An alternative option for "resect and discard" strategy, using magnifying narrow-band imaging: a prospective "proof-of-principle" study

Multicentre study to assess the performance of an artificial intelligence instrument to support qualitative diagnosis of colorectal polyps

OBJECTIVE

Computer-aided diagnosis (CAD) using artificial intelligence (AI) is expected to support the characterisation of colorectal lesions, which is clinically relevant for efficient colorectal cancer prevention. We conducted this study to assess the diagnostic performance of commercially available CAD systems.

METHODS

This was a multicentre, prospective performance evaluation study. The endoscopist diagnosed polyps using white light imaging, followed by non-magnified blue light imaging (non-mBLI) and mBLI. AI subsequently assessed the lesions using non-mBLI (non-mAI), followed by mBLI (mAI). Eventually, endoscopists made the final diagnosis by integrating the AI diagnosis (AI+endoscopist). The primary endpoint was the accuracy of the AI diagnosis of neoplastic lesions. The diagnostic performance of each modality (sensitivity, specificity and accuracy) and confidence levels were also assessed.

RESULTS

Overall, 380 lesions from 139 patients were included in the analysis. The accuracy of non-mAI was 83%, 95% CI (79% to 87%), which was inferior to that of mBLI (89%, 95% CI (85% to 92%)) and mAI (89%, 95% CI (85% to 92%)). The accuracy (95% CI) of diagnosis by expert endoscopists using mAI (91%, 95% CI (87% to 94%)) was comparable to that of expert endoscopists using mBLI (91%, 95% CI (87% to 94%)) but better than that of non-expert endoscopists using mAI (83%, 95% CI (75% to 90%)). The level of confidence in making a correct diagnosis was increased when using magnification and AI.

CONCLUSIONS

The diagnostic performance of mAI for differentiating colonic lesions is comparable to that of endoscopists, regardless of their experience. However, it can be affected by the use of magnification as well as the endoscopists' level of experience.

Diagnostic performance of endocytoscopy with normal pit-like structure sign for colorectal low-grade adenoma compared with conventional modalities

Objectives

A "resect-and-discard" strategy has been proposed for diminutive adenomas in the colorectum. However, this strategy is sometimes difficult to implement because of the lack of confidence in differentiating low-grade adenoma (LGA) from advanced lesions such as high-grade adenoma or carcinoma. To perform real-time precise diagnosis of LGA with high confidence, we assessed whether endocytoscopy (EC) diagnosis, considering normal pit-like structure (NP-sign), an excellent indicator of LGA, could have additional diagnostic potential compared with conventional modalities.

Methods

All the neoplastic lesions that were observed by non-magnifying narrow-band imaging (NBI), magnifying NBI (M-NBI), magnifying pit pattern, and EC prior to pathological examination between 2005 and 2018 were retrospectively investigated. The neoplastic lesions were classified into two categories: LGA and other neoplastic lesions. We assessed the differential diagnostic ability of EC with NP-sign between LGA and other neoplastic lesions compared with that of NBI, M-NBI, pit pattern, and conventional EC in terms of sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC).

Results

A total of 1376 lesions from 1097 patients were eligible. The specificity (94.9%), accuracy (91.5%), and area under the receiver operating characteristic curve (0.95) of EC with NP-sign were significantly higher than those of NBI, M-NBI, pit pattern, and conventional EC.

Conclusions

EC diagnosis with NP-sign has significantly higher diagnostic performance for predicting colorectal LGA compared with the conventional modalities and enables stratification of neoplastic lesions for "resect-and-discard" with higher confidence.

Efficacy and safety of intensive downstaging polypectomy (IDP) for multiple duodenal adenomas in patients with familial adenomatous polyposis: a prospective cohort study

BACKGROUND

Patients with familial adenomatous polyposis (FAP) risk developing multiple duodenal adenomas (MDAs), leading to duodenal cancer and death. We investigated the efficacy and safety of intensive downstaging polypectomy (IDP) for MDAs integrated with new-generation procedures.

