Some 20 years ago had colon cancer, I received some of my treatment at the Mayo Clinic in Florida.
They were great, gave me a quiz to aid in treatment. 
Ruled out farm chemicals, and no family history, so looked at my diet. Nothing unusual found, decided probably caused my eating my beef well done. Said that was a problem, especially when cooked over a  grill, grill gave off noxious fumes which became embedded in meat, could have caused my problem.

No problem since, but get regular colonoscopy .