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Preserving the colon while preventing colorectal cancer is challenging in patients with familial adenomatous polyposis. Although prophylactic colectomy is the current standard of care, some patients with familial adenomatous polyposis may wish to postpone colectomy as long as polyposis can be managed by endoscopic resection. This study examined our endoscopic management and prognostic results for patients with familial adenomatous polyposis who refused to undergo colectomy. We retrospectively analyzed the data of 12 patients with familial adenomatous polyposis treated at our hospital between January 1995 and December 2020. All patients opted to postpone prophylactic colectomy although they had significant polyp burdens and underwent endoscopic management, in which colorectal polyps sized > 5 mm were thoroughly resected during baseline colonoscopies and subsequently, newly arising colorectal polyps sized > 5 mm were periodically resected during surveillance colonoscopies. Patients (median age, 33 years) were followed up for a median of 5.2 years. The median number of colonoscopies and resected lesions per patient was 2 and 14 at baseline as well as, 9 and 32 during surveillance, respectively. The interval between colonoscopies was 1.0 and 7.0 months for baseline and surveillance, respectively. The colons of all 12 patients were preserved, and no invasive colorectal cancer developed. In 10 patients, 35 cases of high-grade dysplasia were observed and managed by endoscopic resection. Repeated endoscopic resection of colorectal polyps sized > 5 mm with appropriate surveillance may be an alternative form of endoscopic management for patients with familial adenomatous polyposis wishing to postpone colectomy., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Background and Aim: Endoscopic diagnosis of advanced histology in colorectal lesions sized <10 mm is essential for appropriate selection of resection methods. The Japan Narrow-band imaging Expert Team (JNET) classification has been recently validated for the evaluation of colorectal lesions. Our objective was to investigate the diagnostic value of the JNET classification for advanced histology in colorectal lesions sized <10 mm., Methods: We enrolled 680 patients with 1472 colorectal lesions sized <10 mm diagnosed according to the JNET classification and who subsequently underwent endoscopic or surgical resection between January and December 2017. We retrospectively examined the relationship between the JNET findings and pathological histology. Multivariate analysis was carried out to assess the predictive power of the JNET findings and clinical characteristics of lesions., Results: Advanced histology was present in 29 (2.0%) lesions. Advanced histology was absent in 68 lesions diagnosed as JNET type 1, whereas 1389 lesions diagnosed as JNET type 2A included 19 lesions of advanced histology (1.4%) with high-grade dysplasia alone. Eleven lesions diagnosed as JNET type 2B comprised eight lesions of advanced histology (72.7%) with four high-grade dysplasia and four submucosal invasive cancer, and two lesions diagnosed as JNET type 3 were submucosal invasive cancer. Multivariate analysis showed that JNET type 2B + 3 was a stronger predictive factor for advanced histology than other clinical risk factors., Conclusion: Narrow-band imaging with magnification according to the JNET classification may be a useful modality for identification of advanced histology in colorectal lesions sized <10 mm., (© 2019 Japan Gastroenterological Endoscopy Society.)

Background and Aim: To assess the visibility of colorectal lesions using blue laser imaging (BLI)-bright and linked-color imaging (LCI) with an eye-tracking system., Methods: Eleven endoscopists evaluated 90 images of 30 colorectal lesions. The lesions were randomly selected. Three images of each lesion comprised white light imaging (WLI), BLI-bright, and LCI in the same position. Participants gazed at the images, and their eye movements were tracked by the eye tracker. We analyzed whether the participants could detect the lesion and how long they took to detect the lesion. We assessed the miss rate and detection time among the imaging modalities., Results: One endoscopist was excluded, and 10 endoscopists were assessed. Overall, 12.6% of lesions were missed with WLI, 6.0% with BLI-bright, and 4.3% with LCI; the miss rate of BLI-bright and LCI was significantly lower than that of WLI (P < 0.01), with no significant difference between the former modalities (P = 0.54). Mean (± SD) detection times were 1.58 ± 1.60 s for WLI, 1.01 ± 1.21 s for BLI-bright, and 1.10 ± 1.16 s for LCI. Detection time for BLI-bright and LCI was significantly shorter than that for WLI (P < 0.0001), with no significant difference between the former modalities (P = 0.34). Regarding the miss rate and detection time between the expert and the non-experts, there was a significant difference with WLI but not with BLI-bright and LCI., Conclusion: Blue laser imaging-bright and LCI improved the detection of colorectal lesions compared with WLI using an eye-tracking system., (© 2019 Japan Gastroenterological Endoscopy Society.)

