Taking a daily dose of aspirin lowers the chance of dying from cancer by more than a third, major research has shown. It reveals that the pills not only reduce the likelihood of contracting the illness, they also protect against it spreading. Oxford scientists say the evidence is so strong that in future the NHS watchdog NICE may issue guidelines telling doctors to prescribe aspirin to cancer sufferers. In one of a series of studies involving 200,000 patients, the academics found aspirin cut the risk of dying of cancer by 37 per cent if patients took it every day for five years. Another study found taking aspirin for three years reduced the chance of men developing cancer by 23 per cent, and women by 25 per cent. Researchers also found once patients had been diagnosed with cancer, their chance of it spreading was cut by 55 per cent if they took daily doses of aspirin for at least six and a half years. For some time scientists have known aspirin protects against certain types of cancer, particularly those affecting the bowel and throat. But this is the first time they have revealed it could also treat the illness by preventing tumours spreading to other organs, or "metastasising", which is often fatal. Professor Peter Rothwell, whose studies were published yesterday in the Lancet, said extra research now needed to be carried out "urgently". Professor Rothwell who is based at the University of Oxford and John Radcliffe Hospital, Oxford, said: "It's certainly time to add prevention of cancer into the analysis of the balance of risk and benefits of aspirin."