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Real-time optical biopsy of colon polyps with narrow band imaging in community practice does not yet meet key thresholds for clinical decisions.

ABSTRACT: Accurate optical analysis of colorectal polyps (optical biopsy) could prevent unnecessary polypectomies or allow a "resect and discard" strategy with surveillance intervals determined based on the results of the optical biopsy; this could be less expensive than histopathologic analysis of polyps. We prospectively evaluated real-time optical biopsy analysis of polyps with narrow band imaging (NBI) by community-based gastroenterologists.We first analyzed a computerized module to train gastroenterologists (N = 13) in optical biopsy skills using photographs of polyps. Then we evaluated a practice-based learning program for these gastroenterologists (n = 12) that included real-time optical analysis of polyps in vivo, comparison of optical biopsy predictions to histopathologic analysis, and ongoing feedback on performance.Twelve of 13 subjects identified adenomas with >90% accuracy at the end of the computer study, and 3 of 12 subjects did so with accuracy ?90% in the in vivo study. Learning curves showed considerable variation among batches of polyps. For diminutive rectosigmoid polyps assessed with high confidence at the end of the study, adenomas were identified with mean (95% confidence interval [CI]) accuracy, sensitivity, specificity, and negative predictive values of 81% (73%-89%), 85% (74%-96%), 78% (66%-92%), and 91% (86%-97%), respectively. The adjusted odds ratio for high confidence as a predictor of accuracy was 1.8 (95% CI, 1.3-2.5). The agreement between surveillance recommendations informed by high-confidence NBI analysis of diminutive polyps and results from histopathologic analysis of all polyps was 80% (95% CI, 77%-82%).In an evaluation of real-time optical biopsy analysis of polyps with NBI, only 25% of gastroenterologists assessed polyps with ?90% accuracy. The negative predictive value for identification of adenomas, but not the surveillance interval agreement, met the American Society for Gastrointestinal Endoscopy-recommended thresholds for optical biopsy. Better results in community practice must be achieved before NBI-based optical biopsy methods can be used routinely to evaluate polyps; ClinicalTrials.gov number, NCT01638091.

SUBMITTER: Ladabaum U

PROVIDER: S-EPMC5518757 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

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Real-time optical biopsy of colon polyps with narrow band imaging in community practice does not yet meet key thresholds for clinical decisions.

Ladabaum Uri U Fioritto Ann A Mitani Aya A Desai Manisha M Kim Jane P JP Rex Douglas K DK Imperiale Thomas T Gunaratnam Naresh N

Gastroenterology 20121003 1

<h4>Background & aims</h4>Accurate optical analysis of colorectal polyps (optical biopsy) could prevent unnecessary polypectomies or allow a "resect and discard" strategy with surveillance intervals determined based on the results of the optical biopsy; this could be less expensive than histopathologic analysis of polyps. We prospectively evaluated real-time optical biopsy analysis of polyps with narrow band imaging (NBI) by community-based gastroenterologists.<h4>Methods</h4>We first analyzed a ...[more]

PMID: 23041328

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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: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 optical biopsy of colon polyps with narrow band imaging in community practice does not yet meet key thresholds for clinical decisions.

Publications

Real-time optical biopsy of colon polyps with narrow band imaging in community practice does not yet meet key thresholds for clinical decisions.

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