Cancer in dogs is almost as prevalent as it is in humans. Could it be prevented?
Dr Vicki Adams, Veterinary Epidemiology Consultant, looks at different ways we can reduce the risk for our own dogs.
As a veterinary epidemiologist, I am aware that that no clinical trial has ever proven that you can prevent cancer in at-risk dogs. However, like us, dogs live longer and healthier lives when they have good genes, drink clean water, get enough exercise and exposure to light, are free from stress, avoid exposure to known and potential carcinogens, breathe clean air, enjoy an efficient endocrine and immune function and eat a healthy diet. It is estimated that 40% of human cancer cases can be prevented; that is about 150,000 cases every year in the UK. Surely, the same can be achieved for our dogs.
In this article I am going to address each of these ten areas of your pet’s life offering advice on how it may be possible to prevent the development of cancer. I hope that after reading this article, you will see how a few small changes could make a big impact and potentially even save a dog’s life.
Genetics
An important first step in selecting a puppy or adult dog is learning everything you can about the immediate family i.e. his or her parents, grandparents, and siblings. Some breeds are notoriously prone to cancer and some lines within those breeds are worse than others, so it is worth asking and doing your own research. Look for good genes and good health when selecting puppies or adopting adult dogs. If you know that your dog may be prone to certain types of cancer, there are steps you can take to make a cancer diagnosis less likely.
Water
Your tap water might carry more toxins than you are aware of. Although it may taste fine and everyone in the house is healthy, the build-up of some chemicals over time can lead to serious health problems, including cancer. If you have concerns about your tap water, you may want to offer your pets filtered water that you change frequently. Using glass or ceramic bowls can also help to prevent toxins from plastic leaching into the water.
Exercise
Obesity can create inflammation, which can lead to the development
of cancer. It is never too late to get your pet to lose weight and get in shape. Monitoring both body weight and body condition score can help you keep your pet from becoming too fat or thin as they age. Although few of us appreciate the important role it plays, the lymph system is a key factor in cancer prevention. Lymph is a clear fluid, similar to blood but lacking red blood cells. It contains the immune cells called lymphocytes (T-cells and B-cells) and circulates through lymphatic vessels that carry waste to the lymph nodes where bacteria, viruses and other toxins are filtered. When lymph circulation is impaired, the body is less efficient in removing harmful substances and conditions become more favourable to the growth of cancer. Active exercise improves lymph circulation and deep, diaphragmatic breathing. Grooming with a brush that moves from the feet to the heart is a simple addition to daily routine that can also stimulate lymph circulation. We all know that exercise is so important. It stimulates the immune system and releases endorphins. Consistent exercise is also beneficial in increasing gastrointestinal motility and this helps normalise faeces and the elimination of toxins from the body.
Light
The right light can help to prevent cancer. However, not just any light. It needs to be Mother Nature’s full-spectrum unfiltered light that activates the hypothalamus and keeps the nervous and endocrine systems balanced. Insufficient light, and the wrong kind of light (such as fluorescent light) adversely affects the health of plants, animals, fish, birds and reptiles. The term mal-illumination has been used to describe this phenomenon which is now known to suppress immune function and contribute to skin damage, cancer and other problems. Exposure to natural light is necessary for our health and our pets’ health. A shady screened porch, the shelter of a tree or an open window or doorway can give us what our bodies need. While some plastics allow the transmission of full-spectrum natural light, glass windows, windshields and sunglasses do not.
Emotional well-being
For many healthcare experts, emotional well-being is as important to cancer prevention as diet and exercise. They believe that emotions are linked to general health via the immune system. A holistic approach would include minimising stress and supporting our pets emotionally by providing a safe and loving environment with balanced opportunities for play and rest and by encouraging social interaction with people and other animals. If one thinks about the power of positive thinking for our own well-being, then we can extend this to the care of our pets. Many believe that negative thoughts generate negative energy and that this can feed a disease such as cancer. We can combat this by visualising and treating our pets as though they are well and happy, not sick. For those of us that talk to our pets, we can also engage with them in positive conversation and meaningful activities every day.
Environmental Factors
Agricultural chemicals and lawn treatments are known to cause cancer in animals. Animals can pick up pesticides, herbicides, insecticides and other chemicals on their feet, through grooming and by sniffing the ground. You can use non-toxic or organic alternative lawn and garden products or you should keep your pets away from chemically treated grass. Household chemicals can also present a risk for our pets. You can choose to stay away from products that have a warning to keep away from children and pets and look for safer alternatives.
