Diagnostic performance of deep-learning-based virtual chromoendoscopy in gastric neoplasms.

BACKGROUNDS: Cycle-consistent generative adversarial network (CycleGAN) is a deep neural network model that performs image-to-image translations. We generated virtual indigo carmine (IC) chromoendoscopy images of gastric neoplasms using CycleGAN and compared their diagnostic performance with that of white light endoscopy (WLE). METHODS: WLE and IC images of 176 patients with gastric neoplasms who underwent endoscopic resection were obtained. We used 1,633 images (911 WLE and 722 IC) of 146 cases in the training dataset to develop virtual IC images using CycleGAN. The remaining 30 WLE images were translated into 30 virtual IC images using the trained CycleGAN and used for validation. The lesion borders were evaluated by 118 endoscopists from 22 institutions using the 60 paired virtual IC and WLE images. The lesion area concordance rate and successful whole-lesion diagnosis were compared. RESULTS: The lesion area concordance rate based on the pathological diagnosis in virtual IC was lower than in WLE (44.1% vs. 48.5%, p < 0.01). The successful whole-lesion diagnosis was higher in the virtual IC than in WLE images; however, the difference was insignificant (28.2% vs. 26.4%, p = 0.11). Conversely, subgroup analyses revealed a significantly higher diagnosis in virtual IC than in WLE for depressed morphology (41.9% vs. 36.9%, p = 0.02), differentiated histology (27.6% vs. 24.8%, p = 0.02), smaller lesion size (42.3% vs. 38.3%, p = 0.01), and assessed by expert endoscopists (27.3% vs. 23.6%, p = 0.03). CONCLUSIONS: The diagnostic ability of virtual IC was higher for some lesions, but not completely superior to that of WLE. Adjustments are required to improve the imaging system's performance.

Pre-administration of super-low volume polyethylene glycol is as effective as senna laxative as bowel preparation for colonoscopy: a randomized controlled phase 2 trial.

BACKGROUND AND PURPOSE: Senna laxatives are commonly used for bowel preparation before colonoscopies in Japan. However, this laxative frequently causes complications such as abdominal pain. This study aimed to establish a novel method of bowel preparation, which involved the pre-administration of super-low volume polyethylene glycol (PEG) for three days followed by the same-day administration of low volume PEG. METHODS: This study was a prospective, multicenter, investigator-blinded, phase 2, randomized control trial. The intake of 13.9 g (120 mL) of PEG or 1 g of a senna laxative for 3 days before the examination was indicated for each group, and 2 L of PEG solution was used for preparation on the examination day. The primary endpoint was the efficacy of bowel cleansing, as assessed by the Boston bowel preparation scale. The secondary endpoints were the adenoma detection rate and occurrence of complications. RESULTS: A total of 250 patients were initially enrolled. A total of 122 patients from each group were included in the intention-to-treat analysis. In the intention-to-treat analysis, the responder rates were the same for the two groups (56.6% vs 50.8%). Additionally, the adenoma detection rate did not differ between the two groups (34.9% vs 41.8%, P = 0.3795). In contrast, adherence was higher in the PEG group (93.4% vs 82.8%, P = 0.0101), and the occurrence of complications was lower in the PEG group (1.7% vs 16.4%, P = 0.0001). CONCLUSION: The novel super-low volume PEG method for bowel preparation was as effective as the conventional method with senna laxatives.

Endoscopic characteristics influencing postpolypectomy bleeding in 1147 consecutive pedunculated colonic polyps: a multicenter retrospective study.

