Please tell me, could a doctor refuse a patient's wishes?

In what sense?: You've asked a very broad question here, and i'm not sure what you're getting at. If a patient were depressed, suicidal, and requested to be put to death, doctors would likely refuse these wishes. They would see that the patient is ill and needs help. On the other hand, doctors certainly listen to patients when going over treatment options for cancer, etc. If i'm missing your point, please re-ask.