Breath test shows promise for noninvasive diagnosis of esophageal, stomach cancer

Issue: March 10, 2017

Breath volatile organic compound analysis showed promise for detecting esophageal and gastric cancer in a multicenter validation study, according to a late-breaking abstract presented at the European Cancer Congress.

“At present the only way to diagnose esophageal cancer or stomach cancer is with endoscopy. This method is expensive, invasive and has some risk of complications,” Sheraz Markar, MBBChir, MA, MSc, MRCS, a National Institute for Health Research Clinical Trials Fellow from Imperial College London, said in a press release. “A breath test could be used as a non-invasive, first-line test to reduce the number of unnecessary endoscopies. In the longer term this could also mean earlier diagnosis and treatment, and better survival.”

Markar and colleagues first reduced a previously identified panel of 13 volatile organic compounds (VOCs) — including butyric, pentanoic and hexanoic acids, butanal, and decanal, according to the press release — down to five VOCs, which maintained a sensitivity of 84% and a specificity of 88% for detection of esophago-gastric cancer. Then they performed a multicenter blinded validation study of 162 patients with gastric or esophageal cancer and 172 controls, whose breath samples were analyzed with selected ion flow-tube mass spectrometry to determine the accuracy of the five-VOC panel for diagnosing esophago-gastric cancer.

The investigators found that four of the five VOCs were significantly dysregulated in the cancer patients compared with controls. After adjusting for confounders like age, comorbidities and medications, the association between the VOCs and esophago-gastric cancer was maintained.

Overall, the five-VOC model diagnosed esophago-gastric cancer with 80% sensitivity and 81% specificity, corresponding to an area under the receiver operating characteristic of 0.85.

“Because cancer cells are different [from] healthy ones, they produce a different mixture of chemicals. This study suggests that we may be able detect these differences and use a breath test to indicate which patients are likely to have cancer of the esophagus and stomach, and which do not,” Markar said in the press release. “However, these findings must be validated in a larger sample of patients before the test could be used in the clinic.”

Markar and colleagues plan to evaluate this test in a larger trial of patients without a cancer diagnosis who are undergoing endoscopy for GI symptoms over the next 3 years, according to the press release. They are also working on similar tests for colorectal, pancreatic and other cancers. – by Adam Leitenberger

Reference:

Markar S, et al. Abstract 6LBA. Presented at: European Cancer Congress; Jan. 27-30, 2017; Amsterdam, the Netherlands.

Disclosures: The researchers report no relevant financial disclosures.