We describe a series of colorectal polyps characterized by mixed adenomatous and serrated features, herein referred to as superficially serrated adenomas. Twenty superficially serrated adenomas were obtained from 11 female and 9 male patients aged 62-87 years. Most lesions endoscopically appeared as small sessile polyps, but larger lesions were plaque-like (2-20 mm; median, 5 mm). Eighteen lesions (90%) were located in the sigmoid colon or rectum. They consisted primarily of straight, adenomatous glands but showed serration confined to the superficial layer. Immunohistochemistry revealed CK20 expression in the upper layer. Proliferating cells, determined by their expression of Ki-67, were localized to the middle to bottom layers. Genetic analyses identified KRAS mutations in 19 lesions and a BRAF mutation in one lesion. Furthermore, RSPO fusions and/or overexpression were observed in 18 lesions and truncating APC mutations were observed in the two remaining lesions. Consistent with the presence of WNT pathway gene alterations, all superficially serrated adenomas showed focal or diffuse nuclear β-catenin accumulation. Since concurrent KRAS mutations and RSPO fusions are reportedly common in traditional serrated adenomas, we reviewed 129 traditional serrated adenomas and found 15 lesions (12%) that were associated with superficially serrated adenoma components. Remarkably, all but one superficially serrated adenoma-associated traditional serrated adenoma exhibited concurrent KRAS mutations and RSPO fusions/overexpression. The present study suggests that superficially serrated adenoma is a morphologically and molecularly distinct type of colorectal serrated polyp that is histogenetically related to traditional serrated adenoma.

Background: The aim of this pilot study is to investigate the diagnostic yield of probe-based confocal laser endomicroscopy (pCLE) in the evaluation of depth of invasion in colorectal lesions., Methods: Patients with colorectal lesions eligible for either endoscopic treatment or surgery were enrolled in the study. Tumor's depth of invasion was classified as mucosal or slight submucosal (M-SM1) and deep submucosal invasion or deeper (SM2 or deeper). White light endoscopy (WLE), magnifying narrow band imaging (M-NBI), and magnifying chromoendoscopy (M-CE) were used to assess colorectal lesions, and pCLE was used to identify tumor's features related to SM2 or deeper. The diagnostic classification of depth of invasion was obtained by correlating pCLE findings with histology results (on-site diagnosis). All colorectal lesions were stratified by a second endoscopist who was blinded to any clinical and histological information with the use of WLE, M-NBI, M-CE, and pCLE (off-line review)., Results: A total of 22 colorectal lesions were analyzed: seven were adenoma, ten intramucosal cancer, and five SM2 or deeper cancer. With respect to pCLE findings, loss of crypt structure was seen in all SM2 or deeper cancers and only in one M-SM1 lesion. Sensitivity, specificity, and accuracy of WLE, M-NBI, and M-CE in off-line review were 60/94/86, 60/94/86, and 80/94/91%, respectively. Sensitivity/specificity/accuracy of pCLE in off-line review were 80/94/91%, respectively. The inter-observer agreement of pCLE between on-site diagnosis and off-line review was 0.64 (95%CI 0.27-1.0)., Conclusions: pCLE may represent a useful tool to evaluate the depth of invasion in colorectal lesions.

Background and Aims: A "skirt" is a slightly elevated flat lesion with wide pits occasionally observed at the margin of laterally spreading tumors (LSTs). However, the endoscopic treatment outcomes of LSTs with skirts have not been clarified. The aim of this study was to evaluate the endoscopic treatment outcomes of LSTs with skirts., Methods: Between February 2006 and March 2014, 996 LSTs were retrospectively examined to assess the clinicopathologic characteristics, procedure time, en bloc resection rate, R0 resection rate, adverse events, and local recurrence rate of endoscopic submucosal dissection (ESD) and of endoscopic resection., Results: Endoscopic treatment was performed in 35 cases of LSTs with skirts (ratio of ESD to endoscopic piecemeal mucosal resection [EPMR], 32:3) and 961 cases of LSTs without skirts (ratio of ESD to EMR to EPMR to polypectomy, 381:275:114:191). LSTs with a skirt were