Association of large serrated polyps with synchronous advanced colorectal neoplasia

Sessile serrated lesions in patients with adenoma on index colonoscopy do not increase metachronous advanced adenoma risk

OBJECTIVES

Post-polypectomy surveillance intervals should be determined based on index colonoscopy findings. However, the risk of metachronous lesions, resulting from the coexistence of adenoma and sessile serrated lesions (SSLs), has rarely been addressed. We evaluated the impact of synchronous SSL on the risk of metachronous lesions within similar adenoma risk groups.

METHODS

We retrieved individuals with one or more adenomas on index colonoscopy in a single-center retrospective cohort and stratified them into four groups depending on the presence of SSL and low-risk/high-risk adenoma (LRA/HRA). Participants who underwent surveillance colonoscopies at least 12 months apart were included. We compared the risks of metachronous lesions including HRA, advanced adenoma (AA), or SSL within similar adenoma risk groups according to the presence of SSL.

RESULTS

Overall 4493 individuals were included in the analysis. The risk of metachronous HRA/AA was not significantly higher in the adenoma with SSL group compared with the adenoma without SSL group, irrespective of LRA (HRA, 6/86 vs. 231/3297, P = 1.00; AA, 0/86 vs. 52/3297, P = 0.64) or HRA (HRA, 11/64 vs. 240/1046, P = 0.36; AA, 3/64 vs. 51/1046, P = 1.00). However, the risk of metachronous SSL in individuals with synchronous SSL was higher than that in those without SSL for both LRA (15/86 vs. 161/3297, P < 0.001) and HRA groups (11/64 vs. 61/1046, P = 0.002).

CONCLUSION

The presence of synchronous SSL did not increase the risk of metachronous HRA/AA, compared with isolated adenoma, but increased the risk of metachronous SSL.

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.

Risk factors of traditional serrated adenoma and clinicopathologic characteristics of synchronous conventional adenoma

BACKGROUND AND AIMS

Traditional serrated adenoma (TSA) is rare and known to have a malignant potential. We aimed to investigate the prevalence and risk factors of TSA and compare the characteristics of synchronous conventional adenoma (AD) in patients with TSA with those of AD in patients with AD only.

METHODS

We reviewed medical records of 31,932 healthy subjects who underwent screening colonoscopy at a single hospital between 2012 and 2017.

RESULTS

TSA was observed in 116 patients (.4%). Among them, 47 patients (40.5%) had TSA only and 69 patients (59.5%) had synchronous AD. Multivariable analysis showed independent risk factors for TSA to include age ≥50 years (odds ratio [OR], 3.34; 95% confidence interval [CI], 1.72-6.49; P < .001), hypertension (OR, 2.07; 95% CI, 1.09-3.92; P = .026), and current smoking (OR, 2.58; 95% CI, 1.28-5.23; P = .008). There were significantly more ADs (2.5 ± 2.0 vs 1.8 ± 1.6, P = .009) and ADs were of larger size (6.7 ± 5.0 vs 5.3 ± 3.6 mm, P = .027) in TSA patients than in AD-only patients. Furthermore, advanced adenoma and high-risk adenoma were more frequently observed in TSA patients than in AD-only patients (24.2% vs 11.2%, P = .002; 43.5% vs 23.6%, P < .001).

CONCLUSIONS

The prevalence of TSA in healthy adults was .4%. Age ≥50 years, hypertension, and current smoking may be risk factors of TSA. Synchronous AD is often observed with TSA and may show more advanced features than those in AD-only patients.

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.

The association between colorectal sessile serrated adenomas/polyps and subsequent advanced colorectal neoplasia

PURPOSE

Colorectal cancer (CRC) screening guidelines recommend increased surveillance of individuals with sessile serrated adenomas/polyps (SSA/Ps), but there is uncertainty about the risk associated with SSA/Ps. We aimed to determine the association between SSA/Ps and subsequent advanced colorectal neoplasia.

METHODS

This case-control study included Kaiser Permanente Washington (KPWA) members who received an index colonoscopy between 1/1/1998 and 12/31/2007, and had hyperplastic polyps (HPs) or SSA/Ps but no conventional adenomas according to study pathologist histologic review. Subsequent pathology reports and biopsies through 1/1/2013 were reviewed for advanced colorectal neoplasia. We linked to the Seattle-Puget Sound Surveillance Epidemiology and End Results (SEER) registry to identify additional CRC cases. We used generalized estimating equations with a logit link to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for advanced colorectal neoplasia, comparing those with SSA/Ps to those with HPs.

RESULTS

There were 161 individuals with index SSA/Ps, 548 with HPs, and 918 subsequent endoscopies included in analyses. Of those with index SSA/Ps, 19 had subsequent advanced colorectal neoplasia; 39 with HPs had subsequent advanced colorectal neoplasia. Compared to those with HPs, those with SSA/Ps were not statistically significantly more likely to have subsequent advanced colorectal neoplasia (adjusted OR 1.79; CI 0.98-3.28). Polyp size ≥ 10 mm, right colon location, and the presence of multiple serrated polyps were also not associated with advanced colorectal neoplasia.

CONCLUSIONS

Our results suggest that there is not a strong association between SSA/Ps and subsequent advanced colorectal neoplasia during the 5 years following SSA/P removal.

Low detection rate of advanced neoplasia within 5 years after polypectomy of small serrated adenoma

AIM

Patients with small serrated adenomas (SAs) (<10 mm) often undergo surveillance colonoscopy before the routine recommended time. We aimed to determine the appropriate surveillance intervals following polypectomy of small SAs for symptomatic patients.

METHOD

We retrospectively reviewed the data of 638 patients, including 122 cases and 516 controls. Subjects in the case group had small SAs at baseline colonoscopy, including sessile SA/polyps and traditional SAs, while subjects in the control group had negative findings. All patients underwent at least one surveillance colonoscopy during the following 5 years.

RESULTS

There was no significant difference in the incidence rate of advanced neoplasia between the two groups over a 5-year duration (3.6% vs 2.6%, p=0.455). Moreover, both groups also showed a low prevalence of SA formation over 1-5 years (3.6% vs 1.0%, p=0.145). Patients with baseline SA tended to undergo the first surveillance colonoscopy earlier than those without adenoma (≤1 year vs 1 to ≤3 years). Seventy-one (11.1%) of the total included subjects underwent inadequate initial colonoscopy, and 30 (42.3%) underwent early surveillance of adenoma formation within 1 year. Patients with a family history of colorectal cancer (OR 4.69, 95% CI 1.48 to 14.71, p=0.017) or inadequate baseline colonoscopy (OR 3.17, 95% CI 1.202 to 8.409, p=0.035) were at a higher risk of metachronous adenoma formation during the surveillance period.

CONCLUSION

Patients with small SAs at baseline gain little benefit from follow-up of colonoscopy within 5 years after complete polypectomy.

Endoscopic features of sessile serrated adenoma/polyps under narrowband imaging: A retrospective study

OBJECTIVE

Sessile serrated adenoma/polyps (SSA/P) are recognized as precancerous lesions in the colon and resemble hyperplastic polyps (HP). Definite endoscopic features under narrow band imaging (NBI) with or without magnification may help differentiate these two lesions. Our study aimed to identify specific endoscopic features of SSA/P by NBI.

