Feasibility and Safety of Endoscopic Control for Patients with Serrated Polyposis Syndrome.

INTRODUCTION: Despite advances in endoscopic treatment, patients with serrated polyposis syndrome (SPS) occasionally require surgery due to numerous or unresectable polyps, recurrence, and treatment-related adverse events. METHODS: We retrospectively evaluated 43 patients with SPS undergoing diagnosis and treatment at Omori Red Cross Hospital from 2011 to 2022. Resection of all polyps ≥3 mm in size was planned during the clearing phase; endoscopic control was defined as complete, endoscopic polyp removal. During the surveillance phase, patients underwent annual colonoscopy and resection of newly detected polyps ≥3 mm in size. RESULTS: Thirty-eight patients (88%) achieved endoscopic control, two (5%) required surgery after endoscopic treatment because of colorectal cancer (CRC), and three (7%) have not yet achieved endoscopic control and are planning treatment. Endoscopic control was achieved with a median of four colonoscopies at 8 months. Ten polyps (median value) were resected per patient during the clearing phase. Three polyps ≥50 mm in size, six located in the appendiceal orifice, and seven with severe fibrosis could be resected by endoscopic submucosal dissection (ESD). All patients underwent treatment with a combination of cold snare polypectomy (CSP), endoscopic mucosal resection/hot polypectomy, and/or ESD. No case required surgery due to difficulty with endoscopic treatment. Delayed bleeding was observed in 2 cases (0.3%). Twenty-one patients underwent colonoscopies during the surveillance phase. Fifty-three polyps were resected using CSP; no CRC, sessile serrated lesions with dysplasia, or advanced adenoma were detected. CONCLUSION: SPS can be effectively, efficiently, and safely controlled with appropriate endoscopic management.

Effectiveness of Strategy-Focused Training in Colorectal Endoscopic Submucosal Dissection: A Retrospective Observational Study.

BACKGROUND: Colorectal ESD, an advanced minimally invasive treatment, presents technical challenges, with globally varying training methods. We analyzed the learning curve of ESD training, emphasizing preoperative strategies, notably gravity traction, to guide ESD instructors and trainee programs. METHOD: This retrospective study included 881 cases guided by an experienced supervisor. Six trainees received "strategy-focused" instruction. To evaluate the number of ESD experiences in steps, the following phases were classified based on ESD experiences of each trainees: Phase 0 (0-50 ESD), Phase 1 (51-100 ESD), Phase 2 (101-150 ESD), and Phase 3 (151-200 ESD). Lesion background, outcomes, and safety were compared across phases. Factors contributing to technical difficulty in early (Phase 0 and 1) and late phases (Phase 2 and 3) were identified, along with the utility of traction ESD with device assistance. RESULT: Treatment outcomes were favorable, with 99.8% and 94.7% en bloc resection and curative resection rates, respectively. Approximately 90% self-completion rate could be achieved after experiencing about 50 cases (92.7% in Phase 1), signifying proficiency growth despite increased case difficulty. In early phases, factors such as left-sided colon, LST-NG morphology, and severe fibrosis pose challenges. In late phases, LST-NG morphology, mild and severe fibrosis remained significant. Traction-assisted ESD, utilized in 3% of cases, comprised planned (1.1%) and rescue (1.9%) methods. Planned traction aided specific lesions, while rescue traction was common in the right colon. CONCLUSION: "Strategy-focused" ESD training consistently yields successful outcomes, effectively adapting to varying difficulty factors in different proficient stages.

The feasibility and safety of endoscopic submucosal dissection of gastric lesions larger than 5 cm.

BACKGROUND: As the indications for endoscopic submucosal dissection (ESD) for early gastric cancer have been revised, diagnostic ESD has increased. However, despite the technical difficulty of ESD for large lesions, the degree to which curative resection can be achieved has not been clarified. This study investigated the feasibility and safety of ESD for gastric lesions larger than 5 cm. METHODS: This retrospective multicenter study included 3474 gastric lesions treated by ESD from April 2012 to December 2021. We compared clinicopathological characteristics and treatment outcomes between lesions ≥ 5 cm and lesions < 5 cm. RESULTS: There were 128 lesions in the ≥ 5 cm group and 3282 lesions in the < 5 cm group. In the ≥ 5 cm group, upper location and fibrosis during ESD were more common, with a lower rate of 0-IIc type. Both en bloc resection rate and R0 resection rate were comparable, but there was a difference in curative resection rate (65.6% in the ≥ 5 cm group and 91.5% in the < 5 cm group). The frequency of adverse events (post-ESD bleeding, perforation, or stenosis) was almost similar, but delayed perforation was significantly more common (1.6% in the ≥ 5 cm group vs. 0.1% in the < 5 cm group). CONCLUSIONS: About two-thirds of curative resections were obtained with ESD for early gastric lesions larger than 5 cm, but delayed complications should be noted (Number: UMIN000047725).

