Together, stomach and oesophageal cancer account for around 1.4 million new cancer diagnoses each year worldwide.
Both tend to be diagnosed late, because the symptoms are ambiguous, meaning the five-year survival rate for these two types of cancer is only 15 per cent.
Currently, the only way to diagnose oesophageal cancer or stomach cancer is with endoscopy – an expensive, invasive method with some risk of complications.
“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 Sheraz Markar from Imperial College London.