All of the survival statistics for this cancer seem awful. What does this mean for me?

Please remember, this is a rare cancer.  The survival statistics for a rare cancer can be misleading.  Many times the numbers are complied over a very long period of time as there are so few cases.  This means survival statistics that are better for those who have had more current treatment might be combined with survival statistics for those who years ago received no treatment at all.  In some cases, with correct treatment, 10 year survival for lower grade appendiceal tumors can currently be as high 70-80%.  Also always remember, if there is only a 20% survival from any particular cancer, that means 20% survive.  There's no reason to think you won't be in that 20%.  At one point I was given no odds for survival at all, and I have been cancer-free for over 5 years.