Diagnostic Value of Adding Magnifying Chromoendoscopy to Magnifying Narrow-Band Imaging Endoscopy for Colorectal Polyps.

BACKGROUND & AIMS: This study examined the additional value of magnifying chromoendoscopy (MCE) on magnifying narrow-band imaging endoscopy (M-NBI) in the optical diagnosis of colorectal polyps. METHODS: A multicenter prospective study was conducted at 9 facilities in Japan and Germany. Patients with colorectal polyps scheduled for resection were included. Optical diagnosis was performed by M-NBI first, followed by MCE. Both diagnoses were made in real time. MCE was performed on all type 2B lesions classified according to the Japan NBI Expert Team classification and other lesions at the discretion of endoscopists. The diagnostic accuracy and confidence of M-NBI and MCE for colorectal cancer (CRC) with deep invasion (≥T1b) were compared on the basis of histologic findings after resection. RESULTS: In total, 1173 lesions were included between February 2018 and December 2020, with 654 (5 hyperplastic polyp/sessile serrated lesion, 162 low-grade dysplasia, 403 high-grade dysplasia, 97 T1 CRCs, and 32 ≥T2 CRCs) examined using MCE after M-NBI. In the diagnostic accuracy for predicting CRC with deep invasion, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for M-NBI were 63.1%, 94.2%, 61.6%, 94.5%, and 90.2%, respectively, and for MCE they were 77.4%, 93.2%, 62.5%, 96.5%, and 91.1%, respectively. The sensitivity was significantly higher in MCE (P < .001). However, these additional values were limited to lesions with low confidence in M-NBI or the ones diagnosed as ≥T1b CRC by M-NBI. CONCLUSIONS: In this multicenter prospective study, we demonstrated the additional value of MCE on M-NBI. We suggest that additional MCE be recommended for lesions with low confidence or the ones diagnosed as ≥T1b CRC. Trials registry number: UMIN000031129.

Long-term Risks of Recurrence After Hospital Discharge for Acute Lower Gastrointestinal Bleeding: A Large Nationwide Cohort Study.

BACKGROUND & AIMS: Currently, large, nationwide, long-term follow-up data on acute lower gastrointestinal bleeding (ALGIB) are scarce. We investigated long-term risks of recurrence after hospital discharge for ALGIB using a large multicenter dataset. METHODS: We retrospectively analyzed 5048 patients who were urgently hospitalized for ALGIB at 49 hospitals across Japan (CODE BLUE-J study). Risk factors for the long-term recurrence of ALGIB were analyzed by using competing risk analysis, treating death without rebleeding as a competing risk. RESULTS: Rebleeding occurred in 1304 patients (25.8%) during a mean follow-up period of 31 months. The cumulative incidences of rebleeding at 1 and 5 years were 15.1% and 25.1%, respectively. The mortality risk was significantly higher in patients with out-of-hospital rebleeding episodes than in those without (hazard ratio, 1.42). Of the 30 factors, multivariate analysis showed that shock index ≥1 (subdistribution hazard ratio [SHR], 1.25), blood transfusion (SHR, 1.26), in-hospital rebleeding (SHR, 1.26), colonic diverticular bleeding (SHR, 2.38), and thienopyridine use (SHR, 1.24) were significantly associated with increased rebleeding risk. Multivariate analysis of colonic diverticular bleeding patients showed that blood transfusion (SHR, 1.20), in-hospital rebleeding (SHR, 1.30), and thienopyridine use (SHR, 1.32) were significantly associated with increased rebleeding risk, whereas endoscopic hemostasis (SHR, 0.83) significantly decreased the risk. CONCLUSIONS: These large, nationwide follow-up data highlighted the importance of endoscopic diagnosis and treatment during hospitalization and the assessment of the need for ongoing thienopyridine use to reduce the risk of out-of-hospital rebleeding. This information also aids in the identification of patients at high risk of rebleeding.

Feasibility Study of Partial Submucosal Injection Technique Combining Underwater EMR for Superficial Duodenal Epithelial Tumors.

