Endoscopic hand suturing using a modified through-the-scope needle holder for mucosal closure after colorectal endoscopic submucosal dissection: Prospective multicenter study (with video).

OBJECTIVES: Endoscopic hand suturing (EHS) is a novel technique for closing a mucosal defect after endoscopic submucosal dissection (ESD). We investigated the technical feasibility of colorectal EHS using a modified flexible through-the-scope needle holder. METHODS: This was a prospective multicenter study conducted at two referral centers between June 2022 and April 2023. This study included colorectal neoplasms 20-50 mm in size located in the sigmoid colon or rectum. A modified flexible through-the-scope needle holder, with an increased jaw width to facilitate needle grasping, was used for colorectal EHS. The primary end-points were sustained closure rate on second-look endoscopy (SLE) performed on postoperative days 3-4 and suturing time for colorectal EHS. Secondary end-points included complete closure rate and delayed adverse events. RESULTS: We enrolled 20 colorectal neoplasms in 20 patients, including four patients receiving antithrombotic agents. The tumor location was as follows: lower rectum (n = 8), upper rectum (n = 2), rectosigmoid colon (n = 4), and sigmoid colon (n = 6), and the median mucosal defect size was 37 mm (range, 21-65 mm). The complete closure rate was 90% (18/20 [95% confidence interval (CI) 68.3-98.8%]), and the median suturing time was 49 min (range, 23-92 min [95% CI 35-68 min]). Sustained closure rate on SLE was 85% (17/20 [95% CI 62.1-96.8%]). No delayed adverse events were observed. CONCLUSION: EHS demonstrated a high sustained closure rate. Given the long suturing time and technical difficulty, EHS should be reserved for cases with a high risk of delayed adverse events.

Chronological Trend of Opportunistic Endoscopic Screening for Gastric Cancer and Atrophic Gastritis.

BACKGROUND: Opportunistic endoscopic screening for gastric cancer was initiated in 2004 at our institute. We investigated chronological trends in gastric cancer detection rates based on individual characteristics and atrophic gastritis prevalence. METHODS: Overall, 15,081 asymptomatic individuals aged ≥40 years without a medical history of gastric cancer underwent first-time esophagogastroduodenoscopy in our institute between February 2004 and December 2017. We retrospectively investigated individual characteristics and endoscopic diagnoses by period (early period: 2004-2007, middle period: 2008-2012, and late period: 2013-2017), clarified the long-term detection rate and the characteristics of endoscopic screening-detected gastric cancer, and evaluated the relationship between gastric cancer and atrophic gastritis. RESULTS: Gastric cancer detection rates in the early, middle, and late periods were 1.01% (76/7,503, men/women: 4,360/3,143, average age: 59.4 years, prevalence of atrophic gastritis: 72%), 0.69% (40/5,820, men/women: 3,668/2,152, average age: 56.8 years, prevalence of atrophic gastritis: 48%), and 0.46% (8/1,758, men/women: 1,083/675, average age: 58.7 years, prevalence of atrophic gastritis: 37%), respectively. Multivariate analysis revealed that male sex (odds ratio 1.92, 95% confidence interval 1.28-2.95), age ≥75 years (2.73, 95% CI 1.32-5.05), and atrophic gastritis (C1-C3: 2.21, 1.36-3.73, O1-O3: 5.36, 3.17-9.30) were significantly associated with the incidence of gastric cancer. CONCLUSIONS: The gastric cancer detection rate and atrophic gastritis prevalence have decreased over time. However, continuing endoscopic screening is important, especially for those at a high risk of developing gastric cancer complicated by severe atrophic gastritis.

Proportions and characteristics of interval cancer in annual fecal immunochemical test screening and postcolonoscopy colorectal cancer: Results from a Japanese multicenter prospective study using questionnaires, the C-DETECT study.

