I think part of the answer is that every cancer patient needs something like a project manager or case officer overseeing *all* of their healthcare.

It doesn't have to be a doctor (family doctors are too overworked to do it anyway), but maybe a social worker or nurse who has some kind of professional standing to coordinate with the different medical teams. Inside hospital, the floor nursing station and resident played that role for me, but on the outside, the cancer centre focussed only on things related to the cancer itself, and I had to coordinate the rest myself.

I bet it would even save the healthcare system money, because we'd end up with many fewer $$$ advanced cases and ER visits.