Effects of colorectal endoscopic submucosal dissection on postoperative abdominal symptoms: a prospective observational study.

BACKGROUND: Endoscopic submucosal dissection (ESD) is an effective procedure to resect large superficial gastrointestinal neoplasms. In gastric ESD, several studies showed the relationship between postoperative abdominal symptoms and endoscopic treatment. However, the influence of colorectal ESD on abdominal symptoms after treatment is still unknown. To the best of our knowledge, this is the first prospective multicenter study performed to investigate the impact of colorectal ESD on postoperative abdominal symptoms. This study aimed to clarify the association between change of abdominal symptoms and ESD. METHODS: This study was a prospective multicenter observational trial that enrolled 141 out of 171 patients who underwent colorectal ESD and answered the Gastrointestinal Symptom Rating Scale (GSRS) questionnaire from March 2015 to August 2019. We evaluated abdominal symptoms in the patients using the GSRS questionnaire before ESD and a few weeks after ESD. RESULTS: Comparing the GSRS before and after ESD, overall scores changed from 1.58 ± 0.58 to 1.48 ± 0.48, and the five subscales (reflux syndrome, abdominal pain, indigestion syndrome, diarrhea syndrome, and constipation syndrome) were slightly improved. Overall scores, indigestion syndrome, and constipation syndrome were statistically significantly different before and after ESD (P < 0.05). CONCLUSIONS: In GSRS, a score of ≥ 3 is often treated as a clinically significant symptom. Therefore, our findings indicated that there was no clinically significant difference. For this reason, colorectal ESD does not affect postoperative abdominal symptoms and is considered a minimally invasive treatment. The analysis of the impact of colon ESD on gastrointestinal symptoms UMIN000016914.

The feasibility of endoscopic submucosal dissection for colorectal lesions larger than 10 cm.

BACKGROUND: Although endoscopic submucosal dissection (ESD) enables en bloc removal of colorectal neoplasms, its effectiveness for larger lesions (≥ 10 cm in diameter) is undetermined. We aimed to investigate the feasibility and safety of ESD for colorectal lesions ≥ 10 cm wide. METHODS: This retrospective study included 3591 consecutive colorectal lesions managed with ESD from June 2012 through December 2020. Clinicopathological characteristics and treatment outcomes were compared between lesions ≥ 10 cm wide and lesions 5-10 cm wide. RESULTS: There were 50 patients in the ≥ 10 cm group and 270 patients in the 5-10 cm group. Among patients in the ≥ 10 cm group, lesions were most often in the rectum (50.0%), and the laterally spreading tumor-granular nodular mixed type (LST-G-M) was most prevalent (41/50, 82%). Although patients in the ≥ 10 cm group a longer mean ESD procedure time (186.0 vs. 94.4 min, p < 0.001), the dissection speed was significantly higher in this group (0.50 vs. 0.41 cm2/min, p = 0.003). The en bloc and curative resection rates were comparable between the ≥ 10 cm and 5-10 cm groups (100% vs. 99.6% and 86.0% vs. 88.5%, respectively). Although the stenosis rate was higher in the ≥ 10 cm group (4% vs. 0%), the delayed bleeding and perforation rates were similar between the two groups. CONCLUSIONS: ESD for colorectal lesions ≥ 10 cm wide is feasible and curative, even though it is associated with higher technical difficulty and longer procedure times compared with ESD for smaller lesions (Number: UMIN 000044313).

Comparison of the diagnostic performance of NBI, Laser-BLI and LED-BLI: a randomized controlled noninferiority trial.

