Location and Size are Useful Features in Diagnosing Sessile Serrated Adenoma/Polyp

@#Introduction: According to the predefined 2010 World Health Organisation criteria, serrated colonic polyps (SCP) are pathologically classified into hyperplastic polyp (HP), sessile serrated adenoma/polyp (SSA/P) with or without cytological dysplasia and traditional serrated adenoma (TSA). Sessile serrated adenoma/polyp is acknowledged as a precursor of colorectal carcinoma through the serrated neoplastic pathway. Hyperplastic polyps display similar histological features to SSA/P, in comparison to other types of SCP. It is noteworthy to discriminate between HP and SSA/P, since only the latter has a malignant potential. Method: A total of 198 cases of SCP were identified and the slides were reexamined and reclassified accordingly. Analysis on the proportion of SSA/P among SCP and underdiagnosed cases of SSA/P was performed. The association between SSA/P and non-SSA/P with demographic data and colonoscopic findings were also studied. Results: From the 198 cases of SCP, 164, 29 and five cases were reclassified as HP, SSA/P and TSA respectively. Sixteen cases of SSA/P were underdiagnosed as HP. From among 29 cases of SSA/P, the majority were ≥ 65 years old (17; 58.6%), male (21; 72.4 %) and Chinese (17; 58.6%). Most of the SSA/P (16; 55.2 %) were located in the right colon and measured ≥ 10mm (9; 31%) in size. Location (p=0.004) and size (p=0.013) of the colonoscopic findings were significantly associated with SSA/P. Conclusion: Underdiagnosed cases of SSA/P among HP were identified most likely because of the resemblance of their histological features. The location and size of SCP may suggest the probability of SSA/P.

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.

Endoscopic Features of Mucous Cap Polyps: A Way to Predict Serrated Polyps

BACKGROUND/AIMS: The aims of the study were to identify whether a mucous-cap predicts the presence of serrated polyps, and to determine whether additional endoscopic findings predict the presence of a sessile serrated adenomas/polyp (SSA/P). METHODS: We analyzed 147 mucous-capped polyps with corresponding histology, during 2011–2014. Eight endoscopic features (presence of borders, elevation, rim of debris, location in the colon, size ≥10 mm, varicose vessels, nodularity, and alteration in mucosal folds) of mucous-capped polyps were examined to see if they can predict SSA/Ps. RESULTS: A total of 86% (n=126) of mucous-capped polyps were from the right sided serrated pathway (right-sided hyperplastic [n=83], SSA/Ps [n=43], traditional serrated adenoma [n=1]), 10% (n=15) were left-sided hyperplastic polyps, and 3% (n=5) were from the adenoma-carcinoma sequence. The presence of a mucous cap combined with varicose vessels was the only significant predictor for SSA/Ps. The other seven characteristics were not found to be statistically significant for SSA/Ps, although location in the colon and the presence of nodularity trended towards significance. CONCLUSIONS: Our study suggests that mucous-capped polyps have high predictability for being a part of the serrated pathway. Gastroenterologists should be alert for a mucous-capped polyp with varicose veins, as these lesions have a higher risk of SSA/P.

Diagnostic value of white light endoscopy and narrow band imaging for colorectal sessile serrated adenoma and hyperplastic polyp / 中华消化内镜杂志

Objective To differentiate colorectal sessile serrated adenoma(SSA)and large hyperplastic polyp(HP)with white light endoscopy and narrow band imaging. Methods Retrospective analysis was performed on the clinical data of 953 patients who underwent endoscopic screening for colorectal cancer at digestive endoscopy center of Peking Union Medical College Hospital from January 2015 to December 2015.Endoscopic features were compared with white light endoscopy and narrow band imaging between SSA and large HP in location, size, Paris classification, surface mucus, NICE classification and varicose microvascular vessel(VMV). Results A total of 28(2.9%)SSAs and 25(2.6%)HPs of diameter not less than 0.5 cm were detected in the total of 953 patients.Statistically significant difference was found in right hemi-colon, diameter not less than 1.0 cm and VMV in two groups(P<0.05). The sensitivities of the above three markers for SSA were 89.3%, 67.9% and 46.4% respectively. The specificities were 64.0%,76.0% and 84.0% respectively. Diagnostic accuracies were 77.4%,71.7% and 64.2% respectively. And the sensitivity, specificity and accuracy of three markers combined(at least two markers)were 75.0%, 88.0% and 81.1%, respectively. Conclusion SSA and large HP could be differentiated with a systemic consideration of lesion location, size, and surface of microvessels by using white light endoscopy and image-enhanced technique.

Morphological features of colorectal sessile serrated adenoma/polyp under white light endoscopy and narrow band imaging / 中国内镜杂志

Objective To investigate the morphological features of colorectal sessile serrated adenoma/polyp (SSA/P) by white light endoscopy (WLE) and narrow band imaging (NBI). Methods A retrospective analysis was made on the morphological characteristics of SSA/P from January 2014 to March 2017, and compared with HP. Results There were 50 cases of SSA/P from 41 patients and 50 cases of HP from 43 patients. SSA/P located in the right colon was more than HP, but the difference was no statistical significance (16 cases vs 14 cases,P > 0.05). SSA/P have 11 cases of Type Is, 21 cases of Type IIa, 16 cases of Type IIb, 2 cases of Type LST, HP have 17 cases of Type Is, 25 cases of Type IIa, 8 cases of Type IIb, there was no significant difference (P > 0.05); SSA/P has more mucus than HP (37 cases vs 11 cases, P < 0.05). In NBI: The proportion of SSA/P with a red mucus cap, indistinctive borders, irregular shape, black dots inside the crypts, Cloud-like surface, Type II-O pit pattern and varicose microvascular vessels were higher than that of HP (P < 0.05). In the differential prediction of SSA/P and HP: Black dots inside the crypts (OR