OBJECTIVES: There are several types of colorectal cancer (CRC) according to the detection methods and intervals, including interval CRC (iCRC) and postcolonoscopy CRC (PCCRC). We aimed to examine their proportions and characteristics. METHODS: We conducted a multicenter prospective study using questionnaires in Japan ("C-DETECT study"), in which differences in CRC characteristics according to detection methods and intervals were examined from consecutive adult patients. Because the annual fecal immunochemical test (FIT) was used in population-based screening, the annual FIT-iCRC was assessed. RESULTS: In total, 1241 CRC patients (1064 with invasive CRC) were included. Annual FIT-iCRC (a), 3-year PCCRC (b), and CRC detected within 1 year after a positive FIT with noncompliance to colonoscopy (c) accounted for 4.5%, 7.0%, and 3.9% of all CRCs, respectively, and for 3.9%, 5.4%, and 4.3% of invasive CRCs, respectively. The comparison among these (a, b, c) and other CRCs (d) demonstrated differences in the proportions of ≥T2 invasion ([a] 58.9%, [b] 44.8%, [c] 87.5%, [d] 73.0%), metastasis ([a] 33.9%, [b] 21.8%, [c] 54.2%, [d] 43.9%), right-sided CRC ([a] 42.9%, [b] 40.2%, [c] 18.8%, [d] 28.6%), and female sex ([a] 53.6%, [b] 49.4%, [c] 27.1%, [d] 41.6%). In metastatic CRC, (a) and (b) showed a higher proportions of BRAF mutations ([a] [b] 12.0%, [c] [d] 3.1%). CONCLUSIONS: Annual FIT-iCRC and 3-year PCCRC existed in nonnegligible proportions. They were characterized by higher proportions of right-sided tumors, female sex, and BRAF mutations. These findings suggest that annual FIT-iCRC and 3-year PCCRC may have biological features different from those of other CRCs.

Potential for expanding indications and curability criteria of endoscopic resection for early gastric cancer in elderly patients: results from a Japanese multicenter prospective cohort study.

BACKGROUND AND AIMS: Evidence for endoscopic resection (ER) in elderly patients with early gastric cancer (EGC) is limited. We assessed its clinical outcomes, and explored new indications and curability criteria. METHODS: We analyzed data from a Japanese multicenter prospective cohort study. Patients aged ≥75 years with EGC treated with ER were included. We classified "eCuraC-2 (corresponding to noncurative ER, defined in the Japanese gastric cancer treatment guidelines)" into "elderly-high (EL-H)" (>10% estimated metastatic risk) and "elderly-low (EL-L)" (≤10%). RESULTS: In total, 3,371 patients with 3,821 EGCs were included; endoscopic submucosal dissection (ESD) was the prominent treatment choice. Among them, 3,586 lesions met the guidelines' ER indications and 235 did not. The proportions of en bloc and R0 resections and perforations were 98.9%, 94.4%, and 0.8%, respectively, in EGCs within the indications. In EGCs beyond the indications, they were 99.5%, 85.4%, and 5.9%, respectively, for lesions diagnosed as ≤3 cm, and 96.0%, 64.0%, and 18.0% for those >3 cm. Curative ER ("eCuraA/B") and EL-L were observed in 83.6% and 6.2% of lesions within the indications, respectively, and in 44.2% and 16.8% of lesions <3 cm beyond the indications, respectively. The 5-year cumulative gastric cancer death rates following eCuraA/B and EL-H were 0.3% (95% CI, 0.2-0.6) and 3.5% (2.0-5.7), respectively. Following EL-L, the rate was 0.9% (0.2-3.5) even without subsequent treatment. CONCLUSIONS: Usefulness of ESD for elderly EGC patients was confirmed by their clinical outcomes. Lesions ≤3 cm and EL-L emerged as new ER indication and curability criterion, respectively.

Endoscopic Removal of Premalignant Lesions Reduces Long-Term Colorectal Cancer Risk: Results From the Japan Polyp Study.

