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).

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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.


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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.”

Reference

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