BODY AND SOUL
The dreaded word that you hope never comes out of your vet’s mouth: cancer. With local leading vets, we break down this devastating disease and weigh its causes, symptoms and treatments.
Breaking down canine cancer and what you and Fido can do to fight it.
just like humans, our canine friends can contract cancer too. Statistics show that this dangerous disease is on the rise: in a 2017 mortality study done by the British Small Animal Veterinary Association, cancer accounted for 27 percent of all deaths in purebred dogs, and an earlier study in 1982 showed that almost one in every two senior dogs over the age of 10 will die from cancer.
Sure, it might seem cataclysmic, but is it the end of your pooch’s life? “It’s important to understand that many cancers today can be treated and more successfully managed than in the past with advances in medical technology and research, while most importantly maintaining a good quality of life,” shares Dr Brian Loon, principal veterinary surgeon of Amber Vet.
To help you and Fido understand this mammoth-like disease, we speak to several vets in order to lay down its causes, symptoms and treatment options.
WHAT IS CANCER?
Cell division occurs all the time within our bodies to replace ageing and dying cells. However, cancer happens when the regulation of cell division is lost and cells continue to divide in an uncontrollable manner. They grow into adjacent or distant body organs and form tumours, which may manifest externally (i.e. a lump’s on a dog’s skin), or internally (i.e. within a dog’s liver or spleen).
Each type of cancer is classified by the type of cell that’s initially affected.
For example, lymphoma originates in the lymphocyte cells of the immune system, often affecting tissues such as the lymph nodes, spleen and bone marrow. Tumours that are localised and demonstrate limited growth are termed benign, while those that spread are termed malignant and are more aggressive.
Though tragic, it is indeed true that there are more cases of canine cancer now. “In the past, I used to have approximately four to six cases a year,” says Dr June Tan, principal veterinary surgeon of Frankel Veterinary Centre. “At present, the number has risen on average to about two to three cancer patients per months. It’s not a good upward trend, I must say.” Dr Eugene Lin, senior veterinary surgeon of The Animal Ark Veterinary Group agrees
with Dr Tan—he sees about 15 to 20 cases of cancer a month. “It’s become easier to diagnose cancer with the advancement of veterinary diagnostic modalities and procedures,” Dr Lin adds.
When we asked our experts which cancers they’ve come across most often, common ones include lymphoma, mammary tumours, mast cell tumors, melanoma, haemangiosarcoma and lipoma.
SYMPTOMS AND CAUSES
If you’re looking for certain tell-tale signs that are sure indicators that your pup has cancer, just like how a fever, cough and sore throat might indicate you have the flu, you might be disappointed to know that there aren’t any.
The symptoms for cancer vary depending on which organ the cancer is residing in. “A cancer in the bladder may result in bloody urine or difficulty in urination, while a cancer in the lungs may result in increased breathing rate,” shares Dr Ong Wei Jin, a veterinarian from Ohana VetCare. “Meanwhile, a tumour in the brain can result in seizures and a cancer of the spleen can result in collapse from sudden massive bleeding into the abdominal cavity.”
Plus, these symptoms are non-specific and might appear in non-cancerous conditions, and not all cancers display warning signs too. “That makes early detection difficult for the paw-rent,” admits Dr Tan. “Cancer cannot be detected through blood works too.”
So what can a cautious paw-rent look out for? Early symptoms of cancer include (though are not limited to) the presence of a steadily growing mass, non-healing sores, exercise intolerance, lethargy, loss of appetite or sudden weight loss, unusual poo like persistent diarrhoea or straining to defecate or pee, stiffness in gait, unexplained vomiting or diarrhoea, or being non-responsive to medication.
However, it is possible to keep a lookout for specific cancers simply because purebreds have a predisposition to particular cancers. For example, Golden Retrievers, Boxers, Bernese Mountain Dogs and Labradors are prone to mast cell tumors, while Rottweilers, Great Danes and German Shepherds are prone to osteosarcoma. “Although all dogs are equally susceptible to cancer, hereditary aspects such as the passing down of genes of certain breeds and lineages can play a part,” explains Dr Tan. Dr Lin adds: “Scottish Terriers are 18 times more at risk of getting cancer of the bladder than other breeds of dogs.”
