Well, I am in the situation you are so afraid of. Chemo, radiation and other treatments suck big time, let alone the effects of the cancer itself.
BUT ... this is not a binary situation, where suddenly life becomes unbearable. There's so much worth living for. And not just the obvious big things in life (kids, family, friends), but also many many small things. Man, that first cup of cappuchino once the effects of chemo wear off alone is almost worth all the puking beforehand :) Or having a nice piece of cheese. Seeing my small herb garden grow. Etc. etc.
The trick is to live a peaceful, content life. Be grateful for what you have. Enjoy your short time on earth.
Of course it’s never binary. And different people value different things.
I don’t think I was clear that I’m not afraid of being simply uncomfortable in my final days, but that there are absolutely medical treatments that can extend one’s life at extreme cost to quality of life. And there’s a threshold where I hope I’ll choose quality over quantity.
Sometimes you don’t know what that cost will be before starting treatment. Sometimes you’re holding out hope that the treatment will help you actually make it out the other side alive and healthy again. Sometimes you want to make it through long enough to see a child graduate, or meet a grandchild on the way, or some other meaningful event. There’s a million reasons one might choose between treatment options. And I don’t begrudge anyone for making the choice that’s right for them.
I’m sorry to hear what you’re going through, but I’m glad that it sounds like you’ve chosen a path that brings you the most fulfillment possible.