(Copying over my comment from there)

For the kind and extent of cancer Ebert had, the long term survival rate (>5 years) is ~5% following radical neck dissection and ancillary therapy: usually radiation and chemotherapy. This is thus a proven procedure – it works – and yet the vast majority of patients refuse it.

Indeed. It takes a lot of willpower to live from day to day. I am reminded of Hal Finney’s article announcing his ALS diagnosis, Dying Outside ( http://lesswrong.com/lw/1ab/dying_outside/ ):

Although ALS is generally described as a fatal disease, this is not quite true. It is only mostly fatal. When breathing begins to fail, ALS patients must make a choice. They have the option to either go onto invasive mechanical respiration, which involves a tracheotomy and breathing machine, or they can die in comfort. I was very surprised to learn that over 90% of ALS patients choose to die. And even among those who choose life, for the great majority this is an emergency decision made in the hospital during a medical respiratory crisis. In a few cases the patient will have made his wishes known in advance, but most of the time the procedure is done as part of the medical management of the situation, and then the ALS patient either lives with it or asks to have the machine disconnected so he can die. Probably fewer than 1% of ALS patients arrange to go onto ventilation when they are still in relatively good health, even though this provides the best odds for a successful transition. With mechanical respiration, survival with ALS can be indefinitely extended.

Or (thank goodness for Evernote which lets me refind those old citations) http://www.fastcompany.com/node/52717/print :

Then the knockout blow was delivered by Dr. Edward Miller, the dean of the medical school and CEO of the hospital at Johns Hopkins University. He turned the discussion to patients whose heart disease is so severe that they undergo bypass surgery, a traumatic and expensive procedure that can cost more than $100,000 if complications arise. About 600,000 people have bypasses every year in the United States, and 1.3 million heart patients have angioplasties — all at a total cost of around $30 billion. The procedures temporarily relieve chest pains but rarely prevent heart attacks or prolong lives. Around half of the time, the bypass grafts clog up in a few years; the angioplasties, in a few months. The causes of this so-called restenosis are complex. It’s sometimes a reaction to the trauma of the surgery itself. But many patients could avoid the return of pain and the need to repeat the surgery — not to mention arrest the course of their disease before it kills them — by switching to healthier lifestyles. Yet very few do. “If you look at people after coronary-artery bypass grafting two years later, 90% of them have not changed their lifestyle,” Miller said. “And that’s been studied over and over and over again. And so we’re missing some link in there. Even though they know they have a very bad disease and they know they should change their lifestyle, for whatever reason, they can’t.”