Pet Cancer is Real! Here’s Everything You Should Know About Cancer in Dogs & Cats
Cancer is a reality. It’s not something limited to movies and TV shows. Or something you read about in journals and on the Internet anymore. Cancer is all around you; it’s affecting the people and pets we know, we care about, we love. Cancer today is the leading cause of death in pets. According to The Truth About Pet Cancer (TAPC, a research documentary), 1 in 1.65 dogs and 1 in 3 cats will succumb to cancer. Which in turn means almost two of every three dogs you meet is already suffering from or will develop cancer in his lifetime.
November is Pet Cancer Awareness Month. Whether you’re a pet-parent or to-be, awareness on pet cancer is extremely essential. While research and advancements in finding treatment to pet cancer still continue, finding out your pet has cancer is not the end of the tunnel. Nearly all forms of pet cancer can be treated completely if action is taken in time. In this article, we’ll talk about:
- Research on Pet Cancer
- Main causes of Cancer in Dogs & Cats
- Signs & Symptoms of Pet Cancer
- Types of Cancer in Pets & their Treatment
- Prevention of Cancer in Dogs & Cats
What is Cancer?
A body is made up of trillions of cells, the building blocks of all tissues. Each cell is designated to perform a specific task in the body. For example, bone and muscle cells give strength and structure to the body while organ cells make up the different body organs. And skin cells protect them from the external environment. You can think of these cells as different employees of the company, each part of different teams designated to perform specific functions – HR, Engineering, Marketing & Sales, etc.
Cells are capable of reproducing or replicating themselves according to their functional requirements. This replication is called Growth. The Sales team and HR, may both grow at different rates, specific to their function. The DNA information stored in the nucleus of the cell decides how each cell grows and performs. Every cell is expected to work as per the rules defined in the DNA.
Sometimes this information undergoes an unexpected corruption or typo. This mutation causes certain cells to grow out of order. These outlaw cells create tumors and tend to grow and spread across the body. This can be imaged as Radical Groups or Unions created within the company. They perform no real function except for defying rules created by the management and disrupting normal business. This is known as Cancer.
Typically, the body’s immune system would identify and fix these cancerous cells. But in the absence of a healthy lifestyle and proper nutrition, the body’s natural defenses against such outbursts are weakened. And hence, cancer thrives in the body. Much like most radical groups, cancers have the tendency to exploit the body’s resources to support the rapid growth of its corrupt cells and finally consume the host body completely. (Does that explain why Terrorism is synonymous to Cancer for our society?)
Research on Pet Cancer
A lot may not be available on Pet Cancer for two major reasons. One, most of the research and study around Pet Cancer has only been recent. Two, there has been a natural spike in the frequency of lifestyle diseases for both humans and pets in the past two decades. Thus, Cancer is a relatively new phenomenon for medical science, even more so for veterinary science.
The WHO has found a clear link between cases of cancer and poor lifestyle. One of the biggest contributors to this spike is food. Commercial, processed pet-foods, laden with preservatives and nutritionally insignificant substances have been under the light for it. We don’t eat the same quality of food today that we used to, 15 or 20 years ago. And neither do our pets. We don’t walk or run the same distance today that we used to, 15 or 20 years ago. And neither do our pets. Something as common as obesity increases the risks of up to 11 cancers.
We also never saw as many new breeds as commonly as we see today. Needless to say, the puppy mills are not really run by experts. Incessant breeding & inbreeding, coupled with lack of mother’s milk for the puppy has resulted in even more disorders. Once considered a disease of the old age, caused due to damage in DNA over years, Cancer has begun manifesting in puppies as young as 18 months of age now. Thanks to the increasing exposure to environmental risks and complex changes in biology with age. (Source: TAPC)
Out of all companion animals, dogs are affected by more forms of cancer. Humans and dogs get cancer at approximately the same rate, while cats get fewer cancers. About 100 types of cancers have been identified in pet animals. Out of which cancer of the mammary gland and lymphoma are most common in dogs, and lymphoma/leukemia in cats. (Source: fetchacure.org)
Causes of Cancer in Dogs and Cats
Just like in humans, there is no one clear culprit for cancer in dogs or cats. Cancer is a complex disease and the definite reason for its occurrence in pets is still a mystery. However, there are a few reasons that could contribute to the development of different types of tumors in dogs or cats.