BACKGROUND AND AIMS: New image-enhanced endoscopy (IEE), blue Light Imaging (LED-BLI) is launched in USA and Europe, whereas Blue Laser Imaging (Laser-BLI) is available only Asian and some countries. No studies have directly compared the diagnostic accuracy of narrow band imaging (NBI), Laser-BLI and LED-BLI for colorectal tumors. The present study aimed to compare the diagnostic accuracy of the three methods for colorectal tumor using the NBI international colorectal endoscopic (NICE) classification and the Japanese NBI Expert Team (JNET) classifications. METHODS: This was a multi-center evaluator-blinded, randomized control trial of patients who underwent endoscopic colorectal tumor resection. The patients were randomly assigned to NBI, Laser-BLI or LED-BLI. Cropped images were sent to blinded external evaluators and diagnosed according to NICE and JNET classifications. The diagnostic accuracy of each endoscopy system was compared with non-inferiority test. RESULTS: A total of 619 colonic tumors were resected from 230 patients and evaluated by external four evaluators. The diagnostic accuracy of NBI for NICE 1, NICE 2, NICE 3 was 90.6%, 90.3% and 99.5%, respectively and for JNET 1, JNET 2A, JNET 2B and JNET 3, it was 94.6%, 72.0%, 79.2% and 99.1%, respectively. In non-inferiority test, Laser-BLI and LED-BLI revealed non-inferiority to NBI in all NICE and JNET categories (p<0.001). CONCLUSIONS: Laser-BLI and LED-BLI had high diagnostic accuracy and non-inferiority of NBI, especially for hyperplastic polyp/sessile serrated lesion and low-grade dysplasia. This is first trial to compare the diagnostic accuracy with NBI, Laser-BLI and LED-BLI and useful to understand the position of each IEE. This trial was registered as UMIN000032107.

Severe acute respiratory syndrome coronavirus 2 prevalence in saliva and gastric and intestinal fluid in patients undergoing gastrointestinal endoscopy in coronavirus disease 2019 endemic areas: Prospective cross-sectional study in Japan.

OBJECTIVES: Gastrointestinal endoscopy (GIE) is useful for the early detection and treatment of many diseases; however, GIE is considered a high-risk procedure in the coronavirus disease 2019 (COVID-19) pandemic era. This study aimed to explore the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity in saliva and gastrointestinal fluids to which endoscopy medical staff are exposed. METHODS: The study was a single-center cross-sectional study. From June 1 to July 31, 2020, all patients who underwent GIE at Yokohama City University Hospital were registered. All patients provided 3 mL of saliva. For upper GIE, 10 mL of gastric fluid was collected through the endoscope. For lower GIE, 10 mL of intestinal fluid was collected through the endoscope. The primary outcome was the positive rate of SARS-CoV-2 in saliva and gastrointestinal fluids. We also analyzed serum-specific antibodies for SARS-CoV-2 and patients' background information. RESULTS: A total of 783 samples (560 upper GIE and 223 lower GIE samples) were analyzed. Polymerase chain reaction (PCR) on saliva samples did not show any positive results in either upper or lower GIE samples. However, 2.0% (16/783) of gastrointestinal fluid samples tested positive for SARS-CoV-2. No significant differences in age, sex, purpose of endoscopy, medication, or rate of antibody test positivity were found between PCR positive and PCR negative cases. CONCLUSIONS: Asymptomatic patients, even those with no detectable virus in their saliva, had SARS-CoV-2 in their gastrointestinal tract. Endoscopy medical staff should be aware of infection when performing procedures. The study was registered as UMIN000040587.

Evaluation of colorectal endoscopic submucosal dissection using a multifunctional snare: a prospective clinical feasibility study (with videos).

