Dataset Information

Real-Time Characterization of Diminutive Colorectal Polyp Histology Using Narrow-Band Imaging: Implications for the Resect and Discard Strategy.

ABSTRACT: Narrow-band imaging (NBI) allows real-time histologic classification of colorectal polyps. We investigated whether endoscopists without prior training in NBI can achieve the following thresholds recommended by the American Society for Gastrointestinal Endoscopy: for diminutive colorectal polyps characterized with high confidence, a ?90% negative predictive value for adenomas in the rectosigmoid and a ?90% agreement in surveillance intervals.Twenty-six endoscopists from 2 tertiary care centers underwent standardized training in NBI interpretation. Endoscopists made real-time predictions of diminutive colorectal polyp histology and surveillance interval predictions based on NBI. Their performance was evaluated by comparing predicted with actual findings from histologic analysis. Multilevel logistic regression was used to assess predictors of performance. Cumulative summation analysis was used to characterize learning curves.The endoscopists performed 1451 colonoscopies and made 3012 diminutive polyp predictions (74.3% high confidence) using NBI. They made 898 immediate post-procedure surveillance interval predictions. An additional 505 surveillance intervals were determined with histology input. The overall negative predictive value for high-confidence characterizations in the rectosigmoid was 94.7% (95% confidence interval: 92.6%-96.8%) and the surveillance interval agreement was 91.2% (95% confidence interval: 89.7%-92.7%). Overall, 97.0% of surveillance interval predictions would have brought patients back on time or early. High-confidence characterization was the strongest predictor of accuracy (odds ratio = 3.42; 95% confidence interval: 2.72-4.29; P < .001). Performance improved over time, however, according to cumulative summation analysis, only 7 participants (26.9%) identified adenomas with sufficient sensitivity such that further auditing is not required.With standardized training, gastroenterologists without prior expertise in NBI were able to meet the negative predictive value and surveillance interval thresholds set forth by the American Society for Gastrointestinal Endoscopy. The majority of disagreement in surveillance interval brought patients back early. Performance improves with time, but most endoscopists will require ongoing auditing of performance. ClinicalTrials.gov ID NCT02441998.

SUBMITTER: Patel SG

PROVIDER: S-EPMC4940991 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

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Real-Time Characterization of Diminutive Colorectal Polyp Histology Using Narrow-Band Imaging: Implications for the Resect and Discard Strategy.

Patel Swati G SG Schoenfeld Philip P Kim Hyungjin Myra HM Ward Emily K EK Bansal Ajay A Kim Yeonil Y Hosford Lindsay L Myers Aimee A Foster Stephanie S Craft Jenna J Shopinski Samuel S Wilson Robert H RH Ahnen Dennis J DJ Rastogi Amit A Wani Sachin S

Gastroenterology 20151030 2

<h4>Background & aims</h4>Narrow-band imaging (NBI) allows real-time histologic classification of colorectal polyps. We investigated whether endoscopists without prior training in NBI can achieve the following thresholds recommended by the American Society for Gastrointestinal Endoscopy: for diminutive colorectal polyps characterized with high confidence, a ≥90% negative predictive value for adenomas in the rectosigmoid and a ≥90% agreement in surveillance intervals.<h4>Methods</h4>Twenty-six en ...[more]

PMID: 26522260

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Project description:Accurate optical characterisation and removal of small adenomas (<10?mm) at colonoscopy would allow hyperplastic polyps to be left in situ and surveillance intervals to be determined without the need for histopathology. Although accurate in specialist practice the performance of narrow band imaging (NBI), colonoscopy in routine clinical practice is poorly understood.NBI-assisted optical diagnosis was compared with reference standard histopathological findings in a prospective, blinded study, which recruited adults undergoing routine colonoscopy in six general hospitals in the UK. Participating colonoscopists (N=28) were trained using the NBI International Colorectal Endoscopic (NICE) classification (relating to colour, vessel structure and surface pattern). By comparing the optical and histological findings in patients with only small polyps, test sensitivity was determined at the patient level using two thresholds: presence of adenoma and need for surveillance. Accuracy of identifying adenomatous polyps <10?mm was compared at the polyp level using hierarchical models, allowing determinants of accuracy to be explored.Of 1688 patients recruited, 722 (42.8%) had polyps <10?mm with 567 (78.5%) having only polyps <10?mm. Test sensitivity (presence of adenoma, N=499 patients) by NBI optical diagnosis was 83.4% (95% CI 79.6% to 86.9%), significantly less than the 95% sensitivity (p<0.001) this study was powered to detect. Test sensitivity (need for surveillance) was 73.0% (95% CI 66.5% to 79.9%). Analysed at the polyp level, test sensitivity (presence of adenoma, N=1620 polyps) was 76.1% (95% CI 72.8% to 79.1%). In fully adjusted analyses, test sensitivity was 99.4% (95% CI 98.2% to 99.8%) if two or more NICE adenoma characteristics were identified. Neither colonoscopist expertise, confidence in diagnosis nor use of high definition colonoscopy independently improved test accuracy.This large multicentre study demonstrates that NBI optical diagnosis cannot currently be recommended for application in routine clinical practice. Further work is required to evaluate whether variation in test accuracy is related to polyp characteristics or colonoscopist training.The study was registered with clinicaltrials.gov (NCT01603927).