METHODS

This prospective phase II study, conducted at a tertiary cancer center, enrolled patients with FAP who had MDAs. We performed IDP including cold snare/forceps polypectomy (CSP/CFP) and underwater endoscopic mucosal resection (UEMR). The primary end point was the downstaging of Spigelman stage at 1-year follow-up.

RESULTS

2424 duodenal polyps in 58 patients with FAP underwent IDP, including 2413 CSPs in 57 patients, seven CFPs in one patient, and four UEMRs in four patients. Only one major adverse event was observed (grade 3 hyperamylasemia) without clinical manifestations. We performed additional UEMR, CSP, and CFP for one, 12, and 22 patients, respectively, during initial follow-up. Overall, 55 patients completed protocol examination; the Spigelman stage was significantly reduced at the 1-year follow-up endoscopy (P < 0.001), with downstaging observed in 39 patients (71 %). Among the 26 patients with Spigelman stage IV at initial examination and protocol completion, 23 (88 %) showed downstaging. There was no major change in Spigelman stages from 1-year follow-up esophagogastroduodenoscopy to a median of 37 months (range 3-56).

CONCLUSIONS

IDP, including new-generation procedures, showed significant downstaging with acceptable adverse events for MDA in patients with FAP, even those with advanced-stage disease. Lesion selection for different resection techniques may be important for suitable and sustainable management of MDA in patients with FAP.

Safety and efficacy of cold versus hot snare polypectomy including colorectal polyps ≥1 cm in size

Cold snare polypectomy (CSP; polypectomy without electrocautery) has spread rapidly worldwide during the past decade in what has been called "Cold Revolution". We performed a PubMed literature search for studies investigating CSP outcomes for colorectal polyps. Five randomized controlled trials (RCTs) assessed the complete resection rates (CRRs). The CRRs were similar regardless of the presence or absence of electrocautery, and the efficacy of submucosal injection for better CRRs is still controversial. Eight RCTs assessed the adverse events. The incidence of intraprocedural bleeding with cold procedures was comparable to or higher than that of hot procedures. The incidences of delayed bleeding were comparable to or lower with cold procedures, especially in patients taking anticoagulants. Fifteen studies have been reported on CSP for large (≥1 cm) colorectal polyps (10 retrospective studies, four prospective single-arm studies, and one prospective RCT). These studies reported that the safe cold procedures (a low intra- and post-procedural bleeding rate without perforation) could be implemented for lesions ≥1 cm. However, considering the incision depth of CSP and the local recurrence rate based on the current evidence, only large sessile serrated lesions (SSLs) can be candidates for cold procedures, and large adenomas should not be candidates for this procedure. Based on the current evidence, CSP seems to be the appropriate standard procedure for sub-centimeter colorectal low-grade adenomas due to its safety and simplicity. Thus, large SSLs can be candidates for cold procedures; however, careful inspection and further prospective studies are warranted to confirm the procedure's clinical relevance.

Diagnostic performance of narrow-band imaging international colorectal endoscopic and Japanese narrow-band imaging expert team classification systems for colorectal cancer and precancerous lesions

BACKGROUND

In recent years, two new narrow-band imaging (NBI) classifications have been proposed: The NBI international colorectal endoscopic (NICE) classification and Japanese NBI expert team (JNET) classification. Most validation studies of the two new NBI classifications were conducted in classification setting units by experienced endoscopists, and the application of use in different centers among endoscopists with different endoscopy skills remains unknown.

AIM

To evaluate clinical application and possible problems of NICE and JNET classification for the differential diagnosis of colorectal cancer and precancerous lesions.

METHODS

Six endoscopists with varying levels of experience participated in this study. Eighty-seven consecutive patients with a total of 125 lesions were photographed during non-magnifying conventional white-light colonoscopy, non-magnifying NBI, and magnifying NBI. The three groups of endoscopic pictures of each lesion were evaluated by the six endoscopists in randomized order using the NICE and JENT classifications separately. Then we calculated the six endoscopists’ sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for each category of the two classifications.

