A test analyzing the amounts of five chemicals in the breath diagnosed stomach and esophageal cancer in 335 patients 85% of the time. It could be a potential alternative to invasive endoscopy as a diagnostic for esophageal and stomach cancers.
According to the National Cancer Institute, cancers of the stomach and esophagus tend to be diagnosed at an advanced stage because they do not have early signs or symptoms. The five-year survival rate for stomach cancer is 30%, while that of esophageal cancer is 18%, according to the NCI.
The study, presented at the European Cancer Congress, comes after previous research showed that patients with stomach or esophageal cancer had different levels of five chemicals in their breath when compared to patients with gastrointestinal symptoms, but no cancer, according to a statement. The five chemicals are butyric, pentanoic and hexanoic acids, butanal and decanal.
The researchers obtained breath samples from 335 patients in three London hospitals. They used ion flow-tube mass spectrometry to measure the levels of the five chemicals in the samples. Of the 335 patients, 163 had been diagnosed with one of the two cancers, while 172 showed no signs of cancer when they underwent endoscopy.
“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,” said Dr. Sheraz Markar, an NIHR clinical trials fellow from Imperial College London, in the statement.
In addition to the 85% accuracy rate, the test also posted 80% sensitivity and 81% specificity.
“Because cancer cells are different to 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 oesophagus and stomach, and which do not,” Markar said. “However, these findings must be validated in a larger sample of patients before the test could be used in the clinic.”
Next up, the team will conduct a larger trial with patients undergoing endoscopy for gastrointestinal symptoms, but who have not yet received a cancer diagnosis. They are also developing breath tests for other forms of the disease, such as colorectal and pancreatic cancers.