associated with a significantly higher recurrence rate (P < .01). In both ESD and EPMR, LSTs with a skirt were associated with a higher recurrence rate when compared with LSTs without a skirt (odds ratio, 12.7; P = .032, and odds ratio, 12.3; P = .061, respectively). Multivariate analysis demonstrated that the presence of the skirt and piecemeal resection were significant predictors of local recurrence., Conclusions: LSTs with skirts had a significantly higher local recurrence rate after endoscopic treatment compared with LSTs without skirts, especially after EPMR. Therefore, ESD should be recommended as an endoscopic treatment for LSTs with skirts to minimize local recurrence., (Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background and Study Aim: A slightly elevated flat lesion with wide pits has occasionally been observed at the margin of laterally spreading tumors (LSTs) and is known as a "skirt." The aim of this study was to evaluate the clinicopathological, endoscopic, and genetic characteristics of a skirt., Patients and Methods: Consecutive LSTs were examined to evaluate the pathological, endoscopic, and genetic characteristics. Pathological characteristics, including the dimension of the cryptic opening (DCO), width of the individual gland (WIG), DCO to WIG ratio, and microvessel diameter were elucidated and compared with those of hyperplastic polyps, low grade dysplasia (LGD), and normal mucosa. The endoscopic findings of pit and microvascular patterns were assessed. Gene mutation analyses were performed for the KRAS, BRAF, NRAS, and PIK3CA genes., Results: A skirt was identified in 35 of 1023 LSTs, and 80 % of lesions with a skirt had a component of either intramucosal or submucosal adenocarcinoma. The DCO, WIG, and DCO to WIG ratio of the skirt were significantly larger than those of other lesions. The microvessel diameters in skirts were significantly smaller than those in LGDs. Regarding the endoscopic findings, 30 skirts showed pits with a coral reef-like appearance, and all skirt regions were found to have a type I capillary pattern. KRAS mutation at codon 146 was found in the nodular part in one of five LSTs with a skirt., Conclusion: The skirt is a newly identified lesion distinct from hyperplastic polyps and LGDs, suggesting the presence of a novel pathway for rectal carcinogenesis from LSTs with a skirt., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background: Many authors have already reported the usefulness of narrow-band imaging (NBI) for the differential diagnosis of non-neoplastic and neoplastic colorectal lesions. However, it is not clear whether magnification is required for differential diagnosis. The aim of this prospective study was to clarify the clinical usefulness of a newly developed NBI system with a dual focus function (dual-focus NBI) compared with conventional white-light imaging (WLI) and NBI without magnification for distinguishing between non-neoplastic and neoplastic lesions., Patients and Methods: Thirty-seven consecutive patients who underwent screening colonoscopy with the novel system between July and December 2013 were analyzed. Patients with polyps >10 mm and those with polyps previously evaluated by histologic examination or colonoscopy were excluded. Lesions were diagnosed in real time with WLI, NBI without magnification, and dual-focus NBI, and then excised endoscopically. Each diagnosis was compared to that in the final histopathology reports. The primary endpoint was the diagnostic accuracy and the confidence level assigned to each modality by the endoscopists. The secondary endpoint was the differentiation ability according to the size of the lesion (≤5 and 6-10 mm)., Results: In all, 100 lesions including 76 adenomatous polyps and 24 hyperplastic polyps were analyzed in 37 patients. The overall diagnostic accuracy, sensitivity, and specificity for differentiating adenomatous from hyperplastic polyps were 87.0, 89.5, and 79.2 % for WLI, 93.0, 94.7, and 87.5 % for NBI without magnification, and 94.0, 96.1, and 87.5 % for dual-focus NBI, respectively. The level of confidence was significantly different between dual-focus NBI and WLI and NBI without magnification for diminutive (≤5 mm) lesions (p < 0.001 and p < 0.01)., Conclusion: Dual-focus NBI is especially useful for differential diagnosis of diminutive colorectal lesions.