Second-hand smoke is a serious problem for pets, just as it is for human infants, especially for those dogs who spend hours every day at the feet of a smoking companion. Dogs living with a smoker have a greater risk of developing nasal cancer, and cats exposed to second-hand smoke have a greater risk of developing lymphoma and oral squamous cell carcinoma.
Busy highways, driveways, parking lots, and areas where lorries and cars idle are dangerous for dogs due to the effects of petrol and diesel exhaust. Since the nose of a dog is much closer to the ground and exhaust pipes than the human nose, dogs are more likely to inhale damaging particles.
Neutering
The facts are convincing: females that have been spayed cannot experience cancer of the ovaries or uterus if they have been removed and testicular cancer is obviously not a problem in neutered males. However, the risks and benefits of neutering is a complex issue that should be discussed with your veterinary practice; understanding your dog’s inherited risks can help you make informed decisions about whether and then when to alter your dog.
There is a growing body of research that has shown an association between early surgical neutering with an increased risk of cancer in several breeds. The discussion around the potential risks and benefits of neutering are complex and breed of dog is an important factor to be taken into account. While spaying reduces the risk of cancer of the reproductive tract and likely mammary cancer, it also increases the risk of developing haemangiosarcoma of the heart compared to intact female dogs. In addition, studies have shown that neutered males and females have an increased risk of developing malignant bone cancer (osteosarcoma) compared to intact male and female dogs. If you do choose to alter your dog, it is important to discuss the method and timing with your vet; there are options and alternatives to traditional surgical ovariohysterectomy (spay) and orchiectomy (castration) in dogs.
Vaccination
The datasheets and specific product characteristics (SPCs) for vaccines all state that they should only be used in healthy animals with the warning not to vaccinate a sick animal. Some vets include stressed and injured animals in the sick category and consider that vaccinating an animal that is undergoing surgery or treatment for an injury is irresponsible as it introduces substances designed to challenge the immune system into an individual in a weakened and vulnerable state. It is well known that a strong immune system is one of the best defences against cancer.
Responding to decades of research by immunologists, veterinary publications no longer recommend annual vaccinations for all diseases and for all animals, although many situations continue to require them (e.g. to stay in a boarding kennel or cattery or to travel out of the country). Many vet practices are embracing a benefit-risk analysis, taking into account the ‘lifestyle’ of the pet, when considering which organisms to vaccinate against and how often this should be done. The effectiveness of vaccination can be tested with blood tests to ascertain antibody levels, giving an indication of whether there is a need to re-vaccinate.
Diet
There is a large body of evidence linking diet to risk of various types of cancer in people. However, there is not as much research into the link between diet and cancer risk in our pets. If you are a Honey’s customer, I don’t need to say anything more about diet because you have probably already come to the realisation that a less processed, biologically appropriate diet for your pet is the best thing you can do for them in terms of disease prevention.
Supplements and CAM (Complimentary and Alternative Medicine)
I need to start this section by stating that no amount of supplements can make up for an unhealthy lifestyle. Many owners ask their vets if there was anything they could do diet and supplement-wise to prevent cancer from striking another four-legged family member. Unfortunately, the short answer is no. There are no proven dietary changes or nutritional supplements that have been definitively shown to prevent cancer in cats, dogs or people.
So, what do dog and cat caregivers need to know about cancer and possible nutritional prevention/treatments? The bottom line is that there are no proven dietary strategies or techniques to prevent cancer development in dogs and cats. Defects in tumour suppressor genes, exposure to environmental toxins, obesity, and chronic inflammation have all been proposed as causes of tumour development in people and many of these same mechanisms are likely to occur in dogs and cats. While genetic factors and environmental toxins may not be avoidable or preventable, avoiding obesity and feeding a complete and balanced diet with no deficiencies or excesses in nutrients are within every caregiver’s control.
Conclusion
Improvements in disease prevention, nutrition, veterinary care and diagnostics mean that today’s cats and dogs are living to ages when accumulated DNA damage can result in cancer. One more factor to consider is that the earlier a problem is detected and a diagnosis is made, the better the chances of successful treatment.
About the author
Vicki J Adams BSc DVM MSc PhD MRCVS is a UK-based Veterinary Epidemiology Consultant. She is closely involved with the Animal Cancer Trust (https://www.animalcancertrustcharity.co.uk) and can be reached by email: vjadams12@gmail.com