BACKGROUND AND AIMS: Endoscopic mucosal resection (EMR) and Underwater EMR have been reported as effective endoscopic treatment for superficial duodenal tumor (SDET). However, a notable problem of EMR for SDET is technical difficulty for the lesion with non-lifting sign, and it of UEMR is that en bloc resection rate is relatively low. Therefore, we performed partial submucosal injection combining UEMR (PI-UEMR). The aim of this study is to evaluate feasibility and safety of this technique for duodenal tumor. METHODS: This is a prospective observational study from tertiary care hospital. We performed PI-UEMR in patients with SDET that is 13-20 mm in diameter, or less than 13 mm with technical difficulty for EMR and UEMR from January 2019 to March 2020. Primary outcome was en bloc resection rate. Secondary outcomes were R0 resection rate, mean total procedure time, intra- and post-procedure complication. RESULTS: Thirty patients were included in this study. Mean age was 62 ± 12 years old. Three fourths lesions were located at anal side from major papilla. Median lesion size was 12 mm [IQR 10-16 mm]. Twenty-four cases were taken endoscopic biopsy in prior hospital and observed biopsy scar. En bloc resection rate was 97%. Ro resection rate was 83%. Mean total procedure time was 17 ± 12 min. And there was an only one case of complication, intra-procedure bleeding that was controllable endoscopically. CONCLUSIONS: PI-UEMR might be very useful and safe technique of endoscopic resection for SDET including relatively large lesions.

Endoscopic hand suturing for mucosal defect closure after gastric endoscopic submucosal dissection may reduce the risk of postoperative bleeding in patients receiving antithrombotic therapy.

OBJECTIVES: Endoscopic hand suturing (EHS) is expected to decrease the risk of post-endoscopic submucosal dissection (ESD) bleeding by closing mucosal defects. We investigated the efficacy of EHS after gastric ESD in patients with antithrombotic agents. METHODS: In this prospective single-arm trial, patients taking antithrombotic agents for cardiovascular disease, arrhythmia, cerebrovascular disease and/or peripheral arterial disease and having <3-cm gastric neoplasms were recruited. The mucosal defects after ESD were closed by EHS in which the needle was delivered through an overtube, and the mucosal rim of the defect was continuously sutured in a linear fashion by manipulating the needle grasped with the needle holder, followed by cutting the remnant suture and retrieval of the needle. The primary endpoint was the incidence of postoperative bleeding within 4 weeks after ESD. RESULTS: Twenty-two lesions in 20 patients (continuing antiplatelet agents in 11, anticoagulant agents in eight, both in one) underwent ESD followed by EHS. All defects (median size, 30 mm; range, 12-51 mm) were completely closed by EHS and remained closed on postoperative day 3. The median number of stitches was six (range, 4-8) and median suturing time was 36 (range, 24-60) min. There were no adverse events during/after EHS or postoperative bleeding. CONCLUSIONS: Postoperative bleeding was not observed in patients taking antithrombotic agents without perioperative cessation. EHS appears to be useful for prevention of post-gastric ESD bleeding in high-risk patients. (Clinical registration number: UMIN000024184).

Clinical usefulness of red dichromatic imaging in hemostatic treatment during endoscopic submucosal dissection: First report from a multicenter, open-label, randomized controlled trial.

