the one and most inportant is get a colonoscopy
they say start at 50 but if it runs in your family or you are real concern than you should get one. colon cancer is a very easy cancer to get rid of if you get your colonoscopy, they find poyls and remove them right there . my husband had one monday . they found 2 and removed them, if he had let them stay there he would of got cancer. colon cancer is very slow growing and if you get it early its cureable.
If you are on this site I'm sure you can or have Googled the subject. The 3 things I keep hearing is exercise, don't smoke and a diet low in animal fats. I do 2 of the 3 (I love steak and bacon!).
Also, watch your stool for blood, unusual narrowing or black stool. Those things need to be discussed with a dr.