Phase 3 trials involve from hundreds to thousands of people. The trials are usually conducted through doctors’ offices, hospital clinics and cancer centres around the country or even around the world. They aim to test if the new treatment (the intervention treatment) is better than the current best standard treatment. They test treatments in real life settings, not the controlled circumstances under which Phase 1 and 2 trials are usually conducted. Participants in Phase 3 trials are put in either the new treatment group or the standard treatment group at random. People in the trial are monitored carefully to see the effect of the treatment on the cancer, and on the length and quality of life.  If the new treatment works better, it may become the new standard treatment. In general, the new treatment needs to go through more than one Phase 3 trial for the treatment results to be accepted.