Genetics or Family History
Some dog breeds are more susceptible than others to developing a tumor, that said, all dogs are at a risk of cancer. A history of cancer in the pet’s lineage puts it directly at risk for the same. Large dog breeds like Rottweilers, German Shepherds, Labradors, Boxers and Great Danes are at maximum risk. The reason for which is still unknown, but certain genetics in these breeds make them more likely to have cancer than others. Pets with a white or light coat are also at a higher risk due to excess and unfiltered exposure to the ultraviolet rays of the sun.
Studies show the rate of cancer in female dogs to be higher than that in male dogs. Given mammary gland (milk-producing gland) cancer is the most common type of cancer in dogs. Female dogs in a population where dogs are not spayed are at a higher risk of cancer. Timely neutering them can help prevent mammary cancer in dogs.
While cancer has recently been detected in younger pets too, a majority of pets develop cancer when they are over 7-10 years of age. Veterinarian cancer specialists suspect that as the immune system grows weaker with age the pet’s ability to control a cancerous cell decreases. It is very likely that an older pet’s body will incorrectly divide a cell causing a mutation that its immune system would no longer be able to fight. The longer a pet lives, the more it is exposed to environmental risk factors like carcinogens and viruses affecting its DNA and RNA, causing cancer.
Environmental Elements and Human Interferance
Living in an urban setup with humans exposes our pets to a lot of elements their bodies were never made to cope with. Building material, smog and pollution, chemicals used in house-cleaning products, cosmetics, insecticides and pesticides etc. can contain carcinogens that lead to cancer.
Leading the domesticated life has also made dogs and cats completely dependent on humans for their well-being. The decisions you make as a pet parent impact your pet’s life in a very substantial manner. Second-hand tobacco smoke, food bowls that are not cleaned thoroughly and overall hygiene can also lead to the generation of cancerous cells in pets’ bodies.
The most crucial among the many landmark choices humans make for their pets is their food. For years, pet food companies have been supplying pets with bags full of by-products and toxins under the “premium” tag. These processed kibbles have been laying the ground for the development of cancer in the later stages of life for a pet. Offering very little to no nutritional value, these pet foods are laden with preservatives, flavoring and a lot of what that should never make it to your child’s bowl. Not only they fail to deliver nutritionally, but they make your pets’ bodies work harder. Hence, wearing out their immune system sooner than it should.
A bad diet can only be worse for a pet when his body does not receive enough activity too. As humans get lazier to perform any physical activity, their pets do not receive enough exercise either. This destroys the two most important pillars in the well-being of a pet; nutrition and exercise. Under-exercised pets get obese and obesity is the warehouse of all lifestyle disorders including cancer.
Then there is the growing vaccine culture which is also considered a reason for cancer development. More vaccinations do not mean more protection. Period. Vaccinations for pets need to be just as much their bodies need. Over-vaccination can have adverse effects on the pet including cancer. There have been cases where cancers in dogs and cats have developed on the spot of vaccination.
Types of Pet Cancer
While there are over 100 types of identified pet cancers, almost 1/3rd of all cancers are skin cancers. Out of these up to 20% are Mast Cell Tumors. Mast cell tumors are most commonly found on the skin, spleen, bone marrow and liver. Dogs develop cancer like humans and hence breast cancer, bone cancer, lymph cancer, gut cancer are common. Cancer in cats is half as common as dogs, but it is far more aggressive in nature. They are prone to lymphoma associated with the feline leukemia virus and oral cancer. Below are the most common types of cancers:
Skin Cancers in Pets
Commonly found in aging dogs, Skin Cancer tends to be lesser common in cats. Although when found in cats they are malignant in nature, while comparatively benign in dogs. While there are different types of skin cancers, the most common types include Melanoma, Squamous Cell Carcinoma, and Mast Cell Tumors.
Just like the human version of this cancer, Melanoma in pets affects their pigmented cells known as melanocytes. Tumors develop in these pigmented cells. They could be benign (gentle) or malignant (aggressive). Melanoma tumors that manifest on areas on the body with hair are generally benign and do not metastasize i.e. spread to other parts of the body. But there is still a 10% chance that a melanoma on a hairy body part is malignant in nature. They could range from being tiny to more than 2.5 inches in diameter and are black, brown, gray or red in color. Of the common dog breeds found in Indian households, Doberman Pinschers between 5 to 11 years are highly susceptible to benign melanomas.
Malignant melanomas usually occur on the snout, mouth, lips or the mucous membrane. These grow at a high pace and rapidly spread to other body organs including the lungs and liver. Pets with a black coat have been observed to develop malignant melanoma in their toe, toenail beds or pads of the feet. Such tumors in the feet often get infected and may be misdiagnosed as simple infections.
