Clinical Study of Real Time Colorectal Polyp Diagnosis During Colonoscopy - the VALID Colonoscopy Study (VALID)

Clinical Study of Real Time Colorectal Polyp Diagnosis During Colonoscopy - the VALID Colonoscopy Study

Real Time Colorectal Polyp Diagnosis in Colorectal Cancer Screening Using Close Focus High Definition Narrow Band Imaging Colonoscopy Compared to Conventional Histopathology Diagnosis - the VALID (Veterans Affairs Lesion Interpretation and Diagnosis) Colonoscopy Study

The investigators hypothesize that high definition colonoscopy with close focus narrow band imaging features has a high diagnostic accuracy for colorectal polyp histology, and can replace formal pathologic assessment in cases of high diagnostic confidence.

A recent single arm prospective cohort study suggested that high definition colonoscopy with narrow band imaging is an acceptable strategy to diagnose polyp histology and determine future surveillance intervals. Endoscopic proficiency in macroscopic features to differentiate polyp histology can be attained in a relatively short time period. A new high definition colonoscope with close focus narrow band imaging features may further improve diagnostic accuracy for polyp differentiation, and can replace formal pathologic assessment in cases of high diagnostic confidence. Primary Aim: Compare the diagnostic accuracy of high definition narrow band imaging colonoscopy with and without close focus features for the macroscopic differentiation of neoplastic and non-neoplastic colorectal lesions using histopathologic diagnosis as the reference standard. Secondary Aims: Compare diagnostic characteristics of the colonoscopes, measure concordance of high confidence and accuracy, compare accuracy of predicted versus actual surveillance interval recommendations, perform a cost-effective analysis of endoscopic versus pathologic diagnoses, and measure complications.

Colonoscopy, Diagnostic Imaging, Colorectal Neoplasm, Primary Prevention, Cost and Cost Analysis, Endoscopy

Technically improved colonoscope with close focus high definition narrow band imaging. Optical specifications include a 2mm near field focal depth.

Measure of the percentage of accurate high confidence predictions by the endoscopist in the differentiation of neoplastic from non-neoplastic colorectal lesions, using the high definition NBI colonoscopy with and without close focus features. High confidence was assigned if the polyp had one or more features of Type 2 (neoplasia) or Type 1 (nonneoplasia) in the NICE classification and no features associated with the other histology Note: one patient may have multiple polyps.

Measure the cost of colonoscopy with macroscopic histopathologic diagnosis of colorectal lesions compared to colonoscopy with conventional microscopic histopathologic diagnosis, on the lesions that were managed based on an accurate endoscopic diagnosis. A reduction in pathology specimens may improve the efficiency of the procedure and has direct pathology cost savings (as well as indirect savings, which were not measured).

Compare the diagnostic characteristics (sensitivity, specificity, positive predictive value and negative predictive value) using the high definition narrow band imaging colonoscopy with and without close focus features. Accuracy: number of endoscopic predictions of adenomatous polyps histologically confirmed to be adenomatous/number of predicted hyperplastic polyps confirmed to be hyperplastic out of all polyps Sensitivity: number of endoscopic predictions (optical diagnosis) of adenomatous (neoplastic) polyps out of all histologically confirmed polyps Specificity: number of endoscopic predictions of hyperplastic (non-neoplastic) polyps out of all histologically confirmed polyps PPV: number of histologically confirmed adenomatous polyps out of all endoscopic predictions of adenomatous polyps NPV: number of histologically confirmed hyperplastic polyps out of all endoscopic predictions of hyperplastic (non-neoplastic) polyps Note: a patient may have multiple polyps

Compared the accuracy of predicted versus actual surveillance colonoscopy interval recommendations by determining number of patients with correct surveillance interval recommendation.

Examine the impact of a learning curve (i.e. NPV of high confidence at each of endoscopist's first 50% of exams versus last 50% exams to endoscopically predict polyp histology). NPV is defined as "number of histologically confirmed hyperplastic polyps out of all endoscopic predictions of hyperplastic (non-neoplastic) polyps.

Inclusion Criteria: Adult patients referred for routine colonoscopy Exclusion Criteria: Known inflammatory bowel disease Personal or family history of polyposis or non-polyposis syndrome Presentation for emergency endoscopy Inability to remove polyp due to coagulopathy or thrombocytopenia Inability to provide informed consent

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