OBJECTIVES: To verify the efficacy and safety of red dichromatic imaging (RDI) in hemostatic procedures during endoscopic submucosal dissection (ESD). METHODS: This is a multicenter randomized controlled trial of 404 patients who underwent ESD of the esophagus, stomach, colorectum. Patients who received hemostatic treatments by RDI during ESD were defined as the RDI group (n = 204), and those who received hemostatic treatments by white light imaging (WLI) were defined as the WLI group (n = 200). The primary endpoint was a shortening of the hemostasis time. The secondary endpoints were a reduction of the psychological stress experienced by the endoscopist during the hemostatic treatment, a shortened treatment time, and a non-inferior perforation rate, in RDI versus WLI. RESULTS: The mean hemostasis time in RDI (n = 860) was not significantly shorter than that in WLI (n = 1049) (62.3 ± 108.1 vs. 56.2 ± 74.6 s; P = 0.921). The median hemostasis time was significantly longer in RDI than in WLI (36.0 [18.0-71.0] vs. 28.0 [14.0-66.0] s; P = 0.001) in a sensitivity analysis. The psychological stress was significantly lower in RDI than in WLI (1.71 ± 0.935 vs. 2.03 ± 1.038; P < 0.001). There was no significant difference in the ESD treatment time between RDI (n = 161) and WLI (n = 168) (58.0 [35.0-86.0] vs. 60.0 [38.0-88.5] min; P = 0.855). Four perforations were observed, but none of them took place during the hemostatic treatment. CONCLUSIONS: Hemostatic treatment using RDI does not shorten the hemostasis time. RDI, however, is safe to use for hemostatic procedures and reduces the psychological stress experienced by endoscopists when they perform hemostatic treatment during ESD. UMIN000025134.

Water pressure method for duodenal endoscopic submucosal dissection (with video).

BACKGROUND AND AIMS: Duodenal endoscopic submucosal dissection (ESD) is considered technically challenging and has a high risk of adverse events. However, we recently made some progress with the ESD technique and device by introducing 2 features: a water pressure (WP) method and a second-generation ESD knife (DualKnife) with a water jet function (DualKnife J). The present study aimed to assess whether these changes improved the clinical outcomes of duodenal ESD. METHODS: This was a retrospective observational study. Among all patients who underwent ESD for superficial duodenal epithelial tumors from June 2010 to December 2018, patients in whom a single expert performed the procedure were included in this study. Various factors, including the use of the WP method and ESD devices (DualKnife or DualKnife J) and the treatment phase (early, mid, and late), were analyzed to determine whether they were associated with intraprocedural perforation and procedure time. Treatment phase was assigned by dividing the study population equally into 3 subgroups according to the treatment phase. RESULTS: The procedure time was significantly shorter, and the proportion of patients with intraprocedural perforations was the lowest in the late phase. Multivariate analysis of the use of the WP method revealed that it significantly decreased the intraprocedural perforation rate (odds ratio, 0.39; 95% confidence interval, 0.16-0.96), and analysis of the use of both the WP method (ß coefficient, -0.40; P < .01) and the DualKnife J (ß coefficient, -0.10; P = .032) revealed they were independently and negatively correlated with procedure time. CONCLUSION: The present study reveals that the WP method significantly reduced the intraprocedural perforation rate and that both the WP method and the DualKnife J significantly shortened procedure times for duodenal ESD.

Predictors of technical difficulty for complete closure of mucosal defects after duodenal endoscopic resection.

BACKGROUND AND AIMS: It has been reported that the prophylactic closure of mucosal defects after duodenal endoscopic resection (ER) can reduce delayed adverse events; however, under certain circumstances, this can be technically challenging. Therefore, the aim of this study was to determine the predictors of difficulty during the complete closure of mucosal defects after duodenal ER. METHODS: This was a retrospective study of duodenal lesions that underwent ER between July 2010 and May 2020. We reviewed the endoscopic images and analyzed the relationships between the degree of closure or closure time and clinical features of the lesions using univariate and multivariate analyses. RESULTS: We analyzed 698 lesions. The multivariate analysis revealed that lesion location in the medial or anterior wall (odds ratio, 2.8; 95% confidence interval, 1.36-5.85; P < .01) and a large lesion size (odds ratio, 1.4; 95% confidence interval, 1.07-1.89; P = .03) were independent predictors of an increased risk of incomplete closure. Moreover, a large lesion size (ß coefficient, .304; P < .01), an occupied circumference over 50% (ß coefficient, .178; P < .01), intraoperative perforation (ß coefficient, .175; P < .01), treatment period (ß coefficient, .143; P < .01), and treatment with endoscopic submucosal dissection (ß coefficient, .125; P < .01) were independently and positively correlated with a prolonged closure time in the multiple regression analysis. CONCLUSIONS: This study revealed that lesion location in the medial or anterior wall and lesion size affected the incomplete closure of mucosal defects after duodenal ER, and lesion size, occupied circumference, intraoperative perforation, treatment period, and treatment method affected closure time.