RESULTS

The sensitivity, specificity, and accuracy of JNET classification type 1 and 3 were similar to NICE classification type 1 and 3 in both the highly experienced endoscopist (HEE) and less-experienced endoscopist (LEE) groups. The specificity of JNET classification type 1 and 3 and NICE classification type 3 in both the HEE and LEE groups was > 95%, and the overall interobserver agreement was good in both groups. The sensitivity of NICE classification type 3 lesions for diagnosis of SM-d carcinoma in the HEE group was significantly superior to that in the LEE group (91.7% vs 83.3%; P = 0.042). The sensitivity of JNET classification type 2B lesions for the diagnosis of high-grade dysplasia or superficial submucosal invasive carcinoma in the HEE and LEE groups was 53.8% and 51.3%, respectively. Compared with other types of JNET classification, the diagnostic ability of type 2B was the weakest.

CONCLUSION

The treatment strategy of the two classification type 1 and 3 lesions can be based on the results of endoscopic examination. JNET type 2B lesions need further examination.

Does cold snare polypectomy completely resect the mucosal layer? A prospective single-center observational trial

BACKGROUND AND AIM

The true incidence of incomplete muscularis mucosa resection with cold snare polypectomy (CSP) is unknown. We examined the incidence of incomplete muscularis mucosa resection both with and without cold snare defect protrusion (CSDP).

METHODS

We prospectively enrolled patients undergoing polypectomy for 4 to 9mm nonpedunculated polyps. We evaluated the presence of CSDP immediately following CSP and biopsied the CSDP or the center of the mucosal defect without CSDP. The presence of the muscularis mucosa and any residual polyp in the biopsies was evaluated histologically. The primary outcome was the incidence of incomplete mucosal layer resection defined as the presence of muscularis mucosa or residual polyp in the biopsies.

RESULTS

From August 2017 to October 2018, 188 patients were screened, and 357 polyps were included. CSDP was detected in 122/355 (34%) evaluated mucosal defects. Excluding five lesions requiring hemostasis immediately following CSP, 352 mucosal defects were biopsied. After excluding 102 biopsies containing normal mucosa, we evaluated 250 biopsies. The overall incidence of incomplete mucosal layer resection was 63% (159/250), 76% (68/90) with CSDP and 57% (91/159) without CSDP (P < 0.01). Both univariate and multivariate analyses showed that size (≥ 6 mm), resection time (≥ 5 s), and serrated lesions were risk factors for CSDP.

CONCLUSIONS

Cold snare defect protrusion (CSDP), which was present with 36%, was a good indicator for incomplete mucosal layer resection. Even in nonCSDP polypectomies, 57% of the mucosal layer was not removed completely. Thus, CSP should be used for intra-epithelial lesions only, and careful pretreatment evaluation is recommended.

Optical Technologies for Endoscopic Real-Time Histologic Assessment of Colorectal Polyps: A Meta-Analysis

OBJECTIVES

Accurate, real-time, endoscopic risk stratification of colorectal polyps would improve decision-making and optimize clinical efficiency. Technologies to manipulate endoscopic optical outputs can be used to predict polyp histology in vivo; however, it remains unclear how accuracy has progressed and whether it is sufficient for routine clinical implementation.

METHODS

A meta-analysis was conducted by searching MEDLINE, Embase, and the Cochrane Library. Studies were included if they prospectively deployed an endoscopic optical technology for real-time in vivo prediction of adenomatous colorectal polyps. Polyposis and inflammatory bowel diseases were excluded. Bayesian bivariate meta-analysis was performed, presenting 95% confidence intervals (CI).