BACKGROUND AND AIMS: The number of colorectal endoscopic submucosal dissections (ESDs) for early colorectal cancer is expected to increase in the future; therefore, cost reduction is a clinically important issue. The SOUTEN snare (Kaneka Medics, Tokyo, Japan) is a novel multifunctional snare developed for hybrid ESD at a low price. If ESD can be performed safely using the SOUTEN snare, the same therapeutic effect can be obtained as with conventional ESD at a lower cost. The aim of this prospective, pilot, clinical feasibility study was to evaluate the safety and efficacy of ESD using the SOUTEN snare (SOUTEN-ESD). METHODS: From October 2018 to January 2019, 119 consecutive patients (121 ESD procedures, 137 colorectal neoplasms) were prospectively enrolled and treated by SOUTEN-ESD at NTT Medical Center Tokyo and Omori Red Cross Hospital. The outcomes of SOUTEN-ESD were evaluated. RESULTS: Among 137 neoplasms, SOUTEN-ESD was completed in all cases. No cases required conversion to hybrid ESD or to a dedicated ESD device. The mean procedure time was 26.1 ± 14.3 minutes. Both the en-bloc resection rate and R0 resection rate were 100%. The rate of perforation was 0%, the rate of delayed bleeding was 2.2%, and the rate of post-ESD coagulation syndrome was 2.9%. CONCLUSIONS: SOUTEN-ESD was safe and had good outcomes. Although further studies are required to examine indications for SOUTEN-ESD and confirm the results of this study, effective ESD with this novel knife is feasible. The SOUTEN snare is a realistic option for colorectal ESD. (Clinical trial registration number: UMIN 000034299.).

Endoscopic submucosal dissection of large pedunculated polyps with wide stalks: a retrospective multicenter study.

BACKGROUND: Endoscopic resection of large pedunculated colorectal polyps is technically difficult, especially when the polyp is large and has such a thick stalk that it is either too difficult or impossible to resect prophylactically by a conventional snare. Here, we evaluated the feasibility of ESD for large pedunculated polyps with wide stalks. METHODS: 29 patients with large pedunculated polyps that were not resectable by polypectomy or endoscopic mucosal resection were enrolled in the study. RESULTS: En bloc resection was achieved in 28/29 polyps. One suspended case was due to severe fibrosis with muscle retraction signs. The mean diameter of the 29 polyp heads was 39.7 (standard deviation 6.9) mm. Submucosal fibrosis was present in 16 polyps (9 mild; 7 severe). The stalks of severely fibrotic polyps were significantly thicker than those of polyps with no or mild fibrosis. The curative resection rate was 85.7 % without severe complications. CONCLUSIONS: ESD is feasible for the removal of large pedunculated polyps with wide stalks when conventional snare resection is difficult or impossible.

Impact of obesity in colorectal endoscopic submucosal dissection: single-center retrospective cohort study.

BACKGROUND: When performing colorectal endoscopic submucosal dissection (ESD) in obese patients, technically difficult cases are sometimes experienced because of difficulty with the insertion of the colonoscope, poor scope maneuverability, or an abundance of fat tissue in the submucosal layer. Since the association between obesity and colorectal ESD has not been investigated, we evaluated the clinical impact of obesity in patients who underwent colorectal ESD. METHODS: We retrospectively reviewed 535 patients who underwent colorectal ESD between April 2012 and February 2019. Patients were divided into three groups based on their body mass index (BMI): a control group (BMI < 25 kg/m2), an overweight group (25 kg/m2 ≤ BMI < 30 kg/m2), and an obese group (BMI ≥ 30 kg/m2), and the short-term clinical outcomes were analyzed to assess the safety and difficulty of colorectal ESD. RESULTS: No significant difference in the procedure times, en bloc resection rates, pathological diagnoses, or complications were seen among the groups. While the amount of sedative per body weight was significantly lower in the group with a higher BMI (flunitrazepam: 1.75 × 10-2 [1.27 × 10-2-2.34 × 10-2] mg/kg vs. 1.48 × 10-2 [1.08 × 10-2-2.03 × 10-2] mg/kg vs. 1.16 × 10-2 [0.98 × 10-2-1.54 × 10-2] mg/kg, P < 0.001; pethidine: 0.63 [0.55-0.72] mg/kg vs. 0.50 [0.46-0.56] mg/kg vs. 0.39 [0.32-0.45] mg/kg, P < 0.001), a reduction in percutaneous arterial oxygen saturation occurred significantly more frequently in the group with a higher BMI (123 [30.2%] vs. 43 [43.9%] vs. 10 [55.6%], P = 0.005). When the procedures were performed by trainees, the number of cases that required a procedure time of longer than 90 min was significantly larger in the group with a higher BMI (27 [10.8%] vs. 14 [21.9%] vs. 3 [25.0%], P = 0.033). CONCLUSIONS: This study showed that colorectal ESD could be performed safely and effectively in obese patients. However, ESD in obese patients requires attention, particularly to changes in respiratory conditions.

