrated adenomas (n = 3; 3%), sessile serrated adenomas/polyps (SSA/Ps) (n = 70; 66%), unspecified SPs (n = 3, 3%), and false positive SPs (n = 5, 5%). For individuals identified by SNOMED codes, SSA/Ps were confirmed in 49/52 individuals, resulting in a PPV of 94% (95%CI: 84–98%). In total, 57% had ≥2 polyps (1: n = 44, 2–3: n = 33 and ≥ 4: n = 27). Some 46% of SPs (n = 71) originated from the proximal colon and 24% were ≥ 10 mm in size (n = 37). Heredity for colorectal cancer, intestinal polyposis syndromes, or both was reported in seven individuals (7%). Common comorbidities included diverticulosis (n = 45, 42%), colorectal cancer (n = 19, 18%), and inflammatory bowel disease (n = 10, 9%).

Conclusion

Colorectal histopathology reports are a reliable data source to identify individuals with SPs.

An update on the morphology and molecular pathology of serrated colorectal polyps and associated carcinomas

Our understanding of serrated colorectal polyps has increased dramatically over the past two decades and has led to a modern classification scheme for these lesions. Sessile serrated polyps with dysplasia represent the most clinically significant serrated polyp; however, the morphologic heterogeneity of dysplasia in sessile serrated polyps has only recently been recognized and correlated with MLH1 immunohistochemistry. Detailed morphologic analysis of traditional serrated adenomas has led to the recognition of flat and early forms of this polyp. Robust data on the risk of metachronous lesions in patients with serrated polyps are also beginning to emerge. This review will summarize our current understanding of serrated polyps and associated carcinomas with a focus on diagnostic criteria, morphologic heterogeneity, molecular findings, and natural history. Controversial issues in the diagnosis and classification of these polyps are also discussed.

Terminology, Molecular Features, Epidemiology, and Management of Serrated Colorectal Neoplasia

In addition to the adenoma to carcinoma sequence, colorectal carcinogenesis can occur via the serrated pathway. Studies have focused on clarification of categories and molecular features of serrated polyps, as well as endoscopic detection and risk assessment. Guidelines from the World Health Organization propose assigning serrated polyps to categories of hyperplastic polyps, traditional serrated adenomas, and sessile serrated lesions (SSLs). Traditional serrated adenomas and SSLs are precursors to colorectal cancer. The serrated pathway is characterized by mutations in RAS and RAF, disruptions to the Wnt signaling pathway, and widespread methylation of CpG islands. Epidemiology studies of serrated polyps have been hampered by inconsistencies in terminology and reporting, but the prevalence of serrated class polyps is 20%-40% in average-risk individuals; most serrated polyps detected are hyperplastic. SSLs, the most common premalignant serrated subtype, and are found in up to 15% of average-risk patients by high-detecting endoscopists. Variations in rate of endoscopic detection of serrated polyps indicate the need for careful examination, with adequate bowel preparation and sufficient withdrawal times. Risk factors for SSLs include white race, family history of colorectal cancer, smoking, and alcohol intake. Patients with serrated polyps, particularly SSLs and traditional serrated adenomas, have an increased risk of synchronous and metachronous advanced neoplasia. Surveillance guidelines vary among countries, but SSLs and proximal hyperplastic polyps require special attention in assignment of surveillance interval-especially in light of concerns regarding incomplete detection and resection.

Clinicopathological features, diagnosis, and treatment of sessile serrated adenoma/polyp with dysplasia/carcinoma

Sessile serrated adenoma/polyps (SSA/Ps) are early precursor lesions in the serrated neoplasia pathway, which results in BRAF-mutated colorectal carcinomas with not only high levels of microsatellite instability but also microsatellite stable. SSA/Ps with advanced histology, including cytological dysplasia or minimally invasive carcinomas, are important lesions because SSA/Ps are considered major contributors to "interval cancers" and these lesions can rapidly become dysplastic or invasive carcinomas. Clinicopathologically, SSA/Ps with dysplasia or invasive carcinoma were associated with advanced age, female sex, and proximal colon. Although SSA/Ps with submucosal invasive carcinoma were smaller and invaded less deeply into the submucosal layer than conventional tubular adenomas with submucosal invasive carcinoma, SSA/Ps with submucosal invasive carcinoma frequently had a mucinous component and exhibited a higher potential for lymphatic invasion and lymph node metastasis. In an SSA/P series, endoscopic characteristics, including (semi)pedunculated morphology, double elevation, central depression, and reddishness, may help accurately diagnose SSA/Ps with advanced histology. Removal of SSA/Ps with dysplasia or invasive carcinoma was recommended. Endoscopic treatment such as endoscopic mucosal resection or endoscopic submucosal dissection is useful for those lesions. However, surgical resection with lymph node dissection might be indicated when SSA/Ps with invasive carcinoma are endoscopically suspected, because these have the high risk of lymph node metastasis. Greater awareness may promote further research into improving the detection, recognition, and complete resection rates of SSA/Ps with dysplasia or invasive carcinoma and reduce the interval cancer rates.

