Effect of educational lecture on the diagnostic accuracy of Japan NBI Expert Team classification for colorectal lesions.

BACKGROUND: An educational and training program is required for generalization of Japan NBI Expert Team (JNET) classification. However, there is no detailed report on the learning curve of the diagnostic accuracy of endoscopists using JNET classification. We examined the effect of an educational lecture on beginners and less experienced endoscopists for improving their diagnostic accuracy of colorectal lesions by JNET classification. METHODS: Seven beginners with no endoscopy experience (NEE group), 7 less experienced endoscopists (LEE group), and 3 highly experienced endoscopists (HEE group) performed diagnosis using JNET classification for randomized NBI images of colorectal lesions from 180 cases (Type 1: 22 cases, Type 2A: 105 cases, Type 2B: 33 cases, and Type 3: 20 cases). Next, the NEE and LEE groups received a lecture on JNET classification, and all 3 groups repeated the diagnostic process. We compared the correct diagnosis rate and interobserver agreement before and after the lecture comprehensively and for each JNET type. RESULTS: In the HEE group, the correct diagnosis rate was more than 90% with good interobserver agreements (kappa value: 0.78-0.85). In the NEE and LEE groups, the correct diagnosis rate (NEE: 60.2 → 68.0%, P < 0.01; LEE: 66.4 → 86.7%, P < 0.01), high-confidence correct diagnosis rate (NEE: 19.6 → 37.2%, P < 0.01; LEE: 43.6 → 61.1%, P < 0.01), and interobserver agreement (kappa value, NEE: 0.32 → 0.43; LEE: 0.39 → 0.75) improved after the lecture. In the examination by each JNET type, the specificity and positive predictive value in the NEE and LEE groups generally improved after the lecture. CONCLUSION: After conducting an appropriate lecture, the diagnostic ability using JNET classification was improved in beginners or endoscopists with less experience in NBI magnifying endoscopy.

Dual Red Imaging Maintains Clear Visibility During Colorectal Endoscopic Submucosal Dissection.

BACKGROUND: The endoscopic lens becomes clouded and its visibility reduces during colorectal endoscopic submucosal dissection (ESD), especially in cases with submucosal fatty tissue. Dual red imaging (DRI) is a novel image-enhanced endoscopic technique that improves endoscopic visibility. AIMS: This study aimed to evaluate the predictive factors of submucosal fatty tissue and the clinical usefulness of DRI in maintaining clear visibility during colorectal ESD. METHODS: The study participants included 586 consecutive patients with 645 colorectal tumors who underwent ESD between January 2014 and July 2017. First, the degree of submucosal fatty tissue was evaluated by reviewing recorded images, and the clinical characteristics of the patients and tumors related to severe submucosal fatty tissue were evaluated. Second, 34 tumors resected using DRI were propensity score-matched in a 1:1 ratio to other resected tumors using white light imaging (WLI), and the degree of endoscope lens cloudiness and clinical outcomes were evaluated. RESULTS: The proportion of tumors located in the right side of the colon, body mass index (≥ 25, BMI), and hemoglobin A1c (≥ 6.5%, HbA1c) were significantly higher in patients with severe submucosal fatty tissue. The visibility in the DRI group was significantly better than in the WLI group. Treatment outcomes in the DRI group were as good as those in the WLI group. CONCLUSIONS: Tumor location in the right side of the colon, BMI (≥ 25), and HbA1c (≥ 6.5%) are the predictive factors of severe submucosal fatty tissue. DRI is useful in maintaining clear visibility during colorectal ESD, especially with submucosal fatty tissue.

Validation study for development of the Japan NBI Expert Team classification of colorectal lesions.

