Endoscopic mucosal resection (EMR) of large non-pedunculated colorectal polyps (LNPCPs) offers excellent efficacy and safety. Referral biopsies are commonly obtained prior to EMR despite their potential adverse effects. We aimed to assess the diagnostic accuracy of referral biopsy as compared with optical evaluations and the polyp's final pathology.

We analyzed a cohort from two centers that included adult patients referred for EMR of LNPCPs between 2017 and 2022. The NICE classification system was used for optical classification. We compared procedural outcomes of lesions with or without a referral biopsy and diagnostic accuracy of referral biopsy and optical evaluation to the final histopathology of the resected polyp.

Of 605 EMR procedures, 398 (65.8%) had referral biopsies. Polyp size was larger in the biopsy group. No significant differences were observed in en-bloc resection rate, adequate lifting, procedural bleeding, or surveillance recurrence rates. Optical biopsies had higher diagnostic concordance with final histology (Cohen's Kappa 0.62 vs. 0.55) and enhanced sensitivity for sessile serrated polyps/hyperplastic polyps (SSP/HP) and cancer as compared to referral biopsies (0.75 vs. 0.72, p < 0.01, and 0.19 vs. 0.0, p < 0.01, respectively). Optical evaluation was more accurate in non-biopsied lesions.

Referral biopsies do not offer additional diagnostic accuracy and may reduce the accuracy of optical evaluation for LNPCPs.

We investigated the ideal acetic acid (AA) concentration for AA-enhanced narrow-band imaging magnifying endoscopy (ANBI-ME) in the diagnosis of superficial colorectal neoplasms and evaluated its clinical efficacy.

During the exploratory phase, we investigated 4 concentrations (1.5%, 2.25%, 3.0%, and 4.5%) in rotation by performing ANBI-ME on 50 superficial colorectal neoplasms at each concentration. A favorable AA concentration was determined by evaluating the diagnostic accuracy, AA whitening duration (AD), peristalsis, and bleeding after endoscopic resection. In the validation phase, we assessed interobserver agreements for ANBI-ME with the determined AA concentration and intermethodologic agreements between that and subsequently conducted crystal violet-stained magnifying endoscopy (CV-ME) with the exploratory set and 98 additional patients.

The diagnostic accuracies were 89.3% (42/47) for 1.5% AA, 92.0% (46/50) for 2.25% AA, 96.8% (61/63) for 3.0% AA, and 97.8% (46/47) for 4.5% AA, with no significant difference (P = .26). A significant positive correlation was observed between AA concentration and AD (P < .001). No significant differences in hyperperistalsis or post-resection bleeding were observed. The optimal AA concentration was determined to be 4.5%. In the validation analysis, the accuracy rates were 72.4% (105/145) with the use of AMBI-ME and 68.3% (99/145) with the use of CV-ME (P = .43). Strong agreements were noted between observers (κ: 0.87 for ANBI-ME, 0.83 for CV-ME) and between the methods (κ: 0.87 and 0.81 for each observer).

For diagnosing colorectal lesions, an AA concentration of 4.5% in ANBI-ME was safe and effective. Its diagnostic performance was similar to CV-ME, and future large-sample studies may confirm its potential as a reliable alternative endoscopic diagnostic method.

 Recognition of submucosal invasive colorectal cancer (T1 CRC) is difficult, with sensitivities of 35 %-60 % in Western countries. We evaluated the real-life effects of training in the OPTICAL model, a recently developed structured and validated prediction model, in Dutch community hospitals.

 In this prospective multicenter study (OPTICAL II), 383 endoscopists from 40 hospitals were invited to follow an e-learning program on the OPTICAL model, to increase sensitivity in detecting T1 CRC in nonpedunculated polyps. Real-life recognition of T1 CRC was then evaluated in 25 hospitals. Endoscopic and pathologic reports of T1 CRCs detected during the next year were collected retrospectively, with endoscopists unaware of this evaluation. Sensitivity for T1 CRC recognition, R0 resection rate, and treatment modality were compared for trained vs. untrained endoscopists.

 1 year after e-learning, 528 nonpedunculated T1 CRCs were recorded for endoscopies performed by 251 endoscopists (118 [47 %] trained). Median T1 CRC size was 20 mm. Lesions were mainly located in the distal colorectum (66 %). Trained endoscopists recognized T1 CRCs more frequently than untrained endoscopists (sensitivity 74 % vs. 62 %; mixed model analysis odds ratio [OR] 2.90, 95 %CI 1.54-5.45). R0 resection rate was higher for T1 CRCs detected by trained endoscopists (69 % vs. 56 %; OR 1.73, 95 %CI 1.03-2.91).

