The writing of my memoir At Five in the Afternoon began 10 days after the operation for prostate cancer. I'd asked for the laptop to be brought in to me in the hospital room, and so began a journey that has ended with an edited book. It's going to be launched this week in Dublin by my three staunch pals, Eileen Dunne, Eamonn Lawlor, and Emer O'Kelly, and in my home town of Castlebar, by the leader of the opposition, Enda Kenny.

The title comes from a poem by the Spanish poet, Federico García Lorca, and refers to the time that the bullfight traditionally begins in Spain. I love the Spanish way of life, so I thought that the line from Lorca's poem would be a good allegory for my own dance with death in the arena. I could read death reflected back in the horrified eyes of the psychoanalytic clients I work with, when I had to tell them that I was suffering from cancer, and therefore had to interrupt their analyses. My brother, Kie, whom I loved, died from cancer at five in the afternoon, and since a lot of the book has to do with immortalising him in words, the title seemed doubly apt.

In those early days of recovery, I wasn't sure whether I was going to make it. The surgeon came into the room to tell me that he had scraped away "as much of the cancer as was possible, but that there was a small piece about the size of a thumbnail, which was attached ... " At that time I was in a very vulnerable condition, heavily medicated, so what people were saying to me was distorted through the filter of the drugs. And the news that the ticking time-bomb of a piece of cancer was still inside plunged me into the deepest mourning.

The head of news, an astute man, was standing by my desk recently when I came out of the radio studio after reading the One O'clock News, and he invited me down to his office to discuss what I'd written in the book that he'd heard about.

When I'd finished my spiel, his reaction took me completely by surprise. He said he thought it was a wonderful achievement to have written a book. That was the first time I realised that a dream which many people share had become a reality for me. I'd never have fulfilled that dream without having suffered from cancer.

There's a wonderful Hispanic song written by a Chilean woman, Violetta Parra, which goes "Gracias a la vida, que me ha dado tanto ... " thank you, Life, for you've given me so much. I sang it aloud as I skipped down the stairs of the studio block that Friday, and out into the summer sunshine. You've given me sound, and the alphabet, and with them the words that I think and declare, mother, friend, brother, and the light shining over the route of my loved one's soul. What a privilege: gracias a la vida!

Cancer was a lens through which I was looking when I wrote the book, and for sure I'd write a different book if I were to begin the enterprise today, but the method I'd use would be the same. Each step on the road of writing it gave onto new perspectives and different ways of seeing things.

Many's the time I said to myself "I can't say that ... " And then another voice would say "Of course you can: you're a writer, so make it work!" But all the time I was breaching the walls of silence that surround the many forms of cancer, that Mary Robinson has identified in her foreword: " ... ignorance, prejudice, violence, fear and hopelessness, all of whose spreading cancers assault us as human beings, and which attack at the roots the free flowering of the human spirit".

What I ended up with was very different to what was expected. From a tiny seed, it has grown into a powerful tree of life that has nourished me with its fruit, and given me shelter underneath its branches during a terrible time of testing. Mrs Robinson's foreword again: "What I have realised is that in writing about all aspects of the cancer theme -- traumatic assault, mortality, endurance -- Michael has created a personal myth to live by."

She recognised that what could easily have been an exploration of darkness has become a shining light that has enabled me to continue, warmed by the light of its lustre. It's like that deep song, the cante jondo of Spain, which starts with the overwhelming experience of grief, but which transfigures over the course of the song so that it ends up in a noisy and joyous celebration of life, with a rattle of heels and a waving of arms that puts the deadly darkness to flight.

It was like what happened to me on The Mooney Show. I went into the studio to talk to Derek about male cancer, and he asked me the question "Michael -- is there any lead in your pencil?" I was expecting him to stick to generalities about the disease, but he posed a question that went to the root of what it means to be a man. Specifically, he was asking me how I personally have dealt with that question.

From an early age, men are taught to fetishise the penis, and if mine wouldn't work as it was supposed to do, what did that make of me? Turn me into a fool? It certainly seemed to relegate me to the second division.