Efficacy of sedation with dexmedetomidine plus propofol during esophageal endoscopic submucosal dissection.

BACKGROUND AND AIM: During endoscopic submucosal dissection for superficial esophageal cancer, patient body movement can sometimes occur, which may cause discontinuation of the procedure. Propofol and dexmedetomidine have recently been found to be useful sedatives for endoscopic submucosal dissection. This study investigated whether sedation using propofol plus dexmedetomidine can suppress the patient's body movements during esophageal endoscopic submucosal dissection and compared this combination with sedation using propofol alone. METHODS: This was a prospective double-blind randomized controlled trial. Patients with superficial esophageal cancers who underwent esophageal endoscopic submucosal dissection at Yokohama City University Hospital were prospectively enrolled and were randomly assigned to the propofol and the propofol plus dexmedetomidine groups. The primary endpoint was the incidence of restlessness. The secondary endpoints were the satisfaction score, maintenance dose of propofol, and number of rescue propofol injections. RESULTS: Sixty-six patients (propofol group: n = 33; combination group: n = 33) were included. The combination group had a significantly lower incidence of restlessness than the propofol group (3.0% vs 27.3%, P = 0.02). In the combination group, the satisfaction scores of the endoscopists were significantly higher, the maintenance dose of propofol was significantly lower, and the number of rescue propofol injections was lower than those in the propofol group (3.0% vs 18.2%, P < 0.001). Although the incidence of bradycardia was significantly higher in the combination group (30.3% vs 3.0%, P < 0.01), no serious adverse effects occurred. CONCLUSION: The propofol plus dexmedetomidine combination provided excellent sedation that effectively suppressed the patient's body movements during esophageal endoscopic submucosal dissection.

Relationship between Stool Form and Quality of Life in Patients with Chronic Constipation: An Internet Questionnaire Survey.

INTRODUCTION: Chronic constipation (CC) is a highly prevalent functional bowel disorder with low treatment satisfaction and impaired quality of life (QOL). However, physicians tend to emphasize only "stool frequency," and relationship between "stool form" and QOL remains unclear. In this study, we aimed to investigate the actual situation of CC treatment in Japan and elucidate the relationship between stool form and QOL in patients with CC. METHODS: We conducted an online questionnaire survey in September 2018 targeting Japanese adult patients already diagnosed with CC and taking prescribed drugs. Assessments included the type of drug treatment, treatment duration, frequency of drug use, frequency of bowel movements (BMs), Bristol Stool Form Scale (BSFS), and Japanese version of the Patient Assessment of Constipation QOL (PAC-QOL) scores. Relationship between BSFS and Japanese PAC-QOL scores was analyzed, and most important factor that influences QOL was investigated. RESULTS: A total of 614 subjects were enrolled. Of these, 398 (64.8%) regularly used magnesium oxide and 162 (26.4%) used stimulant laxative, especially 81 (50.0%) used stimulant laxative "everyday." Mean score of the PAC-QOL was 1.29 ± 0.74, and the lowest score (highest QOL) of 0.94 ± 0.61 was observed in BSFS type 4. Significant difference was seen between BSFS type 4 and all the other types except type 7. Multivariate analysis revealed that normal stool form (BSFS type 4) and BMs ≥3/week are strongly related to decreases of PAC-COL score. In BSFS types 6 and 7, 36% of individuals experienced self-discontinuation of prescribed drugs and 53% self-reduced drug intake because of excessive effects. CONCLUSIONS: Stool form and frequency of BMs are relevant to QOL, especially normal stool form (BSFS type 4) is important for improving the QOL in patients with constipation. Physicians should focus on "stool form" and reconsider the prescription especially in BSFS types 6-7 patients.

Management of Less Than 10-mm-Sized Pedunculated (Ip) Polyps with Thin Stalk: Hot Snare Polypectomy Versus Cold Snare Polypectomy.

