Reiji Higashi

Diagnostic accuracy of narrow-band imaging and pit pattern analysis significantly improved for less-experienced endoscopists after an expanded training program

BACKGROUND Previous reports assessing diagnostic skill using narrow-band imaging (NBI) and pit pattern analysis for colorectal polyps involved only highly experienced endoscopists. OBJECTIVE To evaluate diagnostic skills of less-experienced endoscopists (LEE group) for differentiation of diminutive colorectal polyps by using NBI and pit pattern analysis with and without magnification after an expanded training program. DESIGN Prospective study. PATIENTS This study involved 32 patients with 44 colorectal polyps (27 adenomas and 17 hyperplastic polyps) of < or =5 mm that were identified and analyzed by using conventional colonoscopy as well as non-magnification and magnification NBI and chromoendoscopy followed by endoscopic removal for histopathological analysis. INTERVENTION Before a training course, 220 endoscopic images were distributed in randomized order to residents with no prior endoscopy experience (NEE group) and to the LEE group, who had performed colonoscopies for more than 5 years but had never used NBI. The 220 images were also distributed to highly experienced endoscopists (HEE group) who had routinely used NBI for more than 5 years. The images were distributed to the NEE and LEE groups again after a training class. Magnification NBI and chromoendoscopy images were assessed by using the Sano and Kudo classification systems, respectively. MAIN OUTCOME MEASUREMENTS Diagnostic accuracy and interobserver agreement for each endoscopic modality in each group. RESULTS Diagnostic accuracy was significantly higher, and kappa (kappa) values improved in the LEE group for NBI with high magnification after expanded training. Diagnostic accuracy and kappa values when using high-magnification NBI were highest among endoscopic techniques for the LEE group after such training and the HEE group (accuracy 90% vs 93%; kappa = 0.79 vs 0.85, respectively). LIMITATIONS Study involved only polyps of < or =5 mm. CONCLUSION Using high-magnification NBI increased the differential diagnostic skill of the LEE group after expanded training so that it was equivalent to that of the HEE group.

DNA methylation of colon mucosa in ulcerative colitis patients: Correlation with inflammatory status

Background: Although DNA methylation of colonic mucosa in ulcerative colitis (UC) has been suggested, the majority of published reports indicate the correlation between methylation of colon mucosa and occurrence of UC‐related dysplasia or cancer without considering the mucosal inflammatory status. The aim of this study was to verify whether mucosal inflammation‐specific DNA methylation occurs in the colon of UC. Methods: Of 15 gene loci initially screened, six loci (ABCB1, CDH1, ESR1, GDNF, HPP1, and MYOD1) methylated in colon mucosa of UC were analyzed according to inflammatory status using samples from 28 surgically resected UC patients. Results: Four of six regions (CDH1, GDNF, HPP1, and MYOD1) were more highly methylated in the active inflamed mucosa than in the quiescent mucosa in each UC patient (P = 0.003, 0.0002, 0.02, and 0.048, respectively). In addition, when the methylation status of all samples taken from examined patients was stratified according to inflammatory status, methylation of CDH1 and GDNF loci was significantly higher in active inflamed mucosa than in quiescent mucosa (P = 0.045 and 0.002, respectively). Multiple linear regression analysis revealed that active inflammation was an independent factor of methylation for CDH1 and GDNF. DNA methyltransferase 1 and 3b were highly expressed in colon epithelial cells with active mucosal inflammation, suggesting their involvement in inflammation‐dependent methylation. Conclusions: Methylation in colonic mucosa of UC was correlated with mucosal inflammatory status, suggesting the involvement of methylation due to chronic active inflammation in UC carcinogenesis. (Inflamm Bowel Dis 2011;)

Predictive factors for technically difficult endoscopic submucosal dissection in the colorectum

