this is a common disease. a6,000 this is a common disease. 16,000 new patients a year in the united kingdom. roughly fourfifths patients a year in the united kingdom. roughly four fifths will have an operation that renders them potentially disease—free. currently, cancer patients who receive successful surgery are offered intravenous chemotherapy, to �*mop up�* any cancer cells that might be remaining. the new blood test — or liquid biopsy — looks for fragments of dna that could indicate the presence of cancer tumours in the body. it�*s hoped if there are none, then a patient wouldn�*t need chemotherapy. here�*s professor cunningham again. the whole point about this approach is that we can more reliably detect the patients who need the treatment and spare the patients who don�*t. so it�*s really exactly the sort of tool we�*ve been looking for in practice. as we�*ve heard, the focus here is bowel cancer patients.