Ben A Williams is a GBM survivor of 16 years and has written a book about his experience and the medical establishment. It is very interesting. I downloaded it on my Kindle for $9.99. I do not have GBM - I have grade 3 Oligodendroglioma, but am considered terminal, too.
He used a cocktail approach that he concocted himself by doing alot of research.
Anyway, I recommend his book to all GBM patients and their families as well as other types of BT patients (like me) who are considered terminal.
Do as much research as you can. Knowledge is power.
The title of his book is Surviving Terminal Cancer: Clinical Trials, Drug Coctails, and ...
Good luck everybody. Fight the good fight.