Efficacy of a new image-enhancement technique for achieving hemostasis in endoscopic submucosal dissection.

BACKGROUND AND AIMS: Hemostasis during endoscopic submucosal dissection (ESD) can sometimes be challenging and stressful for the endoscopist. Therefore, we aimed to assess the usefulness of dual red imaging (DRI), a new image enhancement technique that uses 3 wavelengths (540, 600, and 630 nm) to visualize bleeding points and to examine the efficacy of DRI in shortening the time required to achieve hemostasis (hemostasis time) during ESD. METHODS: DRI and white-light imaging (WLI) were used alternately for managing 378 bleeding events in 97 patients undergoing ESD. Hemostasis time for each hemostasis event was measured. Using portable eye-tracking glasses, 4 experienced endoscopists were shown random videos of intraoperative bleeding during ESD (20 cases each on WLI and DRI) and identified the bleeding point in each video. The mean distances of eye movement per unit of time until the bleeding point were identified in each video and compared between the WLI and DRI groups. RESULTS: Average hemostasis time was significantly shorter in the DRI group. The mean distance of eye movement was significantly shorter in the DRI group than in the WLI group for all endoscopists. CONCLUSIONS: DRI can offer useful images to help in clearly detecting bleeding points and in facilitating hemostasis during ESD. It is feasible and may help in successfully performing ESD that is safer and faster than WLI. (Clinical trial registration number: UMIN000018309.).

Endoscopic suturing promotes healing of mucosal defects after gastric endoscopic submucosal dissection: endoscopic and histologic analyses in in vivo porcine models (with video).

BACKGROUND AND AIMS: Endoscopic suturing of mucosal defects after endoscopic submucosal dissection (ESD) is expected to prevent postoperative adverse events. We aimed to endoscopically and histologically evaluate the healing process of post-ESD mucosal defects closed with endoscopic hand suturing (EHS) in in vivo porcine models. METHODS: Twelve mucosal defects (2 cm in size) were created in 2 pigs (6 defects per pig). Initially, 2 defects were created: one was closed with EHS (sutured group) and the other was kept open (control group). On postoperative days (PODs) 7 and 14, 2 additional defects were created in each session, and they were treated in the same manner as in the initial procedure. On POD 21, the entire stomach, with the 6 lesion sites, was extracted for histologic evaluation after endoscopic observation. RESULTS: Endoscopically, all sutured sites remained closed in all sessions (PODs 7, 14, and 21). Histologically, on POD 14, the epithelium and muscularis mucosae were appropriately connected. The mucosae were covered with the epithelium without inversion of the mucosal edge in the sutured group, whereas the ulcer bed was exposed in the control group. Furthermore, the degree of neovascularity and fibroblasts in the submucosa was smaller in the sutured group than that in the control group. CONCLUSIONS: Our findings suggest that endoscopic suturing promotes healing of post-ESD mucosal defects histologically in in vivo porcine models. Thus, endoscopic mucosal closure after ESD might be clinically useful for the prevention of delayed perforation/bleeding if secure suturing is performed endoscopically.

Management of perforation related to endoscopic submucosal dissection for superficial duodenal epithelial tumors.

BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) is being performed more frequently as a local treatment for superficial duodenal epithelial tumors (SDETs). However, ESD for SDETs is technically difficult because of specific anatomic features that increase the risk of perforation and often require surgery. This study was performed to evaluate the management of ESD-related perforation in patients with SDETs. METHODS: Patients who underwent ESD for SDETs from July 2010 to December 2018 were studied. We collected data on complete closure, insertion of endoscopic nasobiliary and pancreatic duct drainage (ENBPD) tubes, and additional interventions. We also evaluated clinical outcomes, including the fasting period, hospital stay, and maximum serum C-reactive protein level. RESULTS: ESD was completed in 264 patients with SDETs. Perforation was observed in 36 patients, including 4 patients with delayed perforation. Among 32 patients with intraoperative perforation, complete closure was achieved in 13 patients. Compared with patients without complete closure, the fasting period and hospital stay were significantly shorter and the maximum serum C-reactive protein level was significantly lower in patients with complete closure, which were equivalent to those in patients without perforation. In patients without complete closure for mucosal defect, no additional interventions were required when an ENBPD tube was inserted, whereas 2 patients without ENBPD tube insertion underwent additional interventions such as percutaneous drainage and a surgical operation. CONCLUSIONS: Perforation associated with ESD for SDETs required complex conservative management with complete closure or insertion of an ENBPD tube.

Feasibility of endoscopic submucosal dissection for colorectal neoplasia at anastomotic sites: a retrospective study.

BACKGROUND: Metachronous colorectal lesions sometimes occur at anastomotic sites following colorectal surgery, which increases the risk of developing colorectal cancer. However, these lesions are difficult to treat even with minimally invasive methods such as endoscopic submucosal dissection (ESD). Thus, we aimed to evaluate the outcomes of ESD for colorectal lesions at anastomotic sites following colorectal surgery. METHODS: We retrospectively investigated 11 patients with post-surgical colorectal lesions at anastomotic sites who later underwent ESD from May 2010 to April 2019 at Keio University Hospital, Tokyo, Japan. We examined the patients' background (tumor location, macroscopic type, tumor size, histological type, and depth of invasion) and treatment outcomes (procedure duration, en bloc resection rate, R0 resection rate, and adverse events). RESULTS: The patients' mean age was 66 years. There were two lesions in the transverse colon, six in the rectum, one in the anal canal, and two in the ileal pouch. The median tumor size was 25 mm. The macroscopic types were the protruded type (1 lesion) and the flat or depressed type (10 lesions). The pathological diagnoses were adenoma (4 lesions), intramucosal cancer (corresponding to high-grade dysplasia) (6 lesions), and muscularis propria cancer (1 lesion). The median procedure duration was 50 min; en bloc resection rate was 88.9% and R0 resection rate was 66.7%. The only adverse event was delayed post-ESD bleeding. CONCLUSIONS: A high en bloc resection rate without perforation was achieved with ESD for lesions at anastomotic sites. Although ESD for lesions at anastomotic sites is a technically challenging procedure because of severe submucosal fibrosis, this approach could prevent the need for repeated surgical resection.

Microsatellite instability in cancer: a novel landscape for diagnostic and therapeutic approach.

Defective DNA mismatch repair creates a strong mutator phenotype, recognized as microsatellite instability (MSI). Various next-generation sequencing-based methods for evaluating cancer MSI status have been established, and NGS-based studies have thoroughly described MSI-driven tumorigenesis. Accordingly, high-frequency MSI (MSI-H) has been detected in 81 tumor types, including those in which MSI was previously underrated. The findings have increased the use of immunotherapy, which is assumed to be efficient in tumors having a high mutation burden and/or neoantigen load. In MSI tumorigenesis, positively and negatively selected driver gene mutations have been characterized in colorectal cancers. Recent advancements in genome-wide studies of MSI-H cancers have developed novel diagnostic and therapeutic approaches, including CXCR2 inhibitor, a synthetic lethal therapy targeting the Werner gene and inhibition of nonsense-mediated mRNA decay. MSI is a predictive marker for chemotherapy as well as immunotherapy. Thus, analyses of MSI status and MSI-related alterations in cancers are clinically relevant. We present an update on MSI-driven tumorigenesis, focusing on a novel landscape of diagnostic and therapeutic approaches.

How I do it: Endoscopic diagnosis for superficial non-ampullary duodenal epithelial tumors.

