Takahiro Horimatsu

MAGNIFYING OBSERVATION OF MICROVASCULAR ARCHITECTURE OF COLORECTAL LESIONS USING A NARROW-BAND IMAGING SYSTEM

We reviewed the magnifying observation of the microvascular architecture of colorectal lesions and discuss the utility of the detailed observation of the microvascular architecture for differential diagnosis during narrow‐band imaging (NBI) colonoscopy. Angiogenesis is critical to the transition of premalignant lesions in a hyperproliferative state to the malignant phenotype. Therefore, diagnosis based on angiogenic or vascular morphologic changes might be ideal for early detection or diagnosis of neoplasms. In this review, we propose the term ‘meshed capillary’ for the distinction between non‐neoplastic and neoplastic lesions and the capillary classification ‘capillary pattern’ for the differential diagnosis of colorectal lesions. We believe that the combined use of NBI optical chromoendoscopy and real chromoendoscopy decreases the time and cost of screening colonoscopy. To assess the feasibility and efficacy of using the NBI system, further studies are required for colorectal lesions and other lesions of the gastrointestinal tract.

Magnifying narrow-band imaging versus magnifying white-light imaging for the differential diagnosis of gastric small depressive lesions: a prospective study

BACKGROUND The accurate diagnosis of gastric small depressive lesions (SDLs), including gastritis and cancerous lesions, is difficult with conventional endoscopy when using white-light imaging (WLI). Narrow-band imaging (NBI) is expected to make a more accurate diagnosis of gastric SDLs than WLI because it provides better visualization of the mucosal surface and microvascular architecture when combined with magnifying endoscopy. OBJECTIVE To compare the real-time diagnostic accuracy of magnifying WLI and magnifying NBI for gastric SDLs. DESIGN Prospective study. SETTING National Cancer Center Hospital East, Kashiwa, Japan. PATIENTS Fifty-seven lesions in 53 consecutive patients were analyzed: 30 cancers and 27 benign lesions. INTERVENTIONS If previously undiagnosed gastric SDLs smaller than 10 mm were identified during an endoscopic examination, magnifying observation with both WLI and NBI was performed for each SDL. Endoscopic diagnosis of SDLs was made by each method on site. MAIN OUTCOME MEASUREMENTS The diagnostic accuracy and the time required for diagnosis. RESULTS The diagnostic accuracy was significantly higher for NBI than for WLI (79% vs 44%; P = .0001), as was its sensitivity (70% vs 33%; P = .0005). The diagnostic specificity of NBI (89%) was higher than that of WLI (67%), but the difference was not statistically significant. The time required for the diagnosis was equivalent with both methods. LIMITATIONS Single-center study, small sample size. CONCLUSIONS Adding NBI to the WLI examination is essential for making an accurate diagnosis of gastric SDLs compared with magnifying WLI alone. (UMIN Clinical Trials Registry identification number C000000421).

Efficacy of preventive endoscopic balloon dilation for esophageal stricture after endoscopic resection

Background and Aim We earlier reported that mucosal defect involving over three-fourths of the circumference of the esophagus after endoscopic mucosal resection (EMR) is a risk factor for the development of the stricture. Although endoscopic balloon dilation (EBD) is a useful procedure to relieve the stricture, there is no standard strategy for preventing development of the stricture. The aim of this study was to evaluate the efficacy and the safety of preventive EBD. Methods From 1993 to 2008, 41 consecutive patients with extensive mucosal defect involving over three-fourths of the esophageal circumference after EMR or endoscopic submucosal dissection (ESD) were investigated. Preventive EBD was carried out for 29 cases within 1 week just after EMR/ESD and was repeated once a week until the mucosal defect was completely healed. The remaining 12 cases were not underwent preventive EBD and used as a historic control. If postEMR/ESD stricture developed regardless of preventive EBD, conventional EBD was given repeatedly until the stricture was completely relieved. Results Preventive EBD decreased the incidence of stricture (59% vs. 92%, P =0.04), reduced the severity of stricture [(⩽2 mm; >2 mm and ⩽5 mm; >5 mm)=(1; 2; 14) vs. (4; 4; 3), P = 0.01] and shortened the duration required for resolving the stricture (29 d vs. 78 d, P =0.04) even when stricture developed. There was no complication associated with preventive EBD procedure. Conclusions Preventive EBD is an effective procedure to prevent postEMR/ESD stricture. Preventive EBD should be considered when EMR/ESD results in a mucosal defect with a circumference greater than three-fourths of the esophageal lumen.