METHODS

A total of 199 patients with histopathologically proven colorectal SSA/P or HP after a polypectomy were enrolled. Magnifying and non-magnifying NBI pictures of 206 matching lesions were evaluated by one expert and two non-expert endoscopists using various endoscopic characteristics retrospectively.

RESULTS

Multivariate analysis indicated that a clouded surface (odds ratio [OR] 6.48, 95% confidence interval [CI] 2.72-15.44, P = 0.000) and dilated and branching vessels (DBV) (OR 7.95, 95% CI 3.71-17.02, P = 0.000) were significant endoscopic features for diagnosing SSA/P compared with HP. The combination of these two features could improve diagnostic specificity to 96%, and the area under the receiver operating characteristic curve was 0.749. However, it seemed that the presence of dark spots (OR 1.93, 95% CI 0.94-4.00, P = 0.075) was not a definite feature in differentiating these two lesions. Neither a mucus cap nor CP-II meshed capillary vessels showed statistical significance in differentiating SSA/P from HP (P = 0.590 and 0.293, respectively).

CONCLUSIONS

A clouded surface and DBV were two indicators for diagnosing SSA/P. Combining these two factors together under NBI with or without magnification achieved better diagnostic performance than when they were used alone.

A Retrospective Analysis of Colorectal Serrated Lesions from 2005 to 2014 in a Single Center: Importance of the Establishment of Diagnostic Patterns

Background

Serrated colorectal lesions are increasingly recognized as an important process in the development of colorectal cancer. Endoscopic and histological diagnosis may be difficult, and knowledge of the serrated lesions is important for the establishment of strategies for treating colorectal lesions. We aimed to analyze serrated lesions diagnosed at a single center and evaluate if there was an increase in their identification over the years.

Design and Setting

A retrospective analysis of colonoscopy reports was performed at a specialized center from 2005 to 2014.

Methods

Colonoscopy reports about any resected endoscopic lesions were reviewed and subjected to histological diagnosis from 2005 to 2014. Then, serrated lesions were evaluated based on morphological characterization, location, size, occurrence of synchronous lesions, and the patient's history of colorectal cancer and polyps.

Results

A total of 2126 colonoscopy examination reports were reviewed, and 3494 lesions were analyzed. On histopathological examination, 1089 (31.2%) were classified as hyperplastic polyps, 22 (0.6%) as sessile serrated adenomas, and 21 (0.6%) as traditional serrated adenomas. There was an increase in the number of cases of sessile and traditional serrated adenomas diagnosed after 2010. Before 2010, two cases of sessile serrated adenomas and seven cases of traditional serrated adenomas were diagnosed; after 2010, 20 cases of sessile serrated adenoma and 14 cases of traditional serrated adenomas were diagnosed.

Conclusion

There was an increase in the diagnosis of sessile serrated adenomas over the years, which can be attributed to better accuracy in colonoscopy and histological classification.

Sessile Serrated Adenomas: How to Detect, Characterize and Resect

Serrated polyps are important contributors to the burden of colorectal cancers (CRC). These lesions were once considered to have no malignant potential, but currently up to 30% of all CRC are recognized to arise from the serrated neoplasia pathway. The primary premalignant lesions are sessile serrated adenomas/polyps (SSA/Ps), although traditional serrated adenomas are relatively uncommon. Compared to conventional adenomas, SSA/Ps are morphologically subtle with indistinct borders, may be difficult to detect endoscopically, are more prevalent than previously thought, are associated with synchronous and metachronous advanced neoplasia, and have a higher risk of incomplete resection. Although many lesions remain “dormant,” progressive disease is associated with the development of dysplasia and more rapid progression to CRC. As a result, SSA/Ps are strongly implicated in the development of interval cancers. These factors represent unique challenges that require a meticulous approach to their management. In this review, we summarize the contemporary literature on the characterization, detection and resection of SSA/Ps.

Clinicopathological features of advanced colorectal serrated lesions: A single-center study in China

OBJECTIVE

A growing body of evidence indicates that patients with colorectal serrated lesions, especially advanced serrated lesions (ASLs), are at risk of subsequent malignancy. This study aimed to analyze the clinicopathological features of ASLs and the association between ASLs and synchronous advanced colorectal neoplasia (sACN) in a single center of China.

METHODS

A retrospective cross-sectional study of consecutive symptomatic patients and healthy individuals who underwent colonoscopy between January 2010 and March 2016 was performed. Clinicopathological characteritics of the patients with ASLs were documented from the colonoscopy database.

RESULTS

Colorectal serrated lesions were pathologically confirmed in 277 (N = 38 981, 0.7%) cases. Among them, 156 (56.3%) were found to have ASLs, with a total of 161 lesions including 71 sessile serrated adenoma/polyps (SSA/P) and 90 traditional serrated adenomas (TSAs). There were no differences in age and gender between the ASL and non-ASL patients. Among the 161 ASLs, 29 (18.0%) were ≥10 mm in diameter. Compared with non-ASLs, ASLs appeared more in the proximal colon (P = 0.007). Flat and subpedunculated lesions were more commonly found in the ASL group compared with the non-ASL group. Nearly all ASLs (160/161) had dysplasia. Moreover, 16 sACN lesions were found in 156 ASL patients, and large diameter (≥10 mm) might be a significant risk factor for sACN (odds ratio 4.35, 95% confidence interval 1.467-12.894, P < 0.05).

CONCLUSIONS

ASLs are more likely to occur in the proximal colon, and mainly present as flat and sub-pedunculated types. Large ASLs are significantly associated with sACN.

Diagnosis and predictors of sessile serrated adenoma after educational training in a large, community-based, integrated healthcare setting

BACKGROUND AND AIMS

Sessile serrated adenomas (SSAs) are precursors of 15% to 30% of colorectal cancers but are frequently underdiagnosed. We sought to measure the SSA detection rate (SDR) and predictors of SSA detection after educational training for community gastroenterologists and pathologists.

METHODS

Colonoscopy and pathology data (2010-2014) from 3 medical centers at Kaiser Permanente Northern California were accessed electronically. Gastroenterologists and pathologists attended a training session on SSA diagnosis in 2012. Mean SDRs and patient-level predictors of SSA detection post-training (2013-2014) were investigated.

RESULTS

Mean SDRs increased from .6% in 2010-2012 to 3.7% in 2013-2014. The increase in the detection of proximal SSAs was accompanied by a decrease in the detection of proximal hyperplastic polyps (HPs). Among 34,161 colonoscopies performed in 2013 to 2014, SDRs for screening, fecal immunochemical test positivity, surveillance, and diagnostic indication were 4.2%, 4.5%, 4.9%, and 3.0%, respectively. SSA detection was lower among Asians (adjusted odds ratio [aOR], .46; 95% confidence interval [CI], .31-.69) and Hispanics (aOR, .59; 95% CI, .36-.95) compared with non-Hispanic whites and higher among patients with synchronous conventional adenoma (aOR, 1.46; 95% CI, 1.15-1.86), HP (aOR, 1.74; 95% CI, 1.30-2.34), and current smokers (aOR, 1.78; 95% CI, 1.17-2.72). SDRs varied widely among experienced gastroenterologists, even after training (1.1%-8.1%). There was a moderately strong correlation between adenoma detection rate (ADR) and SDR for any SSA (r = .64, P = .0003) and for right-sided SSAs (r = .71, P < .0001).