BACKGROUND AND AIMS: Postpolypectomy bleeding is the most common adverse event with pedunculated polyps. We clarified the endoscopic characteristics influencing postpolypectomy bleeding for pedunculated colonic polyps. METHODS: We reviewed clinical data for 1147 pedunculated colonic polyps removed by polypectomy in 5 Japanese institutions. Pedunculated polyps were defined as polyps with a stalk length ≥5 mm. Analyzed clinical data were age, sex, polyp location/size, stalk length/width, prophylactic clipping or endoloop before polypectomy, injecting the stalk, closing the polypectomy site, antithrombotic agent use, and endoscopist experience. Postpolypectomy bleeding was classified as immediate bleeding or delayed bleeding. RESULTS: Immediate and delayed bleeding was observed in 8.5% (97/1147) and 2% (23/1147) of polypectomies, respectively. Comparing immediate bleeding with nonbleeding, multivariate analysis showed that stalk width ≥6 mm (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.1-3.4) was a significant risk factor for immediate bleeding. For polyp size ≥15 mm, prophylactic endoloop use (OR, .17; 95% CI, .04-.72) was a significant inhibiting factor. Comparing delayed bleeding with nonbleeding, multivariate analysis showed that prophylactic clipping before polypectomy (OR, 4.2; 95% CI, 1.3-13) and injecting the stalk (OR, 4.0; 95% CI, 1.4-12) were significant risk factors for delayed bleeding. CONCLUSIONS: The increased risk for delayed bleeding with injecting the stalk and prophylactic clipping before polypectomy suggests that simple resection with coagulation mode is a suitable strategy in endoscopic resection of pedunculated polyps. Moreover, prophylactic endoloop use was highly likely to inhibit immediate bleeding with polyp size ≥15 mm.

Individual feedback and monitoring of endoscopist performance improves the adenoma detection rate in screening colonoscopy: a prospective case-control study.

BACKGROUND AND PURPOSE: Previous reports have suggested that a longer withdrawal time (WT) during colonoscopy led to an improved adenoma detection rate (ADR); however, there are few controlled studies that substantiated monitoring WT as an educational method. We aimed to validate a feedback and monitoring system to improve the ADR in screening colonoscopy in a prospective case-control setting. METHODS: After collecting data in the pre-feedback period (3.5 months), the individual performance and the average ADR and WT values of the facility were provided to 6 endoscopists in the intervention group, while 3 endoscopists were isolated as the control group during the feedback period (2 weeks). The intervention group consisted of two subgroups, the Fast and Slow WT groups, according to the results from the pre-feedback period. The endoscopists in the intervention group were instructed to be aware of their own WT in each examination during the post-feedback period (4 months). The performances of all endoscopists in the post-feedback period were analyzed and compared with those in the pre-feedback period. RESULTS: Among the initial analyses, the correlation analysis and multivariate analysis revealed that WT was an independent predictor for the ADR (P = 0.0101). After providing individual performance feedback and instruction regarding real-time WT monitoring, the WT was significantly prolonged in the Fast WT group (P = 0.0346) but did not change in the Slow WT and control groups. In addition, the ADR of the Fast WT group significantly improved after the intervention (P = 0.024), whereas the ADR of the Slow WT and control groups did not change. CONCLUSION: Providing individual feedback on ADR and WT and monitoring WT helped improve the endoscopists' ADRs.

[A case of rectal villous adenoma with electrolyte depletion syndrome treated with surgical resection].

A 65-year-old man was previously admitted to our university hospital thrice in the last 2 years because of acute kidney failure. This time he was admitted because of frequent diarrhea, anorexia, exacerbation of renal function, and hyponatremia. Rectal wall thickening was detected on computed tomography. Subsequently, a rectal polyp with mucous secretion was found on colonoscopy, which was further diagnosed as a subcutaneous villous adenoma on biopsy. Thus, electrolyte depletion syndrome associated with the rectal polyp was thought to be the cause of his symptoms. Finally, the patient underwent abdominoperineal resection of the rectum. Histopathologically, the rectal lesion was diagnosed as a villous/tubularadenoma without malignancy, and this is such a rare case to be reported.

Submucosal Injection Using Epinephrine-Added Saline in Cold Snare Polypectomy for Colorectal Polyps Shortens Time Required for Resection: A Randomized Controlled Study.