BACKGROUND AND AIM: The Japan narrow-band imaging (NBI) Expert Team (JNET) was organized to unify four previous magnifying NBI classifications (the Sano, Hiroshima, Showa, and Jikei classifications). The JNET working group created criteria (referred to as the NBI scale) for evaluation of vessel pattern (VP) and surface pattern (SP). We conducted a multicenter validation study of the NBI scale to develop the JNET classification of colorectal lesions. METHODS: Twenty-five expert JNET colonoscopists read 100 still NBI images with and without magnification on the web to evaluate the NBI findings and necessity of the each criterion for the final diagnosis. RESULTS: Surface pattern in magnifying NBI images was necessary for diagnosis of polyps in more than 60% of cases, whereas VP was required in around 90%. Univariate/multivariate analysis of candidate findings in the NBI scale identified three for type 2B (variable caliber of vessels, irregular distribution of vessels, and irregular or obscure surface pattern), and three for type 3 (loose vessel area, interruption of thick vessel, and amorphous areas of surface pattern). Evaluation of the diagnostic performance for these three findings in combination showed that the sensitivity for types 2B and 3 was highest (44.9% and 54.7%, respectively), and that the specificity for type 3 was acceptable (97.4%) when any one of the three findings was evident. We found that the macroscopic type (polypoid or non-polypoid) had a minor influence on the key diagnostic performance for types 2B and 3. CONCLUSION: Based on the present data, we reached a consensus for developing the JNET classification.

Long-term outcomes after endoscopic submucosal dissection for superficial colorectal tumors.

BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) is an effective procedure for en bloc resection of superficial colorectal tumors regardless of tumor size or location. However, there are few reports on long-term outcomes for patients with superficial colorectal tumors after ESD. We therefore aimed to evaluate the long-term outcomes after ESD for superficial colorectal tumors. METHODS: ESD was performed on 257 colorectal tumors in 255 consecutive patients at Hiroshima University Hospital between June 2003 and July 2010. We investigated the following variables: patient characteristics, the American Society of Anesthesiologists score, tumor location, tumor size, growth type, histology, en bloc resection rate, achievement of curative resection, procedure time, and adverse events. The 5-year overall survival (OS), 5-year disease-specific survival (DSS), local recurrence, and metachronous tumor occurrence were also analyzed. RESULTS: We identified 224 tumors in 222 patients who were confirmed dead or had follow-up data for more than 5 years. After a median follow-up of 79 months, 5-year OS and DSS rates were 94.6% and 100%, respectively. The local recurrence rate (1.5%) was significantly higher in patients undergoing piecemeal resection (9.1%) compared with en bloc resection (0.6%), in cases of histologic incomplete resection compared with complete resection, and in cases of non-R0 resection compared with R0 resection. The rates of total number of tumors (≥6 mm) and carcinoma metachronous tumors after ESD without additional surgical resection were 18.9% (38/201) and 4.0% (8/201), respectively. CONCLUSIONS: Long-term outcomes after ESD for superficial colorectal tumors are favorable. Patients should be surveyed for both local recurrence and metachronous tumors after ESD.

Diagnostic performance of Japan NBI Expert Team classification for differentiation among noninvasive, superficially invasive, and deeply invasive colorectal neoplasia.

BACKGROUNDS AND AIMS: The Japan NBI Expert Team (JNET) classification is the first universal narrow-band imaging magnifying endoscopic classification of colorectal tumors. Considering each type in this classification, the diagnostic ability of Type 2B is the weakest. Generally, clinical behavior is believed to be different in each gross type of colorectal tumor. We evaluated the differences in the diagnostic performance of JNET classification for each gross type (polypoid and superficial) and examined whether the diagnostic performance of Type 2B could be improved by subtyping. METHODS: We analyzed 2933 consecutive cases of colorectal lesions, including 136 hyperplastic polyps/sessile serrated polyps, 1926 low-grade dysplasias (LGDs), 571 high-grade dysplasias (HGDs), and 300 submucosal (SM) carcinomas. We classified lesions as polypoid and superficial type and compared the diagnostic performance of the classification system in each type. Additionally, we subtyped Type 2B into 2B-low and 2B-high based on the level of irregularity in surface and vessel patterns, and we evaluated the relationship between the subtypes and histology, as analyzed separately for polypoid and superficial types. We also estimated interobserver and intraobserver variability. RESULTS: The diagnostic performance of JNET classification did not differ significantly between polypoid and superficial lesions. Ninety-nine percent of Type 2B-low lesions were LGDs, HGDs, or superficial submucosal invasive (SM-s) carcinomas. In contrast, 60% of Type 2B-high lesions were deep submucosal invasive (SM-d) carcinomas. The results were not different between each gross type. Interobserver and intraobserver agreements for Type 2B subtyping were good, with kappa values of .743 and .786, respectively. CONCLUSIONS: Type 2B subtyping may be useful for identifying lesions that are appropriate for endoscopic resection. JNET classification and Type 2B sub classification are useful criteria, regardless of gross type.