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.

Serum miR-21, miR-29a, and miR-125b Are Promising Biomarkers for the Early Detection of Colorectal Neoplasia.

Purpose: Circulating microRNAs (miRNA) are emerging as promising diagnostic biomarkers for colorectal cancer, but their usefulness for detecting early colorectal neoplasms remains unclear. This study aimed to identify serum miRNA biomarkers for the identification of patients with early colorectal neoplasms. Experimental Design: A cohort of 237 serum samples from 160 patients with early colorectal neoplasms (148 precancerous lesions and 12 cancers) and 77 healthy subjects was analyzed in a three-step approach that included a comprehensive literature review for published biomarkers, a screening phase, and a validation phase. RNA was extracted from sera, and levels of miRNAs were examined by real-time RT-PCR. Results: Nine miRNAs (miR-18a, miR-19a, miR-19b, miR-20a, miR-21, miR-24, miR-29a, miR-92, and miR-125b) were selected as candidate biomarkers for initial analysis. In the screening phase, serum levels of miR-21, miR-29a, and miR-125b were significantly higher in patients with early colorectal neoplasm than in healthy controls. Elevated levels of miR-21, miR-29a, and miR-125b were confirmed in the validation phase using an independent set of subjects. Area under the curve (AUC) values for serum miR-21, miR-29a, miR-125b, and their combined score in discriminating patients with early colorectal neoplasm from healthy controls were 0.706, 0.741, 0.806, and 0.827, respectively. Serum levels of miR-29a and miR-125b were significantly higher in patients who had only small colorectal neoplasms (≤5 mm) than in healthy subjects. Conclusions: Because serum levels of miR-21, miR-29a, and miR-125b discriminated patients with early colorectal neoplasm from healthy controls, our data highlight the potential clinical use of these molecular signatures for noninvasive screening of patients with colorectal neoplasia. Clin Cancer Res; 21(18); 4234–42. ©2015 AACR.

Improving visualization techniques by narrow band imaging and magnification endoscopy

Endoscopy plays an important role in the early detection of gastrointestinal tract neoplasms. Using conventional white light or dye‐based image enhanced endoscopy, it has been difficult to assess pre‐malignant and early neoplastic lesions precisely. However, narrow band imaging (NBI) dramatically improves the detection of these lesions, particularly in combination with magnifying endoscopy. This allows the endoscopist to accomplish accurate diagnosis. Such enhanced detection of pre‐malignant and early neoplastic lesions in the gastrointestinal tract should allow better targeting of biopsy, improved and more appropriate treatment, and thereby contribute to optimal quality of life and patient survival.

Long-term outcome of transoral organ-preserving pharyngeal endoscopic resection for superficial pharyngeal cancer.

BACKGROUND Early detection of pharyngeal cancer has been difficult. We reported that narrow-band imaging (NBI) endoscopy can detect superficial pharyngeal cancer, and these lesions can be treated endoscopically. OBJECTIVE To assess the safety and long-term efficacy of transoral organ-preserving pharyngeal endoscopic resection (TOPER) for superficial pharyngeal cancer. DESIGN AND SETTING Retrospective 2-center cohort study. PATIENTS The study included 104 consecutive patients with superficial pharyngeal cancer. INTERVENTION TOPER with the patients under general anesthesia. MAIN OUTCOME MEASUREMENTS Safety of the procedure, long-term survival, clinical outcome. RESULTS A total of 148 consecutive lesions were resected in 104 patients. There was no severe adverse event. Temporary tracheostomy was required in 17 patients (16%) to prevent airway obstruction. The median fasting period and hospital stay after TOPER were 2 days (range 1-20 days) and 8 days (range 3-58 days), respectively. Ninety-six patients (92%) had no local recurrence or distant metastases. Local recurrence at the primary site developed in 6 patients, but all were resolved by repeat TOPER. With a median follow-up period of 43 months (range 3-96 months), the overall survival rate at 5 years was 71% (95% CI, 59-82). Cause-specific survival rate at 5 years was 97% (95% CI, 93-100). The cumulative development rate of multiple cancers in pharyngeal mucosal sites at 5 years was 22% (95% CI, 12-33). The pharynx was preserved in all patients, and they experienced no loss of function. LIMITATION Retrospective design. CONCLUSIONS Peroral endoscopic resection of superficial pharyngeal cancer is a feasible and effective treatment with curative intent.

