Cancer detection dog training. Border Collie dog training at UK based charity Medical Detection Dogs. The dogs are trained to detect volatile compounds that are associated with cancer cells. Dog noses are highly sensitive and are able to detect molecules in parts per trillion. They are potentially more reliable at detecting positive results compared to conventional blood or urine tests. All the dogs live as family pets but visit the centre for training several times a week. In 2015 the dogs are being trialled by the UK's National Health Service.