 Training in optical recognition of T1 CRCs in community hospitals was associated with increased recognition of T1 CRCs, leading to higher en bloc and R0 resection rates. This may be an important step toward more organ-preserving strategies.

Hot snare excision using electrocautery is widely used for large colorectal polyps (>10 mm); however, adverse events occur due to deep thermal injury. Colorectal polyps measuring 10-14 mm rarely include invasive cancer. Therefore, less invasive therapeutic options for this size category are demanding. We have developed hot snare polypectomy with low-power pure-cut current (LPPC HSP), which is expected to contribute to less deep thermal damage and lower risk of adverse events. This study aimed to evaluate the efficacy and safety of LPPC HSP for 10-14 mm colorectal polyps, compared with conventional endoscopic mucosal resection (EMR).

In this multicenter, retrospective, observational study, clinical outcomes of EMR and LPPC HSP for 10-14 mm nonpedunculated colorectal polyps between January 2021 and March 2022 were compared using propensity score matching.

We identified 203 EMR and 208 LPPC HSP cases. After propensity score matching, the baseline characteristics between the groups were comparable, with 120 pairs. The en bloc and R0 resection rates were not significantly different between EMR and LPPC HSP groups (95.8% vs 97.5%, P = 0.72; 90.0% vs 91.7%, P = 0.82). The rates of delayed bleeding and perforation did not differ between the groups.

Compared with conventional EMR, LPPC HSP showed a similar resection ability without an increase in adverse events. These results suggest that LPPC HSP is a safe and effective treatment for 10-14 mm nonpedunculated colorectal polyps.

Tip-in endoscopic mucosal resection (EMR) has a high en bloc resection rate for large colorectal neoplasms. However, non-experts' performance in Tip-in EMR has not been investigated. We investigated whether Tip-in EMR can be achieved effectively and safely even by non-experts.

This retrospective study included consecutive patients who underwent Tip-in EMR for 15-25 mm colorectal nonpedunculated neoplasms at a Japanese tertiary cancer center between January 2014 and December 2020. Baseline characteristics, treatment outcomes, learning curve of non-experts, and risk factors of failing self-achieved en bloc resection were analyzed.

A total of 597 lesions were analyzed (438 by experts and 159 by non-experts). The self-achieved en bloc resection (69.8% vs 88.6%, P < 0.001) and self-achieved R0 resection (58.3% vs 76.5%, P < 0.001) rates were significantly lower in non-experts with <10 cases of experience than in experts, but not in non-experts with >10 cases. Adverse event (P = 0.165) and local recurrence (P = 0.892) rates were not significantly different between experts and non-experts. Risk factors of failing self-achieved en bloc resection were non-polypoid morphology (OR 3.4, 95% CI 1.6-7.3, P = 0.001), lesions with an underlying semilunar fold (OR 3.6, 95% CI 1.6-7.3, P < 0.001), positive non-lifting sign (OR 3.1, 95% CI 1.2-8.0, P = 0.023), and non-experts with an experience of ≤10 cases (OR 3.6, 95% CI 2.1-6.3, P < 0.001).

The clinical outcomes of Tip-in EMR for 15-25 mm lesions performed by non-experts were favorable.

Accurate assessment of invasion depth of early rectal neoplasms is essential for optimal therapy. We aimed to compare three-dimensional endorectal ultrasound (3D-ERUS) with magnification chromoendoscopy (MCE) regarding their accuracy in assessing parietal invasion depth (T).

Patients with middle and distal rectum neoplasms were prospectively included. Two providers blinded to each other's assessment performed 3D-ERUS and MCE, respectively. The T stage assessed through ERUS was compared to the MCE evaluation. The results were compared to the surgical specimen anatomopathological report. Sensitivity, specificity, accuracy, positive (PPV), and negative (NPV) predictive values were calculated for the T stage and for the final therapy (local excision or radical surgery).

In 8 years, 70 patients were enrolled, and all underwent both exams. MCE and ERUS showed an accuracy of 94.3% and 85.7%, sensitivity of 83.7 and 93.3%, specificity of 96.4 and 83.6%, PPV of 86.7 and 60.9%, and NPV of 96.4 and 97.9%, respectively. Kappa for T stage assessed through ERUS was 0.64 and 0.83 for MCE.

MCE and 3D-ERUS had good diagnostic performance, but the endoscopic method had higher accuracy. Both methods reliably assessed lesion extension, circumferential involvement, and distance from the anal verge.

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.

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.

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.

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.

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.

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.

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.

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).

