I remember what George said and vowed that rather than let Alzheimer's take me, I would take it. I would live my life as ever to the full and die, before the disease mounted its last attack, in my own home, in a chair on the lawn, with a brandy in my hand to wash down whatever modern version of the "Brompton cocktail" some helpful medic could supply. And with Thomas Tallis on my iPod, I would shake hands with Death.

Read incorrectly, that sounds like a threat. No thanks, Vanity Fair !

With a malicious grin that implies I know something you don’t.

In my sleep. In bed. With a half-eaten egg salad sandwich on my chest.

I should have known that I might not like what my brain scan showed, just as I should have known that the symptoms of prostatism that were increasingly bothering me were just as likely to be caused by cancer as by the benign prostatic enlargement that happens in most men as they age. But I continued to think that illness happened to patients and not to doctors, even though I was now retired. Twenty months after I had my brain scanned, I was diagnosed with advanced prostate cancer. I had had typical symptoms for years, steadily getting worse, but it took me a long time before I could bring myself to ask for help. I thought I was being stoical when in reality I was being a coward. I simply couldn’t believe the diagnosis at first, so deeply ingrained was my denial.

It was fear of suffering before dying, and of, you know, lingering on, being in a hospital bed. And I hate hospitals, always have done. I think they're horrible places, even though I spent most of my life working in them. No, it's really - death itself holds no fears for me at all, as far as - I love the famous 18th century philosopher David Hume, who on his deathbed was asked, aren't you terribly worried about what will happen after death? And he said, no, I'm no more worried about not existing after death than I'm worried about not existing before I was born. And that is my view about death. I don't believe in an afterlife. But I know, as a doctor, that dying can be very unpleasant.

When I now think of how the uncertainty about my own future, and the proximity of death, threw me into torment, careering wildly between hope and despair, I look back in wonder at how little I thought about the effect I had on my own patients after I had spoken to them. I did worry that if my tone of voice was too pessimistic the poor patient might spend what little time they had left feeling deeply depressed, simply waiting to die. So I tried to find a balance between telling them the truth and not depriving them of hope. After a patient died, I only occasionally heard back from the family, so I had little way of knowing whether the way I had spoken to them was appropriate or not.

For the last few weeks, I've been completely happy. I've got my next PSA in three weeks' time. It may well show my PSA is starting to go up, and the cancer's coming back. Totally to my surprise, I've acquired this sort of Buddhist Zen outlook. Well, the future doesn't exist. I'm well. I'm happy at the moment. I've had a wonderful, exciting life. I've made lots of mistakes. I've trampled on people - yak, yak, yak, as I discuss in my books. But at the moment, today, the sun is shining. I'm very well. It's not that I'm in denial, but I think, well, all right. It may be bad news in three weeks' time, but that's three weeks away. At the moment, I'm well.

I was looking at ageing in action, in black-and-white MRI pixels, death and dissolution foretold, and already partly achieved. My 70-year-old brain was shrunken and withered, a worn and sad version of what it once must have been. There were also ominous white spots in the white matter, signs of ischaemic damage, small-vessel disease, known in the trade as white matter hyperintensities – there are various names for them. They looked like some evil pox. Not to put too fine a point on it, my brain is starting to rot. I am starting to rot. It is the writing on the wall, a deadline.

A close, loving family and work position in society which is meaningful, which is about making the world a better place rather than getting a bigger - having a bigger bank account.