Traditional serrated adenoma: an overview of pathology and emphasis on molecular pathogenesis

Objective

To provide an overview of the pathology and molecular pathogenesis of traditional serrated adenomas (TSA).

Design

Describe the morphology and molecules that play a role in their pathogenesis.

Results

These exuberant polypoid lesions are typified by tall cells with deeply eosinophilic cytoplasm, elongated nuclei bearing delicate chromatin, ectopic crypt foci, deep clefting of the lining mucosa and an overall resemblance to small bowel mucosa.

Broadly, TSAs arise via three mechanisms. They may be BRAF mutated and CpG island methylator phenotype (CIMP)-high: right sided, mediated through a microvesicular hyperplastic polyp or a sessile serrated adenoma, may also have RNF43 mutations and result in microsatellite stable (MSS) colorectal cancers (CRC). The second pathway that is mutually exclusive of the first is mediated through KRAS mutation with CIMP-low TSAs. These are left-sided TSAs, are not associated with another serrated polyp and result in MSS CRC. These TSAs also have RSPO3, RNF43 and p53 mutations together with aberrant nuclear localisation of β-catenin. Third, there is a smaller group of TSAs that are BRAF and KRAS wild type and arise by as yet unknown molecular events. All TSAs show retention of mismatch repair proteins.

Conclusion

These are characteristic unusual polyps with a complex molecular landscape.

Rectal Aberrant Crypt Foci in Humans Are Not Surrogate Markers for Colorectal Cancer Risk

INTRODUCTION

Over the past 20 years, aberrant crypt foci (ACF) have emerged as potential precursors and biomarkers for colorectal cancer (CRC). However, data regarding their molecular pathogenesis, as well as their endoscopic and histological identification, remain inconsistent.

METHODS

A wide cohort of ACF from 100 control subjects and 100 case patients, including patients with adenoma and CRC, were characterized for endoscopic, morphologic, and molecular features.

RESULTS

We observed that among all the endoscopic features evaluated, only the number of large ACF correlated with CRC risk (P = 0.003), whereas the histological classification, as assessed by 2 different pathologists, was inconsistent and did not differ between control and case patients. Moreover, only a few APC and BRAF mutations and no microsatellite instability were detected in our samples. KRAS mutations were detected in 16.3% of ACF samples, which also exhibited increased MGMT hypermethylation. However, none of those events were found to be predictive of CRC risk.

DISCUSSION

Although ACF might be preneoplastic lesions of the colon, they are not suitable biomarkers for assessing CRC progression.

Can the rate and location of sessile serrated polyps be part of colorectal Cancer disparity in African Americans?

BACKGROUND

Up to 30% of colorectal cancers develop through the serrated pathway. African Americans (AAs) suffer a disproportionate burden of colorectal cancer. The aim of this study was to evaluate clinicopathological features of AA patients diagnosed with sessile serrated polyps (SSPs).

METHODS

We conducted a retrospective study of all colonoscopies (n = 12,085) performed at Howard University Hospital, from January 1st, 2010 to December 31st, 2015, of which 83% were in AA patients, (n = 10,027). Among AAs, pathology reports confirmed 4070 patients with polyps including 252 with SSPs. Demographic and clinical variables (i.e. sex, age, BMI, anatomic location, clinical symptoms, polyp size, and clinical indications were collected at colonoscopy.

RESULTS

In the AA population, the median age was 56 with interquartile range (IQR) of 51 to 62 years, 54% were female, and 48% had a BMI > 30. The most common reason for colonoscopy was screening (53%), whereas the prevalent reasons for diagnostic colonoscopies were changes in bowel habits (18%) and gastrointestinal bleeding (17%). The total number of SSPs among the 252 AA (diagnosed with SSPs) was 338. Of these, 9% (n = 29/338) had some degree of cytological dysplasia, primarily in the ascending colon (n = 6/42, 14%), Transverse colon (n = 2/16, 13%) and rectosigmoid (n = 19/233, 8%). About 24% of patients had more than 2 polyps. Most patients (76%) had distal SSPs (rectal and rectosigmoid), in comparison to 14% of proximal polyps and 10% of bilateral locations. Median SSA/P size for all locations was 0.6 cm.

CONCLUSION

The prevalence of SSPs accounts for 6% of all polyps in AA patients and was diagnosed in 2.5% of all colonoscopies (n = 252/10,027), which is higher than Caucasians in the US. SSPs were predominantly located in the left side, as compared to published literature showing the predominance in the right side of the colon. Screening of CRC will have the chance to detect high risk SSA/P in this population.

Serrated lesions of the colon A window on a more clear classification

Serrated polyps evaluation represents a challenge for pathologists for lacking of univocal criteria that leads to different inter -individual interpretation. The aim of our review is to offer an alternative simpler histologic and endoscopic approach to these lesions for a more correct relationship between endoscopists and pathologists.

Sessile Serrated Adenomas in Young Patients may have Limited Risk of Malignant Progression

GOALS

To provide preliminary evidence that sessile serrated adenomas (SSA) are low-risk polyps in young patients.