Time in the studio suddenly went into slow-motion, and I had the space to think about whether I would give the sort of answer we're used to hearing from politicians: "I'm glad you asked me that question ... " and then they change the signposts around, ignore the question that has been asked, and go off to say what they'd intended to say in the first place. Or shockingly, would I actually tell the truth? This wasn't a conversation between two very close friends: I was live on air to the whole nation.

All of my working life has been about telling the truth: telling the truth about what's happening in the news, and helping the clients in my psychoanalytic practice to express the truth about what's going on in their lives, so that they can face up to what they really want out of life.

So Derek had put it up to me, as a good journalist is supposed to do. He wanted to see whether I was able to stand over what I professed to believe; he's a clever fellow. In addition, there were many people out there who'd been touched by cancer, and I was suddenly very conscious of not wanting to let them down. So although I was stepping out into the unknown, I took a deep breath and I told the truth: "No, Derek, I don't have any lead in my pencil."

The switchboard lit up in RTE with people responding to the truth of that declaration, and in their kindness, a lot of them said that it took a real man to speak so bravely about impotence. More importantly, they said their fathers, brothers, and husbands would now go and visit the doctor to speak about a taboo subject as a result of that interview.

I was free. That's another gift that has flowed from surviving the cancer. I've seen clearly that all of the secrets that I'd held onto, and that I felt ashamed of, that I wasn't able to speak about, were poisoned by a shame which I'd borrowed from other people. So I've handed it back in the pages of my book to the rightful owners, and spoken about those secrets for the first time.

The secrets have to do with emotional and physical abuse, and with bullying. They resulted from people not extending a hand to lift a burden off another human being, when they were in a position to do so. All of that is negative, cancerous stuff, and I felt I had to speak about it because it too was making me ill.

What I found out was that putting words onto the happenings in my life and writing them down is like having dammed-up feelings that had turned stagnant flow freely from my heart at long last, down through my arms, and out onto the printed page. Telling these secrets has liberated me from a prison of silence, and I feel much lighter because of that. I thought the silence was protecting me from feeling foolish and ashamed, but in fact my silence was protecting the abuser, and those who align themselves with abusers.

I know that it's other people who will determine the worth of what I've written. Which brings me to another question. Why would I want to publish what I've revealed about my life in those pages? The obvious answer is that if you've gone to the trouble of writing a book, then it has to be published: why keep it in a bottom drawer?

A valid objection can be made about the tabloids -- having been fed so many kiss-and-tell stories over the years, people are now tired of being "vomited over in public", as a friend of mine has delicately put it.

Of course that wasn't my intention. The book began as a personal exploration with quite a narrow focus, but after the Mooney show interview, it changed to become wider and more universal in scope. Even though I'm in charge of it, the book has taken on a life of its own. The accumulation of the little episodes that I describe form a picture that is more than the sum of its parts.

For example, in the second chapter I document a beating I received as a child from my father. Because it's powerfully written, it can be argued that it overshadows the many years of subsequent kindnesses I received at his hands. Nevertheless, the beating happened, so to that extent it's true.

In the 270 pages of the book that emerged, and that give a glimpse of the 62 years I have lived under the sun, I was guided by the advice that a kindly teacher in Newbridge College, Fr Flanagan, passed on to me once upon a time: "Paint with broad strokes, and boldly, Michael."

The picture that emerges is of an Ireland that I grew up in, examined through the microcosm of an Irish family, and the wider network of community. It's a finished document that tells a story I didn't intend, something that has arrived unannounced and that speaks back to me in its own voice as if I didn't have a hand in the writing of it; nevertheless, it also is true. I've judged that the book contributes to a better understanding of where we've all come from in this republic, but again I have to accept that the final judgement will be made by the readers, who will determine the value of that contribution, and the ultimate meaning of what I have said.