CONCLUSIONS

Educational training significantly increased the detection of SSA, but a wide variation in SDR remained across gastroenterologists. SSA detection was inversely associated with Asian and Hispanic race/ethnicity and positively associated with the presence of conventional adenoma, HP, and current smoking. There was a moderately strong correlation between ADR and SDR.

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.

Clinical outcomes of surveillance colonoscopy for patients with sessile serrated adenoma

Background/Aims

Sessile serrated adenomas (SSAs) are known to be precursors of colorectal cancer (CRC). The proper interval of follow-up colonoscopy for SSAs is still being debated. We sought to determine the proper interval of colonoscopy surveillance in patients diagnosed with SSAs in South Korea.

Methods

We retrospectively reviewed the medical records of patients diagnosed with SSAs who received 1 or more follow-up colonoscopies. The information reviewed included patient baseline characteristics, SSA characteristics, and colonoscopy information.

Results

From January 2007 to December 2011, 152 SSAs and 8 synchronous adenocarcinomas were identified in 138 patients. The mean age of the patients was 62.2 years and 60.1% patients were men. SSAs were located in the right colon (i.e., from the cecum to the hepatic flexure) in 68.4% patients. At the first follow-up, 27 SSAs were identified in 138 patients (right colon, 66.7%). At the second follow-up, 6 SSAs were identified in 65 patients (right colon, 66.7%). At the 3rd and 4th follow-up, 21 and 11 patients underwent colonoscopy, respectively, and no SSAs were detected. The total mean follow-up duration was 33.9 months. The mean size of SSAs was 8.1±5.0 mm. SSAs were most commonly found in the right colon (126/185, 68.1%). During annual follow-up colonoscopy surveillance, no cancer was detected.

Conclusions

Annual colonoscopy surveillance is not necessary for identifying new CRCs in all patients diagnosed with SSAs. In addition, the right colon should be examined more carefully because SSAs occur more frequently in the right colon during initial and follow-up colonoscopies.

The Serrated Polyp Pathway: Is It Time to Alter Surveillance Guidelines?

PURPOSE OF REVIEW

In this manuscript, we review current surveillance guidelines for serrated polyps (SPs) and discuss how recent studies inform the selection of appropriate surveillance intervals for patients with SPs.

RECENT FINDINGS

Large and/or proximal SPs, particularly sessile serrated polyps (SSPs), are associated with increased risk of both synchronous and metachronous neoplasia, including advanced adenomas and colorectal cancer (CRC). Persons harboring multiple SSPs or dysplastic SSPs are at the highest risk. Moreover, a high percentage of large and/or proximal SPs are reclassified as SSPs when read by trained gastrointestinal pathologists, even if they were originally reported as hyperplastic polyps. These findings support the adoption of surveillance guidelines that prescribe closer surveillance of large and/or proximal SPs, regardless of subtype. SSPs remain a challenge to reliably identify, resect, and diagnose via histology. The increased risk of future neoplasia in patients with SSPs is likely driven by a combination of underdetection, inadequate removal, misclassification, and biology. Until further evidence emerges, we support guidelines that recommend close surveillance of patients with a history of large and/or proximal SPs and SSPs specifically in order to mitigate the threat of interval CRC.

Profiling of cytokines, chemokines and other soluble proteins as a potential biomarker in colorectal cancer and polyps

Soluble proteins including cytokines, chemokines and growth factors are small proteins that mediate and regulate immunity. They involved in the pathogenesis of many diseases including cancers. The concentration of these proteins in biological fluids (serum or plasma) and tissues in diseases may suggest pathway activation that leads to inflammatory response or disease progression. Therefore, these soluble proteins may be useful as a tool for screening, diagnosis classification between stages of disease or surveillance for therapy. Enzyme-linked immunosorbent assays (ELISA) and bioassay have been used as a gold standard in cytokine level measurements in clinical practice. However, these methods allow only single cytokine detection at a time and ineffective for screening purposes. Hence, the innovation of multiplexing technology allows measurement of many these soluble proteins simultaneously, thus allowing rapid, cost effective and better efficiency by using a minute amount of sample. In this study, we explored the profiles of key inflammatory cytokines, chemokines and other soluble proteins from the serum derived from colorectal carcinoma (CRC, n=20), colorectal polyps (P, n=20) and healthy volunteers (N, n=20) using multiplexed bead-based immunoassays. We aimed to evaluate if the levels of these soluble proteins can classify these groups of populations and explore the possible application of the soluble proteins as biomarkers in early stage screening and/or surveillance. We observed significant high IL-4, MIP-1β, FasL and TGF-β1 levels but lower levels for RANTES in P-derived serum as compared to N-derived serum. Significant high IL-8, VEGF, MIP-1β, Eotaxin and G-CSF observed in CRC-derived serum when compared to N-derived serum. Between CRC- and P-derived serum, significantly higher levels of IL-8, Eotaxin and G-CSF but lower levels for TGF-β1 were detected in CRC-derived serum. These preliminary results were obtained from small sample size and could be further validated with larger sample size cohort to produce a panel of biomarkers for CRC and P patients. Our findings might be useful in developing a disease-specific panel for biomarker screening assay. This could be used for early diagnosis and/or treatment surveillance.

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).

Detection rate and predictive factors of sessile serrated polyps in an organised colorectal cancer screening programme with immunochemical faecal occult blood test: the EQuIPE study (Evaluating Quality Indicators of the Performance of Endoscopy)

OBJECTIVES

To assess detection rate and predictive factors of sessile serrated polyps (SSPs) in organised colorectal cancer (CRC) screening programmes based on the faecal immunochemical test (FIT).

DESIGN

Data from a case series of colonoscopies of FIT-positive subjects were provided by 44 Italian CRC screening programmes. Data on screening history, endoscopic procedure and histology results, and additional information on the endoscopy centre and the endoscopists were collected, including the age-standardised and sex-standardised adenoma detection rate (ADR) of the individual endoscopists. The SSP detection rate (SSP-DR) was assessed for the study population. To identify SSP-predictive factors, multilevel analyses were performed according to patient/centre/endoscopist characteristics.

RESULTS

We analysed 72 021 colonoscopies, of which 1295 presented with at least one SSP (SSP-DR 1.8%; 95% CI 1.7% to 1.9%). At the per-patient level, SSP-DR was associated with males (OR 1.35; 95% CI 1.17 to 1.54) and caecal intubation (OR 3.75; 95% CI 2.22 to 6.34), but not with the FIT round. The presence of at least one advanced adenoma was more frequent among subjects with SSPs than those without (OR 2.08; 95% CI 1.86 to 2.33). At the per-endoscopist level, SSP-DR was associated with ADR (third vs first ADR quartile: OR 1.55; 95% CI 1.03 to 2.35; fourth vs first quartile: OR 1.89; 95% CI 1.24 to 2.90).