RESULTS

One hundred two studies using optical technologies on 33,123 colorectal polyps were included. Digital chromoendoscopy differentiated neoplasia (adenoma and adenocarcinoma) from benign polyps with sensitivity of 92.2% (90.6%-93.9% CI) and specificity of 84.0% (81.5%-86.3% CI), with no difference between constituent technologies (narrow-band imaging, Fuji intelligent Chromo Endoscopy, iSCAN) or with only diminutive polyps. Dye chromoendoscopy had sensitivity of 92.7% (90.1%-94.9% CI) and specificity of 86.6% (82.9%-89.9% CI), similarly unchanged for diminutive polyps. Spectral analysis of autofluorescence had sensitivity of 94.4% (84.0%-99.1% CI) and specificity of 50.9% (13.2%-88.8% CI). Endomicroscopy had sensitivity of 93.6% (85.3%-98.3% CI) and specificity of 92.5% (81.8%-98.1% CI). Computer-aided diagnosis had sensitivity of 88.9% (74.2%-96.7% CI) and specificity of 80.4% (52.6%-95.7% CI). Prediction confidence and endoscopist experience alone did not significantly improve any technology. The only subgroup to demonstrate a negative predictive value for adenoma above 90% was digital chromoendoscopy, making high confidence predictions of diminutive recto-sigmoid polyps. Chronologic meta-analyses show a falling negative predictive value over time. A significant publication bias exists.

DISCUSSION

This novel approach to meta-analysis demonstrates that existing optical technologies are increasingly unlikely to allow safe "resect and discard" strategies and that step-change innovation may be required. A "diagnose and leave" strategy may be supported for diminutive recto-sigmoid polyps diagnosed with high confidence; however, limitations exist in the evidence base for this cohort.

Analysis of predictive factors for R0 resection and immediate bleeding of cold snare polypectomy in colonoscopy

BACKGROUND

Factors associated with efficacy and safety of cold snare polypectomy (CSP) are not well established. The aim is to elucidate the predictors of R0 resection and immediate bleeding of CSP.

METHODS

We retrospectively reviewed a database of patients who underwent CSP for subcentimetric polyps at the University of Tokyo Hospital in Japan. Using the data regarding the characteristics of patients and polyps, such as location, size, and macroscopic appearance; use of narrow band imaging with magnification (NBI-M); and endoscopists' experience, we revealed the predictive factors associated with R0 resection and immediate post-CSP bleeding by univariate and multivariate analyses.

RESULTS

In total, 399 polyps, in 200 patients without antithrombotics, were removed. Failure of tissue retrieval was noted in 4% of resected lesions. There was no intramucosal carcinoma observed. The overall rate of R0 resection was 46%. Multivariate analysis elucidated that the observation of the polyp with NBI-M was an independent predictor associated with R0 resection (odds ratio [OR] 1.90; p = 0.024). Although immediate post-CSP bleeding occurred in 19 polyps (4.8%), no delayed bleeding or perforation was observed. Multivariate analysis revealed protruded lesion as an independent risk factor for immediate bleeding (OR 3.54; p = 0.018).

CONCLUSIONS

A higher rate of R0 resection with CSP can be achieved by performing colonoscopy with NBI-M, than with white-light imaging. Macroscopic protruding appearance of a polyp is a risk factor for immediate bleeding.

Investigation of the Local Recurrence Rate after Colorectal Endoscopic Mucosal Resection: Is Incomplete Polyp Resection Really a Clinically Important Problem? Analysis of the Rationale for the "Resect and Discard" Strategy

BACKGROUND/AIMS

The "Resect and Discard" strategy is a potentially useful strategy. At present, only the lesion size and accuracy of diagnosis are cited as considerations for clinical adoption of this strategy. On the other hand, histopathology of the resected specimens after Endoscopic Mucosal Resection (EMR) reveals often an unclear or positive-margin status, implying Incomplete Polyp Resection (IPR). If IPR indeed increased the risk of local recurrence, histopathological evaluation of the margin would be indispensable and clinical adoption of this strategy is difficult. The aim of this study is to verify the association between IPR and the risk of local recurrence.

METHODS

The 1872 polyps and 603 EMR cases in 597 patients who had EMR between May 2013 and May 2014 were enrolled. The local recurrence rate until 3 years after the EMR in cases with the target lesions of the "Resect and Discard" strategy was determined in the negative-margin and IPR groups.

RESULTS

The final analysis was performed using the data of 1092 polyps, and 222 were categorized into the IPR group. There were no cases of recurrence in either of the groups.

