My mum has had colon cancer and my grandma (mums mum) had small intestine cancer. are there steps i can take to prevent cancer myself?

Heritable cancer: First it might be good to know which type of cancers they had-- i.e. if they truly were inherited by known pathways (polyposis, Lynch syndrome, etc.) Prevention would include healthy diet (high fiber, no nitrites, no alcohol, etc.) and appropriate screening at a possibly earlier age. Consulting with a pathologist/gastroenterologist or geneticist about the cancer pattern and path may be useful.