Revealed: The dog breeds at the highest risk of dying from cancer
- Symptoms of cancer in dogs include lumps, weight loss and a change in appetite
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A new study reveals the dog breeds with the highest risk of dying from cancer – and it’s not good news for owners of medium-sized pups.
By studying canine death records from three different countries, a biologist in California found the flat-coated retriever has the highest risk of cancer mortality.
Overall, medium-sized dogs have a higher risk of developing cancer than the very largest or smallest breeds, the study found.
The Scottish terrier, Bernese Mountain Dog and Bullmastiff also have ‘notable risk’ of dying from the disease, the expert found.
Meanwhile, breeds with the lowest risk of cancer include Pomeranian, Miniature Pinscher, Shih tzu and Chihuahua.
Overall, medium-sized dogs have a higher risk of developing cancer than the very largest or smallest breeds, the study found
Dogs most and least likely to die from cancer
MOST LIKELY TO DIE FROM CANCER
- Flat-coated Retriever (60% chance of cancer death)
- Bernese Mountain Dog (50%)
- Bullmastiff (approx. 45%)
- Staffordshire Bull Terrier (approx. 40%)
- Scottish Terrier (approx. 40%)
LEAST LIKELY TO DIE FROM CANCER
- Pomeranian (10% or less)
- Pekinese (10% or less)
- Miniature Pinscher (10% or less)
- Shih tzu (10% or less)
- Chihuahua (10% or less)
The study was conducted by Leonard Nunney, a professor of biology at UC Riverside in California, and published in the Royal Society Open Science.
‘Cancer is a leading cause of death in domestic dogs [but] deaths due to cancer vary widely among breeds,’ he says in his paper.
‘Some of these breed differences in cancer risk may be due to the effects of inbreeding.’
Professor Nunney analysed dog mortality rates from three different data sets – one of each from the US, the UK and Finland.
For the results, he considered dog breeds that appeared in at least two of the three datasets – 85 breeds in total.
He found that the smallest dogs, including Pomeranians, Miniature Pinschers, Shih tzus and Chihuahuas have about a 10 per cent chance of dying from cancer.
Dalmatians and Bulldogs were among those with a slightly higher risk – around 20 per cent.
By comparison, many relatively large breeds, such as the Burmese Mountain Dog and Bullmastiff, have a 40 to 50 per cent chance of death from cancer.
But the Flat-coated Retriever – a gun dog breed originating from England – had the highest mortality from cancer, at about 60 per cent.
The expert found that the breed gets a type of sarcoma with higher frequency than it should have for its size.
Despite the general trend of small breeds having lower risk, the Scottish Terrier is one small breed with an unusually high cancer death risk, compared with other small breeds.
‘Terriers in general get more cancer than expected for their size,’ Professor Nunney said.
The flat-coated retriever (FCR) has a significantly elevated rate of death due to cancer (about 60 per cent). Bernese mountain dog (BMD) has around 50 per cent risk, while bulmastiff (BulM) has around 45 per cent and Staffordshire bull terrier (SBT) and Scottish terrier (ScoT) about 40 per cent. Breeds with low levels of cancer are bulldog (BulD) and Dalmatian (Dal)
The Flat-coated Retriever – a gun dog breed originating from England (pictured) – had the highest mortality from cancer
Many relatively large breeds, such as Burmese Mountain Dog (pictured) and Bullmastiff, have a 40 to 50 per cent chance of death from cancer
READ MORE: Revealed: The popular dog breeds bred to look ‘cute’
Much like humans, dogs develop cancer due to genetic factors and environmental stressors.
It’s common for cells to acquire errors or mutations as they divide and form copies of themselves – the process that can lead to cancer.
Bigger animals, and those that live longer, have more cells and a longer lifespan during which those cells divide – so they should have more opportunities to acquire mutations that eventually become cancer.
‘Studies on humans show that tall people get more cancer than short people,’ said Professor Nunney.
‘It’s about a 10 per cent increase over the baseline risk for every 10 centimeters in height.’
However, the very largest breeds, such as Great Danes, have less cancer than medium-sized breeds, the results show.
This is because of an as-yet unexplained phenomenon – the life expectancy of dogs gets lower with increased body size.
‘For every pound increase in typical breed size you lose about two weeks of life,’ Professor Nunney added.
‘A very big dog, you’re lucky if they live past nine years, whereas small dogs can go about 14.’
Breeds with the lowest risk of cancer include Pomeranian (pictured), Miniature Pinscher, Shih Tzu and Chihuahua
Scottish terrier (pictured) is an example of a small breed with a high cancer death risk, compared with other small breeds
Cancer is predominantly a disease of old age, so by having a reduced lifespan the largest dogs have a smaller cancer risk than medium-sized dogs.
In other words, larger dogs may not die from cancer as much as medium-sized dogs, but they’re likely to live shorter lifespans anyway.
Professor Nunney warns that some breeds may have experienced an increased cancer risk due to inbreeding – the mating together of closely related dogs, usually of the same breed.
Mixed breed dogs live about 1.2 years longer than pure bred ones of similar size, according to a prior study, indicating that a drop in the level of inbreeding leads to longer canine lifespans.
‘Inbreeding (and the associated loss of genetic diversity) is a well-known cause of an increased incidence of inherited disease,’ the expert adds.
Similar to symptoms in humans, cancer warning signs in dogs include lumps and bumps, abnormal discharges, non-healing wounds, weight loss, change in appetite and coughing or difficulty breathing.
According to NC State University Veterinary Hospital, up to 80 per cent of skin lumps in pets are not cancerous.
‘But consulting with your veterinarian is the only way to be sure,’ it says.
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