I saw somewhere that Oncology doctors have a very high rate of suicide if they develop cancer. They know what is coming so they just off themselves.
I read an article written by an Oncologist and the struggles he faces when dealing with the unrealistic expectations of family vs what the patient wants. He talked about many cases where he knew the outcome, or knew the odds, and also knew the patient didn't really want to continue, but because family members were in his view, selfish, the patient would struggle on, enduring the treatments only to die at the end. Had the family not pushed them, they would have gotten to enjoy at least some of that short time they had left. My friend is a Hospice Doctor, his main goal is to try and make the patient as comfortable as possible in their last days and he had similar stories. For me, I would talk to a specialist, probably more than one. If they indicated that "we can try but...." then I absolutely would refuse treatment. That's not to say if the odds were in my favor, and it was discovered in time, I wouldn't be the first in line for meds.