BACKGROUND & AIMS: To date, no regional evidence of long-term colorectal cancer (CRC) risk reduction after endoscopic premalignant lesion removal has been established. We aimed to analyze this over a long-term follow-up evaluation. METHODS: This was a prospective cohort study of participants from the Japan Polyp Study conducted at 11 Japanese institutions. Participants underwent scheduled follow-up colonoscopies after a 2-round baseline colonoscopy process. The primary outcome was CRC incidence after randomization. The observed/expected ratio of CRC was calculated using data from the population-based Osaka Cancer Registry. Secondary outcomes were the incidence and characteristics of advanced neoplasia (AN). RESULTS: A total of 1895 participants were analyzed. The mean number of follow-up colonoscopies and the median follow-up period were 2.8 years (range, 1-15 y) and 6.1 years (range, 0.8-11.9 y; 11,559.5 person-years), respectively. Overall, 4 patients (all males) developed CRCs during the study period. The observed/expected ratios for CRC in all participants, males, and females, were as follows: 0.14 (86% reduction), 0.18, and 0, respectively, and 77 ANs were detected in 71 patients (6.1 per 1000 person-years). Of the 77 ANs detected, 31 lesions (40.3%) were laterally spreading tumors, nongranular type. Nonpolypoid colorectal neoplasms (NP-CRNs), including flat (<10 mm), depressed, and laterally spreading, accounted for 59.7% of all detected ANs. Furthermore, 2 of the 4 CRCs corresponded to T1 NP-CRNs. CONCLUSIONS: Endoscopic removal of premalignant lesions, including NP-CRNs, effectively reduced CRC risk. More than half of metachronous ANs removed by surveillance colonoscopy were NP-CRNs. The Japan Polyp Study: University Hospital Medical Information Network Clinical Trial Registry: University Hospital Medical Information Network Clinical Trial Registry, C000000058; cohort study: UMIN000040731.

Endoscopist-related factors affecting adenoma detection during colonoscopy: Data from the J-SCOUT study.

OBJECTIVES: Colonoscopy withdrawal times are associated with the adenoma detection rate (ADR). However, the relationship between ADR and cecal insertion time has been inadequately characterized. We aimed to evaluate endoscopist-related factors involved in the ADR, including the average individual colonoscopy insertion and withdrawal times. METHODS: This observational study used a colonoscopy database with pathology data from routine clinical practice in Japanese institutions. The odds ratios (OR) of endoscopist-related factors related to ADRs were examined using a generalized linear mixed model. RESULTS: Of the 186,293 colonoscopies performed during the study period, 47,705 colonoscopies by 189 endoscopists in four hospitals were analyzed for ADR. The overall ADR was 38.3% (95% confidence interval [CI] 37.8, 38.7). Compared to endoscopists with mean cecal insertion times of <5 min, the OR of ADR for those with mean cecal insertion times of 5-9, 10-14, and ≥15 min were 0.84 (95% CI 0.71, 0.99), 0.68 (95% CI 0.52, 0.90), and 0.45 (95% CI 0.25, 0.78), respectively. Compared to endoscopists with mean withdrawal times of <6 min, the OR of ADR for those with mean withdrawal times of 6-9, 10-14, and ≥15 min were 1.38 (95% CI 1.03, 1.85), 1.48 (95% CI 1.09, 2.02), and 1.68 (95% CI 1.04, 2.61), respectively. There were no significant differences in ADRs by endoscopist specialty, gender, or the total number of examinations performed. CONCLUSION: Individual mean colonoscopy insertion time was associated with ADR and might be considered as a colonoscopy quality indicator as well as withdrawal time.

Short-term outcomes of endoscopic resection for colorectal neuroendocrine tumors: Japanese multicenter prospective C-NET STUDY.