BACKGROUND: Although the use of cold snare polypectomy (CSP) has spread rapidly, its safety for pedunculated (Ip) polyps remains controversial. In particular, the outcomes of hot snare polypectomy (HSP) and CSP for Ip polyps have not been previously compared. AIMS: This study evaluated whether the rate of delayed postpolypectomy bleeding (DPPB) after CSP for Ip polyps was higher than that after HSP for Ip polyps and compared other outcomes (the rates of immediate bleeding and pathological margins) between the HSP and CSP procedures. METHODS: A total of 5905 colorectal polyps in 4920 patients were resected at Omori Red Cross Hospital between October 2012 and June 2019. The polyps were divided into two groups: the HSP group (86 polyps, 64 patients) and the CSP group (102 polyps, 87 patients). The primary outcome measure was the incidence of DPPB. The secondary outcome measures were the incidences of immediate bleeding during the procedure and pathological margins of the resected specimen. RESULTS: The rate of immediate bleeding during CSP was significantly higher than that for the HSP group [38.2% (39/102) versus 3.5% (3/86); p < 0.001]. However, the rate of DPPB was significantly higher in the HSP group than in the CSP group [4.7% (4/86) versus 0% (0/102); p < 0.001]. The rate of DPPB after CSP was 0%. CONCLUSIONS: This is the first study to compare the outcomes of HSP and CSP for Ip polyps. CSP is safer than HSP for Ip polyps measuring < 10 mm in diameter.

The efficacy of a leukotriene receptor antagonist in the treatment of human rectal aberrant crypt foci: a nonrandomized, open-label, controlled trial.

BACKGROUND: Leukotriene receptor antagonists (LTRAs) are broadly used for the management of allergic asthma and have recently been indicated to inhibit carcinogenesis and cancer cell growth. In colorectal cancer (CRC) chemoprevention studies, the occurrence of adenoma or CRC itself is generally set as the trial endpoint. Although the occurrence rate of CRC is the most confident endpoint, it is inappropriate for chemoprevention studies because CRC incidence rate is low in the general population and needed for long-term monitoring. Aberrant crypt foci (ACF), defined as lesions containing crypts that are larger in diameter and darker in methylene blue staining than normal crypts, are regarded to be a fine surrogate biomarker of CRC. Therefore, this prospective study was designed to explore the chemopreventive effect of LTRA on colonic ACF formation and the safety of the medicine in patients scheduled for a poly resection as a pilot trial leading the CRC chemoprevention trial. METHODS: This study is a nonrandomized, open-label, controlled trial in patients with colorectal ACF and polyps scheduled for a polypectomy. Participants meet the inclusion criteria will be recruited, and the number of ACF in the rectum will be counted at the baseline colonoscopic examination. Next, the participants will be assigned to the LTRA or no treatment group. Participants in the LTRA group will continue 10 mg of oral montelukast for 8 weeks, and those in the no treatment group will be observed without the administration of any additional drugs. At the end of the 8-week LTRA intervention period, a polypectomy will be conducted to evaluate the changes in the number of ACF, and cell proliferation in the normal colorectal epithelium will be analyzed. DISCUSSION: This will be the first study to investigate the effect of LTRAs on colorectal ACF formation in humans. TRIAL REGISTRATION: This trial has been registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry as UMIN000029926 . Registered 10 November 2017.

The efficacy of aspirin and metformin combination therapy in patients with rectal aberrant crypt foci: a double-blinded randomized controlled trial.

BACKGROUND: The incidence and mortality rates of colorectal cancer (CRC) continue to increase worldwide. Therefore, new preventive strategies are needed to lower the burden of this disease. Previous studies reported that aspirin could suppress the development of sporadic colorectal adenoma. In addition, metformin is a biguanide derivative that is long widely used for the treatment of diabetes mellitus and has recently been suggested to have a suppressive effect on carcinogenesis and cancer cell growth. Both drugs exhibit a chemopreventive effect, but their efficacy is limited. Aberrant crypt foci (ACF), defined as lesions containing crypts that are larger in diameter and stain more darkly with methylene blue than normal crypts, are more prevalent in patients with cancer and adenomas, and considered a reliable surrogate biomarker of CRC. Thus, we designed a prospective trial as a preliminary study prior to a CRC chemoprevention trial to evaluate the chemopreventive effect of aspirin combined with metformin on colorectal ACF formation in patients scheduled for polypectomy. METHODS: This study is a double-blind randomized controlled trial that will be conducted in patients with both colorectal ACF and colorectal polyps scheduled for polypectomy. Eligible patients will be recruited for the study and the number of ACF in the rectum will be counted at the baseline colonoscopy. Then, the participants will be allocated to one of the following two groups; the aspirin plus placebo group or the aspirin plus metformin group. Patients in the aspirin plus placebo group will receive oral aspirin (100 mg) and placebo for 8 weeks, and those in the aspirin plus metformin group will receive oral aspirin (100 mg) and metformin (250 mg) for 8 weeks. After 8 weeks of administration, polypectomy will be performed to evaluate changes in the number of ACF, and the cell-proliferative activity in the normal colorectal mucosa and colorectal polyps. DISCUSSION: This is the first study proposed that will explore the effect of aspirin combined with metformin on the formation of colorectal ACF in humans. TRIAL REGISTRATION: This trial has been registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry as UMIN000028259 . Registered 17 July 2017.

