‘Cancer’ is a malignant, cellular tumour. A ‘tumour’ is a swelling or tissue growth which has uncontrolled cell multiplication. It can be malignant or benign. If the tumour is malignant, it has a tendency to progressively worsen and may even lead to death. Usually a malignant tumour is accompanied by properties of metastasis i.e. transfer of disease from one part of the body to the other. This means cancer is basically uncontrolled and progressive transformation of normal cells into abnormal cells that worsen very fast. The main symptom of cancer in a canine is a mass or lump. Although each mass or lump may not be malignant (cancerous) but it is best to let veterinarian evaluate it. The vet would surgically take a sample and send it for biopsy.
Common signs of cancer in canines…
- Lumps – any unusual lump or growth.
- Non-healing wounds – if your pet’s wounds are not healing it can be a sign of skin infection, skin disease or even cancer.
- Abnormal discharges – any sort of discharge (pus, blood or vomiting) should be examined by the veterinarian.
- Weight loss and loss of appetite – sudden loss of appetite leading to unusual weight loss and lethargy.
- Difficulty in breathing – this can be due to a heart disease, lung disease or even cancer.
- Changes in bathroom habits– if your pet has blood in urine or stool, also check for increase in frequency.
Types of cancers in canines…
Bone cancer: It accounts to a total of five percent of canine cancer cases. It’s mostly common in legs, arms, skull, jaw, ribs and spine. During initial phases, it may just be considered a swelling in the bone, but as it progresses, it may lead to changes in pet’s behaviour due to severe pain in the affected area.
Liver cancer: It is of two types. First, primary (i.e. a malignant tumour in the liver) and second, metastatic (i.e. cancer spreading to the liver from other parts of the body). Blood in stool, vomiting, loss of appetite, unconditional weight loss, jaundice, frequent urination, increased thirst and lethargy may be some of the symptoms.
Prostate cancer: It results from the effects of testosterone hormone secreted by the prostate gland. Enlargement of prostate gland, abdominal swelling, frequent urination in less amounts, discharge or secretions from the genital area may be some of the symptoms.
Lung cancer: It is caused due to frequent and long exposure to environmental pollutants and passive smoking. Another cause can be spreading of malignant cells from other parts of the body to the lungs. It is believed that lung cancer is rare in dogs.
Stomach cancer: According to research, stomach cancer accounts for just one percent deaths of the total canine cancer deaths. This is a rather rare cancer and is mostly observed in senior (8-9 years and above) male dogs.
In half of the cases, the growth can be detected with physical examination. They are visible in the form of growths, sores, lumps, or can be seen beneath the skin. Testicular tumours, mammary gland tumours, lymph gland tumours and cancers in the mouth can be detected by inspection. Internal cancers are common in the spleen, liver and gastrointestinal tract.
Who is prone to cancer…
It is believed that older dogs are a greater risk as compared to the younger ones. Besides, some breeds are more prone to certain type of cancer. Talking to Dr Neelima Paranjpe from Mumbai, we found that there are some breeds who are at a greater risk of cancer due to the genetic makeup. Boxers, for instance, are more prone to cancer as compared to other breeds. She also added that Golden Retrievers are at a greater risk of skin cancer due to their genetic makeup. “It becomes difficult to explain pet parents that cancer in canines is based purely on genetics and not on their lifestyle,” added Dr Neelima.
According to Dr Aradhana Pandey, the following breeds are more prone to specific types of cancer: Golden Retrievers – Osteosarcoma (bone cancer); Rottweiler – Lymphosarcoma (cancer of the lymph nodes and system) and Hemangiosarcoma (cancer of blood vessels, common in the spleen); Boxer – Lymphos ar coma , Brai n cancers, Mast Cell tumours (a cancer involving specialised cells called mast cell, common in the skin and other body sites); Pugs – Mast cell tumour; Rottweilers and Great Danes – Osteosarcoma.
While, senior vet Dr GB Kaushik talks about how gender can have a connection to cancer in dogs. According to him, mammary cancer is common in unspayed females, whereas males are at a higher risk of testicular tumour.
As far as the treatment is concerned, it can star t immediately after the diagnosis. Some of the treatment options are surgically removing the tumour and in cases where the cancer is inoperable, other treatment options like Radiation and Chemotherapy can be opted for. Radiation means killing the malignant cancer cells by exposing them to high levels of radiations using calibrated X-rays. While, chemotherapy involves treatment with drugs, and is not very target specific. Chemotherapy drugs can have major side effects on your pet even when used in controlled amounts. Dr Aradhana says that side effects vary according to the drug use.