CONCLUSION

The low prevalence of SSPs and the lack of association with the FIT round argue against SSP as a suitable target for FIT-based organised programmes. Strict association of SSP-DR with the key colonoscopy quality indicators, namely caecal intubation rate and high ADR further marginalises the need for SSP-specific quality indicators in FIT-based programmes.

Molecular Signatures of Human Regulatory T Cells in Colorectal Cancer and Polyps

Regulatory T cells (Tregs), a subset of CD4⁺ or CD8⁺ T cells, play a pivotal role in regulating immune homeostasis. An increase in Tregs was reported in many tumors to be associated with immune suppression and evasion in cancer patients. Despite the importance of Tregs, the molecular signatures that contributed to their pathophysiological relevance remain poorly understood and controversial. In this study, we explored the gene expression profiles in Tregs derived from patients with colorectal cancer [colorectal carcinoma (CRC), n = 15], colorectal polyps (P, n = 15), and in healthy volunteers (N, n = 15). Tregs were analyzed using CD4⁺CD25⁺CD127^lowFoxP3⁺ antibody markers. Gene expression profiling analysis leads to the identification of 61 and 66 immune-related genes in Tregs derived from CRC and P patients, respectively, but not in N-derived Treg samples. Of these, 30 genes were differentially expressed both in CRC- and P-derived Tregs when compared to N-derived Tregs. Most of the identified genes were involved in cytokine/chemokine mediators of inflammation, chemokine receptor, lymphocyte activation, and T cell receptor (TCR) signaling pathways. This study highlights some of the molecular signatures that may affect Tregs’ expansion and possible suppression of function in cancer development. Our findings may provide a better understanding of the immunomodulatory nature of Tregs and could, therefore, open up new avenues in immunotherapy.

Serrated lesions and serrated polyposis syndrome

The serrated pathway has been shown to be an alternative colorectal carcinogenetic route potentially accounting for up to one third of all CRCs. Serrated lesions, particularly SSPs, have been a focus of research during the past few years. They have well-established histological and molecular characteristics that account for their potential carcinogenetic risk through the accumulation BRAF, KRAS and methylator profile (CpG) mutations. Their endoscopic identification and resection represent a challenge because of their specific characteristics, and the need for an adequate specimen for histological diagnosis. Knowledge of these lesions is key, as is the adoption of established criteria for their endoscopic description and histological diagnosis. SPS is the maximum expression of involvement by serrated lesions, is associated with increased risk for CRC, and requires attentive endoscopic follow-up, as well as family screening. While the exact etiopathogenic mechanism remains unknown, current research will likely provide us with appropriate answers in the not too distant future.

Findings in young adults at colonoscopy from a hospital service database audit

BACKGROUND

Colorectal cancer (CRC) diagnosed at <50 years is predominantly located in the distal colon and rectum. Little is known about which lesion subtypes may serve as CRC precursors in young adults. The aim of this work was to document the prevalence and histological subtype of lesions seen in patients aged <50 years, and any associated clinical features.

METHODS

An audit of the colonoscopy database at The Queen Elizabeth Hospital in Adelaide, South Australia over a 12-month period was undertaken. Findings were recorded from both colonoscopy reports and corresponding histological examination of excised lesions.

RESULTS

Data were extracted from colonoscopies in 2064 patients. Those aged <50 comprised 485 (24%) of the total. CRC precursor lesions (including sessile serrated adenoma/polyps (SSA/P), traditional serrated adenomas, tubular adenomas ≥10 mm or with high-grade dysplasia, and conventional adenomas with villous histology) were seen in 4.3% of patients aged <50 and 12.9% of patients aged ≥50 (P <0.001). Among colonoscopies yielding CRC precursor lesions in patients under 50 years, SSA/P occurred in 52% of procedures (11/21), compared with 27% (55/204) of procedures in patients aged 50 and older (P = 0.02). SSA/P were proximally located in (10/11) 90% of patients aged under 50, and 80% (43/54) of those aged 50 and older (P = 0.46).

CONCLUSIONS

SSA/P were the most frequently observed CRC precursor lesions in patients aged <50. Most CRCs in this age group are known to arise in the distal colon and rectum suggesting that lesions other than SSA/P may serve as the precursor for the majority of early-onset CRC.

MCM2 expression in serrated polyps demonstrates aberrant cellular proliferation

In normal colonic epithelium, the proliferative zone is limited to the lower half of the colonic crypt. Evaluating the changes in the colonic epithelial proliferation can be useful in understanding pathophysiology of various diseases. Our aim was to investigate the proliferative compartment of serrated polyps (SPs) using MCM2, a protein involved in DNA replication, and assess for changes along the SP spectrum. Immunohistochemistry was performed on serrated polyps (16 microvesicular-type hyperplastic polyps (HP), 58 sessile serrated adenomas (SSA), 7 SSAs with dysplasia) and 6 sections of normal colon using anti-MCM2 antibody. Multiple sections of normal colon showed the following pattern for MCM2 and Ki-67 staining: positive nuclear staining of the lower half of the colonic crypts and/or slightly expanded to the lower two-thirds of the crypt. By MCM2, SPs show expansion of the proliferative compartments; 81.3% of HPs and 100% of SSAs showed some degree of full crypt MCM2 staining. SSAs with dysplasia showed consistent diffuse polyp staining. Aberrant staining in adjacent normal mucosa was also seen in SSAs with dysplasia and in a subset of non-dysplastic SSAs. By using MCM2, we show that serrated polyps exhibit changes in proliferation during progression along the pathway. HPs and SSAs show a similar highly proliferative profile. Aberrant proliferative cell staining patterns in adjacent normal colonic mucosa as seen in SSAs with dysplasia and a subset of SSAs suggest a field effect phenomenon. This indicates that changes in the colonic micro-environment may promote adenoma morphogenesis and predisposition to malignancy.

Detection Rate, Distribution, Clinical and Pathological Features of Colorectal Serrated Polyps

Background:

Colorectal serrated polyp is considered as histologically heterogeneous lesions with malignant potential in western countries. However, few Asian studies have investigated the comprehensive clinical features of serrated polyps in symptomatic populations. The aim of the study was to evaluate the features of colorectal serrated polyps in a Chinese symptomatic population.

Methods:

Data from all consecutive symptomatic patients were documented from a large colonoscopy database and were analyzed. Chi-square test or Fisher's exact test and logistic regression analysis were used for the data processing.

Results:

A total of 9191 (31.7%) patients were detected with at least one colorectal polyp. The prevalence of serrated polyps was 0.53% (153/28,981). The proportions of hyperplastic polyp (HP), sessile serrated adenoma/polyp (SSA/P), and traditional serrated adenoma (TSA) of all serrated polyps were 41.2%, 7.2%, and 51.6%, respectively, which showed a lower proportion of HP and SSA/P and a higher proportion of TSA. Serrated polyps appeared more in males and elder patients while there was no significant difference in the subtype distribution in gender and age. The proportions of large and proximal serrated polyps were 13.7% (21/153) and 46.4% (71/153), respectively. In total, 98.9% (89/90) serrated adenomas were found with dysplasia. Moreover, 14 patients with serrated polyps were found with synchronous advanced colorectal neoplasia, and large serrated polyps (LSPs) (odds ratio: 3.446, 95% confidence interval: 1.010–11.750, P < 0.05), especially large HPs, might have an association with synchronous advanced neoplasia (AN).