Background and Study Aims: Patients with submucosal invasive colorectal cancer (SM-CRC) treated with endoscopic resection who are at low risk of lymph node metastasis and local recurrence may be followed up with observation alone, while additional surgery is recommended for those with high risk features. However, the long-term outcomes that these strategies offer are still unclear. The objective of our study was to retrospectively evaluate the long-term outcomes of patients with SM-CRC managed with endoscopic resection., Patients and Methods: We retrospectively analyzed all patients with SM-CRC treated by endoscopic resection at six institutions between 2000 and 2007. SM-CRCs with (i) negative vertical margin, (ii) well or moderately differentiated adenocarcinoma, (iii) absence of lymphovascular invasion, and (iv) invasion depth < 1000 µm were classified as low risk. Patients with SM-CRCs without these characteristics were classified as high risk. Outcomes were assessed by 5-year recurrence-free survival (RFS) and recurrence rate., Results: During the study period, 428 patients with SM-CRC (low risk, 126; high risk, 302) who underwent endoscopic resection as their first treatment were enrolled (median follow-up 61 months). Among the 120 patients with low risk features treated by endoscopic resection alone, the 5-year RFS and recurrence rates were 98 % and 0.8 %, respectively. Of the 302 patients with high risk features, 196 underwent additional surgery and 106 were managed with endoscopic resection alone. For those who underwent additional surgery, the 5-year RFS and recurrence rates were 97 % and 3.6 %, respectively. Among the 106 patients managed with endoscopic resection alone, RFS and recurrence rates were 89 % (P < 0.05 vs. low risk patients treated by endoscopic resection alone) and 6.6 % (P < 0.05), respectively., Conclusions: Endoscopic resection alone is adequate for the management of patients with SM-CRC and low risk features. However, in those patients with SM-CRC and high risk features, surgery should be considered in addition to endoscopic resection., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background & Aims: Little is known about the long-term outcomes of patients with submucosal invasive colorectal cancer who undergo endoscopic or surgical resection. We performed a retrospective analysis of long-term outcomes of patients treated for submucosal colon and rectal cancer., Methods: We collected data on 549 patients with submucosal colon cancer and 209 patients with submucosal rectal cancer who underwent endoscopic or surgical resection at 6 institutions over a median follow-up period of 60.5 months. Patients were classified into one of 3 groups: low-risk patients undergoing only endoscopic resection (group A), high-risk patients undergoing only endoscopic resection (group B), and high-risk patients undergoing surgical resection that included lymph node dissection (group C). We assessed recurrence rates, 5-year disease-free survival, and 5-year overall survival. Cox regression analysis was used to compare recurrences., Results: The rates of recurrence, disease-free survival, and overall survival in group A for submucosal colon and rectal cancer were 0% versus 6.3% (P < .05), 96% versus 90%, and 96% versus 89%, respectively. For group B, these values were 1.4% versus 16.2% (P < .01), 96% versus 77% (P < .01), and 98% versus 96%, respectively; local recurrence was observed in 5 patients (one with submucosal colon cancer and 4 with submucosal rectal cancer). Tumor location was the only factor that contributed significantly to disease recurrence and death (hazard ratio, 6.73; P = .045). For group C, these values were 1.9% versus 4.5%, 97% versus 95%, and 99% versus 97%, respectively., Conclusions: The risk for local recurrence was significantly higher in high-risk patients with submucosal rectal cancer than in patients with submucosal colon cancer when treated with only endoscopic resection. The addition of surgery is therefore recommended for patients with submucosal rectal cancer with pathologic features indicating a high risk of tumor progression; University Hospital Medical Network Clinical Trials Registry, Number: UMIN 000008635., (Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: Colonoscopic examination is the common pathway for positive screening tests detecting colorectal lesions. We evaluated a specific, quantitative high-throughput automatic immunochemical fecal occult blood test (Auto iFOBT) method for colorectal cancer (CRC) screening and to determine its concordance with physician assessments informed by complete colonoscopy, the gold-standard technique for evaluation of the colonic mucosa., Methods: 1200 CRC symptomatic patients were recruited for a retrospective investigation. Colorectal neoplasia were localized by colonoscopy and cancer outcomes were enumerated according to severity. In addition, stool samples were collected and analyzed by Auto iFOBT to derive sensitivity, specificity, and positive predictive value. Qualitative colonoscopy and Auto iFOBT results were correlated, as were cancer severities and quantitative hemoglobin concentrations., Results: Ninety-one patients were found positive for CRC; 50 mucosal, 20 submucosal, and 21 advanced. At standard cutoff, sensitivity was 60%, 90%, and 95%, respectively. Specificity and positive predictive value for all neoplasia and cancers were 89.6% and 86.4%, and 60.9% and 33.7%, respectively. Cancer severities could be approximated roughly according to hemoglobin concentrations., Conclusions: Specific qualitative 2-day Auto iFOBT is an accurate tool for the detection of colorectal cancer and therefore provides the basis for a large-scale screening program., (Copyright 2010 Elsevier B.V. All rights reserved.)

Recent studies suggest that serrated polyps, including hyperplastic polyps, traditional serrated adenomas, and sessile serrated adenomas, may be morphologically and genetically distinct and linked to microsatellite unstable colorectal cancers, and thus the concept of a hyperplastic polyp-serrate adenoma-carcinoma pathway has been suggested. Furthermore, it has been suggested that transformation from serrated polyps to invasive cancers can be rapid and occurs when the lesions are small; however, direct evidence for this issue is scant. We herein describe a case of a sessile serrated adenoma showing rapid transformation into a submucosal invasive carcinoma with remarkable morphological change in a short period of 8 months. This case is unique and suggestive, as it provided information about the natural history of a sessile serrated adenoma.