Breath Research Narrow Validation for Gastrointestinal Cancer Detection

Inclusion Criteria: Adult participants ≥ 18 years old who meet at least one of the following criteria Colorectal arm: 1. Cancer: Histologically-confirmed CRC\* 2. Control: Non-specific abdominal symptoms with normal or benign colonoscopy findings Pancreatic arm: 1. Cancer: Histologically-confirmed PDAC\* 2. Control: Non-specific abdominal symptoms with a radiologically-normal pancreas Oesophagogastric arm: 1. Cancer: Histologically-confirmed OGC\* 2. Control: Non-specific abdominal symptoms with normal or benign upper gastrointestinal endoscopy findings Oesophageal squamous arm: 1. Cancer: Histologically-confirmed OSCC\* 2. Control: Non-specific abdominal symptoms with normal or benign upper gastrointestinal endoscopy findings Liver arm: 1. Cancer: Histologically- or radiologically-confirmed HCC or CCC\* 2. Control: Non-specific abdominal symptoms with a radiologically-normal liver * Patients with suspected cancer (e.g. based on imaging) but who do not have histological confirmation prior to participating in the study may still be recruited and followed up to determine whether or not a diagnosis of cancer was subsequently confirmed. Exclusion Criteria: * Patients who have already received chemotherapy, radiotherapy or surgery for their cancer * History of another cancer (other than non-melanoma skin cancers) within three years * Participants with co-morbidities preventing breath collection * Unable or unwilling to provide informed consent * (For Oesophagogastric arm only): Allergies to any of the constituents of the nutrient drink including glucose, glycerol, iron sulphate, Maltodextrin (Corn, Potato), Xanthan Gum, Potassium Chloride, tyrosine, phenylalanine, and glutamic acid * (For Colorectal arm only): Participants receiving bowel prep in the previous 7 days