Safety and efficacy of cold snare polypectomy for pedunculated (Ip) polyps measuring less than 10 mm in diameter.

BACKGROUND: Although cold snare polypectomy (CSP) has spread rapidly, it still remains controversial whether CSP is safe for pedunculated (Ip) polyps. PURPOSE: The aim of this study was to evaluate whether CSP for Ip polyps measuring less than 10 mm in diameter might be associated with an increased rate of delayed post-polypectomy bleeding (DPPB). METHODS: A total of 1641 colorectal polyps in 634 patients were resected at Omori Red Cross Hospital between April 2018 and December 2018. The polyps were divided into two groups depending on the morphology: the Ip group (90 polyps), and the non-Ip group (1551 polyps). RESULTS: Among the 1641 polyps, there was no case of DPPB, including in the Ip group. Immediate bleeding occurred in a total of 101 (6.2%) cases. Polyp location in the rectum (OR (95% CI), 3.61 (1.843-7.092); p < 0.001), polyp diameter ≥ 6 mm (OR (95% CI), 2.65 (1.702-4.132); p < 0.001), Ip morphology (OR (95% CI), 15.66 (9.262-26.49); p < 0.001), and treatment with antithrombotic agents (OR (95% CI), 2.18 (1.358-3.501); p = 0.0012) were identified as significant risk factors for immediate bleeding. CONCLUSIONS: This is the first study conducted to examine the safety of CSP for Ip polyps measuring less than 10 mm in diameter. CSP can be performed with a high level of safety even for Ip polyps. Based on our findings, we believe that Ip polyps could be included as an indication for CSP. However, prospective, randomized studies are necessary to confirm our results.

Predictive Factors of Mild and Severe Fibrosis in Colorectal Endoscopic Submucosal Dissection.

BACKGROUND AND STUDY AIMS: Varying degrees of fibrosis in colorectal endoscopic submucosal dissection (ESD) make the procedure difficult. Consensus on the predictive factors of fibrosis degree (mild or severe) has not been established. We conducted a study to identify the predictive factors and to examine the feasibility of ESD for fibrotic lesions. PATIENTS AND METHODS: We included 518 patients who had undergone ESD for 558 lesions from April 2012-September 2018. Patients were classified into fibrosis or no-fibrosis groups, and logistic regression analysis was performed to identify predictive factors of fibrosis. Subgroup analyses were performed for fibrosis degree. RESULTS: The total incidence of fibrosis was 21.1% (mild: 14.1%; severe: 7.1%). Although the curative resection rate (free margin: invasion depth less than 1000 µm: no lymphatic invasion, vascular involvement) was lower in the fibrosis group compared with the control (80.7% vs. 97.6%), neither the en bloc resection rate (99.1% vs. 100%) nor incidence of perforation (0.9% vs. 0.2%) differed between the two groups. Multivariate analysis revealed that a cecal location, preoperative biopsy, straddling fold, laterally spreading tumor-non-granular-pseudo-depressed (LST-NG-PD) type were predictive of mild fibrosis. The presence of a straddling fold and a protruded lesion were independent predictive factors of severe fibrosis. CONCLUSIONS: We identified the predictive factors of mild and severe fibrosis. It is preferable that a more experienced physician performs ESD for the lesions with F2 fibrosis.

Clinical characteristic of esophageal cancer without lugol-voiding lesions in the background esophagus.