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.

Clinicopathologic and endoscopic features of early-stage colorectal serrated adenocarcinoma.

BACKGROUND: Serrated adenocarcinoma (SAC) is a distinct colorectal carcinoma variant that accounts for approximately 7.5% of all advanced colorectal carcinomas. While its prognosis is worse than conventional carcinoma, its early-stage clinicopathologic features are unclear. We therefore aimed to clarify the clinicopathologic and endoscopic characteristics of early-stage SACs. METHODS: Forty consecutive early-stage SAC patients at Hiroshima University Hospital were enrolled; SACs were classified into epithelial serration (Group A, n = 17) and non-epithelial serration (Group B, n = 23) groups. Additionally, we classified serrated adenoma into 4 types: sessile serrated adenoma (SSA), traditional serrated adenoma (TSA), unclassified, and non-serrated adenoma type. RESULTS: There were significant differences between Groups A and B in terms of tumor size (27.6 vs. 43.1 mm), incidences of T1 carcinoma (71% vs. 13%), and having the same color as normal mucosa (47% vs. 17%), respectively (p <0.01). In SACs >20 mm, the incidence of T1 carcinoma in Group A (70%) was significantly greater than that in Group B (13%) (p <0.05). There were significant differences in 'Japan NBI Expert Team' type 3 and type V pit pattern classifications between the 2 groups. The average TSA-type tumor size (42.6 mm) was significantly larger than that of the SSA (17.2 mm) and non-serrated component types (18.3 mm). The incidences of submucosal invasion in SSA- (80%), unclassified- (100%), and non-serrated-type (100%) tumors were significantly higher than that in the TSA type (11%). CONCLUSIONS: Epithelial serration in the cancerous area and a non-TSA background indicated aggressive behavior in early-stage SACs.

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.

Long-term outcomes after treatment for T1 colorectal carcinoma.

PURPOSE: Long-term outcomes of patients with T1 colorectal carcinoma (CRC) treated by endoscopic resection (ER) or surgical resection are unclear in relation to the curative criteria in the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines. The aim of this study was to retrospectively compare the long-term outcomes among patients with T1 CRC in relation to the treatment methods. METHODS: We examined 322 T1 CRC cases treated between January 1992 and August 2008 at Hiroshima University Hospital. Patients who did not meet the curative criteria in the JSCCR guidelines were defined as "non-endoscopically curable" and classified into three groups: underwent ER alone (group A: 45 patients), underwent additional surgery after ER (group B: 106 patients), and underwent surgical resection alone (group C: 92 patients). RESULTS: Of the 322 T1 CRC patients, 79 were categorized as endoscopically curable and 243 as non-endoscopically curable. Among the endoscopically curable T1 CRC patients, recurrence and 5-year OS rates were 0 and 94.2%, respectively. In groups A, B, and C, recurrence rates were 4.4, 6.6, and 4.3%, and OS rates were 85.6, 95.1, and 96.3%, respectively (p < 0.05). Local recurrence or distant/lymph node metastasis was observed in 13 patients (group A: 2; group B: 7; group C: 4). Death due to primary CRC occurred in six patients (group B: 4; group C: 2). CONCLUSION: Long-term outcomes support the curative criteria according to the JSCCR guidelines. ER for T1 CRC did not worsen clinical outcomes in cases that required additional surgical resection.

Clinical significance and validity of the subclassification for colorectal laterally spreading tumor granular type.

