ACETIC ACID GUIDED BIOPSIES VERSUS MAPPING BIOPSIES FOR BARRETT'S SURVEILLANCE: THE ABBA STUDY

Abstract

Aims:

To compare neoplasia detection with AA targeted biopsies and protocol guided non-targeted biopsies during Barrett's surveillance.

Methods:

Multicentre randomized crossover feasibility study. Patients under surveillance for Barrett's metaplasia with no history of dysplasia/cancer were recruited. All patients underwent two gastroscopies 8 weeks apart, one with AA guided biopsy of abnormal areas only (Portsmouth Protocol) and one with non-targeted mapping biopsies (Seattle Protocol). Neoplasia yield and no. biopsies from each strategy was evaluated.

Results:

200 patients recruited from 6 centres. Mean age 66yrs. Mean length C4M6. 175 patients completed both procedures. The prevalence of LGD, HGD and cancer was 11/192 (5.8%). All HGD and cancer was found with both protocols and confirmed with definitive treatment. One LGD was found with Portsmouth protocol and 5 LGD with Seattle protocol. This difference was not significant, and on follow up gastroscopy no neoplastic changes were found in any of the LGD cases. 2139 biopsies were taken using Seattle protocol at a cost of £125,987 (306 biopsies/neoplasia). 226 biopsies with Portsmouth Protocol at a cost of £13,311 (75 biopsies/neoplasia) a 4 fold difference. In terms of HGD/cancer, 1070 biopsies/neoplasia found using Seattle protocol and 113 biopsies/neoplasia using Portsmouth Protocol, a 9.5 fold difference.

Conclusions:

This is the first RCT comparing these techniques. No HGD or cancer was missed with either technique. There was a 4 fold reduction in biopsies per neoplasia detected with Portsmouth compared to Seattle protocol and a 9.5 fold difference when restricted to high risk neoplasia. If implemented nationally then this could lead to a massive reduction in histopathology work load and costs. LGD remains controversial and we believe inflammation could have resulted in false positive LGD as subsequent OGD and biopsies did not reveal any LGD. This feasibility data would support a definitive trial of AA targeted biopsies in a surveillance population.