There are no reports on detailed endoscopic diagnosis of superficial non-ampullary duodenal epithelial tumors (SNADET) except for relatively small case series. Herein, we conducted a prospective observational study to investigate the relationship between endoscopic findings and histopathological diagnosis of SNADET. A total of 163 SNADET diagnosed using magnified endoscopic examination with image-enhanced endoscopy (IEE-ME) were prospectively registered in this study. We investigated location, size, macroscopic type, color, and IEE-ME findings including surface structure (closed- or open-loop) and presence of white opaque substance (WOS) in SNADET. We analyzed association between these findings and histopathological diagnosis of SNADET based on the Vienna classification (VCL) using logistic regression analysis. In univariate analysis, lesion size, superficial structure, and WOS deposition showed statistical significance, and the oral side of the lesion location showed statistical tendency for association with VCL C4/5. In multivariate analysis, lesion size (odds ratio [OR], 2.92; 95% CI, 1.94-4.39; P < 0.05) and negative WOS (OR, 5.59; 95% CI, 1.72-18.1; P < 0.05) were significantly associated with VCL C4/5 lesions. Superficial structures with a closed-loop pattern on the surface showed statistical tendency for predicting VCL C4/5 lesions (OR, 2.15; 95% CI, 0.86-5.37; P = 0.10). Based on these findings, we concluded that negative WOS by IEE-ME and lesion size were independent predictors of VCL C4/5 SNADET. These factors may help us to understand of pathophysiology of SNADET and to select appropriate therapeutic strategies.

Feasibility study comparing underwater endoscopic mucosal resection and conventional endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumor < 20 mm.

BACKGROUND AND AIM: Underwater endoscopic mucosal resection (UEMR) has been reported as an alternative to conventional EMR for superficial non-ampullary duodenal epithelial tumors (SNADET). However, the detailed outcomes are unclear. This study aimed to compare the clinical outcomes between UEMR and EMR for SNADET <20 mm. PATIENTS AND METHODS: This is a retrospective observational study using a prospective maintained database. From November 2017 to December 2018, 104 consecutive cases of attempted UEMR for SNADET <20 mm were prospectively allocated. A total of 240 cases of attempted EMR were chosen as historical controls. We compared technical success rate, defined as the resection rate without conversion to ESD; en bloc resection rate; R0 resection rate; and adverse event rate. Next, multivariate analyses were constructed to identify predictors of conversion to ESD, piecemeal resection, and RX or R1 (RX/R1) resection. RESULTS: Technical success rate of UEMR was significantly higher than that of EMR (87% and 70%, P < 0.01). En bloc resection and R0 resection rates of UEMR were significantly lower than those of EMR (en bloc resection: 87% vs 96%, P < 0.01; R0 resection: 67% vs 80%, P = 0.05). Concerning adverse events, there were no significant differences. In multivariate analyses, attempted EMR, lesion size and depressed type were independent predictors of conversion to ESD. Attempted UEMR was an independent predictor of piecemeal resection and RX/R1 resection. CONCLUSION: The present study indicated that UEMR could be a feasible endoscopic resection method for SNADET (UMIN000025442).

Clinical impact of closure of the mucosal defect after duodenal endoscopic submucosal dissection.