BACKGROUND AND AIM: Colorectal laterally spreading tumor granular type (LST-G) is generally divided into two subtypes based on morphology. Here, we retrospectively investigated the clinical significance of a concrete, objective LST-G subclassification. METHODS: This study examined 636 consecutive cases that were resected endoscopically or surgically. LST-G was subclassified as follows: Type 1, a lesion with homogenous uniform granules with uniform (<5 mm) nodules; Type 2, a lesion with granules and small nodules (≥5 mm, <10 mm); or Type 3, a lesion accompanied by large nodules (≥10 mm). For the validation study, 194 images were compiled from 97 cases investigated using conventional colonoscopy and chromoendoscopy with indigo carmine dye spraying. Images were distributed in a randomized order to students without prior endoscopy experience, less-experienced endoscopists (LEE group), and highly experienced endoscopists (HEE group). Diagnostic accuracy and interobserver agreement were then evaluated. RESULTS: There was no submucosal invasion in Type 1 lesions. The incidence of deep submucosal invasive carcinoma was higher for Type 3 lesions than for Type 2 lesions. Interobserver agreement was good in each group. Diagnostic accuracy was higher in the HEE group than in the student and LEE groups. Chromoendoscopy had a higher accuracy rate than conventional colonoscopy in the LEE and HEE groups (LEE, 0.74 vs 0.69, P < 0.05; HEE, 0.84 vs 0.78, P < 0.05). CONCLUSIONS: This subclassification of LST-G according to the diameters of granules and nodules was both useful for choosing therapeutic strategies in the clinical setting and universally applicable.

Endoscopic submucosal dissection for anorectal tumor with hemorrhoids close to the dentate line: a multicenter study of Hiroshima GI Endoscopy Study Group.

BACKGROUND: The lower rectum close to the dentate line has distinct characteristics, making endoscopic submucosal dissection (ESD) of tumors challenging. We assessed clinical outcomes of ESD for such patients with hemorrhoids. METHODS: Sixty-four patients (mean age, 68 years) underwent ESD for anorectal tumors close to the dentate line. We divided patients into those with (Group A, 45 patients) and without hemorrhoids (Group B, 19 patients). We examined en bloc and histological en bloc resection rates, procedure time, complication rates, and postoperative prognosis after ESD. RESULTS: The mean tumor size was 43 mm. Histologic diagnoses were adenoma (42 %, 27/64), carcinoma in situ (44 %, 28/64), and T1 carcinoma (14 %, 9/64). There was no significant difference in en bloc resection (93 %, 42/45 vs. 95 %, 18/19) or postoperative bleeding rates (16 %, 7/45 vs. 11 %, 2/19) between Groups A and B, respectively. The mean procedural durations were 120 and 124 min, respectively, in Groups A and B. No perforations occurred. There was no significant difference in postoperative anal pain rate between Groups A (18 %, 8/45) and B (16 %, 3/19), and it resolved within a few days in all cases. There was one case of stricture in Group B. Two patients with T1 carcinoma underwent additional surgery, one underwent chemotherapy, and five had no additional treatment. No recurrence occurred during the follow-up period of 38 months. CONCLUSIONS: ESD is safe and effective for anorectal tumors close to the dentate line in patients with hemorrhoids.

Narrow-band imaging (NBI) magnifying endoscopic classification of colorectal tumors proposed by the Japan NBI Expert Team.

Many clinical studies on narrow-band imaging (NBI) magnifying endoscopy classifications advocated so far in Japan (Sano, Hiroshima, Showa, and Jikei classifications) have reported the usefulness of NBI magnifying endoscopy for qualitative and quantitative diagnosis of colorectal lesions. However, discussions at professional meetings have raised issues such as: (i) the presence of multiple terms for the same or similar findings; (ii) the necessity of including surface patterns in magnifying endoscopic classifications; and (iii) differences in the NBI findings in elevated and superficial lesions. To resolve these problems, the Japan NBI Expert Team (JNET) was constituted with the aim of establishing a universal NBI magnifying endoscopic classification for colorectal tumors (JNET classification) in 2011. Consensus was reached on this classification using the modified Delphi method, and this classification was proposed in June 2014. The JNET classification consists of four categories of vessel and surface pattern (i.e. Types 1, 2A, 2B, and 3). Types 1, 2A, 2B, and 3 are correlated with the histopathological findings of hyperplastic polyp/sessile serrated polyp (SSP), low-grade intramucosal neoplasia, high-grade intramucosal neoplasia/shallow submucosal invasive cancer, and deep submucosal invasive cancer, respectively.

Endoscopic submucosal dissection as total excisional biopsy for clinical T1 colorectal carcinoma.