CONCLUSION

This is the world's first report conducted to examine the correlation of IPR and the local recurrence rate for clinical practice of "Resect and Discard" strategy. There is the possibility that pathological evaluation of the margins after EMR in patients with small polyps can be skipped.

Management and risk factors for incomplete resection associated with jumbo forceps polypectomy for diminutive colorectal polyps: a single-institution retrospective study

BACKGROUND

Cold forceps polypectomy is simple and widely used in clinical practice. However, there are concerns about the risk of incomplete resection using this technique. In recent years, it has been reported that polypectomy with jumbo forceps (JF) is an effective treatment modality for diminutive polyps (DPs) because JF are able to remove large tissue samples with the combined advantage of a higher complete histological resection rate for DPs than standard forceps. To our knowledge, no studies have evaluated the risk factors for incomplete resection when polypectomy with JF is performed for DPs.

METHODS

From among 1129 DPs resected using JF at Hiroshima City Asa Citizens Hospital between November 2015 and December 2016, we retrospectively evaluated the clinical outcomes of 999 tumors with known histopathology and investigated the relationship between incomplete resection and clinicopathological factors.

RESULTS

Most lesions [985 (87%)] were low-grade dysplasia and 14 (1%) were high-grade dysplasia. The en bloc resection rate was 92% (918/999) and the histological en bloc resection rate was 78% (777/999). Multivariate analysis showed that the significant independent predictors of incomplete resection were tumor size ≥ 4 mm [odds ratio (OR) 3.8; 95% confidence interval (CI) 2.65-5.37; p < 0.01], non-tangential direction of forceps in relation to the tumor (OR 1.73; 95% CI 1.21-2.45; p < 0.01), and lack of muscularis mucosae in the pathological specimen (OR 15.7; 95% CI 9.16-27.7; p < 0.01).

CONCLUSIONS

This study identified significant independent predictors of incomplete resection of DPs which may be helpful when planning polypectomy with JF.

Clinical outcomes of the "resect and discard" strategy using magnifying narrow-band imaging for small (< 10 mm) colorectal polyps

Background and study aim  The "resect and discard" strategy is a new paradigm for the management of small colorectal polyps that reduces the cost and effort related to pathological diagnosis after polypectomy. This retrospective study aimed to clarify the clinical outcome of the "resect and discard" strategy for small colorectal polyps. Patients and methods  The clinical records were reviewed from 501 consecutive patients who underwent the "resect and discard" strategy for colorectal polyps smaller than 10 mm at our hospital between January 2008 and December 2010. All colorectal lesions were evaluated onsite under magnifying narrow-band imaging after careful conventional white-light imaging. In cases of low grade adenoma predicted with high confidence, colonoscopists selected the "resect and discard" option without formal histopathology. The mid-term outcomes were evaluated to validate the curability of the "resect and discard" strategy. Results  The present study included 501 consecutive patients with 816 lesions. The mid-term outcomes were examined for 476 (95 %) patients who received follow-up for at least 1 year after undergoing the "resect and discard" strategy. The median observation period was 83 months (range 12 - 117 months). No patient died from colorectal cancer related to the procedure, resulting in a disease-specific survival rate of 100 %. There were no local and/or distant recurrences detected during follow-up. Conclusions  The "resect and discard" strategy for small colorectal polyps under strict preoperative diagnosis achieves excellent mid-term outcome.

Clinical significance of colorectal polyp detection on colonoscopy insertion

Background

Colorectal lesions are generally evaluated during the withdrawal phase of colonoscopy. Minimising the risk of missed lesions is crucial to determine an appropriate future surveillance colonoscopy interval.

Objective

This study aimed to evaluate the clinical significance of detecting sigmoid colon lesions during the insertion phase.

Methods

This retrospective study included 172 consecutive patients undergoing colonoscopy between October 2017 and April 2018. The total number of detected polyps, mean polyps per procedure, mean polyps per positive procedure, and histological and clinical characteristics of detected lesions were recorded. The primary endpoint was the difference in sigmoid colon polyp detection rates during insertion and withdrawal.