The Asia-Pacific Colorectal Screening (APCS) score and its derivatives have been used to predict advanced colorectal neoplasia (ACN). However, it remains unknown whether they apply to the current Chinese population in general clinical practice. Therefore, we aimed to update the APCS score system by applying data from two independent asymptomatic populations to predict the risk of ACN in China.

We developed an adjusted APCS (A-APCS) score by using the data of asymptomatic Chinese patients undergoing colonoscopies from January 2014 to December 2018. Furthermore, we validated this system in another cohort of 812 patients who underwent screening colonoscopy between January and December 2021. The discriminative calibration ability of the A-APCS and APCS scores was comparatively evaluated.

Univariate and multivariate logistic regression were applied to assess the risk factors for ACN, and an adjusted scoring system of 0 to 6.5 points was schemed according to the results. Utilizing the developed score, 20.2%, 41.2%, and 38.6% of patients in the validation cohort were classified as average, moderate, and high risk, respectively. The corresponding ACN incidence rates were 1.2%, 6.0%, and 11.1%, respectively. In addition, the A-APCS score (c-statistics: 0.68 for the derivation and 0.80 for the validation cohort) showed better discriminative power than using predictors of APCS alone.

The A-APCS score may be simple and useful in clinical applications for predicting ACN risk in China.

This case demonstrates the utility of the "purse string" to close large defects and shows that optical diagnosis may have pitfalls in evaluating the invasion of neoplastic lesions, particularly large ones.

An expanding range of advanced mucosal imaging technologies have been developed with the goal of improving the detection and characterization of lesions in the gastrointestinal tract. Many technologies have targeted colorectal neoplasia given the potential for intervention prior to the development of invasive cancer in the setting of widespread surveillance programs. Improvement in adenoma detection reduces miss rates and prevents interval cancer development. Advanced imaging technologies aim to enhance detection without significantly increasing procedural time. Accurate polyp characterisation guides resection techniques for larger polyps, as well as providing the platform for the "resect and discard" and "do not resect" strategies for small and diminutive polyps. This review aims to collate and summarise the evidence regarding these technologies to guide colonoscopic practice in both interventional and non-interventional endoscopists.

Cold snare polypectomy (CSP), a safe procedure for removing colon polyps, has a low prevalence of postpolypectomy bleeding (PPB). Previous studies have failed to demonstrate differences in PPB rates between CSP and hot snare polypectomy (HSP), possibly because of their small sample sizes. This study analyzed PPB rates after CSP and HSP.

This was a retrospective analysis of colorectal lesions (diameter <10 mm) treated using endoscopic resection at our institution between January 2015 and December 2019. Resections were performed using CSP or HSP, depending on the endoscopist's preference. Endoscopic and histologic findings were recorded in the endoscopic database at our institution. Propensity score (PS) matching was performed to match patient age, lesion size, macroscopic features, location of the lesions, clipping after resection, and antithrombotic agent use. The CSP and HSP groups were compared to determine the adverse event (PPB) rates.

The CSP and HSP groups included 12,928 and 2408 lesions (total of 5371 patients), respectively. Univariate analysis revealed that the overall prevalence of PPB after HSP was higher than that after CSP (odds ratio [OR], 5.39; 95% confidence interval [CI], 2.50-11.60). After PS matching (2135 lesions per group), the prevalence of PPB after HSP remained higher than that after CSP (OR, 6.0; 95% CI, 1.34-26.8).

For colorectal lesions <10 mm in diameter, the risk of PPB after CSP is significantly lower than that after HSP, after PS matching. CSP for lesions <10 mm could be safely performed compared with HSP.

Depth diagnosis is extremely crucial in making a treatment choice between endoscopic resection and surgery in the early stages of cancers. Among several imaging modalities, we use magnifying endoscopy to diagnose lesions by close observation of the findings at mucosal surface layer. In combination with topical staining, magnifying endoscopy enables us to assess the definite pit structure, which referred to as magnifying chromoendoscopy (MCE). The pit pattern classification by MCE was proposed and is now widely accepted as the standard diagnostic criteria for colorectal lesions. Meanwhile, image enhanced endoscopy (IEE) represented by narrow-band imaging was developed to improve the visibility of surface and vascular findings without dyeing. Recent collaborative work performed by endoscopic experts in Japan yielded the unified diagnostic criteria, the Japan NBI Expert Team (JNET) classification, based on the findings of IEE with magnification. In this review, focusing on MCE and IEE with magnification, we aimed to give an outline of the pit pattern classification and the JNET classification, and further discuss their accuracy rate of depth diagnosis of early colorectal lesions by performing a review of the related literature. Both modalities have a high accuracy rate of nearly 90% for depth diagnosis. IEE with magnification is an ideal modality because it helps observe lesions without dye spraying; however, lesions with JNET type 2B have an inadequate diagnostic ability, which should be complemented by MCE. We conclude that accurate diagnosis is possible by examining lesions using both modalities properly to overcome the limitations of each modality.