BACKGROUND

SSAs are the dominant polyp of the serrated neoplasia pathway and as such are the precursor of up to 20% of colorectal carcinomas (CRC). Up to 90% of these cancers are expected to harbor a BRAF mutation. SSAs are being diagnosed with increasing frequency in young patients, placing a significant burden on colonoscopic services. Evidence to direct the surveillance intervals for these young patients is not available.

STUDY

We utilized 2 patient cohorts comprising (1) a consecutive series of patients who underwent outpatient colonoscopy through a tertiary hospital and (2) a consecutive series of resection specimens for CRC processed through a gastrointestinal pathology service. The prevalence of SSAs by age was determined in the patients undergoing colonoscopy and compared with the ages of patients with BRAF mutated CRC in the pathology series.

RESULTS

The prevalence of SSAs was similar irrespective of age. By comparison, BRAF mutated CRCs were very rare (3.8% of cases) in patients younger than 50 years of age and uncommon (9.3% of cases) in patients younger than 60 years of age, but increased to 39.8% in patients older than 80 years of age.

CONCLUSIONS

These results suggest that SSAs develop at a young age, but have a prolonged dwell time and are unlikely to develop into cancer in patients younger than 60 years of age. These findings highlight the need for further targeted research to determine the most appropriate surveillance intervals for young patients with sporadic SSAs.

Serrated Lesions of the Colon-Rectum: A Focus on New Diagnostic Tools and Current Management

Prompt diagnosis and correct management of the so called "serrated lesions" (SLs) of the colon-rectum are generally considered of crucial importance in the past years, mainly due to their histological heterogeneity and peculiar clinical and molecular patterns; sometimes, they are missed at conventional endoscopy and are possibly implicated in the genesis of interval cancers. The aim of this review is to focus on the diagnostic challenges of serrated lesions, underlying the role of both conventional endoscopy and novel technologies. We will show how an accurate and precise diagnosis should immediately prompt the most appropriate therapy other than defining a proper follow-up program. It will be emphasized how novel endoscopic techniques may provide better visualization of mucosal microsurface structures other than enhancing the microvascular architecture, in order to better define and characterize specific patterns of mucosal lesions of the gastrointestinal tract. Standard therapy of SLs of the colon-rectum is still very debated, also due to the relatively lack of studies focusing on treatment issues. The high risk of incomplete resection, together with the high rate of postcolonoscopy interval cancers, suggests the need of an extra care when facing this kind of lesions. Given this background, we will outline useful technical tips and tricks in the resection of SLs, taking aspects such as the size and location of the lesions, as well as novel available techniques and technologies, other than future perspectives, including confocal laser endomicroscopy into consideration. Follow-up of SLs is another hot topic, also considering that their clinical impact has been misunderstood for a long time. The incidence of the so called interval colorectal cancer underlines how some weaknesses exist in current screening and follow-up programs. Considering the lack of wide consensus for the management of some SLs, we will try to summarize and clarify the best strategies for their optimal management.

Endoscopic diagnosis of sessile serrated adenoma/polyp with and without dysplasia/carcinoma

Sessile serrated adenoma/polyps (SSA/Ps) are early precursor lesions in the serrated neoplasia pathway, which results in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potentials. Detecting serrated lesions, including SSA/Ps with and without dysplasia/carcinoma, is critical, but SSA/Ps can be difficult to detect, are inconsistently identified by endoscopists and pathologists, and are often incompletely resected. Therefore, SSA/Ps are considered to be major contributors to “interval cancers”. If colonoscopists can identify the specific endoscopic characteristics of SSA/Ps, their detection and the effectiveness of colonoscopy may improve. Here, the endoscopic features of SSA/Ps with and without dysplasia/carcinoma, including the characteristics determined using magnifying endoscopy, are reviewed in the context of previous reports. Endoscopically, these subtle polyps are like hyperplastic polyps, because they are slightly elevated and pale. Unlike hyperplastic polyps, SSA/Ps are usually larger than 5 mm, frequently covered by a thin layer called the ‘‘mucus cap’’, and are more commonly located in the proximal colon. Magnifying narrow-band imaging findings, which include dark spots inside the crypts and varicose microvascular vessels, in addition to the type II-open pit patterns detected using magnifying chromoendoscopy, effectively differentiate SSA/Ps from hyperplastic polyps. The lesions’ endoscopic characteristics, which include their (semi)pedunculated morphologies, double elevations, central depressions, and reddishness, and the use of magnifying endoscopy, might help to detect dysplasia/carcinoma within SSA/Ps. Greater awareness may promote further research into improving the detection, identification, and complete resection rates of SSA/Ps with and without dysplasia/carcinoma and reduce the interval cancer rates.

Serrated neoplasia pathway as an alternative route of colorectal cancer carcinogenesis

In the past two decades, besides conventional adenoma pathway, a subset of colonic lesions, including hyperplastic polyps, sessile serrated adenoma/polyps, and traditional serrated adenomas have been suggested as precancerous lesions via the alternative serrated neoplasia pathway. Major molecular alterations of sessile serrated neoplasia include BRAF mutation, high CpG island methylator phenotype, and escape of cellular senescence and progression via methylation of tumor suppressor genes or mismatch repair genes. With increasing information of the morphologic and molecular features of serrated lesions, one major challenge is how to reflect this knowledge in clinical practice, such as pathologic and endoscopic diagnosis, and guidelines for treatment and surveillance.