Narrow-band imaging of the gastrointestinal tract

A narrow-band imaging (NBI) system is now commercially available worldwide from Olympus Medical Systems as an endoscopic diagnostic tool for the gastrointestinal (GI) tract. The most important strengths of the NBI system are enhancements in endoscopic visualization of superfi cial neoplastic lesions and the microvascular architecture. As endoscopic magnifi cation maximizes the latter strength, NBI is expected to yield breakthroughs in endoscopic diagnosis. Angiogenesis is critical in the transition from the premalignant to the malignant phenotype, so detection and diagnosis based in part on morphologic changes to the microvessels are ideal. These advantages will potentially allow us to easily identify and accurately diagnose superfi cial neoplasms of the GI tract. In contrast, conventional endoscopic diagnosis using white light is based on subtle morphological changes such as superfi cially elevated, fl at, or depressed lesions and on minimal changes in color such as reddish discoloration. However, these fi ndings are diffi cult to recognize, especially for inexperienced endoscopists, who require much skill training. As a result, the diagnosis may be inaccurate or a precancerous lesion or superfi cial cancer in the GI tract may be overlooked. From the point of view of the effective cancer screening, these disadvantages must be overcome. When combined with magnifying endoscopy, NBI can clearly demarcate the margin between a nonneoplastic lesion and a cancerous lesion and can increase the contrast of morphological changes of the mucosal surface and microvessels. Inoue and colleagues and Yao and colleagues have already reported the importance of fi ndings of microvascular irregularities in cancer of the esophagus and stomach, respectively. However, in images magnifi ed while using white light, these changes have been diffi cult to identify. With NBI, these changes are easily recognized, thus renewing our awareness of the importance of microvascular irregularities in cancerous lesions. Herein, we review publications on use of an NBI system in the GI tract.

NBI magnifying endoscopic classification of colorectal tumors proposed by the Japan NBI Expert Team (JNET)

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.

Usefulness of endoscopic radial incision and cutting method for refractory esophagogastric anastomotic stricture (with video).

BACKGROUND There is no effective treatment for gastroesophageal anastomotic strictures that are refractory to repeated endoscopic balloon dilation (EBD). However, EBD is still selected worldwide to manage such refractory strictures. To relieve the symptoms of dysphagia and keep a wide lumen, we developed a new incisional treatment, radial incision and cutting (RIC). OBJECTIVE To evaluate the efficacy and safety of the RIC method for the treatment of refractory anastomotic strictures. DESIGN Retrospective cohort study. SETTING National Cancer Center and University Hospital. PATIENTS This study involved 54 consecutive patients with refractory anastomotic stricture after esophagogastric surgery. INTERVENTION RIC. MAIN OUTCOME MEASUREMENTS The safety and clinical success of RIC and the long-term patency after RIC compared with those of continued EBD. RESULTS The median procedure time of RIC was 14 minutes (range, 4-40 minutes). No serious adverse events associated with RIC were observed. Immediately after RIC, 81.3% (26/32) of patients were able to eat solid food without symptoms of dysphagia. As a short-term effect, the dysphagia improved after RIC in 93.8% (30/32) of the patients. As a long-term effect, 63% (17/27) and 62% (13/21) of patients were able to eat solid food 6 and 12 months after RIC, respectively. The 6-month and 12-month patency rates were significantly different between the RIC group and the continued EBD group (65.3% vs 19.8%, P < .005; 61.5% vs 19.8%, P < .005). LIMITATIONS Nonrandomized retrospective study. CONCLUSIONS RIC is an effective and safe method. The demonstration of the validity of this method may place RIC as a new medical treatment for patients with refractory stricture after surgical resection for esophagogastric diseases.