> if you have any symptoms

What kinds of symptoms are people actually seeing? Or, without graphic details of your bowel habits, is this a "you'd know it when you see it" type of situation, where it would probably be obvious?

WebMD just says: change in bowel habits, blood in stool (would this be obvious?), anemia (how would you notice this?), unusual gas (uh, what is normal?), unexplained weight loss, fatigue, vomiting?

Unexplained weight loss and vomiting seem obvious, but the rest I'm not sure I'd even notice.