Everyone is different, and I think all of us Stg IV's have heavily contemplated this.
I'm in hospital now for digestive issues (I *think* I'll escape tomorrow!!
).
My room-mate here (55-yr old male) was previously a chemo-mate at the clinic, and a month ago he stopped chemo for his pancreatic cancer.
QOL just wasn't worth it anymore for him, and he spent a wonderful month 'back home' with siblings and that part of the family.
His sons brought him back here to Phoenix last week 'for the time remaining.'
He is getting terrible ascites (6 lts of drainage every 3 days) from the tumor, and the only relief is pericentesis (draining).
His family just wheeled him out of here to go home for hospice nursing.
He isn't long for this world, maybe a week; but will it be ascites, or breathing, or cardiac that actually causes death can't be foreseen.
At least he'll have family around him and be pain-free.
Point is, the end will be different for everybody, but you probably will have some control of the final path.
PLEASE STOP WORRYING ABOUT THE END!!
You are only at the beginning of the journey, and have much of life ahead of you. Enjoy it and everything in it.
My tumors are severe and inoperable, and I've survived 25 months on chemo; still kickin' cancer's butt and working the bucket list!
HTH, Rick