OBJECTIVES: The incidence of colorectal neuroendocrine tumors (NETs) has increased with colorectal cancer screening programs and increased colonoscopies. The management of colorectal NETs has recently shifted from radical surgery to endoscopic resection. We aimed to evaluate the short-term outcomes of various methods of endoscopic resection for colorectal NETs. METHODS: Among those registered in the C-NET STUDY, patients with colorectal NETs who underwent endoscopic treatment as the initial therapy were included. Short-term outcomes, such as the en bloc resection rate and R0 resection (en bloc resection with tumor-free margin) rate, were analyzed based on treatment modalities. RESULTS: A total of 472 patients with 477 colorectal NETs received endoscopic treatment. Of these, 418 patients with 421 lesions who met the eligibility criteria were included in the analysis. The median age of the patients was 55 years, and 56.9% of them were men. The lower rectum was the most commonly affected site (88.6%), and lesions <10 mm accounted for 87% of the cases. Endoscopic submucosal resection with a ligation device (ESMR-L, 56.5%) was the most common method, followed by endoscopic submucosal dissection (ESD, 31.4%) and endoscopic mucosal resection using a cap (EMR-C, 8.5%). R0 resection rates <10 mm were 95.5%, 94.8%, and 94.3% for ESMR-L, ESD, and EMR-C, respectively. All 16 (3.8%) patients who developed treatment-related complications could be treated conservatively. Overall, 23 (5.5%) patients had incomplete resection without independent clinicopathological risk factors. CONCLUSION: ESMR-L, ESD, and EMR-C were equally effective and safe for colorectal NETs with a diameter <10 mm.

Cost-effectiveness of preventive aspirin use and intensive downstaging polypectomy in patients with familial adenomatous polyposis: A microsimulation modeling study.

OBJECTIVE: Although there is increasing evidence to suggest the cost-effectiveness of aspirin use to prevent colorectal cancer (CRC) in the general population, no study has assessed cost-effectiveness in patients with familial adenomatous polyposis (FAP), who are at high risk of developing CRC. We examined the cost-effectiveness of preventive use of low-dose aspirin in FAP patients who had undergone polypectomy in comparison with current treatment practice. DESIGN: We developed a microsimulation model that simulates a hypothetical cohort of the Japanese population with FAP for 40 years. Three scenarios were created based on three intervention strategies for comparison with no intervention, namely intensive downstaging polypectomy (IDP) of colorectal polyps at least 5.0 mm in diameter, IDP combined with low-dose aspirin, and total proctocolectomy with ileal pouch-anal anastomosis (IPAA). Cost-effective strategies were identified using a willingness-to-pay threshold of USD 50,000 per QALY gained. RESULTS: Compared with no intervention, all strategies resulted in extended QALYs (21.01-21.43 QALYs per individual) and showed considerably reduced colorectal cancer mortality (23.35-53.62 CRC deaths per 1000 individuals). Based on the willingness-to-pay threshold, IDP with low-dose aspirin was more cost-effective than the other strategies, with an incremental cost-effectiveness ratio of $57 compared with no preventive intervention. These findings were confirmed in both one-way sensitivity analyses and probabilistic sensitivity analyses. CONCLUSION: This study suggests that the strategy of low-dose aspirin with IDP may be cost-effective compared with IDP-only or IPAA under the national fee schedule of Japan.

Factors associated with increased duration of endoscopic submucosal dissection for rectal tumors: a 22-year retrospective analysis.

BACKGROUND AND AIMS: Colorectal endoscopic submucosal dissection (ESD) is widely used in several countries. However, it is associated with technical difficulties. Rectal ESD is considered an intermediate step in colorectal ESD training. Nevertheless, some rectal lesions require a longer procedure time than usual, and the reason for the prolonged time taken for these specific lesions remains unclear. Therefore, this study aimed to clarify the factors associated with prolonged rectal ESD. METHODS: In total, 483 rectal lesions resected using ESD from February 1998 to June 2021 were investigated. Prolonged ESD procedure time was defined as the time from the first submucosal injection to lesion removal exceeding 120 minutes, whereas other procedures were defined as average ESD procedure time. Clinicopathologic and endoscopic findings were compared between the 2 groups using univariate and multivariate analyses. RESULTS: One hundred forty-four lesions were resected using a prolonged ESD procedure time of 202.9 ± 92.3 minutes, whereas 339 lesions were resected using an average ESD procedure time of 77.8 ± 29.4 minutes. Multivariate analysis revealed that tumors involving the dentate line (P = .026), resection size ≥50 mm (P < .001), invasion depth ≥T1b (P = .006), and circumferential range ≥2/3 (P = .001) were independent risk factors for prolonged-duration ESDs, regardless of whether the procedure was performed by an expert or not. CONCLUSIONS: The results of the present study suggest that the location of a lesion involving the dentate line, resection size ≥50 mm, circumferential range ≥2/3, and invasion depth ≥T1b are the independent risk factors for prolonged ESD procedure time.