Lugol chromoendoscopy is useful for the detection of early esophageal squamous cell cancer (ESCC). Multiple lugol-voiding lesions (LVLs) on lugol chromoendoscopy are associated with a very high risk of multiple cancers arising in the esophagus. Due to the widespread use of narrow band image technology in many institutions, esophageal cancer without LVLs in the background esophagus is sometimes detected. This retrospective study aims to clarify the clinical characteristic of esophageal cancer without LVLs in the background esophagus. A total of 191 consecutive patients with 204 ESCCs had undergone endoscopic submucosal dissection (ESD) from 2011 and 2014. Amongst these lesions, the number of LVLs in the background esophagus per endoscopic view was counted excluding main lesion, and the grading was divided into no LVLs ESCC (nL-ESCC) group and LVLs ESCC (L-ESCC) group. This study evaluated the clinical characteristics and the cumulative incidence of metachronous ESCC after ESD in both groups. Thirty-six patients with 36 lesions and 155 patients with 168 lesions were separated into the nL-ESCC group and L-ESCC group, respectively. On multivariate analysis, the nL-ESCC group was found to be more common in females, who were non-drinkers, or with erosive esophagitis. During follow-up periods, the cumulative incidence of metachronous ESCC at 3-years was 14.4% and 0.00% in the L-ESCC and nL-ESCC groups, respectively (P < 0.01). Our study showed that esophageal cancer without LVLs in the background esophagus was mostly occurred in females, who were non-drinkers, or with erosive esophagitis, which are uncommon features of ESCC.

Risk factors for incomplete polyp resection after cold snare polypectomy.

BACKGROUND: Incomplete polyp resection (IPR) is recognized as a risk factor for interval colorectal cancer (ICC), and is, therefore, an important issue in polypectomy. Cold snare polypectomy (CSP) is a procedure that does not involve electrocautery and has no burn effect. Therefore, there is the possibility that the risk of ICC associated with IPR is higher in cases undergoing CSP than in those undergoing hot polypectomy. However, little is known about the risk factors for IPR after CSP. PURPOSE: Precise identification of the risk factors can lead to prevention of IPR after CSP. Therefore, we performed this observational study for accurate identification of the risk factors for IPR after CSP. METHODS: Medical records of a total of 501 patients with 1177 colorectal polyps that were resected at Omori Red Cross Hospital between October 2017 and March 2018 were retrospectively reviewed. The lateral and deep margins of the resected polyps were evaluated to check for the resection completeness. RESULTS: Among the 1177 polyp resections, 1163 were included in the final analysis. IPR was detected in 206 (17.7%) cases. Performance of the resection by a trainee (OR (95% CI) 1.87 (1.328-2.632); P < 0.001) was identified as an independent risk factor for IPR in patients undergoing CSP. CONCLUSIONS: Performance of the polypectomy by a trainee was identified as a significant risk factor for IPR in patients undergoing CSP. Prospective, randomized studies are necessary in the future to develop effective methods for the prevention/control of IPR after CSP.

Delayed Bleeding After Colorectal Endoscopic Submucosal Dissection: When Is Emergency Colonoscopy Needed?

BACKGROUND: Endoscopic submucosal dissection (ESD) is an effective treatment for early-colorectal cancer. Although delayed bleeding is a serious potential complication, there is no consensus on the optimal protocol to determine which cases require emergency colonoscopy. AIMS: This study aimed to assess the risk factors for delayed bleeding after ESD and evaluate the "watch and wait" strategy for delayed bleeding. The "watch and wait" strategy was used for delayed bleeding, unless the shock index was ≥ 1 and/or a moderate amount of hematochezia occurred more than five occurrences. METHODS: This study included 404 patients who had undergone endoscopic resection for 439 lesions between April 2012 and February 2018. Patients were classified into the bleeding group or the no-bleeding group to investigate the risk factors for delayed bleeding, and to assess the necessity of emergency colonoscopy. RESULTS: Twenty-seven patients into the bleeding group and 412 into the no-bleeding group were classified. However, no case required emergency colonoscopy for hemostasis under "watch and wait strategy." Multivariate analysis revealed the risk factors for bleeding were rectal lesion (OR 5.547, 95% CI 1.456-21.130; P = 0.012) and lesion size ≥ 40 mm (OR 3.967, 95% CI 1.003-15.696; P = 0.05). CONCLUSIONS: Risk factors for delayed bleeding are rectal lesions and lesion size ≥ 40 mm. This watch and wait strategy resulted in no requirements for emergency colonoscopy or blood transfusion, and no serious conditions caused by delayed bleeding.