I believe it’s called medical triage, and it’s a real problem. Usually, in first world countries it’s more between top notch care (Immunotherapy, Hadrontherapy), regular care, and pain management.
For cancer, it would be taken by specialised hospital on a multi disciplinary team based on what they can do, and the expected life quality/expectancy afterwards (a 75 year old having to wear a diaper sucks, but the same at 30 is worse)
Note also that the way, they do it in the US based on who can pay what is even worse. Your life isn’t more important if you can put your winter apartment in Aspen for rent this winter to pay for your treatment.
Triage is also a classic one in Emergency. If you watch the Netflix documentary about Paris 2015 shootings, they interviewed one of the doctor who was doing field triage. One of these ninja are cutting onion moments