Linked color imaging enhances endoscopic detection of sessile serrated adenoma/polyps

BACKGROUND AND STUDY AIMS

 Although new image-enhanced endoscopy (IEE) technologies such as blue laser imaging (BLI), BLI-bright, and linked color imaging (LCI) have been developed, their utility for the detection of sessile serrated adenoma/polyps (SSA/Ps) is still unclear. This study aimed to evaluate the utility of BLI, BLI-bright, and LCI for SSA/P detection in still image examinations and in a prospective randomized controlled trial (RCT).

PATIENTS AND METHODS

 A group of 6 expert and non-expert endoscopists read 200 endoscopic still images containing SSA/P lesions using white light image (WLI), BLI, BLI-bright, and LCI. Color differences were calculated using the color space method. A prospective RCT of tandem colonoscopy with WLI and LCI was performed. Patients with SSA/P and those with a history of SSA/P that had been endoscopically removed were enrolled and randomly allocated to WLI-LCI or LCI-WLI groups. Additional endoscopic detection rates for SSA/P were compared between the 2 groups.

RESULTS

 LCI showed the highest SSA/P detection rate among the 4 modes for both expert and non-expert endoscopists. The detection rate with LCI for the 6 expert endoscopists (mean 98.3 ± standard deviation 2.0 %) was significantly higher than that with WLI (86.7 ± 6.0 %, P  < 0.01). Likewise, the detection rate with LCI for the 6 non-expert endoscopists (92.3 ± 2.9 %) was significantly higher than that with WLI (72.7 ± 11.5 %, P  < 0.01). The color difference of SSA/P with LCI was the highest among the 4 modes, and was significantly higher than with WLI (median 15.9, (interquartile range 13.7 - 20.6) vs. 10.2, (7.6 - 14.2); P  < 0.0001). In the RCT, a total of 44 patients (WLI-LCI 22 vs. LCI-WLI 22) underwent colonoscopy. The additional detection rate for SSA/P in the second inspection in the WLI-LCI group (21.6 %, 8/37) was significantly higher than in the LCI-WLI group (3.2 %, 1/31; P  = 0.02). The small, flat, non-mucus and isochromatic SSA/Ps in the transverse colon were detected more frequently in the second inspection with LCI.

CONCLUSIONS

 LCI was the most sensitive mode for SSA/P detection among WLI, BLI, BLI-bright, and LCI in the still image examinations. Our RCT strongly suggests that LCI is superior to conventional WLI for SSA/P detection during colonoscopy. UMIN000017599.

Mucins and associated O-glycans based immunoprofile for stratification of colorectal polyps: clinical implication for improved colon surveillance

Sessile serrated adenoma/polyps (SSA/P) are premalignant lesions of colorectal cancer that are difficult to distinguish histologically from hyperplastic polyps (HP) of minimal to no malignant potential. Specific markers for differentiating SSA/P from HP can aid clinicians for optimizing colon surveillance intervals. The present study investigates the potential of mucins and associated O-glycans to distinguish SSA/P from HP. Expression of colonic mucins (MUC1, MUC4, MUC17, MUC2, and MUC5AC) and O-glycans [Sialyl LewisA (CA19-9) and Tn/Sialyl-Tn on MUC1] were analyzed in HP (n=33), SSA/P (n=39), and tubular adenoma (TA) (n=36) samples by immunohistochemistry. A significantly reduced expression of MUC4 (p=0.0066), elevated expression of MUC17 (p=0.0002), and MUC5AC (p<0.0001) was observed in SSA/P cases in comparison to HP cases. Interestingly, significantly higher number of SSA/P cases (p<0.0001) exhibited MUC5AC expression in the goblet cells as well as filled the crypt lumen compared to only goblet cells in majority of the HP cases. Improved diagnostic potential was revealed by multivariate logistic regression analysis where combinatorial panel of MUC5AC/MUC17 discriminated SSA/P from HP (SN/SP=85/82%). Finally, the decision tree model based marker panel (CA19-9/MUC17/MUC5AC) predicted HP, SSA/P and TA with SN/SP of 58%/95%, 79%/90% and 97%/83%, respectively. Overall, the mucin and associated O-glycan based panel defined in the present study could aid in discriminating SSA/P from HP to devise better colon surveillance strategies.

Endoscopic and molecular characterization of colorectal sessile serrated adenoma/polyps with cytologic dysplasia

BACKGROUND AND AIMS

Sessile serrated adenoma/polyps (SSA/Ps), which are precursor lesions of colorectal cancer (CRC) with BRAF mutation and the CpG island methylator phenotype (CIMP), develop cytologic dysplasia (CD) during the progression of colorectal tumorigenesis. In the present study we aimed to clarify the endoscopic and molecular signatures of SSA/Ps, with and without CD.

