A new cancer treatment will be trialled in dogs in Scotland after scientists revealed the DNA of the disease is “very similar” in both people and canines.
Mucosal melanoma, which affects mucosal linings in the body such as those in the mouth and nose, is rare and deadly, killing up to 75 per cent of patients within five years and dogs in 12 months.
The surgery to remove the tumours can also be devastating to the appearance of dogs, with some owners reporting that passers-by comment on their pet’s disfigurement when they are out on a walk.
Kelly Blacklock, professor of small animal soft tissue surgery at the Royal (Dick) School of Veterinary Studies, said: “These [dog] patients are often, regardless of what we do, dying of their tumour, which has spread in a very short space of time. If I never have to operate on another one of these tumours, ever again, I would be absolutely delighted, and so too are the human maxillofacial surgeons.”
Blacklock is seeking dogs suffering mucosal melanoma to test a new treatment made from the rainforest tree blushwood, which has been shown to prime the body’s immune system to attack tumour cells.
As the same type of drug has already been used successfully to treat other human and canine cancers, Blacklock believes further research into its potential for dogs will fast-track its use for people.
She said: “We’re proposing that because we have this canine patient … he’s a normal patient, he’s not a research patient and he lives in the same environment as us, he eats the same food as us, he has an identical tumour as us. If his treatment works well, we propose that the translational potential is very much higher than that of a laboratory species.”
NHS Scotland has recorded 18 cases of mucosal melanoma between 2014 and 2023, while the Dick veterinary school has already seen 20 dogs affected in 2024. Blacklock explained that streamlining research of the condition in both species would increase the evidence base about the disease.
Her team compared samples they had taken from dogs suffering the tumours in their mouths with tissue removed from NHS Lothian patients with the illness.
Blacklock said they found the genetic fingerprint of the tumours in both animals and humans was very much the same. The disease could also be broken down into two subgroups and this too “is identical in humans and in dogs”.
For the first phase of the trial they are aiming to recruit eight dogs with relatively small cancers. QBiotics, which makes the drug Stelfonta using the Australian tree, is funding the research.
Blacklock said: “You inject the treatment into the tumour and it kills the tumour cells. So the tumour becomes a wall of mucus and literally dies and falls out.” This can potentially reduce the need to remove healthy tissue.
She added that laboratory testing suggested that if the cancer had already spread to other sites, these metastases also responded to the drug and it appeared the immune system was primed to reject the development of more tumour cells.
Carol Paterson, a retired vet, with William the rottweiler
William, a gentle 40kg rottweiler who lived on the Isle of Mull, was put down last year after mucosal melanoma began to spread. Carol Paterson, who looked after the dog with her wife Mandy Eaglen, said the first symptom she noticed was the smell of his breath in her van when driving home with William following a trip to Yorkshire.
A retired vet herself, she found the growth and conducted her own biopsy to make the diagnosis.
Paterson said: “If you told me I would spend £17,000 on my dog I would have said, ‘You must be joking.’” But William, aged nine, had been beside Eaglen as she was treated for ovarian cancer — a disease which ultimately took her life. Paterson, 67, said: “William would be lying on the bed with her, lying on the sofa with her … It was my feeling that I had to do everything for William because of how he was there for Mandy.”
The Dick Vet operated on the dog and before his hair grew back, Paterson said he had a smile like the Joker from Batman, as a result of the surgery. He was happy and well for about a year before the cancer returned.
Paterson said that it was a big step to enter a pet into a clinical trial but when prognosis is poor, research can help.
