Detection Of Intestinal Metaplasia And High Grade Dysplasia In Barrett's Esophagus Using Novel Imaging Techniques - A Randomized Controlled Trial.

Barrett's esophagus (BE) is the pre-malignant lesion for adenocarcinoma of the esophagus and esophagogastric junction. It is a condition in which the squamous mucosa of the distal esophagus is replaced by columnar mucosa, specifically intestinal metaplasia. The incidence of esophageal adenocarcinoma has been rapidly rising and has increased 3-6 fold over the past two decades. This has driven efforts to identify patients with the pre-malignant lesion i.e. BE. Intestinal metaplasia within the columnar lined esophagus is the epithelial type that predisposes patients to the development of adenocarcinoma; the other two epithelial types being cardiac and fundic.

Since intestinal metaplasia is now included in the definition and is the epithelial type associated with cancer, obtaining biopsies from the columnar lined distal esophagus is mandatory. The sensitivity and the positive predictive value of standard EGD for diagnosing BE has been reported as 82% and 34% respectively. This is secondary to the patchy and mosaic presence of intestinal metaplasia in the columnar distal esophagus. Endoscopic screening is advocated in patients with chronic GERD symptoms for detection of BE with random biopsies being obtained if a columnar appearing distal esophagus is visualized. Once intestinal metaplasia is detected with these random biopsies and the diagnosis of BE is confirmed, patients are subsequently enrolled in a surveillance program. Similarly, the presence of dysplasia or early adenocarcinoma within a segment of BE is patchy and focal and standard endoscopy and random biopsies may fail to detect these lesions. New endoscopic imaging techniques to improve the accuracy of endoscopic diagnosis have recently been developed, and most are currently under evaluation.

METHODS Study Overview:Patient presenting to GI lab for BE screening and surveillance Informed consent signed and patient randomized, if endoscopic BE is suspected to NBI target biopsies or standard endoscopy with biopsies as the first procedure If randomized to NBI first: patterns noted, target biopsies obtained from specific patterns Same patient returns in 3-6 weeks for 2nd procedure Standard endoscopy: 4 quadrant every 2 cms. random biopsies (i.e. standard BE surveillance) Findings of NBI and random biopsies compared after all patients complete protocol and results analyzed A process similar to the one outlined above will be used in comparing autofluorescence imaging to conventional endoscopy in patients with Barrett's mucosa.

Study Design:This study is part of a multicenter randomized controlled trial being conducted at two sites, the other one being Medical University of South Carolina. Patients will be randomized (opaque sealed envelopes generated by statistician) to undergo NBI/AFI or standard endoscopy with biopsies on day 1. The same patient will return for the alternative procedure with biopsies within 3-6 weeks of the 1st procedure and will be maintained on acid suppressive therapy during this time interval. Each patient will thus act as his/her own control. At the time of performing the 2nd procedure (either NBI/AFI target biopsies or standard endoscopy), the endoscopist will be blinded and will not be aware of the biopsy results from the 1st procedure. Every attempt will also be made to keep the endoscopists blinded to the past history of the patient i.e. non dysplastic BE, LGD, HGD etc.

Risk and benefit to the study participant:Data on newer imaging method like NBI and AFI are mostly in the form of case series. This has not led to a change in the standard of care. The early data is very encouraging but not conclusive due to lack of randomized, controlled trials. Hence, we chose a study design of randomized controlled trial of the newer modalities versus the existing conventional endoscopy. This design necessitates the performance of a repeat endoscopy. Upper endoscopy is very safe, routinely done procedure with a low risk of complications. A repeat procedure may, indeed, increase the potential for risks associated with the procedure but the magnitude is small. The added advantage of second endoscopy would be increased detection of dysplasia and adenocarcinoma resulting in potential benefit to the patients. The main reason for the performance of the current study is the limitation of conventional endoscopy with the implication that dysplasia and adenocarcinoma will be missed on the initial endoscopy. In clinical practice, this usually warrants a follow up endoscopy that is performed at 1-3 yr intervals due to time and cost constraints. For the study population of this trial, the second endoscopy has the potential for increased detection of dysplasia/early adenocarcinoma in the Barrett's segment that could lead to initiation of curative therapy.