Project description:Background and study aims Optical real-time diagnosis (= resect-and-discard strategy) is an alternative to histopathology for diminutive colorectal polyps. However, clinical adoption of this approach seems sparse. We were interested in evaluating potential clinical uptake and barriers for implementation of this approach. Methods We conducted an international survey using the "Google forms" platform. Nine endoscopy societies distributed the survey. Survey questions measured current clinical uptake and barriers for implementing the resect-and-discard strategy , perceived cancer risk associated with diminutive polyps and potential concerns with using CT-colonography as follow-up, as well as non-resection of diminutive polyps. Results Eight hundred and eight endoscopists participated in the survey. 84.2 % (95 % CI 81.6 %-86.7 %) of endoscopists are currently not using the resect-and-discard strategy and 59.9 % (95 % CI 56.5 %-63.2 %) do not believe that the resect-and-discard strategy is feasible for implementation in its current form. European (38.5 %) and Asian (45 %) endoscopists had the highest rates of resect-and-discard practice, while Canadian (13.8 %) and American (5.1 %) endoscopists had some of the lowest implementation rates. 80.3 % (95 % CI 77.5 %-83.0 %) of endoscopists believe that using the resect-and-discard strategy for diminutive polyps will not increase cancer risk. 48.4 % (95 % CI 45.0 %-51.9 %) of endoscopists believe that leaving diminutive polyps in place is associated with increased cancer risk. This proportion was slightly higher (54.7 %; 95 % CI 53.6 %-60.4 %) when asked if current CT-colonography screening practice might increase cancer risks. Conclusion Clinical uptake of resect-and-discard is very low. Most endoscopists believe that resect-and-discard is not feasible for clinical implementation in its current form. The most important barriers for implementation are fear of making an incorrect diagnosis, assigning incorrect surveillance intervals and medico-legal consequences.

Project description:Psoriasis is a common chronic inflammatory and hyperproliferative immune-mediated skin disorder. Narrow-band UVB (NB-UVB) phototherapy is a convenient first-line treatment of psoriasis, though the mechanisms underlying its efficacy have not been completely elucidated. In order to improve our understanding of NB-UVB phototherapy, gene expression profiling was used to characterize gene expression in lesional epidermis from psoriasis patients undergoing NB-UVB phototherapy. Increased expression of melanogenesis pathway genes was observed to be the earliest response. At the end of treatment, genes involved in diverse biological processes were affected, such as pigmentation, cell adhesion, ectodermal development and metabolism. The relationship between gene expression and treatment outcome was further studied using Partial Least Squares Discriminant Analysis (PLS-DA). Gene ontology analysis showed that genes responding to phototherapy and highly correlated to treatment outcome were involved in oxidation reduction, growth and mitochondria organization. In particular SPATA18, a key regulator of mitochondria quality, was found to be significantly downregulated in psoriasis, and its upregulation following phototherapy was required for optimal clinical improvement. Our data suggest that oxidation reduction is a critical event for the resolution of psoriatic plaques. Twelve patients diagnosed with plaque type psoriasis were recruited to the study. NB-UVB irradiation was administered to the whole body two to three times a week. Treatment comprising approximately 24 sessions was given during two to three months. A total of six 4 mm diameter punch biopsies were taken from lesions on each psoriasis patient: two prior to UV treatment (pre-UV), two at the middle stage of UV treatment (after about one month of treatment, mid-UV) and two before the last treatment session (post-UV). Twelve healthy age-, sex- and skin type-matched volunteers were also recruited and two punch biopsies were taken from the buttocks. RNA was extracted from Laser capture microdissected epidermis.

Dataset Information

Real-Time Characterization of Diminutive Colorectal Polyp Histology Using Narrow-Band Imaging: Implications for the Resect and Discard Strategy.

Publications

Real-Time Characterization of Diminutive Colorectal Polyp Histology Using Narrow-Band Imaging: Implications for the Resect and Discard Strategy.

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