A blood test which can detect traces of cancer cells could spare thousands of patients unnecessary chemotherapy every year.
A major bowel cancer trial is examining whether the test can show if surgery has removed all of the tumour.
Doctors say half of patients with stage 3 bowel cancer are cured by surgery alone so by using chemotherapy they are over-treating many people.
About 1,600 bowel cancer patients are being recruited to the UK study. คาสิโนบาคาร่า