Results

A total of 172 colonoscopies were performed for each patient and 322 lesions were detected. Sixty-two (19%) polyps were detected during insertion, 312 (97%) during withdrawal, and 52 (16%) during both insertion and withdrawal. Although all polyps except for those in the sigmoid colon could be detected during withdrawal, 10 of 87 (11%) polyps in the sigmoid colon could only be detected during insertion.

Conclusions

In this study, attempts to detect polyps, even in the insertion phase, showed the clinical significance to decrease the risk of missed adenomatous polyps in the sigmoid colon.

Diagnostic performance of magnifying endoscopy with narrow-band imaging in differentiating neoplastic colorectal polyps from non-neoplastic colorectal polyps: a meta-analysis

Colorectal polyps are commonly seen in colonoscopy and the management of neoplastic polyps and non-neoplastic polyps are different. It is necessary to distinguish neoplastic polyps from non-neoplastic polyps in real-time. Therefore, we conducted a meta-analysis to assess the diagnostic accuracy of magnifying endoscopy with narrow-band imaging (ME-NBI) in diagnosing neoplastic colorectal polyps from non-neoplastic colorectal polyps. PubMed and EMBASE were searched for trials that used magnifying endoscopy with ME-NBI for diagnosing neoplastic colorectal polyps. Sixteen articles and 20 fourfold tables were obtained. Sensitivity (Sen), specificity (Spe), positive likelihood ratios (+ LRs), negative likelihood ratios (- LRs) and diagnostic odds ratios (DORs) were calculated. A summary receiver-operating characteristic (SROC) curve was constructed, and the area under the ROC curve (AUC) was calculated. We performed subgroup analyses based on polyp size and assessment criteria: (1) According to data extracted from 20 fourfold tables, the pooled Sen and Spe of ME-NBI for diagnosing neoplastic colorectal polyps < 10 mm were 0.94 (95% CI 0.92-0.95) and 0.76 (95% CI 0.72-0.80),respectively. The pooled Sen and Spe of ME-NBI for diagnosing all neoplastic polyps were 0.98 (95% CI 0.98-0.99) and 0.88 (95% CI 0.85-0.90), respectively. (2) Data pertaining to the following three assessment methods were analysed from 15 fourfold tables: surface pattern (SP), vessel pattern (VP) and the combination of SP and VP. The AUCs for these assessment criteria were 0.9533, 0.9518 and 0.9954, respectively. Conclusions were made that ME-NBI has high diagnostic accuracy in diagnosing neoplastic colorectal polyps based on the combination of SP with VP and is helpful in making real-time diagnoses.

Clinical impact of surveillance colonoscopy using magnification without diminutive polyp removal

BACKGROUND AND AIM

In Western countries, endoscopic removal of all adenomas during colonoscopy is recommended. The present study evaluates the usefulness of magnifying colonoscopy without removal of diminutive (≤5 mm) colorectal polyps.

METHODS

Patients with diminutive polyps who were observed for over 5 years using magnification at Hiroshima University Hospital were selected retrospectively. Lesions ≥6 mm in size, depressed lesions, and lesions with type V pit pattern were indications for endoscopic resection. We investigated the characteristics of lesions indicated for endoscopic resection detected on surveillance colonoscopy and the risk factors for the incidence of lesions indicated for endoscopic resection.

RESULTS

A total of 706 consecutive patients were enrolled. Sixty-eight lesions indicated for endoscopic resection were detected, averaging 9.0 ± 4.8 mm, and 33 (49%) lesions were located in the right colon. Pathological diagnoses were adenoma, Tis carcinoma, and T1 carcinoma in 58 (85%), eight (12%), and two (3%) lesions, respectively. Five lesions were considered to grow from previously detected diminutive polyps. Relative risks for the incidence of a lesion indicated for endoscopic resection were 1.76 (95% confidence interval [CI], 1.004-3.23) for males compared with females, 3.76 (95% CI, 2.03-7.50) for more than three polyps at initial colonoscopy compared with one polyp, and 2.84 (95% CI, 1.43-5.24) for patients with carcinoma at initial colonoscopy compared with patients with no lesion indicated for endoscopic resection. Nine carcinomas were resected endoscopically.