BACKGROUND/AIMS: Only the depth of submucosal invasion can be estimated prior to determining the indications for endoscopic submucosal dissection (ESD) as a curative treatment for colorectal carcinoma (CRC). Here we evaluated the outcomes of ESD for clinical T1 CRCs. METHODS: Of 660 patients who underwent ESD for CRC at the Hiroshima University Hospital between June 2003 and December 2013, we examined the outcomes of 37 (6%; 26 men, 11 women; mean age ± SD, 68 ± 12 years) who underwent ESD as total excisional biopsy for various reasons, in spite of an endoscopic diagnosis of T1 CRC. RESULTS: The mean lesion size was 25 ± 14 mm; 14 lesions were protruding and 23 were superficial. The en bloc resection rate was 100% (37/37). The histological en bloc resection rate was 92% (34/37). ESD resulted in a positive vertical margin in 3 cases. Deep submucosal invasion was seen in 3 cases, 2 of which had severe submucosal fibrosis. Although severe submucosal fibrosis was not found in other cases, pathologic examination of the deepest invasive portion of the tumor revealed poorly differentiated adenocarcinoma. The rates of post-ESD bleeding and perforation were 8% (3/37) and 5% (2/37), respectively. All patients recovered under conservative therapy. No cases of recurrence were noted in patients without additional surgical resection when the lesions satisfied the curative conditions listed in the 2014 Japanese Society for Cancer of the Colon and Rectum guidelines. CONCLUSION: En bloc resection by ESD as total excisional biopsy for clinical T1 CRC is a highly effective treatment and establishes a precise histological diagnosis.

Towards safer and appropriate application of endoscopic submucosal dissection for T1 colorectal carcinoma as total excisional biopsy: future perspectives.

According to the Japanese Society for Cancer of the Colon and Rectum Guidelines 2014 for the Treatment of Colorectal Cancer, cases with T1 colorectal carcinoma should be considered for additional colectomy with lymph node dissection when histologically complete en bloc resection is endoscopically carried out and when one of the four risk factors listed below is present. These four risk factors are: (i) submucosal (SM) invasion depth ≥1000 µm; (ii) positive vascular invasion; (iii) poorly differentiated adenocarcinoma, signet ring cell carcinoma, or mucinous carcinoma; and (iv) grade 2/3 budding at the deepest part of SM invasion. However, the probability of lymph node metastasis is extremely low if none of these risk factors are present, with the exception of SM invasion depth ≥1000 µm. Consequently, it is assumed that there will be an increasing number of cases where no additional surgery is done, or cases of moderate invasive carcinoma in which endoscopic treatment is carried out to achieve an excisional biopsy, for which complete resection is applicable. In these cases, the preoperative diagnosis, resection techniques such as endoscopic submucosal dissection, features of resected specimens, and the accuracy of pathological diagnosis are all extremely important.

Predictors of incomplete resection and perforation associated with endoscopic submucosal dissection for colorectal tumors.

BACKGROUND AND OBJECTIVE: Colorectal endoscopic submucosal dissection (ESD) is technically challenging. Our aim was to identify predictors of incomplete resection and perforation in colorectal ESD. DESIGN: Retrospective study. SETTING: Academic Japanese endoscopy unit. PATIENTS AND MAIN OUTCOME MEASUREMENTS: A total of 267 consecutive cases of colorectal tumors treated by ESD from May 2010 to February 2013 were analyzed. Predictors of incomplete resection and perforation, including lesion size, growth type, pathological diagnosis, use of hemostatic forceps, degree of fibrosis, history of biopsy, history of local endoscopic treatment, and endoscopic operability. RESULTS: The incomplete resection rate was 4.1%. The perforation rate was 5.6%. Univariate analysis identified severe fibrosis (P = .032), submucosal (SM) deep (>1000 µm) invasion (P = .033) and poor endoscopic operability (P = .030) as predictors of incomplete resection, and severe fibrosis (P = .038), postendoscopic treatment (P = .016), and poor endoscopic operability (P = .012) as predictors of perforation. Multivariate analysis identified poor endoscopic operability and SM deep invasion as independent predictors of incomplete resection, and poor endoscopic operability and severe fibrosis as independent predictors of perforation. There was no adjustment of P values for multiple testing. LIMITATION: A single-center study by a single colonoscopist. All statistical results should be taken as descriptive only. CONCLUSIONS: Poor endoscopic operability and SM deep invasion were significant independent predictors of incomplete resections. Poor endoscopic operability and severe fibrosis were significant independent predictors of perforation. These features may provide helpful information when planning colorectal ESD.

