Electronic nose sniffs out Barrett’s oesophagus

A novel electronic nose device can reliably detect Barrett’s oesophagus (BO) and may present an efficient, minimally invasive option for early detection of oesophageal adenocarcinoma (OAC), according to a recent study.

“This proof-of-concept study indicates that exhaled breath [volatile organic compounds (VOCs)] hold great potential for the noninvasive identification of patients most likely to have BO, thus at higher risk of developing OAC,” researchers said. “Hence, it could be possible to reduce mortality from OAC in patients at risk, who otherwise would not have undergone upper endoscopy.”

A total of 402 participants were enrolled into the study, 129 of whom had BO (mean age, 61.6±10.5 years; 74.4 percent male). The remaining 273 did not have BO (mean age, 59.1±12.6 years; 46.5 percent male), though 141 patients in this group had gastro-oesophageal reflux disease (GORD); only 132 participants were qualified as healthy controls. [Gut 2020;doi:10.1136/gutjnl-2019-320273]

Breath VOC profiles differed significantly between BO and control participants. The resulting cross-validated prediction model was able to identify BO with a sensitivity of 91 percent (95 percent confidence interval [CI], 84–95) and a specificity of 74 percent (95 percent CI, 69–79).

Moreover, the area under the curve [AUC] of the model was 0.91 (95 percent CI, 0.87–0.94). There were no adverse events observed during the breath analysis.

At a different cut-off point, the receiver operating curve gains a specificity boost to 86 percent, helping to avoid false-positive results. However, this decreased the test sensitivity to 71 percent.

The novel nose device was also able to differentiate BO from GORD, though to a lesser degree. The resulting model had an AUC of 0.73 (0.67–0.79), with a specificity value of 74 percent (95 percent CI, 66–81). The sensitivity was moderately low at 64 percent (95 percent CI, 55–72), though this was improved to 96 percent (95 percent CI, 90–99) with an increased length of the BO segment (≥3 cm).

The above findings were robust to sensitivity analyses and statistical adjustments, such that there were no meaningful changes in the primary findings when analysis was restricted only to patients using proton pump inhibitors for at least 1 month before index and to patients with a hiatal hernia.

The electronic nose device used in the present study carries three metal-oxide sensors and uses “chemical-to-electrical interfaces” to detect VOCs in the breath and produce quantified profiles. Other analytical methods also make use of breath samples for disease detection, the researchers explained. Some, for instance, focus on a specific VOC and employ highly accurate quantification techniques, such as gas chromatography-mass spectroscopy.

However, these tend to be expensive, time-consuming and highly technical. “Therefore, electronic nose technology seems better suited for population-based screening than chemical analytical techniques, because it is fast, potentially cost-effective and allows for real-time breath analysis results,” they added.

“Given the high tolerability, high acceptability and low costs, breath testing may be a promising approach to be used for noninvasive screening for BO in a primary care setting,” said the researchers.