AIMS: Immediate bleeding after cold snare polypectomy (CSP) for colorectal polyps might interfere with confirmation of residuals and prolong the time required for resection. We investigated whether submucosal epinephrine-added saline injection reduces the time required for the CSP procedure. METHODS: We conducted a single-center, prospective, randomized controlled trial (clinical trial registration number: UMIN000046770). Patients with colorectal polyps ≤ 10 mm were randomly allocated to either CSP with epinephrine-added submucosal injection (CEMR group) or conventional CSP (CSP group). The primary outcome was the time required for resection defined as the time from the initiation of resection (the first insertion of the snare in the CSP group or the injection needle in the CEMR group) to the end of resection (confirming complete resection endoscopically after recognizing the cessation of immediate bleeding) in each lesion, and the secondary outcome was the time to spontaneous cessation of immediate bleeding after resection defined as the time from ensnaring the lesion to confirming the spontaneous cessation of immediate bleeding. RESULTS: A total of 126 patients were randomly assigned. Finally, 261 lesions in 118 patients (CEMR group, n = 59; CSP group, n = 59) were analyzed. The time required for resection calculated using the least-square mean was significantly shorter in the CEMR group (106.3 s, 95% CI 97.5 to 115.4 s) than in the CSP group (130.9 s, 95% CI 121.2 to 140.7 s) (P < 0.001). The time to spontaneous cessation of immediate bleeding was also significantly shorter in the CEMR group (20.4 s, 95% CI 14.3 to 26.5 s) than in the CSP group (74.2 s, 95% CI 67.6 to 80.7 s) (P < 0.001). Neither group had cases requiring hemostasis, perforation, or delayed bleeding. CONCLUSIONS: CEMR shortened the time for resection by shortening the time to cessation of immediate bleeding compared with conventional CSP in colorectal polyps ≤ 10 mm.

Hemostasis using a covered self-expandable metal stent for pseudoaneurysm bleeding from the perihilar bile duct.

Although there are many reports of hemostasis with covered self-expandable metal stent (CSEMS) for bleeding from the papilla of Vater and the intrapapillary and distal bile duct, there are rare reports of its use for hemostasis in the perihilar bile duct. We report the case of a patient undergoing supportive care for perihilar cholangiocarcinoma with acute cholecystitis after side-by-side placement of uncovered SEMS for perihilar bile duct obstruction. Percutaneous transhepatic gallbladder aspiration was performed upon admission, and hematemesis occurred the next day. Since computed tomography scanning showed a pseudoaneurysm in the right uncovered SEMS, hemostasis by interventional radiology (IVR) was performed thrice for massive bleeding; however, hemostasis could not be achieved. When endoscopic retrograde cholangiopancreatography was performed for scrutiny and treatment of melena and increased hepatobiliary enzyme, the endoscopic visual field could not be secured by bleeding, and changes in hemodynamics were observed; thus, IVR was required, but it was difficult to perform. Since bleeding from the right bile duct was expected, hemostasis was performed using CSEMS. This is the first report of hemostasis performed by placing a covered SEMS for bleeding from a pseudoaneurysm of the intrahepatic bile duct.

Risk Factors Indicating Difficulty During Gastric Endoscopic Submucosal Dissection for Inexperienced Endoscopists: A Retrospective Study.

AIM: Factors that may make endoscopic submucosal dissection (ESD) difficult for operators have been evaluated according to results based on the performance of experienced endoscopists. This study aimed to verify the predictors of difficult gastric ESD for ESD beginners. METHODS: From January 2015 to December 2021, 466 superficial gastric neoplasms were treated with ESD at Showa University Hospital. Excluding 103 lesions that performed ESD by experts who experienced more than 80 ESDs, a total of 363 lesions were included. The lesions were divided into two groups according to the ESD performance experience of the operator: ESD beginner (EB; ESD experience≤30 cases) and ESD intermediate (EI; ESD experience 31-80 cases) groups. Relationships between difficult ESD (having at least one of the following: procedure time>60 min, incomplete resection, change of operator, and occurrence of severe complications) and clinicopathological findings of the lesion were analyzed. RESULTS: The complete resection rates and the difficult ESD rates in the EB and EI groups were 99.3%, 94.8%, and 61.2%, 50.7%, respectively. In the EB group, univariate analysis showed that difficult ESD rate was significantly higher in the non-lower third lesions, the lesser curvature lesions, and cancerous lesions. In the EI group, univariate analysis showed that difficult ESD rate was significantly higher in lesion with ≥20 mm size, lesser curvature lesions, lesions with ulcers, and submucosal cancers. Multivariate analysis showed that the lesser curvature location and cancerous histology in the EB group and ≥20 mm lesion size, the lesser curvature location and submucosal invasion in the EI group were independent predictors of difficult ESD. CONCLUSIONS: The lesser curvature location is recognized as independent ESD difficulty factor for both beginners and intermediates. Cases with lesions located in the lesser curvature should not be selected for gastric ESD training by beginners.