Endoscopic Resection of Undifferentiated Early Gastric Cancer.

Endoscopic resection (ER) is widely performed for early gastric cancer (EGC) with a negligible risk of lymph node metastasis (LNM) in Eastern Asian countries. In particular, endoscopic submucosal dissection (ESD) leads to a high en bloc resection rate, enabling accurate pathological evaluation. As undifferentiated EGC (UD-EGC) is known to result in a higher incidence of LNM and infiltrative growth than differentiated EGC (D-EGC), the indications for ER are limited compared with those for D-EGC. Previously, clinical staging as intramucosal UD-EGC ≤2 cm, without ulceration, was presented as 'weakly recommended' or 'expanded indications' for ER in the guidelines of the United States, Europe, Korea, and Japan. Based on promising long-term outcomes from a prospective multicenter study by the Japan Clinical Oncology Group (JCOG) 1009/1010, the status of this indication has expanded and is now considered 'absolute indications' in the latest Japanese guidelines published in 2021. In this study, which comprised 275 patients with UD-EGC (cT1a, ≤2 cm, without ulceration) treated with ESD, the 5-year overall survival (OS) was 99.3% (95% confidence interval, 97.1%-99.8%), which was higher than the threshold 5-year OS (89.9%). Currently, the levels of evidence grades and recommendations for ER of UD-EGC differ among Japan, Korea, and Western countries. Therefore, a further discussion is warranted to generalize the indications for ER of UD-EGC in countries besides Japan.

Cost-effectiveness analysis of computer-aided detection systems for colonoscopy in Japan.

OBJECTIVES: The usefulness of computer-aided detection systems (CADe) for colonoscopy has been increasingly reported. In many countries, however, data on the cost-effectiveness of their use are lacking; consequently, CADe for colonoscopy has not been covered by health insurance. We aimed to evaluate the cost-effectiveness of colonoscopy using CADe in Japan. METHODS: We conducted a simulation model analysis using Japanese data to examine the cost-effectiveness of colonoscopy with and without CADe for a population aged 40-74 years who received colorectal cancer (CRC) screening with a fecal immunochemical test (FIT). The rates of receiving FIT screening and colonoscopy following a positive FIT were set as 40% and 70%, respectively. The sensitivities of FIT for advanced adenomas and CRC Dukes' A-D were 26.5% and 52.8-78.3%, respectively. CADe colonoscopy was judged to be cost-effective when its incremental cost-effectiveness ratio (ICER) was below JPY 5,000,000 per quality-adjusted life-years (QALYs) gained. RESULTS: Compared to conventional colonoscopy, CADe colonoscopy showed a higher QALY (20.4098 vs. 20.4088) and lower CRC incidence (2373 vs. 2415 per 100,000) and mortality (561 vs. 569 per 100,000). When the CADe cost was set at JPY 1000-6000, the ICER per QALY gained for CADe colonoscopy was lower than JPY 5,000,000 (JPY 796,328-4,971,274). The CADe cost threshold at which the ICER for CADe colonoscopy exceeded JPY 5,000,000 was JPY 6040. CONCLUSIONS: Computer-aided detection systems for colonoscopy has the potential to be cost-effective when the CADe cost is up to JPY 6000. These results suggest that the insurance reimbursement of CADe for colonoscopy is reasonable.

"Endoscopic" adenoma detection rate as a quality indicator of colonoscopy: First report from the J-SCOUT study.