METHODS

A series of 208 serrated lesions, including 41 hyperplastic polyps, 90 SSA/Ps, 33 SSA/Ps with CD, and 44 traditional serrated adenomas, were observed and resected using magnifying endoscopy. BRAF and KRAS mutations and methylation of CIMP markers (MINT1, MINT2, MINT12, MINT31, and p16) were analyzed through pyrosequencing. Molecular alterations were then compared with endoscopic and pathologic characteristics.

RESULTS

Among SSA/Ps without CD, the Type II-Open pit pattern (Type II-O), BRAF mutation, and CIMP were tightly associated with a proximal colon location. SSA/Ps in the distal colon infrequently exhibited Type II-O and CIMP. By contrast, most SSA/Ps with CD showed Type II-O plus adenomatous pit patterns (Type III or IV), BRAF mutation, and CIMP, irrespective of their locations.

CONCLUSIONS

Our results suggest that the Type II-O plus III/IV pit pattern is a common feature of SSA/Ps with CD in both the proximal and distal colon and that this pit pattern is a hallmark of serrated lesions at high risk of developing into CRCs.

Serrated polyps - a concealed but prevalent precursor of colorectal cancer

Serrated polyps have long been considered to lack malignant potential but accumulating data suggest that these lesions may cause up to one-third of all sporadic colorectal cancer. Serrated polyps are classified into three subtypes, including sessile serrated adenomas/polyps (SSA/Ps), traditional serrated adenomas (TSAs), and hyperplastic polyps (HPs). SSA/P and TSA harbour malignant potential but TSA represents only 1-2%, wheras SSA/P constitute up to 20% of all serrated lesions. HPs are most common (80%) of all serrated polyps but are considered to have a low potential of developing colorectal cancer. Due to their subtle appearence, detection and removal of serrated polyps pose a major challenge to endoscopists. Considering that precancerous serrated polyps are predominately located in the right colon could explain why interval cancers most frequently appear in the proximal colon and why colonoscopy is less protective against colon cancer in the proximal compared to the distal colon. Despite the significant impact on colorectal cancer incidence, the aetiology, incidence, prevalence, and natural history of serrated polyps is incompletely known. To effectively detect, remove, and follow-up serrated polyps, endoscopists and pathologists should be well-informed about serrated polyps. This review highlights colorectal serrated polyps in terms of biology, types, diagnosis, therapy, and follow-up.

British Society of Gastroenterology position statement on serrated polyps in the colon and rectum

Serrated polyps have been recognised in the last decade as important premalignant lesions accounting for between 15% and 30% of colorectal cancers. There is therefore a clinical need for guidance on how to manage these lesions; however, the evidence base is limited. A working group was commission by the British Society of Gastroenterology (BSG) Endoscopy section to review the available evidence and develop a position statement to provide clinical guidance until the evidence becomes available to support a formal guideline. The scope of the position statement was wide-ranging and included: evidence that serrated lesions have premalignant potential; detection and resection of serrated lesions; surveillance strategies after detection of serrated lesions; special situations-serrated polyposis syndrome (including surgery) and serrated lesions in colitis; education, audit and benchmarks and research questions. Statements on these issues were proposed where the evidence was deemed sufficient, and re-evaluated modified via a Delphi process until >80% agreement was reached. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool was used to assess the strength of evidence and strength of recommendation for finalised statements. Key recommendation: we suggest that until further evidence on the efficacy or otherwise of surveillance are published, patients with sessile serrated lesions (SSLs) that appear associated with a higher risk of future neoplasia or colorectal cancer (SSLs ≥10 mm or serrated lesions harbouring dysplasia including traditional serrated adenomas) should be offered a one-off colonoscopic surveillance examination at 3 years (weak recommendation, low quality evidence, 90% agreement).

Distinctive crypt shape in a sessile serrated adenoma/polyp: Distribution of Ki67-, p16INK4a-, WNT5A-positive cells and intraepithelial lymphocytes

Serrated lesions in the colorectum are currently predominantly classified as hyperplastic polyps (HPs), sessile serrated adenomas/polyps (SSA/Ps), and traditional serrated adenomas (TSAs) according to their morphology. However, the histological morphology and the molecular changes in the serrated lesions are still unclear. We performed immunohistochemistry for Ki67, p16^INK4a, and WNT5A in human HPs (n=22), SSA/Ps (n=41), and TSAs (n=19). The distribution of Ki67 and p16^INK4a positive cells in TSAs was different from that in HPs and SSA/Ps. Co-expression of Ki67 and P16^INK4a was infrequent in HPs and SSA/Ps; p16^INK4a-positive cells were found in the crypt cleft and stromal WNT5A-positive stromal cells were localized near the cleft in SSA/Ps, while intraepithelial lymphocytes (IELs) in SSA/Ps were more abundant than HPs. In conclusion, our study provides evidence that HPs branch because of the increase in and patchy distribution of senescent and proliferative cells, with increased and misdistributed stromal and inflammatory cells, which might contribute to creation of L- and/or T-shaped crypts, which are of distinctive shapes in SSA/Ps. Our findings may facilitate better understanding and therapy in the serrated lesions.

