The acetic acid method of biopsy (Portsmouth protocol) was shown to be feasible in Barrett’s surveillance, with clinician and patient acceptance; moreover, the reduced number of biopsies with this technique indicate that acetic acid biopsies could produce cost savings, according to a study published in Endoscopy. However, the method’s sensitivity and specificity still need to be demonstrated in a fully-powered and definitive trial.
It is unknown whether clinicians or patients would accept a change in practice from a nontargeted mapping biopsy protocol to a targeted biopsy protocol for the detection of Barrett’s esophagus. This mixed-methods feasibility study, which included a pilot randomized, multicenter, crossover trial with qualitative interviews, was designed to compare rates of neoplasia detection for nontargeted biopsies (Seattle protocol) versus acetic acid-targeted biopsies (Portsmouth protocol).
Additionally, investigators aimed to assess patient and clinician experience and acceptance, feasibility, and enablers/barriers to study participation and implementation with the acetic acid biopsy technique. 200 Patients at 6 UK centers who were under Barrett’s surveillance with no history of neoplasia underwent 2 gastroscopies 6 to 8 weeks apart, acting as their own control, 1 endoscopy with each protocol. Participants were randomized to either acetic acid-assisted gastroscopy (targeted biopsies) followed by the Seattle protocol gastroscopy (nontargeted mapping biopsies), or vice versa. Study outcomes included recruitment and retention, neoplasia yield, and number of necessary biopsies.
Of the 200 patients recruited, 96.0% (n=192) underwent at least one gastroscopy, and 87.0% (n=174) underwent both procedures. Neoplasia prevalence was 9 of 192 (4.7%). Both protocols detected cancer and high-grade dysplasia, as well as 5 low-grade dysplasias (2 with acetic acid, 4 with nontargeted biopsies, and 1 with both techniques). In the nontargeted arm, a total of 2045 biopsies were taken, compared with 211 in the acetic acid arm. In the paired analysis, a 6.50-fold decrease was seen in the number of per-pathology biopsies found by the Portsmouth protocol compared with the Seattle protocol, and a 9.65-fold decrease was seen when analysis was limited to high-risk neoplasia (high-grade dysplasia and cancer). Both clinicians and patients found the acetic acid technique to be acceptable. The investigators estimated that based on the study’s data, a noninferiority, tandem, crossover trial would require approximately 2828 patients.
This study demonstrated the feasibility of performing a multicenter crossover endoscopy in a Barrett’s surveillance population. The low neoplasia yield makes this design and technique acceptable for both patients and clinicians. The investigators concluded that. “The data support development of a fully powered definitive study to investigate whether acetic acid-guided biopsies could replace Seattle protocol-guided biopsies for Barrett’s surveillance.”
Longcroft-Wheaton G, Fogg C, Chedgy F, et al. A feasibility trial of acetic acid-targeted biopsies versus nontargeted quadrantic biopsies during Barrett’s surveillance: the ABBA trial [published online October 15, 2019]. Endoscopy. doi: 10.1055/a-1015-6653