Conclusions:

The overall detection rate of colorectal serrated polyps in Chinese symptomatic patient population was low, and distribution pattern of three subtypes is different from previous reports. Moreover, LSPs, especially large HPs, might be associated with an increased risk of synchronous AN.

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.

High yield of synchronous lesions in referred patients with large lateral spreading colorectal tumors

BACKGROUND AND AIMS

There are few data on the prevalence of synchronous colorectal lesions in patients who have large lateral spreading tumors (LLSTs). We sought to describe the rate of synchronous lesions found in patients who underwent endoscopic resection of large sessile adenomas and serrated lesions.

METHODS

This is a retrospective assessment of a prospectively created database of 728 consecutive patients with resected LLSTs who underwent complete clearing of the colon during 2 colonoscopies by a single expert endoscopist.

RESULTS

The 728 patients with resected LLSTs and complete clearing had 4578 synchronous lesions, including 584 patients (80.2%) with at least 1 synchronous conventional adenoma, 132 (18.1%) with at least 1 synchronous conventional adenoma ≥ 20 mm in size, 294 (40.4%) with at least 1 synchronous advanced conventional adenoma, and 6 patients with a synchronous lesion with cancer. Patients with an index large sessile conventional adenoma compared with those with an index large serrated lesion had on average more synchronous conventional adenomas (4.8 vs 2.9, P = .001) and fewer synchronous serrated lesions (1.4 vs 4.5, P < .001). Of the 97 patients with a serrated class index lesion, 28 (28.9%) met criteria for serrated polyposis.

CONCLUSIONS

There is a very high prevalence of synchronous lesions, including other large and advanced synchronous lesions, in patients with flat or sessile conventional adenomas and serrated colorectal polyps. Patients with LLSTs in the colon need detailed clearing of the rest of the colon. Patients referred for endoscopic resection of serrated lesions ≥ 20 mm have a very high prevalence of serrated polyposis. This study has potential implications for further stratification of high-risk patient groups in postpolypectomy surveillance guidelines.

Presence of small sessile serrated polyps increases rate of advanced neoplasia upon surveillance compared with isolated low-risk tubular adenomas

BACKGROUND AND AIMS

The U.S. Multi-Society Task Force (USMSTF) stratifies patients with sessile serrated polyps (SSPs) without cytologic dysplasia of <10 mm in size as at low risk for metachronous advanced neoplasia and recommends management similar to low-risk conventional tubular adenomas. Evidence supporting the recommended surveillance interval for these low-risk SSPs is limited. We aimed to assess rates of metachronous advanced neoplasia based on the presence of an initial low-risk SSP compared with isolated low-risk tubular adenomas.

METHODS

Colonoscopy data were retrieved for 2260 patients found to have an adenoma or SSP on pathology records between 2005 and 2011 at an academic medical center. The 788 patients who met study design criteria were stratified into 4 groups based on the presence of a high- or low-risk adenoma (HRA or LRA) and of a synchronous SSP on initial colonoscopy. The rates of advanced neoplasia at surveillance colonoscopy were then compared between groups.

RESULTS

The rate of advanced neoplasia at surveillance in the LRA inclusive of SSP group (12/66, 18.2%) was greater than in the LRA without any SSP group (29/370, 7.8%; P = .019). The rate of advanced neoplasia at surveillance in patients with isolated low-risk SSP (10/56, 17.9%) remained significantly greater than those with isolated low-risk tubular adenomas (29/370, 7.8%; P = .024). The rate of advanced neoplasia upon surveillance in the LRA inclusive of SSP group (18.2%) was comparable with the rate observed in the index HRA without any SSP group (15.9%) (40/252, P = .709).

CONCLUSIONS

The rate of advanced neoplasia upon surveillance in patients with initial low-risk SSPs is higher than in patients with initial isolated low-risk tubular adenomas and more similar to patients with initial high-risk tubular adenomas. These findings suggest that the rate of metachronous advanced neoplasia in patients with what are considered by USMSTF as "low-risk" SSPs is higher than in those without SSPs. Therefore, a surveillance interval that accounts for the presence of SSPs even in small lesions without cytologic dysplasia should be considered.

Optimizing post-polypectomy surveillance: A practical guide for the endoscopist

Several gastrointestinal societies strongly recommend colonoscopy surveillance after endoscopic and surgical resection of colorectal neoplasms. Common denominators to these recommendations include: high-quality baseline colonoscopy before inclusion in a surveillance program; risk stratification based on clinicopathological profiles to guide surveillance intervals; and endoscopist responsibility for providing surveillance advice. Considerable variability also exists between guidelines (i.e. regarding risk classification and surveillance intervals). In this review, we examine key factors for quality of post-polypectomy surveillance practice, in particular bowel preparation, endoscopic findings at baseline examination and adherence to surveillance recommendations. Frequently asked questions by the practising endoscopist are addressed.

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.

Recent advances in colonoscopy

Colonoscopy is an important and frequently performed procedure. It is effective in the prevention of colorectal cancer and is an important test in the investigation of many gastrointestinal symptoms. This review focuses on developments over the last 5 years that have led to changes in aspects of colonoscopy, including patient preparation, technical factors, therapeutic procedures, safety, and quality.

[Serrated polyps and their association with synchronous advanced colorectal neoplasia]

INTRODUCTION

Large serrated polyps (SP), proximal SP, SP with dysplasia and the presence of multiple sessile serrated adenomas/polyps (SSA/P), which we refer to as SP with increased risk of metachronous lesions (SPIRML), have been associated with an increased risk of advanced colon lesions on follow-up. It is unclear, however, whether SPIRML are also associated with an increased risk of synchronous advanced colorectal neoplasia (ACN).

AIM

The aim of this study was to estimate the prevalence of SPIRML and to evaluate the association between SPIRML and synchronous ACN.

METHODS

A cross-sectional population-based study in all patients (1,538) with histological diagnosis of SP obtained from colonoscopies, sigmoidoscopies and colonic surgery performed in Navarra Health Service hospitals (Spain) in 2011. Demographic parameters and synchronous colonic lesions (adenomas, advanced adenomas [AA] and ACN) were analyzed.

RESULTS

One fourth of the sample (384 patients) presented SPIRML. These were older patients, with a slight predominance of women, and with no differences in body mass index (BMI) compared to patients without SPIRML. In the univariate analysis, patients with SPIRML showed an increased risk of adenoma, AA and ACN. In the multivariate analysis, the SPIRML group had a higher risk of synchronous AA and ACN (odds ratio [OR]: 2.38 [1.77-3.21] and OR: 2.29 [1.72-3.05], respectively); in the case of ACN, this risk was statistically significant in both locations (proximal or distal), with OR slightly higher for the proximal location. Different subtypes of SPIRML had a higher risk of AA and synchronous NA.

CONCLUSION

SPIRML were common in patients with SP, and their presence was associated with an increased risk of synchronous ACN.