Risk factors for delayed bleeding after endoscopic submucosal dissection for colorectal neoplasms.

PURPOSE: Although delayed bleeding is a major complication of endoscopic submucosal dissection (ESD) for colorectal neoplasms, few reports have assessed the risk factors for delayed bleeding after colorectal ESD. METHODS: This study included 363 consecutive patients in whom 377 colorectal neoplasms were resected using ESD between April 2006 and August 2012. We classified patients and lesions into two groups on the basis of presence or absence of delayed bleeding and retrospectively compared the clinicopathological characteristics and clinical outcomes of ESD between the two groups. RESULTS: Delayed bleeding occurred in 25 (6.6 %) of 377 lesions, and all cases of delayed bleeding were successfully controlled by endoscopic procedures. With respect to patient-related factors, there was no significant difference between the groups in mean age, sex ratio, and current use of antithrombotic agents. With respect to lesion-related factors, there was no significant difference between the groups in mean lesion size, growth pattern, and mean procedure time (p = 0.6). Lesions located in the rectum (vs colon, p = 0.0005) and lesions with severe submucosal fibrosis (vs no or mild fibrosis, p = 0.022) were significantly related to delayed bleeding. Upon multivariate analysis, lesions located in the rectum (vs colon, odds ratio 4.19; p = 0.0009) were significantly related to delayed bleeding after colorectal ESD. CONCLUSIONS: This study demonstrated that location of lesions in the rectum was a significant independent risk factor for delayed bleeding after ESD for colorectal neoplasms.

Condition of muscularis mucosae is a risk factor for lymph node metastasis in T1 colorectal carcinoma.

BACKGROUND: The Japanese Society for Cancer of the Colon and Rectum Guidelines for the Treatment of Colorectal Cancer 2010 state that curable T1 colorectal carcinoma (CRC) after endoscopic resection shows favorable histologic grade, absence of vessel involvement, submucosal invasion depth of <1,000 µm, and low-grade tumor budding. METHODS: We evaluated 322 consecutive T1 CRCs with LN dissection between January 1993 and March 2012. According to the muscularis mucosae condition, CRCs were classified into three groups: type A, clearly identified; type B, incompletely disrupted with deformity; or type C, completely disrupted. We examined the relationship between the muscularis mucosae condition, clinicopathological findings, and lymph node (LN) metastasis. RESULTS: The overall incidence of LN metastasis was 11.8 % (38/322): 0 % (0/46) for the type A group, 7.2 % (7/97) for the type B group, and 17.3 % (31/179) for the type C group. In univariate analysis of type B and C groups, unfavorable histologic grade, submucosal invasion of ≥1,000 µm, positive lymphatic invasion, high-grade tumor budding, and the type C group were associated with a significantly higher incidence of LN metastasis. In multivariate analysis, high-grade tumor budding (P < 0.001, odds ratio [OR] = 4.86), unfavorable histologic grade (P = 0.026, OR = 4.83), positive lymphatic invasion (P < 0.001, OR = 4.17), and the type C group (P = 0.012, OR = 3.38) were significantly associated with LN metastasis. The type C group showed a high incidence of moderate/severe lymphatic invasion. CONCLUSIONS: The condition of the muscularis mucosae was an indicator of LN metastasis in T1 CRC.

Endoscopic prediction of deep submucosal invasive carcinoma: validation of the narrow-band imaging international colorectal endoscopic (NICE) classification.

