You have to remember too, these people are typically very...

You have to remember too, these people are typically very ill.
For some of them, it is the way out of their suffering.
My brother went through many different treatments, however, even with the great work from the doctors involved, and how much the students would have learned from the radical treatments being offered, his body reacted more than adversely, not because of the treatment itself, but because of the advancement of the cancer at the time.
He got to a point where he felt he was just suffering more than he could cope with, and he just rode it out.
That is something which happens, as one by one I watched my family make these decisions.
One of my other brothers is fortunately on a very special treatment, and he is quite strong, so still here three years after being diagnosed with pancreatic cancer, even with all the travelling he has to do. Skinny as a rake, but still able to look after himself.
people will get off treatments, even if the treatment shows signs of improvement, because by then, a a lot of times, there are many other issues which form part of the decision.
A very insidious disease which can cloud judgement, which is why the support of family and friends is so important