BACKGROUND AND STUDY AIMS Because of technical difficulty, colorectal endoscopic submucosal dissection (CR-ESD) is not widely performed. We aimed to determine risk factors for such technical difficulty as defined by long procedure duration (≥  150 min), perforation, and piecemeal resection. PATIENTS AND METHODS Patients with consecutive colorectal tumors treated with ESD between April 2006 and December 2010 were enrolled in a prospective cohort study. For prediction of technical difficulty, three types of factor were investigated: tumor location, tumor type, and colonoscopy-related. Cases were subsequently categorized into earlier and later periods (April 2006 - August 2008, 123 lesions; September 2008 - December 2010, 124 lesions). Variables were analyzed using multiple logistic regression, with subgroup analyses for each period. RESULTS 247 lesions were analyzed. Flexure location was an independent risk factor for technical difficulty as measured by longer procedure duration (odds ratio [OR] 4.1, 95 % confidence interval [95 %CI] 1.1 - 14.9), piecemeal resection (4.7, 1.1 - 17.2), or perforation (8.8, 1.1 - 56.8). Tumor with scarring or locally recurrent was a risk factor for longer procedure duration (4.7, 1.7 - 13.7), and for piecemeal resection (7.8, 2.4 - 25.0). Tumor of size  ≥  50 mm or spreading across ≥  2 folds was the strongest independent risk factor for longer duration (6.3, 2.8 - 15.4), and was an independent risk factor for longer duration in both time periods (earlier, 3.3, 1.1 - 10.4; later, 27.4, 7.4 - 138.0). Flexure location was an independent risk factor for perforation (13.9, 1.5 - 129.1) and for piecemeal resection (5.1, 0.9 - 25.2) in the earlier but not the later period. CONCLUSIONS Factors predicting technical difficulty of CR-ESDs were clarified. Their importance was influenced by the increasing experience of the endoscopist.

ADVANTAGES OF USING THIN ENDOSCOPE‐ASSISTED ENDOSCOPIC SUBMUCOSAL DISSECTION TECHNIQUE FOR LARGE COLORECTAL TUMORS

Background:  Our purpose was to evaluate the effectiveness of a newly developed non‐invasive traction technique known as thin endoscope‐assisted endoscopic submucosal dissection (TEA‐ESD) procedure for the removal of colorectal laterally spreading tumors (LST).

A novel extra-wide-angle-view colonoscope: a simulated pilot study using anatomic colorectal models.

BACKGROUND A major factor that may contribute to a higher adenoma miss rate during colonoscopy is undetected lesions located behind haustral folds, flexures, or rectal valves. OBJECTIVE To assess the efficacy of a prototype, novel, extra-wide-angle-view colonoscope that provides a simultaneous lateral-backward view that complements the forward view lens. DESIGN A simulated pilot study of two anatomic colorectal models, each prepared with 8 polyps positioned in obvious locations and 8 polyps placed behind folds. Thirty-two endoscopists with different levels of experience performed examinations on models in a random order by using the extra-wide-angle-view colonoscope and a standard colonoscope. MAIN OUTCOME MEASUREMENTS The detection rates of simulated polyps. RESULTS The mean detection rate for all simulated polyps with the extra-wide-angle-view colonoscope was significantly higher than that with the standard colonoscope (68% vs 51%; P < .0001). The detection rate for polyps behind folds was significantly higher in the extra-wide-angle-view colonoscope than in the standard colonoscope (61.7% vs 46.9%; P = .0009). LIMITATIONS Not a clinical study. CONCLUSION The novel, extra-wide-angle-view colonoscope may represent an advancement in colorectal polyp detection. The value of the colonoscope for clinical use awaits further study.

Feasibility of a novel colonoscope with extra-wide angle of view: A clinical study

BACKGROUND AND STUDY AIMS Lesions may be missed during colonoscopy because of anatomical features such as mucosal folds. This feasibility study assessed the safety and efficacy of a novel colonoscope with extra-wide angle of view, which provides a simultaneous lateral-backward view to complement the forward view. PATIENTS AND METHODS Consecutive patients undergoing colonoscopy using the prototype colonoscope were enrolled in this multicenter, single-arm study. The number of adverse events, and the first detection of adenomas during withdrawal by the lateral-backward view and the forward view were evaluated. RESULTS A total of 47 patients underwent colonoscopy examination to the cecum. The mean insertion and withdrawal times were 6.4 ± 4.9 minutes and 8.6 ± 4.2 minutes, respectively. Of 47 detected polyps, 28 adenomatous polyps were found (mean size 3.3 ± 3.1 mm). A total of 29 polyps (61.7 %) and 16 adenomatous polyps (57.1 %) were first detected with the lateral-backward view. The lateral-backward view first detected 5/6 adenomatous polyps (83.3 %) in the ascending colon and all (2/2) adenomatous polyps in the sigmoid colon. No adverse events occurred during the study. CONCLUSIONS This exploratory study suggested that a novel colonoscope with extra-wide angle of view is safe and feasible, and has the potential to improve colorectal adenoma detection. TRIAL REGISTER UMIN000016450.

