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Friday 17 August 2018

Early treatment of cancer is the best way to cure it

Minnie’s owner makes sure that she always has the best in life
Minnie’s owner makes sure that she always has the best in life

Pete Wedderburn - Animal Doctor

Sally does everything to give her six year old Dachshund, Minnie, the best possible care. She has looked into the ideal way to look after a dog, and she does everything she's meant to do, from regular exercise to an optimal diet to once daily tooth brushing and coat grooming.

It's no accident that Minnie is a healthy little dog, with a shiny coat, clean teeth, optimal body condition and no bad habits. If you do everything you're supposed to do, life will work out better for your pet.

Last month, Sally's careful attention to her pet reaped another reward. When she was brushing Minnie's teeth, she noticed a blemish on the inside of her upper lip. It was less than half a centimetre in diameter, like a small pimple. But what was it? Her first thought was just to ignore it, but then she thought to herself that if she found a similar blemish inside her own lip, she'd be happier to see the doctor. So surely she should take Minnie to the vet?

At first, I wasn't too worried when Sally showed my the small mark on the inside of Minnie's lip. Maybe she had cut her lip when chewing something hard? Perhaps this was a healing cut of some kind? But it didn't really look like that type of mark: it didn't look like an injury. It was more like a fleshy pink lump. It was very small, but still...

There's a saying in the veterinary world that "the most dangerous thing to do is to 'wait and see what happens" when it comes to small growths. Sally had made it very clear to me that she wanted to do absolutely everything possible to care for Minnie in the optimal way, so that meant that prompt action was needed.

I took Minnie in to our clinic for a day, and gave her a short general anaesthetic. This lasted no more than ten minutes, but it was enough time for me to use a small biopsy instrument to cut out the tiny raised area, then to close the defect with one simple absorbable stitch. The piece of excised tissue looked even smaller once it had been cut out: it was around half the size of a small frozen pea. I placed it into a small pot of formalin, and packaged it up to send off to the pathology laboratory that processes our samples. When Minnie went home that evening, she had fully recovered. Sally even commented that it was as if nothing had happened to her. She ate her supper normally that evening, and there was no hint of anything unusual.

The result returned from the laboratory three days later. I was expecting a benign result: something like "granulation tissue", which is the natural healing reaction of the body to a small injury. To my surprise, it turned out that the small growth had indeed been a form of cancer: a rare type in dogs, but one that is well-known in humans. It was a malignant melanoma.

The oral cavity is the fourth most common site for tumours in dogs and cats. That said, it still isn't very common, at twenty cases per a hundred thousand dogs. It was extremely fortunate that Sally had been so cautious: the most effective way of treating this tumour was early removal, when the growth is still very small.

As with cancer in humans, when a malignancy is identified, the ideal approach is to carry out so-called "staging". This involves gathering a minimum database of health screening, including a complete blood count, urinalysis, x-ray pictures of the chest and simple needle biopsies from the lymph nodes of the head. This process effectively screens the patient for any hint of spread of the cancer. The biggest danger for patients like Minnie is that in around half of these cases, the cancer spreads at a very early stage. If this can be spotted quickly, the spread can sometimes be stopped in its tracks.

The good news for Minnie was that when we did these extra tests, they were all normal: she was one of the lucky ones. Only one action was needed to give her the optimal chance of a cure. I took her in for another day at our clinic, and we carried out one more operation. I removed a circle of tissue around 3cm in diameter, and as deep as I could go. I wanted to be extra-sure that no trace of malignant cells had been left in her mouth. Again, she recovered well from the surgery, and I was happy that we had done as much as possible to help her.

Not all cases of melanoma are so easily treated. When the tumour is bigger, it's much more complicated, and complete surgical removal is not always possible. Other treatments can be done, including radiation therapy, chemotherapy and the latest concept: immunotherapy.

This innovative technique involves extracting some DNA from the tumour, then cloning this on to a special type of bacteria. The modified bacteria is then injected into the animal, prompting its immune system to develop antibodies against the DNA. These antibodies then act against the DNA of any cancer cells that are left in the body after surgical removal of the main tumour. This is a new method, and it isn't readily available yet, but it gives a hint of how cancer treatments may progress in the future.

I expect that Minnie will be absolutely fine: the best way to treat cancer in pets is to be cautious, carrying out radical surgery as early as possible. And thanks to Sally's extra careful care, that's exactly what we've done for Minnie.

Wexford People

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