Design: Prospective, open-label, stepped-wedge cluster randomised trial
Population: 2267 patients under Barrett's surveillance in 18 Dutch community hospitals
Primary outcome: Neoplasia detection rate (any dysplasia or adenocarcinoma)
Effect: 7.4% vs 7.1%; OR 0.97 (0.65–1.44); suspicious lesions 14.0% vs 6.4%

The ACID-trial, a stepped-wedge cluster randomised trial in 18 Dutch community hospitals published in the BMJ on 21 October, moved hospitals in random order from standard Barrett's surveillance to surveillance with acetic acid chromoendoscopy after endoscopist training. Random four-quadrant biopsies continued throughout. It included 2267 patients without known dysplasia.

Neoplasia, meaning low or high grade dysplasia or adenocarcinoma, was found in 7.4% with acetic acid and 7.1% without, a difference consistent with none. Acetic acid more than doubled the number of patients with a suspicious area (14.0% vs 6.4%), but targeted biopsies did not find more neoplasia.

Acetic acid is cheap and often recommended to help spot subtle lesions. In routine community practice, this trial suggests it adds work and biopsies without changing detection. Careful high-definition inspection with adequate time, and random biopsies per protocol, remain the core of surveillance.

Expert centres may still find it useful for characterising a visible lesion; this trial addressed routine surveillance.

Do not rely on acetic acid chromoendoscopy to improve detection in routine Barrett's surveillance.
Continue random four-quadrant biopsies as per protocol.
Take adequate inspection time with high-definition white light.
Expect more suspicious-looking areas, and more biopsies, if acetic acid is used.
Refer visible lesions to a Barrett's expert centre for assessment.

Why it matters

It tests a commonly recommended add-on in ordinary hospitals and finds no gain.

The statistics, in plain English

The odds ratio of 0.97 (95% CI 0.65 to 1.44) is centred on no effect. The upper limit means a modest benefit cannot be fully excluded, but a large one is unlikely. Only 82% of those allocated actually received acetic acid.