A 3-year study on Progression Free Survival (PFS). The study’s aim is to contribute an empirically derived patient perspective about the use of progression-free survival as an appropriate endpoint in clinical trials of cancer therapy. PFS is the length of time after cancer treatment that a patient lives with the disease without tests showing that it is worsening. Although PFS is used in clinical trials as a means of testing how well a new treatment might work, a longer PFS does not necessarily mean that overall survival is improved. So if patients derive PFS benefits but overall live no longer and they suffer unacceptable side-effects from the treatment then this PFS may be of little value. This is an extremely important study that has generated much interest already.