Does Blood In Stool Indicate Colon Cancer?

No, blood in stool does not necessary mean cancer. The other choice you can look for is ulcer. Blood on stool means you're bleeding in a part from your colon to your rectum. Black stool means you're bleeding in the stomach or in small intestine and it's been digested.
You do need to seek medical attention because you never know what it might be. It can indicate many things. Take care.

Not necessarily.  If it's bright red it's most likely a hemmoroid. If you have cramping along with it , it may be lower bowel inflamation and or a bowel infection for which you need medicationl  However don't mess around with this. Get it checked out. Hemroids are treated with medication an seldom need surgery.