High-risk metachronous polyps are more frequent in patients with traditional serrated adenomas than in patients with conventional adenomas: a multicenter prospective study

BACKGROUND AND AIMS

Although the malignant progression of serrated polyps has been clearly documented, the malignant potential of the traditional serrated adenoma (TSA) subtype has not been established. We compared the prevalence of metachronous polyps in surveillance colonoscopies between patients with TSA and those with conventional adenomas (CAs).

METHODS

Four hundred twenty patients were diagnosed with TSAs by current diagnostic criteria at 10 tertiary care university hospitals in Korea from January 2003 to December 2005; 186 patients who received surveillance colonoscopy after removal of initial polyps were enrolled. During the same time period, 372 age- and sex-matched patients diagnosed with CAs were used as a control group.

RESULTS

TSA patients had a significantly higher recurrence rate of colorectal polyps compared with CA patients (66.1% vs 43.5%, respectively). TSA patients had a greater number (3 vs 2) and larger size (8.6 ± 5.7 vs 6.3 ± 5.2 mm) of recurrent polyps compared with CA patients. TSA patients also had a higher rate of CA (54.8% vs 37.9%), serrated adenoma (14.0% vs. 0.8%), and hyperplastic polyp (33.3% vs. 13.7%) recurrence compared with CA patients. TSA patients had significantly greater odds of having a recurrent high-risk polyp than CA patients (odds ratio, 2.37; 95% confidence interval, 1.55-3.63).

CONCLUSIONS

In comparison with patients with CAs, patients with TSAs have a higher metachronous occurrence rate of all polyp subtypes including CAs, serrated adenomas, and hyperplastic polyps. Moreover, the presence of TSAs is an independent predictor of a high-risk polyp occurrence.

Frequent co-occurrence of high-grade dysplasia in large flat colonic polyps (>20 mm) and synchronous polyps

Background

Large colonic polyps are associated with advanced dysplasia, but prevalence and characteristics of synchronous polyps in patients with large flat colonic polyps are poorly investigated. This study aims to characterize clinicopathological features of large flat colonic polyps and their impact on occurrence and characteristics of synchronous polyps.

Methods

A total of 802 patients that underwent endoscopic mucosal resection (EMR) of flat colonic polyps >20 mm from 2003 to 2014 in an academic endoscopy unit were retrospectively analyzed for size, location and histology of large polyps and synchronous polyps.

Results

Average size of large polyps was 34.1 mm (range 20–150 mm, standard deviation 16.1 mm). Histology included 52.5 % adenomas with low-grade dysplasia (LGD), 26.7 % with high-grade dysplasia (HGD), 9.6 % serrated polyps and 11.2 % adenocarcinomas. The majority of large polyps were localized in the proximal colon (61 %). 72.2 % of adenocarcinomas were found in the distal colon, while 80.5 % of all serrated polyps were detected in the proximal colon. Increase in polyp size, advanced age and location in the distal colon were associated with presence of HGD/adenocarcinoma in large polyps, as identified by multivariate analysis. Synchronous polyps were detected in 67.2 % of patients undergoing complete colonoscopy during EMR. Presence of HGD/adenocarcinoma in the large polyp, localization of any synchronous polyp in the rectosigmoid colon and occurrence of multiple synchronous polyps were associated with presence of HGD/adenocarcinoma in synchronous polyps.

Conclusions

Synchronous polyps are frequently found in patients with large flat colonic polyps. The prevalence of synchronous polyps with high grade dysplasia is highest in patients with large flat polyps containing HGD/adenocarcinoma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-015-0312-4) contains supplementary material, which is available to authorized users.

Long-term risk of colorectal cancer in individuals with serrated polyps

OBJECTIVE

Although serrated polyps may be precursors of colorectal cancer (CRC), prospective data on the long-term CRC risk in individuals with serrated polyps are lacking.

DESIGN

In a population-based randomised trial, 12,955 individuals aged 50-64 years were screened with flexible sigmoidoscopy, while 78 220 individuals comprised the control arm. We used Cox models to estimate HRs with 95% CIs for CRC among individuals with ≥1 large serrated polyp (≥10 mm in diameter), compared with individuals with adenomas at screening, and to population controls, and multivariate logistic regression to assess polyp risk factors for CRC.

RESULTS

A total of 103 individuals had large serrated polyps, of which 81 were included in the analyses. Non-advanced adenomas were found in 1488 individuals, advanced adenomas in 701. Median follow-up was 10.9 years. Compared with the control arm, the HR for CRC was 2.5 (95% CI 0.8 to 7.8) in individuals with large serrated polyps, 2.0 (95% CI 1.3 to 2.9) in individuals with advanced adenomas and 0.6 (95% CI 0.4 to 1.1) in individuals with non-advanced adenomas. A large serrated polyp was an independent risk factor for CRC, adjusted for histology, size and multiplicity of concomitant adenomas (OR 3.3; 95% CI 1.3 to 8.6). Twenty-three large serrated polyps found at screening were left in situ for a median of 11.0 years. None developed into a malignant tumour.

CONCLUSIONS

Individuals with large serrated polyps have an increased risk of CRC, comparable with individuals with advanced adenomas. However, this risk may not be related to malignant growth of the serrated polyp.

TRIAL REGISTRATION NUMBER

The Norwegian Colorectal Cancer Screening trial is registered at clinicaltrials.gov (NCT00119912).

How does the serrated polyp pathway alter CRC screening and surveillance?

Screening and surveillance for colorectal cancer (CRC) reduces mortality through the detection of early-stage adenocarcinoma, and more importantly the detection and removal of premalignant polyps. While adenomas have historically been considered the most common and screening-relevant precursor lesions, there is accumulating evidence showing that the serrated pathway is an important contributor to CRC, and a disproportionate contributor to interval or postcolonoscopy CRC, particularly in the proximal colon. The serrated pathway is characterized by mutations in the BRAF gene, high levels of methylation of promoter CpG islands (CIMP-high), and the sessile serrated adenoma/polyp (SSA/P) is the most important precursor lesion. The study of serrated polyps has been complicated by evolving nomenclature, substantial variation among pathologists in the identification of SSA/Ps, high variability in endoscopic detection rates, and uncertainty regarding the relation to synchronous and metachronous colonic neoplasia. This paper presents an overview of the serrated polyp pathway and discusses its clinical implications including its impact on CRC screening.

Programmatic screening for colorectal cancer: the COLONPREV study

The COLONPREV study is an ongoing multicenter, nationwide, randomized controlled trial aimed at evaluating the efficacy of once-only colonoscopy and biennial fecal immunochemical testing with respect to the reduction of CRC-related mortality at 10 years in average-risk colorectal cancer screening population. Following a pragmatic approach, this study may contribute to establishing the most cost-effective strategy in a programmatic, population-based setting. In this review, we report the results obtained at the first screening round, as well as others achieved in nested evaluations using the COLONPREV dataset with the aim of clarifying some controversial issues on the different strategies of colorectal cancer screening.