Impact of narrow-band imaging in screening colonoscopy.

Narrow band‐imaging (NBI) enhances mucosal visualization of the vascular network and surface structure and helps to increase the visibility of neoplasia by improving contrast. Studies on the detectability of colorectal neoplastic lesions using NBI have primarily been reported in Western countries, but the published opinions and conclusions remain controversial at the present time. Our earlier prospective pilot study demonstrated that NBI colonoscopy significantly improved detection of flat lesions, which are more likely to be missed, particularly on the right side of the colon. It is especially important that even examiners performing routine screening colonoscopies become sufficiently familiar with flat and depressed lesions and then take full advantage of the endoscopic systems and specific image enhancement functions currently available for improved detection of flat and diminutive lesions. Adequate bowel preparation is another important consideration.

Analysis of K-ras, BRAF, and PIK3CA mutations in laterally-spreading tumors of the colorectum.

Background and Aims:  Laterally‐spreading tumors (LST) are a newly‐recognized category of colorectal neoplasia, and are defined as lesions larger than 10 mm in diameter and extending circumferentially rather than vertically. However, genetic features of this new category of tumors are not fully elucidated. The aim of this study was to evaluate genetic alterations in LST.

Simultaneous Measurements of Faecal Calprotectin and the Faecal Immunochemical Test in Quiescent Ulcerative Colitis Patients Can Stratify Risk of Relapse

Background Both faecal calprotectin [Fcal] and the faecal immunochemical test [FIT] are useful to predict clinical relapse of ulcerative colitis [UC]. However, the difference between Fcal and FIT in ability to predict relapse has scarcely been reported. Whether the combined use of these two faecal markers increases the predictability is also unknown. Methods UC patients in clinical remission who underwent colonoscopy were enrolled prospectively, and the Fcal and FIT values were examined at enrolment. Their clinical course was observed for 2 years or until relapse. The correlation between the incidence of relapse and the values of the two markers was examined. Results A total of 113 patients were enrolled, and 48 [42%] relapsed. Fcal ≥ 75 μg/g and FIT ≥ 110 ng/mL were defined as Fcal-positive and FIT-positive, respectively, according to the receiver operating characteristic curves. Both Fcal-positive and FIT-positive statuses were independent predictive factors of clinical relapse (hazard ratio [HR] 2.29; 95% confidence interval [CI], 1.23-4.49; p = 0.0086, and HR 2.91; 95% CI, 1.49-5.50; p = 0.0022, respectively). Categorisation of patients into three groups according to the faecal marker status [FIT-positive, FIT-negative and Fcal-positive, and both negative] can efficiently stratify the risk of relapse with graded increases in risk [FIT-negative and Fcal-positive: HR 2.05; 95% CI, 1.02-4.43; p = 0.0045, and FIT-positive: HR 5.43; 95% CI, 2.57-11.76; p < 0.0001, compared with both negative]. Conclusions Fcal vs FIT showed distinct properties regarding the prediction of relapse in UC. A risk assessment using both faecal markers could increase the predictability for relapse.

An Energy Dispersive X-ray Spectroscopy Analysis of Elemental Changes of a Persimmon Phytobezoar Dissolved in Coca-Cola.

To investigate the mechanism of phytobezoar dissolution by Coca-Cola(®), persimmon phytobezoar pieces removed from a 60-year-old Japanese woman were analyzed by energy dispersive X-ray spectroscopy. The amount of calcium significantly decreased after dissolution treatment using Coca-Cola(®), suggesting a potential contribution of calcium to dissolution mechanisms. Moreover, immersion in Coca-Cola(®) for 120 hours on the exterior surface revealed that Coca-Cola(®) did not permeate persimmon phytobezoars. This is the first study to investigate the mechanisms of persimmon phytobezoar permeability and dissolution induced by Coca-Cola(®).