OBJECTIVES: To examine whether reasonable detection rate of endoscopically diagnosed lesions as adenoma ("endoscopic" adenoma detection rate [ADR]) could be calculated with a database generated from colonoscopy reports and whether it could be used as a surrogate colonoscopy quality indicator of "pathological" ADR. METHODS: A lesion-by-lesion database of colonoscopies performed between 2010 and 2020 at eight Japanese endoscopy centers and corresponding pathology database were integrated. Differences in numbers of detected polyps, "endoscopic" and "pathological" adenomas, and what these differences could be attributed to were examined. Polyp detection rate (PDR), "endoscopic" and "pathological" ADRs, and correlation coefficients between "pathological" ADR and PDR or "endoscopic" ADR by each endoscopist were calculated. RESULTS: Overall, 129,065 colonoscopy reports were analyzed. Among a total of 146,854 polyps, more "endoscopic" adenomas (n = 117,359) were observed than "pathological" adenomas (n = 70,076), primarily because adenomas were not resected on site, rather than because of a misdiagnosis. In all patients analyzed, PDR, "endoscopic" and "pathological" ADRs were 56.4% (95% confidence interval [CI] 56.2-56.7), 48.0% (95% CI 47.7-48.3), and 32.7% (95% CI 32.5-33.0), respectively. "Endoscopic" and "pathological" ADRs from each endoscopist showed a high correlation in hospitals where adenomas were usually resected at the time of examination. CONCLUSIONS: By appropriately describing endoscopically diagnosed lesions as "adenomas" in endoscopy reports, "endoscopic" ADR might be used as a surrogate colonoscopy quality indicator of "pathological" ADR (UMIN000040690).

Unexpected adhesive bowel obstruction after endoscopic submucosal dissection of early sigmoid colon cancer.

Various complications of colorectal endoscopic submucosal dissection (ESD) have been reported, including bleeding, penetration, perforation, and coagulation syndrome. However, the occurrence of bowel obstruction after ESD is rare. We report a case of adhesive bowel obstruction after ESD for a laterally spreading tumor in the sigmoid colon. The 35-mm tumor was successfully removed by ESD without intraoperative complications. The patient had a fever, lower abdominal pain, and a small amount of bloody stool the day after ESD. Endoscopy revealed minor bleeding from the ESD scar, which was treated by hemostatic clips. Pathological analysis showed adenocarcinoma was exposed to the vertical margin; therefore, the resection was non-curative. At 39 days after ESD and 36 days after discharge, the patient had abdominal pain and nausea. She was readmitted with a diagnosis of adhesive bowel obstruction. Conservative treatment was ineffective; therefore, she underwent sigmoidectomy combined with partial resection of the small intestine because of small intestinal stenosis caused by inflammation. The pathological examination showed localized peritonitis around the sigmoid colon where ESD was performed. There was more fibrosis along the serous surface of the small intestine than on the sigmoid colon. We concluded that there was a micro-perforation that could not be detected by endoscopy or physical examination. This case indicates that adhesive bowel obstruction may occur as a complication of ESD.

Detection rates of colorectal neoplasia during colonoscopies and their associated factors in the SCREESCO study.

BACKGROUND AND AIM: Colonoscopy quality, including lesion detectability, is variable, and factors influencing lesion detection are not fully understood. This study investigated lesion detection rates during colonoscopies and the associated factors in the SCREEning of Swedish COlons (SCREESCO) study. METHODS: In this cross-sectional analysis of data from SCREESCO, a large-scale randomized controlled trial of colorectal cancer screening in the Swedish population aged 60 years, we assessed data of first-time colonoscopies performed in both colonoscopy and fecal immunochemical test (FIT) arms. RESULTS: This study included 16 552 individuals. The adenoma detection rate was 23.9% and 37.8% in colonoscopy and FIT arms, respectively. Regarding colonoscopy procedures, a withdrawal time ≥ 6 min was associated with higher detection rates of advanced adenomas (adjusted odds ratio [AOR] 2.474, 95% confidence interval [CI] 1.295-4.723), adenomas (2.181, 1.515-3.140), and proximal serrated lesions (pSLs) (1.713, 1.007-2.915). Antispasmodic use was associated with higher detection rates of these lesions and sessile serrated lesions (SSLs) (AOR, 95% CI: 1.523, 1.295-1.791; 1.361, 1.217-1.522; 1.450, 1.247-1.687; and 1.810, 1.512-2.167, respectively). Insertion time > 20 min was related to lower detection rates of adenomas, pSLs, and SSLs (AOR, 95% CI: 0.753, 0.639-0.887; 0.640, 0.495-0.828; and 0.704, 0.518-0.955, respectively). The relationship between a recent period and higher detection rates of pSLs and SSLs was also demonstrated. CONCLUSION: Lesion detectability in SCREESCO was mostly acceptable with room for improvement. In addition to sufficient withdrawal time, antispasmodic use and acquiring skills enabling short insertion time may improve lesion detection. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02078804.

