"Using Dilute Vinegar to Find Changes in Cells During Endoscopy for Patients With Barrett's Oesophagus" (The ABBA Study) (ABBA)

"Using Dilute Vinegar to Find Changes in Cells During Endoscopy for Patients With Barrett's Oesophagus" (The ABBA Study)

Acetic Acid Guided Biopsies in Barrett's Surveillance for Neoplasia Detection Versus Non-targeted Biopsies (Seattle Protocol): A Feasibility Study for a Randomised Tandem Endoscopy Trial. The ABBA Study.

University Hospitals, Leicester, University of Portsmouth, Brighton and Sussex University Hospitals NHS Trust, Western Sussex Hospitals NHS Trust, Royal Bournemouth and Christchurch Hospitals NHS Foundation Trust, Gloucestershire Hospitals NHS Foundation Trust

Problem statement Barrett's oesophagus is a pre-cancerous condition affecting 375,000 people in the U.K. There is a 0.5-3% yearly risk of progressing to oesophageal cancer, from which only 5% of patients will survive for 5 years after diagnosis. Diagnosing the disease at the stage of dysplasia (pre-cancerous) and early cancer improves survival. This has led to the current surveillance strategy of gastroscopy with non-targeted mapping biopsies taken from the Barrett's oesophagus every two years. The large number of biopsies required is time consuming and expensive, yet dysplasia and cancerous tissue is still missed due to the non-targeted biopsy sampling strategy. Acetic acid has been used effectively in the early detection of cervical dysplasia and cancer, and has also been used with success in a high risk Barrett's population (patients with suspected dysplasia or previously treated dysplasia), but not been studied in the lower risk Barrett's surveillance population. A diagnostic study of non-targeted mapping biopsies (current practice) versus targeted biopsies (acetic acid) in a surveillance population is needed before widespread adoption of this technique is possible.

This is a feasibility study to enable powering of a larger study. The investigators would assume a disease detection of 4.5% with acetic acid chromoendoscopy and 1.5% with protocol driven mapping biopsies. However, these assumptions are largely driven from a single centre cohort study and as such need clarification before they could be used for the purposes of powering a study. Based on the historical cohort studies and wide consultation within the British Society of Gastroenterology research committee and consultation with experts in the field, it is estimated that 200 patients would be reasonable for recruitment to enable the reproducibility and generalisability of this data to be established. The purpose of this study is not to produce statistically significant data in itself but to establish likely event rates and effect size to inform the power calculation for the definitive study.

Patients undergo current gold standard Barrett's surveillance with quadrantic Seattle protocol biopsies

Patients undergo dye spray gastroscopy with Acetic Acid and targeted biopsies for areas of dysplasia.

During endoscopy Acetic acid will be sprayed onto Barrett's oesophagus and targeted biopsies of taken.

During endoscopy patients will undergo current standard quadrantic Seattle protocol biopsies of Barrett's oesophagus

Feasibility as assessed by the ratio of patients approached to recruited, percentage of patients who complete both endoscopies

To determine the feasibility of recruiting 200 Barrett's surveillance patients in 18 months. Ratio of patients approached to recruited, percentage of patients who complete both endoscopies.

To assess participant acceptability of the study design through quantitative measures related to study procedures and in-depth qualitative feedback. Qualitative feedback through semi-structured telephone interviews. Patients will be asked how acceptable they found having two endoscopies and whether they would be willing to undergo a study of similar design. This will measured by responses based on a telephone interview questionnaire.

Comparison of dysplasia rates as assessed by the number of biopsies in each endoscopy required to detect dysplasia

To identify the degree of difference in dysplasia (pre-cancerous changes) detection rates between acetic acid gastroscopy (targeted biopsies) and standard gastroscopic practice (non-targeted mapping biopsies) to inform the power calculation for a definitive study. Number of biopsies in each endoscopy required to detect dysplasia.

Feasibility of training and implementation of acetic acid guided dysplasia detection technique. Online training module with pre and post training examination. Seminar based training day with further examination thereafter and correlation of scores following the above methods. The endoscopists will be tested on a validated video library pre and post training. A further test will be performed following 3-6 months to assess for drop off in ability. Percentage of correct answers will be calculated for each test

To explore the acceptability to clinicians and patients of the concept of using a targeted biopsy technique for surveillance instead of non-targeted, mapping biopsies. Semi-structured qualitative interview to explore clinician's attitude to the use of acetic acid following training and implementation of the study. Clinician's will be asked via a telephone interview on a scale of how confident they would be to use acetic acid alone in the surveillance of Barrett's without performing non-targeted biopsies. Clinical's attitudes will be assessed pre and post training as well as at the end of the study.

To identify potential facilitators and barriers to recruitment and retention for the definitive trial. Qualitative patient interview for both those enrolled in the study and those who have declined to identify themes that may assist recruitment into a larger study. This will be measured by means of a telephone questionnaire.

Monitoring of adverse outcomes to describe adverse events for the two methods. Number of adverse events recorded in total.

Inclusion Criteria: Aged 18 years or above Biopsy proven Barrett's metaplasia At least 2cm of Barrett's metaplasia (C0 M2) Willing and able to give informed consent Exclusion Criteria: Less than 2cm (C0 M2) of Barrett's metaplasia Significant oesophagitis Known or prior oesophageal cancer Known or prior oesophageal dysplasia (indefinite for dysplasia CAN be included) Previous endoscopic therapy Known allergy to acetic acid Previous inclusion in the study