Acetic acid-guided biopsies in Barrett’s surveillance for neoplasia detection versus non-targeted biopsies (Seattle protocol): A feasibility study for a randomized tandem endoscopy trial. The ABBA study

Abstract

Background and study aims Barrett’s esophagus is a potentially pre-cancerous condition, affecting 375,000 people in the UK. Patients receive a 2-yearly endoscopy to detect cancerous changes, as early detection and treatment results in better outcomes. Current treatment requires random mapping biopsies along the length of Barrett’s, in addition to biopsy of visible abnormalities. As only 13 % of pre-cancerous changes appear as visible nodules or abnormalities, areas of dysplasia are often missed. Acetic acid chromoendoscopy (AAC) has been shown to improve detection of pre-cancerous and cancerous tissue in observational studies, but no randomized controlled trials (RCTs) have been performed to date. Patients and methods A “tandem” endoscopy cross-over design. Participants will be randomized to endoscopy using mapping biopsies or AAC, in which dilute acetic acid is sprayed onto the surface of the esophagus, highlighting tissue through an whitening reaction and enhancing visibility of areas with cellular changes for biopsy. After 4 to 10 weeks, participants will undergo a repeat endoscopy, using the second method. Rates of recruitment and retention will be assessed, in addition to the estimated dysplasia detection rate, effectiveness of the endoscopist training program, and rates of adverse events (AEs). Qualitative interviews will explore participant and endoscopist acceptability of study design and delivery, and the acceptability of switching endoscopic techniques for Barrett's surveillance. Results Endoscopists’ ability to diagnose dysplasia in Barrett’s esophagus can be improved. AAC may offer a simple, universally applicable, easily-acquired technique to improve detection, affording patients earlier diagnosis and treatment, reducing endoscopy time and pathology costs. The ABBA study will determine whether a crossover “tandem” endoscopy design is feasible and acceptable to patients and clinicians and gather outcome data to power a definitive trial.

A feasibility trial of Acetic acid-targeted Biopsies versus nontargeted quadrantic biopsies during BArrett’s surveillance: the ABBA trial

“…The feasibility study had three components: i) training of trial endoscopists in the acetic acid technique; ii) a pilot tandem endoscopy diagnostic study using a randomized crossover design; iii) telephone interviews with patients and clinicians. The full trial protocol has been published [19], and a brief overview is given below.…”

Quality indicators in diagnostic upper gastrointestinal endoscopy

“…54 A randomized cross-over trial comparing AA-guided biopsies versus non-targeted biopsies as per Seattle protocol is underway (the ABBA study), and the results may provide more definitive evidence to promote this technique over current standard of care. 55,56 For NBI, a simple validated system to identify dysplasia and EAC within BE segments has been developed [Barrett's international NBI group (BING) criteria]. 57 This classification is based on a simple evaluation of the BE surface and vascular patterns (regular versus irregular).…”

“…54 A randomized cross-over trial comparing AA-guided biopsies versus non-targeted biopsies as per Seattle protocol is underway (the ABBA study), and the results may provide more definitive evidence to promote this technique over current standard of care. 55,56…”