Small intestinal bleeding and stricture caused by Meckel's diverticulum.

A 44-year-old man presented to our hospital with lower gastrointestinal bleeding. We performed balloon-assisted enteroscopy, which revealed diverticulum and stricture at the ileum. The patient underwent segmental small bowel resection and diagnosed with Meckel's diverticulum. We should keep in mind the possibility of intestinal stricture due to Meckel's diverticulum.

Clinicopathological and molecular features of colorectal serrated neoplasias with different mucosal crypt patterns.

OBJECTIVES: Endoscopic examination shows that serrated neoplasias (SNs), such as serrated adenomas and sessile serrated adenomas, exhibit different mucosal crypt patterns. However, it remains unclear whether advanced serrated polyps with different mucosal crypt patterns have different clinicopathological or molecular features. METHODS: We classified the mucosal crypt patterns of 86 SNs into three types (hyperplastic, adenomatous, and mixed pattern) and evaluated their clinicopathological and molecular features. RESULTS: We found significant differences in the proliferative activity status between SNs with mixed/adenomatous patterns and those with the hyperplastic patterns. SNs with the hyperplastic pattern were frequently located in the proximal colon and had a macroscopically superficial appearance, whereas SNs with the adenomatous pattern were often located in the distal colon and had a protruding appearance. Furthermore, a significant difference was observed in the frequency of the CpG island methylator phenotype (CIMP), involving the methylation of two or more CIMP-related genes (MINT1, MINT2, MINT31, p16, and MLH1), between SNs with the hyperplastic pattern and those with the mixed/adenomatous patterns (18/32 (56%) vs. 8/28 (29%) or 7/26 (27%); P=0.0309 or P=0.0249, respectively). Moreover, the prevalence of KRAS mutations was significantly higher in SNs with the adenomatous pattern than in those with the hyperplastic pattern (7/26 (27%) vs. 1/32 (3%); P=0.0173). In comparison with other patterns, the mixed pattern was detected more frequently in mixed serrated polyps (MSPs), which contain separate histological components. Some MSPs exhibited concordant molecular alterations among the different histological components. CONCLUSIONS: The clinicopathological and molecular features of SNs correlated strongly with their mucosal crypt patterns, which were observed using chromoendoscopy.

Risk Stratification Score Improves Sensitivity for Advanced Colorectal Neoplasia in Colorectal Cancer Screening: The Oshima Study Workgroup.

INTRODUCTION: Noninvasive colorectal cancer (CRC) screening methods with higher sensitivity for advanced colorectal neoplasia (ACN) than the fecal immunochemical test (FIT) alone are warranted. This study aimed to elucidate the diagnostic performance of a risk stratification score calculated using baseline individual characteristics and its combination with FIT for detecting ACN. METHODS: This cross-sectional analysis of data from a prospective cohort in Izu Oshima, Japan, included asymptomatic individuals age 40-79 years who underwent both 2-day quantitative FIT and screening colonoscopy. The 8-point risk score, calculated based on age, sex, CRC family history, body mass index, and smoking history, was assessed. Colonoscopy results were used as reference. RESULTS: Overall, 1,191 individuals were included, and 112 had ACN. The sensitivity and specificity of the 1-/2-day FIT (cutoff: 50-200 ng Hb/mL) for ACN were 17.9%-33.9% (4.9%-22.0% for right-sided ACN) and 91.8%-97.6%, respectively. The risk score's c-statistic for ACN was 0.66, and combining the score (cutoff: 5 points) with 1-/2-day FIT (cutoff: 50-200 ng Hb/mL) yielded a sensitivity and specificity for ACN of 46.4%-56.3% (43.9%-48.8% for right-sided ACN) and 76.6%-80.8%, respectively. The specificity of the risk score and FIT combination for all adenomatous lesions was 82.4%-86.4%. DISCUSSION: The 8-point risk score remarkably increased the sensitivity for ACN, particularly for right-sided ACN. Although the specificity decreased, it was still maintained at a relatively high level. The risk score and FIT combination has the potential to become a viable noninvasive CRC screening option.

