Radiotherapy has been around for decades, and is often extremely effective. But researchers are still discovering new ways to use it. This includes testing new drugs alongside radiotherapy. “The aim is to increase the chance of a cure by making the radiotherapy more effective at killing cancer cells,” says Professor Anthony Chalmers, a Cancer Research UK-funded radiotherapy expert at the University of Glasgow. But avoiding making side effects worse is a challenge. So research is focused on finding drugs that enhance the effects of radiotherapy on cancer cells, while leaving normal cells unaffected.