The study aims to create a simple breath test to find cancers in the digestive system, like in the oesophagus (food pipe), stomach, liver, pancreas, and bowel. These cancers can cause symptoms that are hard to tell apart from less serious illnesses, making it tough to catch early. The breath test looks for tiny particles called volatile organic compounds (VOCs), which are often linked to these cancers. If the breath test shows a positive result, the patient can get more tests quickly. This might help find cancer sooner, allowing for better treatment options.

Participants will offer a breath sample, usually before a planned hospital procedure, and fill out a short health history form. Some might drink a nutritional supplement before a second breath test. This helps check if the breath test is accurate.

• Participants should be at least 18 years old.
• Cannot join if they have had treatments like chemotherapy or surgery for cancer recently.
• Some participants will drink a special nutrient drink before testing.