Can I say no? Can I stop?

Yes, and yes. Saying no cannot change the care you get. We must look after you just as well as before. You can also leave at any time, without finishing, without saying why, without anyone's permission.

Your consent form may call you a subject, and the trial team may call you a participant. Either way, nothing in medicine moves forward without people who agreed to go first.

Written by two physicians. Checked against patient information from the US National Cancer Institute and Cancer Research UK.