Impossible decisions

Hi there. Given a diagnosis of stage 4 tongue cancer a couple of days ago. Two routes of action. Either total glossectomy followed by radiotherapy and maybe chemo. Or palliative radiotherapy. I had Acute promyelocytic leukemia (APML) in 2016, followed by therapy induced Myelodysplastic syndrome which quickly became AML. That led to an Allo Stem Cell Transplant Christmas 2019. I have been plagued with complications since including relying on a wheelchair most days. BUT the transplant has given me over 5yrs I didn't think I would see. Time with my sons, visits to new places, new experiences.

This new proposed surgery will be life changing with no guarantees and starting from a more fragile place. I have no idea how to decide. Do I choose potential longer prognosis, or shorter time but with maybe a better quality of life???? My medical team have another meeting next week and they may say inoperable. But I have a pre op assessment tomorrow incase. If I have the final choice I am so conflicted. And swing wildly in one direction or the other within minutes. How did anyone find a place where you were at peace with your decision whichever way you went? How do you deal with regret of not going the other way?