I'm hesitatating writing this, but maybe you're interested in hearing it. As another facing some pretty serious cancer issues with a similar prognosis (I'm not going to get into details), my advice would be not to throw the towel in too quickly!
Just to share, I've been put on a pretty aggressive chemo plan (by a doctor I enjoy dealing with immensely), and it appears that my formerly fairly aggressive growth has been stopped in it's tracks - at #4 of 6 planned treatments. We'll know better soon after a PET scan (more detailed than a CAT scan) scheduled soon. Still, this form I have been diagnosed with has a nasty habit of returning after being forced into remission just about 100% of the time. It can be knocked down again, but remission won't last as long. Wash, rinse, and repeat until they can't get you into a remission. So, damn sure it's spooky knowing HOW you're going to die, but you STILL DON"T KNOW WHEN. I'm 72, and figure my chance at seeing 80 are pretty damned limited, but what time I have left is something I plan on enjoying - and oh hell yes, that's going to involve some bike riding....
Get mad if you need to, maybe check out some options you haven't checked yet - like a second opinion? Best of luck!! -Al