Feasibility of Large-Scale Identification of Sessile Serrated Polyp Patients Using Electronic Records: A Utah Study

BACKGROUND/AIMS

The serrated pathway accounts for 15-25% of sporadic colorectal cancer (CRC). In our study, we sought to accurately characterize sessile serrated polyps (SSP) in a population by electronically interrogating colonoscopy patients' endoscopy and pathology reports using a rules-based text search of pre-defined SSP-related terms. To this aim, we compared a sample of putative SSP and hyperplastic polyps (HP) using our algorithm to a determination of SSP or HP by pathologist and molecular examination to determine the feasibility of large-scale identification of SSP in electronic medical records.

METHODS

In 23,990 endoscopy reports from colonoscopies with pathology performed at a University of Utah Healthcare facility in 2000-2012, we identified serrated lesions and categorized each as putative SSP or HP using a text search algorithm. We obtained 93 tissue samples for histologic and molecular analysis.

RESULTS

Serrated polyps were categorized as putative SSP (N = 920) and putative HP (N = 7159) by text search algorithm. Histologic examination of 93 samples identified 37 SSP, 11 probable SSP, and 45 HP. Of 26 putative SSP, 25 were SSP/probable SSP (96%) by histology. Of 67 putative HP, 44 were HP (66%) by histology. Reducing size criterion from ≥1 to ≥5 mm in the search algorithm caused improved sensitivity (77.1%) without decline in specificity (97.8%).

CONCLUSIONS

A simple rules-based search to identify SSP provides "proof of principle" that SSP can be identified in a large electronic record set. Pilot data indicate defining large, right-sided polyps as ≥5 mm provides adequate sensitivity to detect SSP from electronic records while maintaining high specificity.

The clinical impact of serrated colorectal polyps

Serrated polyps (SPs) of the colorectum pose a novel challenge to practicing gastroenterologists. Previously thought benign and unimportant, there is now compelling evidence that SPs are responsible for a significant percentage of incident colorectal cancer worldwide. In contrast to conventional adenomas, which tend to be slow growing and polypoid, SPs have unique features that undermine current screening and surveillance practices. For example, sessile serrated polyps (SSPs) are flat, predominately right-sided, and thought to have the potential for rapid growth. Moreover, SSPs are subject to wide variations in endoscopic detection and pathologic interpretation. Unfortunately, little is known about the natural history of SPs, and current guidelines are based largely on expert opinion. In this review, we outline the current taxonomy, epidemiology, and management of SPs with an emphasis on the clinical and public health impact of these lesions.

Evaluation for the Clinical Efficacy of Colon Capsule Endoscopy in the Detection of Laterally Spreading Tumors

BACKGROUND AND AIM

The manner in which colorectal lesions are being detected with PillCam COLON2 capsule endoscopy (CCE2) has markedly improved in recent days. However, limited data are available on CCE2 for detecting laterally spreading tumors (LSTs). The aim of this study was to compare CCE2 with optical colonoscopy (OC), which is currently the gold standard used in the detection of LSTs.

METHODS

We performed a prospective, single-academic center study comparing CCE2 with OC in patients with LSTs diagnosed using OC, which was performed during the 3-month period prior to CCE2. We focused on the sensitivity and specificity of CCE2 for detecting LSTs. LSTs were classified into the LST-granular type (LST-G) or the LST-non-granular type (LST-NG).

RESULTS

Thirty patients (mean age 59.5 years) were enrolled. Of them, 21 LSTs (7 LST-Gs and 14 LST-NGs) were evaluated in this study. The mean diameter of the LSTs was 27 ± 15 mm (range 10-60 mm). Histopathological diagnoses of the LSTs were as follows: tubular adenoma, 12 cases (57%); sessile serrated adenoma/polyp (SSA/P), 4 cases (19%); Tis carcinoma, 1 case (5%); and T1 carcinoma, 4 cases (19 LSTs were found in the following locations: cecum, 1 case (5%); ascending colon, 6 cases (29%); transverse colon, 6 cases, (29%); descending colon, 1 case (5%); sigmoid colon, 3 cases (13%); and rectum, 4 cases (19%). The colon cleansing level was adequate in all cases. The sensitivity and specificity of CCE2 for detecting LSTs were 81 and 100% respectively. For detecting LST-Gs and LST-NGs, the sensitivity and specificity were 71 and 100%, and 86 and 100%, respectively. There were 4 false-negative cases (LST-G (18 mm), cecum; LST-G (20 mm), sigmoid colon; LST-NG (25 mm), transverse colon; LST-NG (20 mm), transverse colon).

CONCLUSIONS

The sensitivity for detecting LSTs is lower with CCE2 than it is with OC, especially for LSTs located on the right colon or for SSA/P.

Investigating The Frequency of Serrated Polyps/Adenomas and Their Subtypes in Colonic Polyp Samples

BACKGROUND

The purpose of this study was to determine the frequency of Serrated polyps of colonic polyps samples in Hazrat_e Rasoul_e Akram Hospital over ten years.

MATERIALS

The target group in this study was patients with colonic polyps in Hazrat_e Rasoul_e Akram Hospital. Pathologic evaluation of these patients was done. Serrated polyps, by location, gender, age and type of polyps were divided and frequency of them were determined separately.

