The fear of being diagnosed with death, and also the price to pay, there is no guaranteed of your survival and the cost is between 100k to a quarter of a million.
If you are not rich and you survive, you have to start all over again, which might also means hard time till death, if you don't survive your spouse have to start all over again with hard times.
Sooo ..... this are very personal thoughts depend on how you try to navigate the meaning of life. Some people prioritize survival above all else even if it means burning everything he own just to survive, while some just embrace death and let things flow as it is.
There is no real dumb decision to be honest, its either you maximize benefiting others or yourself.
I have 5 relative that kena cancer from stage 3 to 4, spine, whole body spread, prostate, lungs , nose ........ and I have seen the process, from the ones who is willing to spend whatever they have to stay alive, and others that don't spend , while having some that spend from doctor's advice but not going beyond for a miricle trail ... In the end all pass away except for the nose cancer one.
if go for treatment, need to spend a lot of money for treatment, suffer and no guarantee for cure.