Scientists at the Princess Margaret Cancer Centre are using an emerging blood test technology to look for small traces of cancer in a patient's bloodstream. It will make it easier and faster to detect recurring cancer in its earliest stages but more research needs to be done before it can be used confidently or on people without cancer. Guest host Piya Chattopadhyay speaks with Dr. Lillian Siu is a senior scientist at UHN's Princess Margaret Cancer Centre and a scientific lead at the Peter Gilgan Centre for Early Cancer Detection Research about the potential of this breakthrough research.