Case of Colorectal Cancer After Cold Snare Polypectomy Successfully Salvaged on Endoscopic Submucosal Dissection.

Cold snare polypectomy is a well-established method for the resection of colorectal polyps measuring less than 10 mm in size. It may be performed in patients with early colorectal cancers because of the difficulty of endoscopic diagnosis. However, the therapeutic effect of cold snare polypectomy on cancers is unknown, and the need for appropriate surveillance and additional treatment for these patients remains to be fulfilled. Endoscopic submucosal dissection has been reported as a safe and effective method for treating recurrent or residual colorectal neoplasia following hot endoscopic mucosal resection. This report is of a case of a colorectal tumor measuring 8 mm that was treated using cold snare polypectomy and resulted in residual cancer. Endoscopic submucosal dissection was selected as salvage treatment for the residual lesion, and histopathological examination revealed free horizontal and vertical margins. We believe that performing endoscopic submucosal dissection at the site of the cancer resected with cold snare polypectomy ensured that there was no residual cancer left. It may be hypothesized that endoscopic submucosal dissection could evolve as the treatment of choice for patients with colorectal cancer after cold snare polypectomy.

Successful Management of Pharyngeal Perforation Caused by Overtube Insertion During Endoscopic Submucosal Dissection.

A woman in her 70s underwent endoscopic submucosal dissection (ESD) for gastric-type adenoma in the anterior wall of the upper gastric body with intravenous anesthesia. We decided to use an overtube to control the air volume in the stomach. The overtube was inserted under endoscopic guidance using a sufficient amount of lubricating jelly. We encountered resistance when the top of the overtube was advanced to the pharynx; therefore, we stopped the overtube insertion and pulled the tube out immediately. We observed a linear injury in the posterior wall of the hypopharynx. The injury was deep and diagnosed as a pharyngeal perforation. Computed tomography (CT) revealed free air in the neck, with mediastinal emphysema. Conservative treatment was initiated after consultation with the otorhinolaryngologist; the patient received nothing per mouth and was administered intravenous antibiotics. The patient did not develop a fever and no signs of inflammation were observed. CT performed on postoperative day (POD) 5 revealed the disappearance of the mediastinal emphysema and a soft diet was introduced. The patient was discharged on POD 7. The ESD was postponed to two months later and was performed successfully. The scar of the perforation site was confirmed. In this report, we describe an extremely rare adverse event associated with overtube insertion. Although the incidence of pharyngeal perforation is low and its management is controversial, it was done without surgical intervention in the present case.

Molecular features of colorectal polyps presenting Kudo's type II mucosal crypt pattern: are they based on the same mechanism of tumorigenesis?

BACKGROUND AND STUDY AIMS: The molecular features of serrated polyps (SPs) with hyperplastic crypt pattern, also called Kudo's type II observed by chromoendoscopy, were evaluated. METHODS: The clinicopathological and molecular features of 114 SPs with a hyperplastic pit pattern detected under chromoendoscopy (five dysplastic SPs, 63 sessile serrated adenoma/polyps (SSA/Ps), 36 microvesicular hyperplastic polyps (MVHPs), and 10 goblet cell-rich hyperplastic polyps (GCHPs)) were examined. The frequency of KRAS and BRAF mutations and CpG island methylator phenotype (CIMP) were investigated. RESULTS: Dysplastic SPs and SSA/Ps were frequently located in the proximal colon compared to others (SSA/Ps vs. MVHPs or GCHPs, P < 0.0001). No significant difference was found in the frequency of BRAF mutation among SPs apart from GCHP (60 % for dysplastic SPs, 44 % for SSA/Ps, 47 % for MVHPs, and 0 % for GCHPs). The frequency of CIMP was higher in dysplastic SPs or SSA/Ps than in MVHPs or GCHPs (60 % for dysplastic SPs, 56 % for SSA/Ps, 32 % for MVHPs, and 10 % for GCHPs) (SSA/Ps vs. GCHP, P = 0.0068). When serrated neoplasias (SNs) and MVHPs were classified into proximal and distal lesions, the frequency of CIMP was significantly higher in the proximal compared to the distal SNs (64 % vs. 11 %, P = 0.0032). Finally, multivariate analysis showed that proximal location and BRAF mutation were significantly associated with an increased risk of CIMP. CONCLUSIONS: Distinct molecular features were observed between proximal and distal SPs with hyperplastic crypt pattern. Proximal MVHPs may develop more frequently through SSA/Ps to CIMP cancers than distal MVHPs.