I've also been able to paint in many of those pages, portraits of my women friends. They formed a meitheal of care, and rallied round when cancer had laid me low. I recall the daily phone calls, and the little gifts which made recovery easier: creams and lotions that helped my skin, dried out by the drugs, tonics full of vitamins to help me get back onto my feet. They also shared with me the stories of their lives, so that when I wasn't able to speak from the fright and the weight of sorrow, they gave voice to my feelings by telling me the anecdotes which illustrated for me what I was feeling.

That's another thing: cancer leaves you broken-hearted. The women I've worked with in my consulting rooms who've suffered from breast cancer say the same thing. It seems to arise from a sundering of the trust that's been built up between you and life, rather like the way you come to depend in Spain on there being another day of blue skies tomorrow. Cancer interrupts the continuity of that dependency, and the result is shocking to the core. I needed the supplement of being able to depend on the quiet strength of those who were well, to nurture me back into a semblance of normality.

And when I was recovered, and I went back to them to ask whether I had their permission to include in the book the stories with which they'd nourished me in private, they kissed me on both cheeks in the continental way, ruffled my hair, and stood beside me: deá-chroí, good-hearted women who weaved with silver lanterns a hammock of support. I hope I've done justice in the book to their unconditional and loving ministrations and given a true likeness of their generosity. Truly, Anna and Helen from Spain, Barbara, Mary and Ursula here at home laid down their lives for their friend.

Ursula, my German friend, didn't make it. She died from pancreatic cancer around this time last year. At her request, I gave the eulogy to a small grouping who gathered to remember her life and to sing her favourite hymns at St Finian's Lutheran church, when the last September leaves clung onto autumn's boughs, still green along the Adelaide road in Dublin. She endured to keep on this side of the river Styx for as long as she was able. As in the photographs she'd taken of some great trees that had fallen some millions of years before, those traces of her presence were all she had to offer in the twilight days at season's change, but Ursula had offered all, in love.

Perhaps in this context it would be important to say something about my partner, Terry. I couldn't have undergone the operation and its aftermath without his dedicated support: such survival wouldn't have been possible on my own. This time has been exceptional, summoning in him an unyielding response of hope. I was given to understand that whatever I was feeling at whatever time of day or night was important to him, and wouldn't be dismissed.

Terry listened uncomplainingly to the various paragraphs of my memoir as they were finished, and contributed his adept observations on the content, on the style, and on me. Mostly these found their way unedited into the manuscript, such is his psychological understanding of the human condition.

It is his choice to remain in the background of my book. Surely the suffering of those who are touched by cancer, who smooth the way in the background, and swallow their helplessness at the unbearable burden of seeing a loved one in so much pain, deserve a recognition for their valour. At the dawn of day, perhaps my book could stand as a testament to a renewal of life, new life which has been made possible by the unselfish commitment of those who hide in the shadows, but who reach out with both hands to lift impossible burdens, and who willingly shoulder half the load.

So At Five in the Afternoon is about our living, and our loving, and the strength that a family of like-minded friends can offer to those who've been touched by cancer. That strength can incorporate the absence of death: Kie and Ursula live on in the poetry of my book, and their spirit animates the lively conversation of those friends who live alongside me, and who have proved true during a time of testing, and whom I love.

Cancer has also made me impatient of tolerating ambivalence, and the company of those who display it. All of the shouldn'ts, and oughtn'ts, and mustn'ts are really irrelevant after you've been touched by a palpable hit from cancer's rapier. As I wrote in the penultimate paragraph of the book: "I have told it like it is, what I have seen and what I have heard. I have said it, and my saying is true. Because of the cancer, there's no longer any space available to hide in; neither is there any time left over for being silent. I have told the truth to save my life."

What I've written is of that order of magnitude: it's that important to me. The book has literally saved my life. It occupied my waking hours and my dreaming hours for the past year and a half, and kept my mind off the indignities that all those touched by cancer have to undergo. It has kept me trudging ever onwards during the darkest of days, which thankfully, are becoming fewer. Gracias a la vida, que me ha dado tanto ... thank you, Life, for you've given me so much.

'At Five in the Afternoon -- My Battle with Male Cancer', published by Brandon, €16.99. In shops from Wednesday

- Michael Murphy