Overheard in the office:
Investigator on the phone : Hi, I am doing this study, and I would like to talk to you about your Rectal cancer
Participant : I don't have rectal cancer. I have Colo-rectal cancer
Investigator on the phone : Yes, it's the same. Your cancer is in your rectum.
Participant (screams) : I have cancer in my Ass?
If you are wondering how the participant didn't notice, the rectal cancer was diagnosed during a routine screening.