The causes of malignant melanoma in dogs and cats are still being researched. But genetic factors and trauma are noted to play a significant role. Compulsive licking of a certain part also increases the chances of cells mutating during division and becoming cancerous.
The first step in the treatment of malignant melanoma is usually surgery. In certain cases where the tumor cannot be removed or has infected other lymph nodes in the body, radiation is used. 70% of all Melanomas are cured by chemotherapy and surgery or radiation, but recurrence is observed and common. In cases of oral melanoma, pets are given a vaccine which enables their body’s immune system to attack the tumor cells extending their survival time.
- Squamous Cell Carcinoma
Exposure to the sun causes Squamous Cell Carcinoma in pets, which makes pets with a white or thin coat more likely to be affected by it. Although these tumors do not spread to surrounding organs or nodes, they are aggressive in nature and majorly destroy the tissue surrounding the tumor spot. These tumors generally occur around the abdomen or genitals of the pet, but may also be found elsewhere. Wart-like in appearance, these bumps are firm and raised.
Squamous Cell Carcinoma tends to affect pets between 6 and 10 years. Basset Hounds, Collies, Dalmatians and Beagles are among common Indian household dog breeds at high risk. Pets with a short or light colored coat are also more prone to developing this cancer while compared to others.
Such tumors can be removed surgically without the need for radiation or chemotherapy. But in cases of Squamous Cell Carcinoma in pets where the tumor is at an inoperable location, photodynamic therapy, and a drug – piroxicam are used for treatment.
- Mast Cell Tumors
Mast Cell Tumors occur in the mast cells of the immune system of the pets. They are more common in dogs as compared to cats. Research is still in process to find what causes these tumors. While there has been evidence of inflammation and irritants on the skin being responsible for such tumors, veterinarians believe genetics and the levels of estrogen and progesterone hormones may cause the spread and growth of mast cell tumors.
Mast cell tumors in dogs and cats usually occur on the trunk of the body but are also found on the legs in some cases. They are rubber-like and slow-growing in most cases. But when aggressive in nature, they spread rapidly and may ulcerate leading to sore, inflamed areas on the pet’s body.
Treatment of mast cell tumors in pets involve surgery with or without radiation, based on the location and size of the tumor. Chemotherapy and/or steroids may also be recommended based on the severity and grade of cancer. These tumors are most commonly found in Boxers and Pugs and in some frequency also in Labradors and Beagles.
Mammary Gland or Breast Cancers in Pets
Cancers in mammary glands of unspayed female dog and cats occur quite frequently. That said, male dogs and dogs spayed later in their lives are not entirely safe from it either. The mammary glands produce milk to provide for newborn puppies. They are located in two rows extending from the chest to lower abdominal area of dogs and cats. Mammary cancer that is malignant in nature is more common in cats than in dogs. Though the condition is most likely to occur in female pets, there are rare but noted incidences of male pets developing a mammary gland cancer.
Single or multiple masses growing in the mammary area, loss of tissue on the surface of the skin with inflammation are an indicator of possible breast cancer. The mass could be freely moving (an indicator of benign cancer) or fixed to the skin or body wall (indicating malignant nature). There are many types of breast cancer in pets, based on their nature. Few common types are simple adenomas, complex adenomas, fibroadenomas, and duct papillomas. These are benign in nature. Osteosarcomas, fibrosarcomas, solid carcinomas, and papillary cystic adenocarcinomas are malignant in form.
A surgical removal of the masses is the best and most preferred form of treatment for mammary gland cancer in pets. Many a time, mammary cancer would affect more than one mammary gland on the same side of the body. Radical mastectomy or removing all the glands on the affected side of the body is recommended. Such occurrences are higher in cats than dogs and dogs may not need removal of as much tissue. Radiation and Chemotherapy may follow the surgery.
Toy and Miniature Poodles, English Springer Spaniels, Cocker Spaniels, English Setters, German Shepherds, and Maltese and Yorkshire Terriers are genetically predisposed to breast cancer. The average age for detection is 10.5 years and is very uncommon in pets under 5 years.
Brain Tumors in Pets
Unfortunately, brain cancer is very common among older pets over 5 years of age, more so in dogs than cats. But they vary in their degree and malignancy and most can be treated effectively. Breeds susceptible to developing a brain tumor include Boxers, Boston Terriers, and Golden Retrievers. Brain Tumors can be classified into two categories. Primary Brain Tumors, where cancer manifests in the brain cells and within its membrane itself. Meningioma, glioma, choroid plexus papilloma and pituitary adenoma or adenocarcinoma are primary brain tumors. Secondary Brain Tumors include types where cancer affects the brain as a result of spreading or metastasizing from another primary part of the body. These include hemangiosarcoma, mammary carcinoma, and melanoma.