CONCLUSION

Diminutive low-grade adenomas detected by using magnifying colonoscopy may not necessarily require removal.

Polyp characterization at colonoscopy: Clinical implications

Although advancements in endoscopic imaging of colorectal mucosa have outstripped the pace of research in the field, the potential clinical applications of these novel technologies are promising. Chief among these is the ability to diagnose colorectal polyps in vivo. This feature appears most applicable to diminuitive polyps, which have very little malignant potential yet represent over 70% of resected polyps. In an ideal application, the capability to predict diminutive hyperplastic polyp histology in vivo precludes the need for excision whereas dimunitive adenomas do require excision, but not necessarily histopathologic analysis if the diagnosis is made in vivo with adequate confidence. However, the vast array of new advanced imaging modalities and polyp classification tools have been difficult to reconcile. We aim to highlight the current status of real-time colorectal polyp diagnosis and identify the barriers that remain to its widespread implementation.

Serum metabolomics analysis for early detection of colorectal cancer

BACKGROUND

Although colorectal cancer (CRC) is one of the most common causes of cancer mortality, early-stage detection improves survival rates dramatically. Because cancer impacts important metabolic pathways, the alteration of metabolite levels as a potential biomarker of early-stage cancer has been the focus of many studies. Here, we used CE-TOFMS, a novel and promising method with small injection volume and high resolution, to separate and detect ionic compounds based on the different migration rates of charged metabolites in order to detect metabolic biomarkers in patients with CRC.

METHODS

A total of 56 patients with CRC (n = 14 each of Stages I-IV), 60 healthy controls, and 59 patients with colonic adenoma were included in this study. Metabolome analysis was conducted by CE-TOFMS on serum samples of patients and controls using the Advanced Scan package (Human Metabolome Technologies).

RESULTS

We obtained 334 metabolites in the serum, of which 139 were identified as known substances. Among these 139 known metabolites, 16 were correlated with CRC stage by upregulation and 44 by downregulation, with benzoic acid (r = -0.649, t = 11.653, p = 6.07599E-24), octanoic acid (r = 0.557, t = 9.183, p = 7.9557E-17), decanoic acid (r = 0.539, t = 8.749, p = 1.24352E-15), and histidine (r = -0.513, t = 8.194, p = 3.90224E-14) exhibiting significant correlation.

CONCLUSIONS

To the best of our knowledge, this is the first report to determine the correlation between serum metabolites and CRC stage using CE-TOFMS. Our results show that benzoic acid exhibited excellent diagnostic power and could potentially serve as a novel disease biomarker for CRC diagnosis.

Clinical impact and characteristics of the narrow-band imaging magnifying endoscopic classification of colorectal tumors proposed by the Japan NBI Expert Team

BACKGROUND AND AIMS

The Japan NBI Expert Team (JNET) was established in 2011 and has proposed a universal narrow-band imaging (NBI) magnifying endoscopic classification of colorectal tumors. The aim of this study was to evaluate the clinical usefulness of the JNET classification for colorectal lesions.

METHODS

We analyzed 2933 colorectal lesions, which were diagnosed by NBI magnifying observation before endoscopic treatment or surgery. The colorectal lesions consisted of 136 hyperplastic polyps/sessile serrated polyps (HPs/SSPs), 1926 low-grade dysplasia (LGD), 571 high-grade dysplasia (HGD), 87 superficial submucosal invasive (SM-s) carcinomas, and 213 deep submucosal invasive (SM-d) carcinomas. We evaluated the relationship between the JNET classification and the histologic findings of these lesions.

RESULTS

The sensitivity, specificity, positive and negative predictive values, and accuracy of Type 1 lesions for the diagnosis of HP/SSP were, respectively, 87.5%, 99.9%, 97.5%, 99.4%, and 99.3%; of Type 2A lesions for the diagnosis of LGD were 74.3%, 92.7%, 98.3%, 38.7%, and 77.1%; of Type 2B lesions for the diagnosis of HGD/SM-s carcinoma were 61.9%, 82.8%, 50.9%, 88.2%, and 78.1%; for Type 3 lesions for the diagnosis of SM-d carcinoma were 55.4%, 99.8%, 95.2%, 96.6%, and 96.6%, respectively.