BACKGROUND: A simple endoscopic classification to accurately predict deep submucosal invasive (SM-d) carcinoma would be clinically useful. OBJECTIVE: To develop and assess the validity of the NBI international colorectal endoscopic (NICE) classification for the characterization of SM-d carcinoma. DESIGN: The study was conducted in 4 phases: (1) evaluation of endoscopic differentiation by NBI-experienced colonoscopists; (2) extension of the NICE classification to incorporate SM-d (type 3) by using a modified Delphi method; (3) prospective validation of the individual criteria by inexperienced participants, by using high-definition still images without magnification of known histology; and (4) prospective validation of the individual criteria and overall classification by inexperienced participants after training. SETTING: Japanese academic unit. MAIN OUTCOME MEASUREMENTS: Performance characteristics of the NICE criteria (phase 3) and overall classification (phase 4) for SM-d carcinoma; sensitivity, specificity, predictive values, and accuracy. RESULTS: We expanded the NICE classification for the endoscopic diagnosis of SM-d carcinoma (type 3) and established the predictive validity of its individual components. The negative predictive values of the individual criteria for diagnosis of SM-d carcinoma were 76.2% (color), 88.5% (vessels), and 79.1% (surface pattern). When any 1 of the 3 SM-d criteria was present, the sensitivity was 94.9%, and the negative predictive value was 95.9%. The overall sensitivity and negative predictive value of a global, high-confidence prediction of SM-d carcinoma was 92%. Interobserver agreement for an overall SM-d carcinoma prediction was substantial (kappa 0.70). LIMITATIONS: Single Japanese center, use of still images without prospective clinical evaluation. CONCLUSION: The NICE classification is a valid tool for predicting SM-d carcinomas in colorectal tumors.

Characteristic magnifying narrow-band imaging features of colorectal tumors in each growth type.

PURPOSE: We investigated the surface characteristics and vascular patterns of colorectal tumors according to growth type by means of magnifying narrow-band imaging (NBI). METHODS: Four hundred ninety-seven colorectal tumors larger than 10 mm (204 tubular adenomas [TAs], 199 frankly invasive intramucosal carcinomas to shallow invasive submucosal [M/SM-s] carcinomas, and 94 deeply invasive submucosal [SM-d] carcinomas) were analyzed. These colorectal tumors were classified according to growth type as follows: polypoid type, n = 224; laterally spreading tumor-granular (LST-G) type, n = 133; and LST-non-granular (LST-NG) type, n = 140. Surface and vascular patterns were evaluated in relation to histology and growth type. RESULTS: The absent and irregular surface patterns were observed in approximately 40 % of the SM-d carcinomas of the polypoid and LST-G type. The unclear surface pattern was more frequent in tumors of the LST-NG type than in those of other growth types, regardless of histology. Among TAs and M/SM-s carcinomas, the dense vascular pattern was most frequent in polypoid type, the dense and corkscrew vascular patterns were most frequent in the LST-G type, and the honeycomb and avascular and/or fragmentary patterns were most frequent in the LST-NG type. The avascular and/or fragmentary vessel pattern was more frequent in SM-d carcinomas than in TA and M/SM-s carcinomas, regardless of growth type. CONCLUSIONS: A part of LST-NG was difficult to identify the NBI magnifying surface pattern. Although NBI magnifying findings were almost same in each type lesion in SM-d lesion, those of LST-NG were different from those of LST-G and polypoid type in M/SM-s lesion.

Risk factors for vertical incomplete resection in endoscopic submucosal dissection as total excisional biopsy for submucosal invasive colorectal carcinoma.

PURPOSE: Endoscopic submucosal dissection (ESD) for colorectal tumor is a minimally invasive treatment. Histologic information obtained from the entire ESD specimen is important for therapy selection in submucosal invasive colorectal carcinoma (SMca). This study aimed to identify risk factors for vertical incomplete resection (vertical margin-positive [VM+]) when ESD was performed as total excisional biopsy for SMca. METHODS: From June 2003 through December 2011, 78 SMca cases were resected by ESD at Hiroshima University Hospital. Patient and tumor characteristics, intraoperative variables, and histopathology were compared between the VM+ group and the vertical complete resection (vertical margin-negative) group. The ability of magnifying endoscopy (ME) and endoscopic ultrasonography (EUS) to predict VM+ was assessed. RESULTS: ESD resulted in VM+ in eight cases (10.3 %), with a greater percentage invading to a depth of ≥2,000 vs. <2,000 µm (P = 0.047). Severe submucosal fibrosis was found in five of the eight cases (62.5 %, P = 0.017). Poor differentiation was seen at the deepest invasive portion in six cases (75.0 %), and two of six cases had an invasion depth <2,000 µm. Of 39 EUS cases, 36 not showing deep invasion close to the muscularis propria were completely resected by ESD. CONCLUSIONS: Submucosal fibrosis and poor differentiation at the deepest invasive portion may be risk factors for VM+ in colorectal ESD for tumors with submucosal deep invasion. ME plus EUS is more likely to help determine whether ESD is indicated as complete total excisional biopsy for SMca.