Sessile serrated adenoma: from identification to resection

Until the past two decades, almost all colorectal polyps were divided into two main groups: hyperplastic polyps and adenomas. Sessile serrated adenomas presented endoscopic, pathological and molecular profiles distinct from others polyps. Previously under-diagnosed, physicians now identified sessile serrated adenomas. The serrated neoplastic pathway is accounting for up to one-third of all sporadic colorectal cancers and sessile serrated adenomas have been identified as the main precursor lesions in serrated carcinogenesis. By analogy with the adenoma-adenocarcinoma sequence, the sessile serrated adenomas-adenocarcinoma sequence, has been identified. The development of endoscopic resection techniques permits the consideration of a non-surgical approach as the first option regardless of the size of the lesion. Sessile serrated adenoma warrants the watchfulness of physicians and requires an optimal quality of the colonoscopy procedure, a thorough evaluation of the lesion, an adequate endoscopic resection and follow-up colonoscopies in accordance with sessile serrated adenomas guidelines. We herein present a review on sessile serrated adenomas focusing on their pathological specificities, epidemiology, treatment modalities and follow-up.

Association between serrated polyps and the risk of synchronous advanced colorectal neoplasia in average-risk individuals

BACKGROUND

Serrated polyps of the colorectum have distinct histological features and malignant potential.

AIM

To assess the association between the presence of serrated polyps and synchronous advanced colorectal neoplasia.

METHODS

Among 4989 asymptomatic Chinese individuals aged 50-70 years who underwent screening colonoscopy, 281 cases with advanced neoplasia (adenoma ≥1 cm, with tubulovillous/villous histology, with high-grade dysplasia, or invasive adenocarcinoma) were compared with 4708 controls without advanced neoplasia for age, sex, smoking history, body mass index, family history of colorectal cancer and the presence of serrated polyps. Independent predictors of advanced neoplasia were determined by multivariate logistic regression analysis.

RESULTS

The prevalence of advanced neoplasia and serrated polyps (excluding small distal hyperplastic polyps) was 5.7% and 5.6%, respectively. 3.7% and 0.4% subjects had proximal and large (≥10 mm) serrated polyps, respectively. Independent predictors of synchronous advanced colorectal neoplasia were the presence of sessile serrated adenomas (OR: 4.52; 95% CI: 2.40-8.49), proximal serrated polyps (OR: 2.23, 95% CI: 1.38-3.60), large serrated polyps (OR: 59.25; 95% CI: 18.85-186.21), hyperplastic polyps (OR: 1.66; 95% CI: 1.03-2.67), three or more serrated polyps (OR: 4.86; 95% CI: 1.24-19.15) and one or more non-advanced tubular adenomas (OR: 3.58, 95% CI: 2.59-4.96).

CONCLUSION

Detection of proximal, sessile and/or large serrated polyps at screening colonoscopy is independently associated with an increased risk for synchronous advanced neoplasia.

Sessile serrated adenomas: an evidence-based guide to management

The concept of serrated colorectal neoplasia and a serrated pathway to colorectal cancer (CRC) is relatively new and continuing to evolve, but it has become highly relevant to gastroenterologists, pathologist, and oncologists alike. Sessile serrated adenomas (SSA) are now thought to be the major precursor lesion of serrated pathway cancers, which represent up to one-third of all sporadic CRC cases. However, despite their increasingly recognized importance, relatively little is known about the epidemiology and natural history of SSAs, and the molecular and epigenetic aspects are incompletely understood. Endoscopists must be aware of the unique features of SSAs so that the practice of colonoscopic screening for CRC can include optimized detection, removal, and appropriate surveillance of SSAs and other serrated precursor lesions. In this review, we discuss the history, epidemiology, and pathologic aspects of SSAs, as well as a recommended management approach and a discussion of uncertainties and opportunities for future research.

Pathogenesis and management of serrated polyps: current status and future directions

Hyperplastic or serrated polyps were once believed to have little to no clinical significance. A subset of these polyps are now considered to be precursors to colorectal cancers (CRC) in the serrated pathway that may account for at least 15% of all tumors. The serrated pathway is distinct from the two other CRC pathways and involves an epigenetic hypermethylation mechanism of CpG islands within promoter regions of tumor suppressor genes. This process results in the formation of CpG island methylator phenotype tumors. Serrated polyps are divided into hyperplastic polyps, sessile serrated adenomas/polyps (SSA/Ps), and traditional serrated adenomas (TSAs). The SSA/P and the TSA have the potential for dysplasia and subsequent malignant transformation. The SSA/Ps are more common and are more likely to be flat than TSAs. Their flat morphology may make them difficult to detect and thus explain the variation in detection rates among endoscopists. Challenges for endoscopists also include the difficulty in pathological interpretation as well surveillance of these lesions. Furthermore, serrated polyps may be inadequately resected by endoscopists. Thus, it is not surprising that the serrated pathway has been linked with interval cancers. This review will provide the physician or clinician with the knowledge to manage patients with serrated polyps.

Serrated neoplasia of the colon: what do we really know?

Colonoscopy offers incomplete protection from colorectal cancer, particularly in the right colon. Part of this inadequacy may be related to serrated neoplasia. Serrated polyps of the colorectum are now understood to be a heterogeneous group of polyps, some of which are cancer precursors, such as the sessile serrated adenoma (SSA) and the traditional serrated adenoma (TSA). In contrast to conventional adenomas, there is limited published literature on the epidemiology and natural history of these lesions. Furthermore, existing guidelines regarding screening and surveillance practices for these polyps are based largely on expert opinion without firm evidence. In this review, we describe the current understanding of the molecular biology, histopathology, and endoscopic features of serrated neoplasia of the colorectum, with an emphasis on aspects relevant to the practicing gastroenterologist.

Kudo’s pit pattern classification for colorectal neoplasms: A meta-analysis

AIM: To analyze the current available evidence of Kudo’s pit pattern classification for diagnosing colorectal neoplasms.

METHODS: A search was performed on Pubmed/Embase to identify studies reporting the outcomes of the pit pattern classification in colorectal polyps. Retrieved records were evaluated and selected by two independent investigators. The number of patients, polyps and diagnostic performance of Kudo’s pit pattern classification were retrieved from suitable studies. Pooled sensitivities and specificities were calculated using fixed or random effect models according to their heterogeneity. Publication bias was evaluated using funnel plot, Egger’s test, and Begg’s test. Sensitivity analysis was performed by omitting one study at a time and selecting a subgroup consisting of 11 magnifying chromoendoscopy studies.

RESULTS: 20 eligible studies were included in which a total of 5111 colorectal lesions in 3418 patients were identified for the differentiation of neoplastic and non-neoplastic polyps. Pit pattern classification in all the studies of mucosal patterns with magnification resulted in a pooled sensitivity of 89.0% (95%CI: 85.2-91.9) and pooled specificity of 85.7% (95%CI: 81.3-89.2) and the area under the SROC curve was 0.9354. There was significant publication bias (P = 0.038 and 0.006 for sensitivity and specificity using Egger’s test, P = 0.035 and 0.139 for sensitivity and specificity using Begg’s test, respectively). No single study significantly affected the pooled result, and the magnifying chromoendoscopy subgroup yielded a sensitivity of 92.7% (95%CI: 89.2-95.2) and specificity of 87.3% (95%CI: 81.6-91.4).