CONCLUSIONS

Types 1, 2A, and 3 of the JNET classification were very reliable indicators for HP/SSP, LGD, and SM-d carcinoma, respectively. However, the specificity and positive predictive value of Type 2B were relatively lower than those of others. Therefore, an additional examination such as pit pattern diagnosis using chromoagents is necessary for accurate diagnosis of Type 2B lesions.

Accuracy of computer-aided diagnosis based on narrow-band imaging endocytoscopy for diagnosing colorectal lesions: comparison with experts

PURPOSE

Real-time characterization of colorectal lesions during colonoscopy is important for reducing medical costs, given that the need for a pathological diagnosis can be omitted if the accuracy of the diagnostic modality is sufficiently high. However, it is sometimes difficult for community-based gastroenterologists to achieve the required level of diagnostic accuracy. In this regard, we developed a computer-aided diagnosis (CAD) system based on endocytoscopy (EC) to evaluate cellular, glandular, and vessel structure atypia in vivo. The purpose of this study was to compare the diagnostic ability and efficacy of this CAD system with the performances of human expert and trainee endoscopists.

METHODS

We developed a CAD system based on EC with narrow-band imaging that allowed microvascular evaluation without dye (ECV-CAD). The CAD algorithm was programmed based on texture analysis and provided a two-class diagnosis of neoplastic or non-neoplastic, with probabilities. We validated the diagnostic ability of the ECV-CAD system using 173 randomly selected EC images (49 non-neoplasms, 124 neoplasms). The images were evaluated by the CAD and by four expert endoscopists and three trainees. The diagnostic accuracies for distinguishing between neoplasms and non-neoplasms were calculated.

RESULTS

ECV-CAD had higher overall diagnostic accuracy than trainees (87.8 vs 63.4%; [Formula: see text]), but similar to experts (87.8 vs 84.2%; [Formula: see text]). With regard to high-confidence cases, the overall accuracy of ECV-CAD was also higher than trainees (93.5 vs 71.7%; [Formula: see text]) and comparable to experts (93.5 vs 90.8%; [Formula: see text]).

CONCLUSIONS

ECV-CAD showed better diagnostic accuracy than trainee endoscopists and was comparable to that of experts. ECV-CAD could thus be a powerful decision-making tool for less-experienced endoscopists.

Feasibility of cold snare polypectomy in Japan: A pilot study

AIM: To investigate the feasibility of cold snare polypectomy (CSP) in Japan.

METHODS: The outcomes of 234 non-pedunculated polyps smaller than 10 mm in 61 patients who underwent CSP in a Japanese referral center were retrospectively analyzed. The cold snare polypectomies were performed by nine endoscopists with no prior experience in CSP using an electrosurgical snare without electrocautery.

RESULTS: CSPs were completed for 232 of the 234 polyps. Two (0.9%) polyps could not be removed without electrocautery. Immediate postpolypectomy bleeding requiring endoscopic hemostasis occurred in eight lesions (3.4%; 95%CI: 1.1%-5.8%), but all were easily managed. The incidence of immediate bleeding after CSP for small polyps (6-9 mm) was significantly higher than that of diminutive polyps (≤ 5 mm; 15% vs 1%, respectively). Three (5%) patients complained of minor bleeding after the procedure but required no intervention. The incidence of delayed bleeding requiring endoscopic intervention was 0.0% (95%CI: 0.0%-1.7%). In total, 12% of the resected lesions could not be retrieved for pathological examination. Tumor involvement in the lateral margin could not be histologically assessed in 70 (40%) lesions.

CONCLUSION: CSP is feasible in Japan. However, immediate bleeding, retrieval failure and uncertain assessment of the lateral tumor margin should not be underestimated. Careful endoscopic diagnosis before and evaluation of the tumor residue after CSP are recommended when implementing CSP in Japan.