When life slapped Adam Blain right in the brain, he decided to hit back with a book laughing in the face of cancer.

The 44-year-old lawyer from Muswell Hill found out in May he had glioblastoma, a rare and extremely aggressive form of the disease, with a life expectancy of about 18 months from diagnosis.

Still reeling from the horrendous news, he began to chronicle his journey at first just in funny texts to friends and jotted down thoughts on his laptop, and now as a short book Pear Shaped, full of black humour and startling honesty.

“It’s a terrifying disease,” explains the Barnet-born lawyer. “What’s shocking is there’s no known connection between this and any particular cause, environmental or genetic. So it’s like being hit by a lightning bolt.”

He has had to endure surgery, hair loss and (bad) jokes from his friends as they try to come to terms with what is happening and Adam’s book is peppered with sarcastic comments about cotton wool buds being stuffed up his nostrils, his ears popping during the removal of his catheter and all the gory details of his condition, such as an idea to turn his head into a weird version of Connect Four.

“It didn’t really have a purpose,” explains Adam. “Writing a book was never on my bucket list – it came out of nowhere and just happened.

“There’s no game plan. Partly it’s nice to have an achievement under my belt. And partly I’m afraid one day this disease will catch up with me and I will have to stop work and it’s to help raise money for my family.”

He adds: “Whether or not there will be a sequel is another matter. We’ll see what happens to my health.”

The father-of-three was just two months into a new job as a corporate lawyer at Pemberton Greenish when his wife Lucinda Melcher, an oncologist, insisted he have an MRI to check out his persistent headaches.

“It was supposed to rule out anything unpleasant and it didn’t happen like that,” says Adam, whose chances of survival are improved by his age and fitness.

“She got the results – I was trying to get back to work as quickly as I could because I just don’t take sick days – and that was it, you just really don’t know what has hit you.

“It was just complete and utter shock for... well... I still haven’t got over it.”

A few days later he was having a pear-shaped tumour removed from his brain and this was followed by radiotherapy and chemotherapy.

He is now on a hiatus from treatment and is amazingly back at work full-time but Adam is well aware that the cancer will almost certainly return.

“I feel different each day,” he says. “Some days I feel OK. Fairly recently I had a scan that was clear with no visible sign of recurrence which makes you feel a bit better. But then at the same time the oncologist is absolutely clear that at some stage this will get me.”

His main concern is for wife Lu and children Jonah, 12, Sacha, ten and Thea, five, and the practicalities of how they will cope when he is gone.

“Coming to terms with your imminent death is very traumatic – especially if you have got a family. We will be a man down in our team and an income down.

“I feel grief and, surprisingly, guilt for having hoisted this on the family and for leaving them. It’s trivial things like me and my wife Lu giving each other an hour lie in at the weekend and giving each other time off. Unless she gets a babysitter she will be doing that alone.”

The book shies away from talking about his family though and is an irreverent, sarcastic and funny snapshot of his experience.

He says: ”It’s not that I haven’t been to the depths of despair but somehow that hasn’t made it into the book.”

He adds: “Part of this book was letting off steam and part of it was being hopelessly realistic that I might get a pot of money for my family. Everything I look at is in double vision. One is now and one is afterwards.

“It’s very morbid but I’m trying to leave everything as it should be to give my wife and children the best possible position I can.”

Pear Shaped is available now via Amazon