I had a cancer surgery and removed a part of my kidney due to renal cell cancer inside the kidney a few years ago. I got the diagnose Crohns the same month. My specialists both suggested that they would not let me have any Crohns medicine that supresses the immune system, because the cancer could return. my GI would not even let me use prednisone for more than just a few months, he didn't like the idea at all, but I had a flare, that had been active prior to the kidney surgery and it continued during and after the surgery as well.
I used prednisone to try to stop the flare, but as soon as I tapered off of prednisone, the flare returned and got worse than before.
I then decided to try Low Dose Naltrexone (google it). LDN is a fantastic medication, only 4.5 mg each night, my flare stopped within a few weeks and the diseases has been kept on bay for more than two years now. Due to anecdotals LDN may also prevent a cancer from "flaring" because LDN is increasing our endorphins by 300 %, due to pilots done recently. LDN is a medication that gives zero side effects (exept for the first 10 days) and that is inexpensive. (20 $ / 1 month).
LDN is working better if you avoid sugar, flour, starches.
Dr. Chris Steele a famous TV doctor in UK (he is UK's dr.Oz) is promoting LDN, look at this video:
http://www.youtube.com/watch?v=CVpjsDK0LPA