Crohn's doesn't necessarily "cause" colon cancer...crohn's activity in the colon that is very severe and prolonged can increase the risk of colon cancer slightly compared to someone that doesn't have IBD (same with UCers since their inflammation is limited to the colon/rectom, so there risk of colon cancer increases slightly as well) but the good news is with having an IBD and getting regular colonoscopies there is a much better chance they'll find cancer in it's very early stages if there is any cancer to find.
A lot of people have success with the SCD and many also find it very restrictive (so it's a personal preferance) the main goal should be to elimintate specific things that are known to exacerbate symptoms of IBD which are fast-foods, processed foods/beverages, caffeine, animal fats, refined sugar and artificial sweetners. Trying to eat healthy whole foods rather than anything packaged, drinking chamomile tea can also have it's benefits with the intestines/stomach.
Being scared is normal and you will adjust, even though it's often like a roller-coaster ride with this DD but if you're mild then hopefully you'll stay that way...regular daily exercise is also a huge benefit mentally and physically.
I should also mention that if you're not taking a good probiotic that you should definitely look into that...taken daily and indefinitely (flaring or not) can be a huge benefit for IBDers since we tend to have bacterial over-growth issues.
:)