Third Asia-Pacific consensus recommendations on colorectal cancer screening and postpolypectomy surveillance.

The Asia-Pacific region has the largest number of cases of colorectal cancer (CRC) and one of the highest levels of mortality due to this condition in the world. Since the publishing of two consensus recommendations in 2008 and 2015, significant advancements have been made in our knowledge of epidemiology, pathology and the natural history of the adenoma-carcinoma progression. Based on the most updated epidemiological and clinical studies in this region, considering literature from international studies, and adopting the modified Delphi process, the Asia-Pacific Working Group on Colorectal Cancer Screening has updated and revised their recommendations on (1) screening methods and preferred strategies; (2) age for starting and terminating screening for CRC; (3) screening for individuals with a family history of CRC or advanced adenoma; (4) surveillance for those with adenomas; (5) screening and surveillance for sessile serrated lesions and (6) quality assurance of screening programmes. Thirteen countries/regions in the Asia-Pacific region were represented in this exercise. International advisors from North America and Europe were invited to participate.

Conditional inference tree models to perceive depth of invasion in T1 colorectal cancer.

BACKGROUND AND AIM: Accurate diagnosis of invasion depth for T1 colorectal cancer is of critical importance as it decides optimal resection technique. Few reports have previously covered the effects of endoscopic morphology on depth assessment. We developed and validated a novel diagnostic algorithm that accurately predicts the depth of early colorectal cancer. METHODS: We examined large pathological and endoscopic databases compiled between Jan 2015 and Dec 2018. Training and validation data cohorts were derived and real-world diagnostic performance of two conditional interference tree algorithms (Models 1 and 2) was evaluated against that of the Japan NBI-Expert Team (JNET) classification used by both expert and non-expert endoscopists. RESULTS: Model 1 had higher sensitivity in deep submucosal invasion than that of JNET alone in both training (45.1% vs. 28.6%, p < 0.01) and validation sets (52.3% vs. 40.0%, p < 0.01). Model 2 demonstrated higher sensitivity than Model 1 (66.2% vs. 52.3%, p < 0.01) in excluding deeper invasion of suspected Tis/T1a lesions. CONCLUSION: We discovered that machine-learning classifiers, including JNET and macroscopic features, provide the best non-invasive screen to exclude deeper invasion for suspected Tis/T1 lesions. Adding this algorithm improves depth diagnosis of T1 colorectal lesions for both expert and non-expert endoscopists.

Post-polypectomy surveillance: the present and the future.

An appropriate post-polypectomy surveillance program requires the effectiveness of reducing colorectal cancer and safety. In addition, the post-polypectomy surveillance program should consider the burden of limited medical resource capacity, cost-effectiveness, and patient adherence. In this sense, a risk-stratified surveillance program based on baseline colonoscopy results is ideal. Major international guidelines for post-polypectomy surveillance, such as those from the European Union and the United States, have recommended risk-stratified surveillance programs. Both guidelines have recently been updated to better differentiate between high- and low-risk individuals. In both updated guidelines, more individuals have been downgraded to lower-risk groups that require less frequent or no surveillance. Furthermore, increased attention has been paid to the surveillance of patients who undergo serrated polyp removal. Previous guidelines in Japan did not clearly outline the risk stratification in post-polypectomy surveillance. However, the new colonoscopy screening and surveillance guidelines presented by the Japan Gastroenterological Endoscopy Society include a risk-stratified post-polypectomy surveillance program. Further discussion and analysis of unresolved issues in this field, such as the optimal follow-up after the first surveillance, the upper age limit for surveillance, and the ideal method for improving adherence to surveillance guidelines, are warranted.