Other than genes, factors such as environmental elements and weak immune systems have been singled out as causes of cancer. “For example, ultraviolet radiation from the sun as in the case of skin cancers, or free radicals in processed food, radiation, or even viruses,” says Dr Ong. “A healthy immune system is also important in the prevention of cancer.
Cats affected by retroviral infections, such as feline immunodeficiency virus and feline leukaemia virus, are more prone to some forms of cancer. This is analogous to HIV-affected humans being more prone to some forms of cancer.”
PREDICTION AND TREATMENTS
Can you anticipate that your furkid will develop cancer? The upshot: No. “Cancer cannot be predicted with certainty,” shares Dr Loon. “The exact causes are not wellknown in general till today.”
While it is true that cancer tends to strike senior pooches because old age weakens their immune system, that doesn’t mean that young pups are cancerfree either. “I have removed a cancerous testicle from a three-month-old dog before,” shares Dr Lin.
So what can paw-rents do when they feel suspicious masses or spot odd symptoms such as sudden weight loss in their canine companions? “The best thing any paw-rent can do is to seek the opinion of a veterinarian when something is amiss,” advises Dr Ong. Dr Tan agrees: “Being able to recognise the symptoms and treating them quickly will improve the prognosis of the treatment.”
It is critical that paw-rents have a firm diagnosis before thinking of treatment
options. This includes being certain whether the lump is firstly cancerous or not, what type of cancer it is, and what stage or grade is it at. “Staging refers to the extent of the growth of the tumor while the grade refers to how fast it might spread,” shares Dr Tan. “An early grade tumour, such as grade one, is small and non-spreading compared to a stage four cancer, which is big and invasive to other body parts.”
To identify the type of cancer your pooch might have—whether it is benign or malignant—it’s best to undergo a biopsy or cytology of the growth. Biopsy procedures could be as simple as performing a fine needle aspiration and looking at the cell under the microscope in the clinic, or it could be as complex as performing an open surgery or a minimally invasive endoscopic surgery to obtain biopsies, which will be sent to the pathology laboratory. After the type of cancer has been identified, it’s crucial to see how much it has grown through procedures like chest x-rays and ultrasounds.
Traditional treatment for canine cancer includes surgery to remove the tumor, chemotherapy, and radiation, the latter of which is not available in Singapore. In the last 10 years, immunotherapy—which alters the immune system to fight cancer cells—has also been developed in the form of vaccines as well. However, the type of treatment depends entirely on the location, stage, grade and type of cancer— the earlier the mass is removed when it’s smaller, the higher the chance for a full cure.
Other alternative treatments include but are not limited to traditional Chinese medicine and acupuncture, gene therapy and molecular target inhibitors.
“Unfortunately, there is no sure way to avoid cancer,” admits Dr Lin. “But we can help to reduce the chances of our beloved pets contracting cancer by ensuring they’re not exposed to carcinogens, like chemicals, molds and toxic plants, and to apply sunblock or limit their exposure to solar radiation if they like being in the sun.”
Vets such as Dr Ong suggest boosting your pup’s immune system. “It’s the first line of defence in detecting and destroying cancer cells, so it’s best if your furkid is in general good health,” says Dr Ong.
“This includes a good body condition score by regular exercise, a well-balanced diet supplemented with antioxidants, early sterilisation of female dogs, and the removal of any retained testicles in male dogs.”
Regular health checks are a definite must, especially for ageing pooches, as these assessments might include imaging studies depending on the vet clinic, which can help detect masses at their earlier stages. “We can detect liver and spleen cancers via ultrasound exams before they are palpably physical or show any signs of illness,” says Dr Loon.
Even still, health checks occur once or twice a year at most. To fill in the gaps, Dr Ong suggests keeping a close eye on your pooch at home. “We cannot stress the importance of early detection enough,” he says. “That would mean spending time with your pets to pick up on any unusual lumps and learning how to do basic physical examinations on your pet as well.”