RESULTS

Of 381 patients studied, 224 (58.79%) and 157(41.20%) were males and females, respectively. Mean age of patients was 59.25 years. In initial diagnosis, frequency of Adenomatous polyp, Hyperplastic polyp and Mixed polyp were 92.44% and 5.33%, and 2.22%, respectively. In final diagnosis (Second evaluation), frequency of Adenomatous polyp, Hyperplastic polyp, Mixed polyp, Sessile Serrated Adenoma/ Polyp, Traditional Serrated Adenoma and SPU (Serrated Polyp Unclassifiable) were 90.44%, 4.88%, 2.44%, 1.11%, 0.66% and 0.44%, respectively. 72.13% and 27.86% of polyps were low grade dysplasia and high grade dysplasia, respectively. According to the results of this study, the incidence of all types of polyps detected was more in men than women. Rectum and sigmoid were most abundant in the area polyp in both initial and final diagnosis.

CONCLUSION

Despite the low prevalence of Serrated polyps in patients, early diagnosis is the best action to reduce morbidity and mortality. Probability of the risk of progression from low grade to high grade dysplasia and transforming into Adenocarcinoma is high in Serrated polyps.

Endoscopic diagnosis of colorectal serrated lesions: Current status and future perspectives based on the results of a questionnaire survey

Serrated lesions, especially sessile serrated adenoma/polyps (SSA/P) are considered one of the most important precursors of colorectal cancers. However, it is still difficult to endoscopically differentiate SSA/P from hyperplastic polyps. In the present review, we mainly focus on the current status and future perspectives of endoscopic diagnosis of colorectal serrated lesions based on the results of a questionnaire survey and report from the Endoscopic Forum Japan (EFJ) 2015 held in Tokyo in August 2015. The proposed diagnostic strategy recommended for colorectal serrated lesions is as follows. (i) For detection, use of an updated image-enhanced endoscopy system including autofluorescence imaging (AFI) and narrow-band imaging (NBI) may be promising. (ii) For differential diagnosis (hyperplastic polyp or SSA/P) of diminutive, small and large serrated lesions, NBI with magnification and magnifying chromoendoscopy using both indigocarmine and crystal violet should be applied, respectively. (iii) For differential diagnosis of SSA/P (with or without cytological dysplasia), magnifying chromoendoscopy, endocytoscopy and updated AFI system modalities might be promising.

Serrated Polyps at CT Colonography: Prevalence and Characteristics of the Serrated Polyp Spectrum

Purpose To report the prevalence and characteristics of serrated polyps identified in a large, average-risk population undergoing screening computed tomographic (CT) colonography. Materials and Methods This HIPAA-compliant retrospective study was approved by the institutional review board of the University of Wisconsin School of Medicine and Public Health. The need for informed consent was waived. Nine thousand six hundred examinations from 8289 patients were enrolled in a single-institution CT colonography-based screening program (from 2004 to 2011) and were evaluated for the presence of nondiminutive serrated lesions and advanced adenomas. The prevalence and characteristics of these lesions were tabulated. Generalized estimating equation regressions of polyp characteristics that may contribute to visualization of serrated lesions were investigated, including polyp size, location, and morphologic appearance; histologic findings; and presence or absence of contrast material tagging. Results Nondiminutive serrated lesions (≥6 mm) were seen at CT colonography-based screening with a prevalence of 3.1% (254 of 8289 patients). Sessile serrated adenomas (SSAs) and traditional serrated adenomas (TSAs) constituted 36.8% (137 of 372) and 4.3% (16 of 372) of serrated lesions, respectively; hyperplastic polyps (HPs) accounted for 58.9% (219 of 372 lesions). SSA and TSA tended to be large (mean size, 10.6 mm and 14.1 mm, respectively), with size categories and polyp subgroups significantly associated (P < .0001). SSA tended to be proximal in location (91.2%, 125 of 137 lesions) and flat in morphologic appearance (39.4%, 54 of 137 lesions) compared with TSA and HP. The presence of high-grade dysplasia in serrated lesions was uncommon when compared with advanced adenomas (one of 372 lesions vs 22 of 395 lesions, respectively; P < .0001). Multivariate analysis showed that contrast material tagging markedly improved serrated polyp detection with an odds ratio of 40.4 (95% confidence interval: 10.1, 161.4). Conclusion Serrated lesions are seen at CT colonography-based screening with a nondiminutive prevalence of 3.1%. These lesions tend to be large, flat, and proximal in location. Adherent contrast material coating on these polyps aids in their detection, despite an often flat morphologic appearance. (©) RSNA, 2016 Online supplemental material is available for this article.

The frequency of early colorectal cancer derived from sessile serrated adenoma/polyps among 1858 serrated polyps from a single institution

BACKGROUND AND AIM

Sessile serrated adenoma/polyps (SSAPs) are suspected to have a high malignant potential, although few reports have evaluated the incidence of carcinomas derived from SSAPs using the new classification for serrated polyps (SPs). The aim of study was to compare the frequency of cancer coexisting with the various SP subtypes including mixed polyps (MIXs) and conventional adenomas (CADs).