Distinct molecular features of different macroscopic subtypes of colorectal neoplasms.

BACKGROUND: Colorectal adenoma develops into cancer with the accumulation of genetic and epigenetic changes. We studied the underlying molecular and clinicopathological features to better understand the heterogeneity of colorectal neoplasms (CRNs). METHODS: We evaluated both genetic (mutations of KRAS, BRAF, TP53, and PIK3CA, and microsatellite instability [MSI]) and epigenetic (methylation status of nine genes or sequences, including the CpG island methylator phenotype [CIMP] markers) alterations in 158 CRNs including 56 polypoid neoplasms (PNs), 25 granular type laterally spreading tumors (LST-Gs), 48 non-granular type LSTs (LST-NGs), 19 depressed neoplasms (DNs) and 10 small flat-elevated neoplasms (S-FNs) on the basis of macroscopic appearance. RESULTS: S-FNs showed few molecular changes except SFRP1 methylation. Significant differences in the frequency of KRAS mutations were observed among subtypes (68% for LST-Gs, 36% for PNs, 16% for DNs and 6% for LST-NGs) (P<0.001). By contrast, the frequency of TP53 mutation was higher in DNs than PNs or LST-Gs (32% vs. 5% or 0%, respectively) (P<0.007). We also observed significant differences in the frequency of CIMP between LST-Gs and LST-NGs or PNs (32% vs. 6% or 5%, respectively) (P<0.005). Moreover, the methylation level of LINE-1 was significantly lower in DNs or LST-Gs than in PNs (58.3% or 60.5% vs. 63.2%, P<0.05). PIK3CA mutations were detected only in LSTs. Finally, multivariate analyses showed that macroscopic morphologies were significantly associated with an increased risk of molecular changes (PN or LST-G for KRAS mutation, odds ratio [OR] 9.11; LST-NG or DN for TP53 mutation, OR 5.30; LST-G for PIK3CA mutation, OR 26.53; LST-G or DN for LINE-1 hypomethylation, OR 3.41). CONCLUSION: We demonstrated that CRNs could be classified into five macroscopic subtypes according to clinicopathological and molecular differences, suggesting that different mechanisms are involved in the pathogenesis of colorectal tumorigenesis.

Primary micropapillary carcinoma of the colon: a case report and literature review.

We report a case of micropapillary carcinoma (MPC) of the transverse colon. A 56-year-old woman was admitted to our hospital with hematochezia. A lower gastrointestinal examination revealed an irregular ulcerative tumor of approximately 60 mm diameter with marginal elevation in the transverse colon. Abdominal computed tomography showed multiple swollen lymph nodes. A histological examination of the resected specimen revealed that cancer cells had invaded the subserosa. Microscopically, small papillary cells proliferated with lacuna spaces and the cribriform glandular configuration was observed. Immunohistochemically, the basal surface of the neoplastic cell clusters was diffusely positive for MUC1. No primary tumor was observed except for the colon. Therefore, this tumor was diagnosed as a primary MPC of the colon. Since a colorectal MPC was first reported in 2005, seven case reports and three pathological reviews have been presented in the English literature. MPC has an aggressive behavior with a high incidence of lymphovascular invasion and nodal metastases. We should take intensive chemotherapy for colorectal MPC into account, even if surgical resection is curative.