CONCLUSION: Kudo’s pit pattern classification is an accurate diagnostic method for the differentiation of neoplastic colorectal lesions. Publication bias is significant in the current available literature.

Impact of the consideration of serrated polyps to the interval of colonoscopic surveillance in the NHS Bowel Cancer Screening Programme

AIM

Most international post polypectomy surveillance guidelines do not recommend surveillance for serrated polyps. In the present study the additional impact of serrated polyps on surveillance intervals from international adenoma surveillance guidelines was investigated.

METHOD

Endoscopic and pathology records were audited of participants in the NHS Bowel Cancer Screening Programme (guaiac faecal occult blood test, gFOBT) in 2011. Surveillance intervals were calculated for current guidelines and also for serrated polyps based on previously described aggressive and conservative strategies.

RESULTS

In total, 389 patients were included of whom 141 (36.2%) were high risk (advanced adenoma: adenoma ≥ 10 mm, villous elements, high grade dysplasia, or adenoma ≥ 3 in number) needing surveillance at ≤ 3 years. Thirty-three (8.5%) had significant serrated polyps, of whom 18 (4.6% of the total) had significant serrated lesions and simultaneous advanced adenoma or ≥ 3 adenomas. Adopting an aggressive surveillance strategy, the mean overall absolute additional proportion of all such patients in the surveillance group at 3 years or less was 4.0% (3.9% - 4.1%; 4.2% women; 3.8% men). These proportions varied according to endoscopist from 2.3% to 4.7%. For more conservative strategies the increase was only 1%.

CONCLUSION

The impact of including serrated polyps in current guidelines would result in a small increase in surveillance intervals for FOBT based bowel cancer screening. About half of those who might need surveillance for serrated polyps would already receive surveillance for being in a high risk adenoma group.

The endoscopist's guide to serrated polyposis

AIM

Serrated polyposis is a condition of the colon characterized by multiple serrated polyps. This review aims to provide a practical guide to the day-to-day management of serrated polyposis, including diagnosis, endoscopic identification of serrated polyps, surveillance, the role of endoscopic and surgical management and the screening of family members.

METHOD

The literature was searched using PubMed and MEDLINE databases for the terms "serrated polyp", "serrated polyposis" and "hyperplastic polyposis". English-language abstracts were read and the full article was retrieved if relevant to the review. Expert opinion from the authors was also sought.

RESULTS

Advances in our knowledge of the molecular pathways involved in serrated polyposis and an improved clinical picture of the disease from retrospective studies have led to better understanding of its pathogenesis and natural history. However, there are still areas not answered by the literature, and hence empirical management or expert opinion has to be followed.

CONCLUSION

Improvements in our understanding of serrated polyposis, together with improvements in endoscopic equipment and technique, have enabled the endoscopist to be at the forefront of managing this condition from diagnosis to endoscopic surveillance and control of the polyps.

Colorectal advanced neoplasms occur through dual carcinogenesis pathways in individuals with coexisting serrated polyps

Background

Individuals with serrated polyps (SP) are at higher risk for synchronous colorectal advanced neoplasms (AN) and cancers. However, it remains unclear whether there is a unique involvement of the serrated pathway and/or the classical adenoma-carcinoma sequence in this setting.

Methods

Colorectal ANs, which include tubular adenomas ≥10 mm, adenomas with villous histology, high-grade intraepithelial neoplasms, and cancers, were collected retrospectively. The groups included ANs with (AN+SP) or without (AN-only) coexisting SPs. Clinicopathological findings were compared between groups. BRAF and KRAS mutations in ANs and SPs, and methylation levels at long interspersed element-1 (LINE-1) in adjacent mucosa were determined by pyrosequencing.

Results

Seventy-five ANs from 40 patients in the AN+SP group, and 179 ANs from 119 patients in the AN-only group were analyzed. There were no significant differences in clinicopathological findings between the two groups, except that intraepithelial neoplasia in the AN+SP group was more likely to be located in the right colon (P = 0.018). BRAF mutations were significantly more frequent in the AN+SP group (P = 0.003), while KRAS mutations showed no significant differences between groups (P = 0.142). The majority of high-grade intraepithelial neoplasms in both groups showed a contiguous component of conventional adenoma. Individuals with large and right-sided SPs had significantly more conventional adenomas compared to those without such SPs (P = 0.027 and P = 0.031, respectively). Adjacent mucosa from individuals with multiple and large SPs showed significantly lower methylation levels at LINE-1 compared to individuals without such associated SPs (P = 0.049 and P = 0.015, respectively).

Conclusion

Our data suggest that both the adenoma-carcinoma sequence and the serrated pathway are operational in individuals with coexisting ANs and SPs. The reduced methylation levels at LINE-1 in the background mucosa suggest the possibility of an underlying ‘field defect’.

Serrated polyps: clinical implications and future directions

Serrated polyps were once thought to have no clinical implications with regards to the development of colorectal cancer (CRC). Over the past several years, published data have enabled clinicians to develop a better understanding of these lesions. The serrated pathway associated with these lesions involves an epigenetic mechanism characterized by abnormal hypermethylation of CpG islands located in the promoter regions of tumor suppressor genes. It is often associated with BRAF mutations and may account for 15-35% of all CRC. This pathway may also play a major role in proximal neoplasia and missed cancer. There are three distinct subtypes of serrated neoplasia; hyperplastic (70% of all serrated polyps), sessile serrated adenoma/polyp (SSA/P) (25%) and traditional serrated adenoma (<2%). The last two forms are considered to be precursors for CRC. SSA/P are associated with synchronous CRC especially if the polyps are large (≥1 cm), multiple, or if they are in the proximal colon. Lesions containing serrated neoplasia are usually flat or sessile, may be large, and occasionally have a mucous cap. Serrated lesions provide many challenges for the clinician and may be difficult to detect and completely remove. Furthermore, pathologists may misclassify SSA/P as HP. For the first time, the Multi-Society Task Force guidelines for colorectal polyp surveillance have included the management of serrated lesions in their published recommendations. In addition, an expert panel has also recently issued recommendations regarding serrated neoplasia. In this article, we provide the reader with a summary as well as the latest developments regarding serrated colonic lesions.

Advanced endoscopic resection in the colon: recent innovations, current limitations and future directions

The major health burden of colorectal cancer is reduced by colonoscopic polypectomy. The majority of polyps encountered are diminutive in size and easily removed; however, endoscopic removal of lesions >20 mm in size is also effective and safe. Techniques have progressed, advancing the boundaries of endoscopic therapy to include resection of circumferential lesions and selected submucosal invasive cancers. While there are cost and safety advantages over surgical management, specific limitations of endoscopic resection remain, chiefly bleeding, perforation and recurrence. Recent studies highlight the utility of risk stratification and demonstrate the effectiveness of endoscopic treatment of complications; however, strategies for prevention remain elusive. Prediction of submucosal invasive cancers through systematic assessment of lesion morphology and surface pattern is now established. Harnessing submucosal invasive cancer prediction and risk stratification allows a shift toward lesion-specific therapy, the next paradigm in the management of advanced colonic lesions.