Though the side effects are not as severe as that in humans but some of them can include:
- Increased thirst – drinking large amount of water.
- Increased need to urinate (from drinking so much water!).
- Some mild behaviour changes.
- Loss of appetite.
- Low white blood cell count (WBC).
- Tissue damage at injection site.
- Nausea or vomiting.
- Diarrhoea (usually occurs 2-5 days after administration).
“The international circuit is concentrating on Targeted Cancer Therapies. By chemotherapy we are killing all actively dividing cells whereas in this targeted approach, techniques are being developed to target just the cancer growth,” said Dr Gautam Anand. Targeted cancer therapies are drugs or other substances that block the growth of cancer cells and prevent them from spreading by interfering with specific molecules involved in tumour growth and progression.
Since the research for canines is not at a very advanced stage, most vets take help from human radiologists. They help in surgical techniques depending on the organ affected, MRI (magnetic resonance imaging), CT scan, etc that help in targeting the cancer more effectively. “Also some of the new techniques that have been developed recently for canines are stinting, which means putting a stint through the tumour which would result in blocking the blood supply to it and intratumoral therapies. In intratumoral therapy we directly target the drug to the tumour for a targeted approach,” added Dr Gautam.
Talking about the efficiency of the treatment methods, Dr Aradhana tells us that it depends on a number of factors like: the type of cancer, the organ affected, the age of the dog, physical condition of the dog etc. She also said that if diagnosed at the proper time and early stages, cancer in canines can be cured completely.
“Usually when the patient is in the terminal stage or in cases of bone, brain, chest and abdominal cancer, we suggest that instead of chemotherapy or radiation, the pet be put to sleep. In these cases the physical suffering is immense and providing treatment would just mean prolonging their suffering,” added Dr Neelima.
It is known that diet plays an important part during and after the treatment. Changes made in your pet’s diet may prove to be beneficial. The use of simple sugars should be limited whereas complex sugars (carbohydrates) and highly digestible proteins should be used in moderate amounts.
Dr Aradhana suggests, ‘‘Since tumour cells require glucose to grow, thus we should reduce the intake of direct glucose in pets as our aim is to minimise the energy available to the tumour to limit its growth. Simple carbohydrates like bread, pasta etc are direct source of energy so it needs to be reduced. Foods with low glucose carbohydrates like fruits (viz. apples, berries, etc), honey, brown rice, oatmeals, etc should be given.” “A large quantity of proteins coming from egg white, chicken, etc should be given because it helps in maintaining muscles. Vitamin D inhibits cell growth and also promotes cell death that plays an important role in the prevention of cancer. Vitamin D supplementation should be done guardedly and should not be more than 10,000 IU per kilogram of food,” Dr Aradhana added. Your vet would guide you best to make specific dietary changes in the diet of your beloved.
The silver lining…
One thing that helps canine fight cancer better than humans is that they are not psychologically affected by the disease. As long as the pet is with the pet parents and they are spending quality time with each other, it is really helpful for the pets. “They are usually in high spirits which certainly helps in the treatment,” added Dr Neelima. Citing an example of one of her patients, she said that one of her patients who is suffering from cancer is really naughty and playful. She has successfully taken the first round of chemotherapy and is ready for the second round. “By giving targeted treatment in the form of radiology and chemotherapy, we can increase the life expectancy of pets by 1- 2 years and most importantly their suffering is reduced to a great deal,” she added.
Preventing cancer in dogs…
Following some simple steps can help in preventing cancer in dogs:
- Foods – Make sure that the pet food has the least amount of preservatives and added colours because these are believed to be directly linked with canine cancer. They should be given food that is rich in fatty acids and antioxidants.
- Clean water – Make sure you provide your pet with adequate clean drinking water. It’s a known fact that drinking lots of water is a common way to prevent bladder cancer.
- Exercise – Regular exercising should be an important part of your lil’ one’s daily routine. Walk, run, play, hop… make them do whatever they like. This would help in controlling their weight and in turn lead to a total weight management routine.
- Spaying and neutering – Neutered males have a lower risk of testicular cancer as compared to the ones who are not neutered. Similarly female dogs who are spayed before coming to the season are at a lower risk of mammary gland cancer. A female spayed before sexual maturity (6-9 months of age) has one-seventh the risk of mammary cancer.
- Avoid passive smoking – Passive smoking is as dangerous to pets as it is to infants. Make sure you kick that butt to make yours and your pet’s life healthier.
(With inputs from Dr Aradhana Pandey, Doggy World, New Delhi; Dr Neelima Paranjpe, Pluto Pet Clinic, Mumbai; and Dr Gautam Anand, Dr Anand’s Pets Clinic, New Delhi.)