The Importance of Natural Causes of Cancer

"I'm not on any medication. I don't... Gee, I don't ... I don't have anything," David Letterman says of his health. He had a bladder tumor when he was 19 and has always been waiting for that to come back and get him. "My whole new show is about my preoccupation with sort of death and hitting this age where I'm thinking about middle age and natural causes," the actor adds.