To explore the potential factors that affect the accuracy of endoscopic diagnosis for Japan narrow-band imaging (NBI) Expert Team (JNET) type 2B colorectal lesions.

The clinical data were collected from 261 patients with JNET type 2B colorectal lesions diagnosed in Nanfang Hospital between July, 2018 and July, 2021. We analyzed the macroscopic type, size, location or pit pattern classification of the lesions for their potential influence of the diagnostic accuracy of JNET type 2B lesions.

The 261 lesions included 91 low-grade intramucosal neoplasia lesions (34.9%), 132 high-grade intramucosal neoplasia lesions (50.6%), 13 submucosal invasive cancer lesions (5.0%), and 25 deep submucosal invasive cancer lesions (9.6%). The coincidence rate between endoscopic prediction and pathological diagnosis of these lesions was 55.6% (145/ 261). The macroscopic type and size of the lesions were significantly associated with the diagnostic accuracy of JNET type 2B lesions (P < 0.001). There was a significant difference in the diagnostic accuracy among the lesions with different pit pattern types (P < 0.001).

Both the macroscopic type and size affect the accuracy of endoscopic diagnosis of JNET type 2B colorectal lesions. JNET classification combined with pit pattern types can have better accuracy in predicting the pathological diagnosis of these lesions.

One-piece endoscopic mucosal resection (EMR) for lesions >15 mm is still unsatisfactory, and attempted 1-piece EMR for lesions >25 mm can increase perforation risk. Therefore, modifications to ensure 1-piece EMR of 15- to 25-mm lesions would be beneficial. The aim of this study was to investigate whether Tip-in EMR, which anchors the snare tip within the submucosal layer, increases en bloc resection for 15- to 25-mm colorectal lesions compared with EMR.

In this prospective randomized controlled trial, patients with nonpolypoid colorectal neoplasms of 15-25 mm in size were recruited and randomly assigned in a 1:1 ratio to undergo Tip-in EMR or standard EMR, stratified by age, sex, tumor size category, and tumor location. The primary endpoint was the odds ratio of en bloc resection adjusted by location and size category. Adverse events and procedure time were also evaluated.

We analyzed 41 lesions in the Tip-in EMR group and 41 lesions in the EMR group. En bloc resection was achieved in 37 (90.2%) patients undergoing Tip-in EMR and 30 (73.1%) who had EMR. The adjusted odds ratio of en bloc resection in Tip-in EMR vs EMR was 3.46 (95% confidence interval: 1.06-13.6, P = 0.040). The Tip-in EMR and EMR groups did not differ significantly in adverse event rates (0% vs 4.8%) or median procedure times (7 vs 5 minutes).

In this single-center randomized controlled trial, we found that Tip-in EMR significantly improved the en bloc resection rate for nonpolypoid lesions 15-25 mm in size, with no increase in adverse events or procedure time.

If patients with surgically resectable colorectal cancershave synchronous colorectal neoplasms that are difficult to remove by endoscopic mucosal resection, preemptive endoscopic submucosal dissection (ESD) can avoid excessive colorectal resection. The aim of this study was to evaluate the efficacy of the strategy of preemptive ESD and surgery for synchronous colorectal neoplasms.

Patients who underwent preemptive ESD and surgery for synchronous colorectal neoplasms between September 2002 and December 2017 were enrolled in this retrospective cohort study. The proportion of cases in which extended surgery could be avoided following curative ESD was calculated. Clinicopathological characteristics were evaluated for all patients and long-term outcomes were analyzed for patients who underwent curative ESD and surgery.

A total of 45 consecutive patients with 47 endoscopically-resected lesions and 46 surgically-resected lesions were retrospectively evaluated. Curative ESD was achieved in 44 lesions (93.6%) and an extended surgical procedure could be avoided in 42 patients (93.3%). Intraoperative perforation occurred in two lesions (4.3%), delayed perforation in one lesion (2.1%), and delayed bleeding in two lesions (4.3%). Final stages were as follows: stage 0, 3 patients (7.1%); stage I, 23 patients (54.8%); stage II, 3 patients (7.1%); stage III, 12 patients (28.6%); and stage IV, 1 patient (2.4%). The 5-year overall survival rates of patients with all pathological stages, stage 0-II, and stage III-IV were 93.7%, 100%, and 79.1%, respectively.

The strategy of preemptive ESD and surgery for synchronous colorectal neoplasms is minimally invasive and has a favorable prognosis.