BACKGROUND AND AIMS: Delayed adverse events (bleeding or perforation) are major concerns associated with duodenal endoscopic submucosal dissection (ESD). The aim of this study was to assess the efficacy of prophylactic closure of the mucosal defect after duodenal ESD. METHODS: This is a retrospective study from a university hospital. One hundred sixty-eight patients (173 lesions) who underwent duodenal ESD between July 2010 and June 2017 were included in this study. The study participants were divided into 3 subgroups according to the degree of closure: complete group, incomplete group, and unclosed group. The proportion of delayed adverse events, maximum serum level of C-reactive protein (CRP), and total length of hospital stay were compared among these subgroups. Moreover, a multivariate logistic regression model was constructed to identify the risk factors for delayed adverse events. RESULTS: The proportion of delayed adverse events in the complete group, incomplete group, and unclosed group were 1.7%, 25%, and 15.6%, respectively. The difference between the complete group and the other groups was significant (P < .01). The maximum serum CRP level was much lower (1.51 ± 2.18 mg/dL vs 6.28 ± 10.0 mg/dL, P < .01), and the length of hospital stay was significantly shorter in the complete group than in the incomplete/unclosed group (median [range] 5 [5-14] days vs 8 [4-59] days, P < .01). Multivariate analysis revealed that complete closure had a significant decrease in delayed adverse events (odds ratio [OR], 0.055; 95% confidence interval [CI], 0.01-0.29; P < .01), and a lesion located distal from the descending part showed a statistical tendency to an increase in delayed adverse events (OR, 4.48; 95% CI, 0.85-23.6; P = .08). CONCLUSION: The present study revealed that complete closure of the mucosal defect after duodenal ESD significantly decreased the number of delayed adverse events and improved other outcomes.

Gastric lymphatic flows may change before and after endoscopic submucosal dissection: in vivo porcine survival models.

BACKGROUND AND STUDY AIM: Standard gastrectomy with lymphadenectomy is recommended following endoscopic submucosal dissection (ESD) due to the risk of lymph-node metastasis for resected cancers. However, when lymphatic flows remain unchanged after ESD, a minimally invasive function-preserving surgery based on the sentinel node (SN) concept may be applicable. In this study, using porcine survival models, we aimed to investigate whether gastric lymphatic flows were modified following ESD. METHODS: Twelve pigs, each with one simulating lesion 3 cm in size, were used. Indocyanine green (ICG) fluid was endoscopically injected into the submucosa in four quadrants surrounding the lesion. Following laparoscopic observation of lymphatic flows, the lesions were resected by ESD. After 4 weeks, ICG fluid was injected in four quadrants surrounding the scar and lymphatic flows were observed in the same manner as the initial procedure. The distribution of lymphatic flows, including stained SNs, was compared. RESULTS: In ten lesions (83.3%), the distribution of flows remained unchanged. However, in one lesion, the flow along the right gastric epiploic artery (R-GEA) disappeared on the lesser curvature of the middle stomach. In addition, in one lesion, the flow along R-GEA emerged on the lesser curvature of the lower stomach. CONCLUSIONS: Our study revealed that, despite ESD, lymphatic flows remained unchanged in most parts of the stomach. The SN concept may be applied after ESD, except for lesions on the lesser curvature. However, in the case of the lesser curvature, special care must be given to the SN concept.

Current Status and Challenges of Endoscopic Treatments for Duodenal Tumors.

BACKGROUND: Superficial tumors of the duodenum, other than ampullary tumors, have been traditionally considered rare. However, reports of this kind of tumor have increased in recent times, and the demand for minimally invasive treatments have also increasing. SUMMARY: Adenomas and intramucosal carcinomas are target lesions for treatment. A preoperative diagnosis has not been established, but unnecessary biopsies increase the difficulty of treatment and should be avoided. Cold snare polypectomy, endoscopic mucosal resection (EMR), and underwater EMR are treatment options for small lesions. Endoscopic submucosal dissection enables secure resection even for large lesions, but it is technically demanding and associated with a higher complication rate. After endoscopic resections, exposure of digestive juices is believed to cause delayed complications. To prevent these complications, several closing and covering methods are proposed, with favorable clinical results. Key message: A treatment method should be chosen based on each patient's situation. With any of the treatment methods, post-resection measures are required to prevent delayed complications. Secure closure of resection wounds seems promising.

Endoscopic string clip suturing method: a prospective pilot study (with video).

