Guest - Daisys gift: the remarkable cancer-detecting dog who saved my life

Claire Guest was walking her dogs when Daisy, a fox red Labrador, nudged her breast insistently and stared up into her face with her big brown eyes. Sensing something was wrong, Claire visited her GP and soon found out she had a very deep and difficult to diagnose form of breast cancer. Daisy had saved her life, simply by smelling her cancer.

With her scientific background and deep love of dogs, Claire intuited that Daisy and her canine pals could save many more lives, and set up the charity Medical Detection Dogs. Though faced with many challenges, Claire and her dogs have proven to be a remarkable asset to cancer detection, and have changed the lives of many seriously ill people and their families.

This is the story of how our relationship with dogs can unleash life-saving talents, changing not only the medical world, but our own lives too.

CLAIRE GUEST has been involved in the training of dogs for tasks involving scent for over twenty years.

She is currently Chief Executive and Director of Operations for the charity Medical Detection Dogs, an organisation that trains dogs to identify human disease by odour. They are currently working on a number of pioneering research projects involving canine olfaction, including the training of dogs to detect cancer, blood sugar changes and Addisons disease.

In 2011, she was awarded an Honorary Doctor of Science in recognition of her outstanding contribution to the development of new approaches for the detection of life-threatening diseases.

This book is dedicated to my mum, my dad, and my sisters Louise, Nicole and Simone, who have supported me all my life. It is also for all the dogs I have loved and who have loved me.

TAIL WAGGING FURIOUSLY, head cocked and eyes bright, Tangle the chocolate-brown cocker spaniel gazed up at me. Lets play! his face and body language seemed to say.

Seek, seek, I said, sweeping my arm away to underline the instruction.

Tangle trotted off and worked his way along a line of stainless steel dishes set out at intervals on the floor. He reached the second from the end and dropped to the ground, head turned to me for approval.

Good boy, I said, digging into the bag at my waist for his favourite chewy treat. I bent down to ruffle the soft fur on his head, hoping that my little boy had got it right and had detected, accurately, the presence of bladder cancer in the urine sample he had sniffed. All I knew was that there was one sample from a patient with cancer among the seven, and the other six had been donated by healthy volunteers.

This was a properly conducted scientific trial, and only the scientists and doctors could unlock the codes on the samples to say whether he had got it right. I was confident, but also, naturally, worried.

Tangle and five other dogs were being tested in controlled conditions to assess whether a dogs sense of smell can be harnessed to help humans, not only by sniffing out drugs or explosives, or by guiding the blind along cluttered pavements, or by alerting the deaf to doorbells or telephones, but in a scientific environment, with cancer cells as the target.

There are lots of stories about dogs detecting cancer in their owners. I have one myself: my dog Daisy alerted me to my own breast cancer, which was then successfully treated, but which was so deep that by the time I had found the lump myself it would almost certainly have been too late. But these stories are anecdotal: there was no proper, authenticated proof and, although anyone who was close to a dog was likely to have faith in these accounts, the sceptics could challenge them.

That is why the scientific tests to see if dogs could find cancer in complete strangers were so vital and, if proved positive, they would help to demonstrate why dogs would, I believe, prove invaluable in the battle to detect cancer early.

The next two weeks were spent on tenterhooks, waiting for the final results of the tests. Then there was the Eureka moment, the phone call that told me our dogs had done it: their success rate was high enough for the prestigious British Medical Journal to later accept an article demonstrating the power of dogs noses in the battle against cancer.

Tangle, who had the best results of the six, spearheaded our breakthrough with the medical profession, and since then we the scientists, doctors and dog handlers have been very busy. We have been working long hours to establish that dogs, with noses so many more times sensitive than ours, can become a valuable tool in the detection of different cancers, using entirely non-invasive techniques.

Tangle was a pioneer, the star whose success put a stamp of scientific credibility on our work. His picture went round the world; he appeared on numerous television programmes and gave demonstrations to audiences across the country. His silhouette is immortalised in the logo of Medical Detection Dogs, the charity set up to explore the future of using dogs to alert to cancer.

He took it all in his four-legged stride. He loved fuss and attention but most of all he loved to play, and his play was our work.

For me, Tangles success was something I knew would happen. He was one of my own dogs, an amazing fella who worked his socks off until he retired in 2013, his place now taken by a team of other dogs, all trained to a high level to detect those scents we, as human beings, cannot smell. Sadly, in 2015 he passed on, but he will always be remembered, by me and many others, as the dog who made history.

Everything that has come since that groundbreaking trial, with the setting up of a national charity with the Duchess of Cornwall as our patron, is, for me, the culmination of a lifetimes devotion to animals. More than devotion: an affinity with them that has overridden everything else life has thrown at me.

As a child I endured chronic shyness and at school I was badly bullied; I have had a failed marriage; a massive breakdown that took me to the brink of suicide; breast cancer.

But through everything, I have had dogs. I am now doing my dream job, in charge of the day-to-day running of the charity I helped to set up to train detection dogs. Within a few years, I predict and hope that diagnosis using dogs will be a factor used routinely for a range of cancers.

And as a powerful offshoot, we discovered that dogs can be taught to use their amazing sense of smell to alert people with diabetes when their blood sugars are starting to move from normal, either too high or too low. We are training dogs to live with people with diabetes, and others with diseases like Addisons and nut allergies, giving them peace of mind. Early alerts mean that the number of hospital admissions is hugely reduced, the dangers of collapse are minimised, and the parents of a child with diabetes can sleep at night, not constantly waking every hour or two to monitor their childs blood. The change to their lives, brought by a waggy-tailed, wet-nosed smelling machine, is incredible, and their stories still make me cry, even though I am so aware of what dogs can do.

This is my story: but more than that, it is the story of Ruffles, Dill, Woody, Tangle, Daisy and all the other dogs whose affection and devotion to us, their owners, goes beyond anything we could ever have imagined. Dogs, our loyal, grateful pets, who ask for nothing more than food, a bed and love, will in future be saving even more lives than they already do.