METHODS

A total of 18,667 CADs were identified between April 2005 and December 2011, and 1858 SPs (re-classified as SSAP, hyperplastic polyp (HP), traditional serrated adenoma (TSA), or MIX) were removed via snare polypectomy, endoscopic mucosal resection, or endoscopic sub-mucosal dissection.

RESULTS

Among 1160 HP lesions, 1 (0.1%) coexisting sub-mucosal invasive carcinoma (T1) was detected. Among 430 SSAP lesions, 3 (0.7%) high-grade dysplasia (HGD/Tis) and 1 (0.2%) T1 were detected. All of the lesions were detected in the proximal colon, with a mean tumor diameter of 18 mm (SD 9 mm). Among 212 TSA lesions, 3 (1%) HGD/Tis were detected but no T1 cancer. Among 56 MIX lesions, 9 (16%) HGD/Tis and 1 (2%) T1 cancers were detected, and among 18,677 CAD lesions, 964 (5%) HGD/Tis and 166 (1%) T1 cancers were identified.

CONCLUSIONS

Among the resected lesions that were detected during endoscopic examination, a smaller proportion (1%) of SSAPs harbored HGD or coexisting cancer, compared to CAD or MIX lesions. Therefore, more attention should be paid to accurately identifying lesions endoscopically for intentional resection and the surveillance of each SP subtype.

Factors associated with reclassification of hyperplastic polyps after pathological reassessment from screening and surveillance colonoscopies

INTRODUCTION

A substantial interobserver variation in the differential diagnosis of hyperplastic polyps (HPs) and sessile or traditional serrated adenomas (SSAs/TSAs) has been described.

METHODS

The aim of this study is to determine the magnitude of reclassification of HPs and associated factors after pathological reassessment of specimens from screening and surveillance colonoscopies, and to estimate its consequences for follow-up recommendations.

RESULTS

Among 1694 screening and surveillance colonoscopies, a total of 536 polyps were initially diagnosed as HPs and remained unchanged in 88.5% (n = 474), whereas 7.6 (n = 41) and 1.1% (n = 6) were reclassified as SSA and TSA, respectively. Compared to definite HPs, SSAs were found more frequently in men than in women (82.9 vs. 61.2%, p < 0.05), and in individuals ≥65.0 years (51.2 vs. 31.6%, p = 0.05). Also, more SSAs were >5 mm in size (36.6 vs. 6.3%, p < 0.05) and were localized in the proximal colon (31.7 vs. 11.8%, p < 0.05). In a mixed model analysis, age ≥65.0 years (OR 4.13, 95% CI 1.22-14.2), snare polypectomy (OR 23.6, 95% CI 4.86-115), and coincident advanced adenomas (OR 7.56, 95% CI 1.31-43.5) were significantly (p < 0.05) associated with reclassification to SSAs. Only 0.53% of patients had received false recommendations for follow-up visits based on the incorrect HP diagnosis. A c.1799T>A, p.V600E BRAF mutation was detected in 21.9 % (n = 9) of reclassified SSAs.

CONCLUSION

Considering these factors may be helpful in serrated lesions that are difficult to allocate. Incorrect recommendations regarding control colonoscopy intervals due to misdiagnosed HPs can explain only a small fraction of interval colorectal cancers.

Long-Term Impact of the Dutch Colorectal Cancer Screening Program on Cancer Incidence and Mortality-Model-Based Exploration of the Serrated Pathway

BACKGROUND

We aimed to predict the long-term colorectal cancer incidence, mortality, and colonoscopy demand of the recently implemented Dutch colorectal cancer screening program.

METHODS

The Adenoma and Serrated pathway to Colorectal Cancer model was set up to simulate the Dutch screening program consisting of biennial fecal immunochemical testing combined with the new Dutch surveillance guidelines, between 2014 and 2044. The impact of screening and surveillance was evaluated under three sets of natural history assumptions differing in the contribution of the serrated pathway to colorectal cancer incidence. In sensitivity analyses, other assumptions concerning the serrated pathway were varied. Model-predicted outcomes were yearly colorectal cancer incidence, mortality, and colonoscopy demand per year.

RESULTS

Assuming an aging population, colorectal cancer incidence under 30 years of screening is predicted to decrease by 35% and 31% for a contribution of 0% and 30% of the serrated pathway to colorectal cancer, respectively. For colorectal cancer mortality, reductions are 47% and 45%. In 2044, 110,000 colonoscopies will be required annually assuming no contribution of the serrated pathway (27 per 1,000 individuals in the screening age range). Including the serrated pathway influences predicted screening effectiveness if serrated lesions are neither detected nor treated at colonoscopy, and/or if colorectal cancers arising from serrated lesions have substantially lower survival rates than those arising from adenomas.

CONCLUSIONS

The Dutch screening program will markedly decrease colorectal cancer incidence and mortality but considerable colonoscopy resources will be required.

IMPACT

Predictions of long-term screening effectiveness are preferably based on both pathways to colorectal cancer to transparently describe the impact of uncertainties regarding the serrated pathway on long-term predictions.