BACKGROUND AND AIMS: We developed a suturing method with string and clips for a single-channel endoscope. The feasibility of the string clip suturing method is evaluated in this prospective pilot study. METHODS: This study involved 10 consecutive patients who underwent endoscopic submucosal dissection (ESD) for a duodenal tumor. Polyester string was tied to the arm of a partially out thrust clip. The clip and string can be passed through the instrument channel (3.2 mm) of a single-channel endoscope. The clip with string was placed at the distal edge of the large mucosal defect. A second clip was hooked on the string and placed on the opposite side. Both clips were gathered by pulling the free end of the string, and additional clips were placed to achieve complete closure. This method was compared with that for the previous 10 patients without mucosal closure after duodenal ESD. RESULTS: Mean size of resected specimens was 39.1 ± 12.4 mm. The success rate of the string clip suturing method was 100% (10/10). The mean procedure time was 23.4 ± 13.8 minutes. Perforation during ESD occurred in 1 patient and was successfully closed by this method. None of the treated patients developed serious adverse events after the procedure. Compared with the no-suture group, the length of stay was significantly shorter (P = .038). CONCLUSION: The string clip suturing method appears to be a safe and effective method for closure of large mucosal defects. (Clinical trial registration number: UMIN000023698.).

Potential for peritoneal cancer cell seeding in endoscopic full-thickness resection for early gastric cancer.

BACKGROUND AND AIMS: During endoscopic full-thickness resection (EFTR) for cancers, whether exposure of the lumen to the abdominal cavity during the procedure is acceptable is controversial because of the potential risk of tumor cell seeding. To assess the possibility of transplantation as a result of contact with tumor cells during the procedure, we prospectively investigated the ability of cancer cells to be detached by touching the tumor surface. METHODS: In 48 patients with a single early gastric cancer resected by endoscopic submucosal dissection, stamp cytology was performed by touching the surface of the specimens to glass slides. Samples were obtained from cancerous and noncancerous areas, constituting the study and control groups, respectively. The detection rate of malignant class IV or V (C-IV/C-V) samples was investigated with Papanicolaou staining. The rate of CD44v9-positive cases, a cancer stem cell marker, was assessed in C-IV/C-V samples with immunohistochemical staining. RESULTS: Detection rates of C-IV/C-V samples in the cancerous group (53/192 slides, 27.6%) differed significantly from those of the C-IV/C-V samples in the noncancerous group (0/96 slides, 0%). Among the 53 slides of C-IV/C-V samples in the cancerous group, CD44v9 cells were expressed in 18 slides (34.0%). CONCLUSIONS: These data suggest that cancer cells, including cancer stem cells, in early gastric cancers are easily detached via contact with the tumor surface. In EFTR, a nonexposure approach is recommended to avoid the risk of iatrogenic cancer cell seeding via contact with and transplantation of cancer cells.

Rebamipide solution: a novel submucosal injection material to promote healing speed and healing quality of ulcers induced by endoscopic submucosal dissection.

BACKGROUND AND AIMS: Rebamipide is administered perorally to protect the gastric mucosa. We assessed the efficacy and safety of a novel rebamipide solution as a submucosal injection material for endoscopic submucosal dissection (ESD) using an in vivo porcine model. METHODS: An endoscopist blinded to the test agents performed ESDs of hypothetical 30 mm lesions using a 2% rebamipide solution at 2 sites (rebamipide group) and a saline solution at 2 other sites (control group) in the stomachs of 8 pigs. The technical outcomes were compared between the 2 groups. The gastric ulcer stages were evaluated by endoscopy once weekly for 4 weeks after the ESD to determine the healing score (1-6). The pigs were killed at 1 week (n = 2), 2 weeks (n = 2), and 4 weeks (n = 4) after the ESD for pathologic evaluation of ESD-induced ulcers and scarring. RESULTS: There were no significant differences in any of the technical outcomes between the 2 groups, and no adverse events related to the ESD in any of the animals. The healing score was significantly higher in the rebamipide group than in the control group at 2 weeks (P = .027), 3 weeks (P = .034), and 4 weeks (P = .012). In the histopathologic assessment, fibrosis was significantly less extensive in the rebamipide group than in the control group at 2 weeks (P = .02) and 4 weeks (P = .04). CONCLUSIONS: The rebamipide solution appeared to promote both the speed and quality of healing of ESD-induced ulcers by suppressing fibrosis.