Ben Williams will tell you everything:
http://www.virtualtrials.com/williams.cfm
You can read his online update on treating brain tumors which contains information on supplements. You may want to consider high doses of melatonin while on radiation (read the online update). Also buy his book:
Surviving Terminal Cancer: Clinical Trials, Drug Cocktails, and Other Treatments Your Oncologist Won't Tell You About.
Good luck, keep posting here and others will give you their experiences.
-JG