Comparisons of Gut Microbiota Among Healthy Control, Patients With Conventional Adenoma, Sessile Serrated Adenoma, and Colorectal Cancer

BACKGROUND: Studies on gut microbiota regarding colorectal carcinogenesis, including sessile serrated adenoma (SSA), have been scarce. The aim of this study is to investigate the role of mucosa-associated gut microbiota in the colorectal carcinogenesis. METHODS: We collected biopsy samples of normal rectal mucosa during colonoscopy from healthy control and patients with conventional adenoma, SSA, and colorectal cancer (CRC), respectively (n = 6). Pyrosequencing for 16S rRNA gene of bacteria was performed to compare gut microbiota. RESULTS: The most abundant phylum in total samples was Proteobacteria (55.6%), followed by Firmicutes (27.4%) and Bacteroidetes (11.6%). There was no significant difference in relative abundance of the phylum level among the four groups. Fusobacterium nucleatum, known to be frequently detected during colorectal carcinogenesis, was found in only one sample of patient with SSA. The rarefaction curves showed that the diversity of mucosal communities of patients with CRC is the lowest among the four groups and the diversity of mucosal communities of patients with SSA is higher than that of healthy control. Among the four groups, Shannon's and Simpson's index for diversity was the lowest and the highest in the patients with CRC, respectively; it did not reach statistical significance. The proportion of genus Pseudomonas was very high in the samples of patients with stage II–IV CRC compared with those with stage I CRC (59.3% vs. 0.3%, P = 0.064). CONCLUSIONS: Our study suggests no significant role of mucosa-associated gut microbiota in the colorectal carcinogenesis. Further study for many samples or using fecal material could be helpful.

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.

Characteristics and outcomes of endoscopically resected colorectal cancers that arose from sessile serrated adenomas and traditional serrated adenomas

BACKGROUND/AIMS: The efficacy and safety of endoscopic resection of colorectal cancer derived from sessile serrated adenomas or traditional serrated adenomas are still unknown. The aims of this study were to verify the characteristics and outcomes of endoscopically resected early colorectal cancers developed from serrated polyps. METHODS: Among patients who received endoscopic resection of early colorectal cancers from 2008 to 2011, cancers with documented pre-existing lesions were included. They were classified as adenoma, sessile serrated adenoma, or traditional serrated adenoma according to the baseline lesions. Clinical characteristics, pathologic diagnosis, and outcomes were reviewed. RESULTS: Overall, 208 colorectal cancers detected from 198 patients were included: 198 with adenoma, five with sessile serrated adenoma, and five with traditional serrated adenoma. The sessile serrated adenoma group had a higher prevalence of high-grade dysplasia (40.0% vs. 25.8%, P<0.001) than the adenoma group. During follow-up, local recurrence did not occur after endoscopic resection of early colorectal cancers developed from serrated polyps. In contrast, two cases of metachronous recurrence were detected within a short follow-up period. CONCLUSIONS: Cautious observation and early endoscopic resection are recommended when colorectal cancer from serrated polyp is suspected. Colorectal cancers from serrated polyp can be treated successfully with endoscopy.

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.

Sessile Serrated Adenoma with High-grade Dysplasia / 이화의대지

Until recently, colorectal polyps were classified predominantly as hyperplastic or adenomatous. While adenomatous polyps are well-characterized precursor lesions of adenocarcinomas, hyperplastic polyps have been considered as benign lesion. However, some hyperplastic polyps with serrated morphology of the crypts have been recognized to have distinctive features and these polyps were termed 'serrated adenomas'. Recent data show that sessile serrated adenomas (SSA) might be the precursors of serrated colonic cancers, underlining the necessity of identifying them. SSA is approximately 3% of all polyps, commonly appears as flat or sessile and yellowish due to mucus production. In the pathogenesis of SSA, progression to high grade dysplasia or early invasive carcinoma may be associated with serrated neoplasia pathway different from adenoma-carcinoma sequence. We report a case with a colon polyp diagnosed as sessile serrated adenoma with high grade dysplasia after endoscopic submucosal dissection.

A Significant Number of Sessile Serrated Adenomas Might Not Be Accurately Diagnosed in Daily Practice

BACKGROUND/AIMS: The diagnosis of hyperplastic polyps (HPs) may involve a conglomeration of subgroups of serrated polyps. The diagnosis of HPs may therefore be revisited if this is sessile serrated adenoma (SSA). The aim of this study was to determine clinically and endoscopically relevant information associated with reclassification to SSA. METHODS: After reviewing the data from 1,372 patients who underwent colonoscopic polypectomy, 49 HPs larger than 10 mm were analyzed in this study. Two gastrointestinal pathologists reclassified each of the original 49 HPs as conventional HPs, SSAs, and others. RESULTS: Among the 49 initially diagnosed HPs, 18.4% were reclassified into SSAs or mixed polyps. Overall architectural features were useful for the diagnosis of SSA, but cytological features were less useful. The patient and polyp characteristics did not differ between HPs with and without reclassification of the initial pathological diagnosis. CONCLUSIONS: A significant number of SSAs might not be accurately diagnosed in daily clinical practice without any predilection for size, shape, and location. Therefore, when large HPs are diagnosed in clinical practice, it is necessary for physicians to have greater awareness of the diagnosis of SSA and to individualize subsequent surveillance.