Palliative measures to treat the symptoms, surgery, radiation, and chemotherapy form the basis of treatment of brain cancer in dogs and cats. In most cases, brain cancers are treated but not cured. Additional therapies to reduce pain and inflammation can help improve the quality of the pet’s life.
Oral Tumors in Pets
Oral tumors in pets can be benign or malignant. A benign oral tumor is slow growing and does not spread to other parts. But a malignant oral tumor is rapid in growth and spreads to different areas of the body damaging them. Benign Oral Tumors include Peripheral Odontogenic Fibromas or POFs. These are formed in the periodontal ligament located in the tooth socket. Acantomatous Ameloblastoma is an aggressive benign tumor which does not spread to other parts of the body but is highly destructive locally. The most common types of Malignant Oral Tumors include Oral Melanoma, Squamous Cell Carcinoma, and Fibrous Sarcoma.
Treatment of Oral Tumors in dogs and cats require a surgerical removal. If the cancer is complex, an area of the jawbone may be entirely removed. These surgeries are extensive and are conducted by specialists. An oral melanoma can be treated by vaccination after the surgery. Benign oral tumors rarely reoccur post-surgery, but the more aggressive ones may resurface with the need for an extensive surgery.
Lymphoma or Lymphosarcoma in Pets
Originating in the lymphoid tissues of the lymph nodes, bone marrow, and the spleen, Lymphoma or Lymphosarcoma is the most common types of cancer in dogs and cats. Environmental factors like pesticides, chemicals or residing in an industrialized urban setup may increase the chance of your pet developing Lymphoma.
Lymphoma in cats mostly affects those with the Feline Leukemia Virus or Feline Immunodeficiency Virus (FIV). It may develop at any age, and cats without the above-mentioned viruses are at risk too. Cats may develop Lymphoma in their lymph nodes, digestive tract, lungs, and even kidneys. Depending on the location of the tumor, symptoms displayed are varied and unspecific. An examination by your vet and blood work is the only way to be certain.
Sadly, there is no cure for Lymphoma. But it can be managed successfully to an extent, depending on its degree and progression. Surgery, Chemotherapy, and Radiation are possible ways of treatment. Keeping your pet away from toxins, feeding them a healthy diet and lots of clean water and giving them enough exercise. If you parent a breed that is susceptible to Lymphoma, ensure regular vet visits. If you parent a cat, keep them away from those already infected with FeLV or FIV.
Testicular Cancers in Dogs & Cats
The testicles or testis has several cell types any of which could turn cancerous. The germ cells, responsible for generating sperms when cancerous lead to Seminomas. The supporting and nourishing Sertoli cells may have Sertoli Cell Tumors. And the hormone-producing interstitial cells become Leydig or Interstitial Cell Tumors. Testicular Tumors are common in older male dogs that haven’t been castrated. More so, when the testicle(s) fail to descend to its natural position and stays stuck to the belly cavity.
You can look out for signs like the increase in the size of one testis and shrinking of the other, difficulty passing motions, growing mammary glands or teats. Even attraction by other male dogs can be a sign of hormonal imbalance due to testicular cancer.
Bone Cancers in Pets
While not as common in cats, bone cancer is usually found in dogs over the age of 7 years. Bone Tumors in dogs and cats can be classified into two types. Primary, one that has evolved directly in the bone; and Secondary, one that has spread due to the metastasizing of a tumor in another part of the body. Primary bone tumors include Osteosarcoma, Chondrosarcoma, Fibrosarcoma, and Hemangiosarcoma. Out of these, Osteosarcoma is the most common and accounts for about 95% of all bone cancers.
The treatment of osteosarcoma in pets often calls for an amputation. A surgery removing the cancerous area is a good way to ensure the tumor is completely removed and your pet’s pain reduced. Thankfully, pets may take about 4 weeks to get used to working around on 3 limbs, depending on their lifestyle and the environment provided.
When surgery isn’t an option, localized radiation may help defeat cancer cells. Since bone cancer is extremely rapid in metastasizing, a round of chemotherapy follows the surgery to ensure that all remaining cells (if they have strayed) are eliminated.
It is very important to provide your pet with a stress-free environment after the surgery to ensure his recovery is positive and he doesn’t feel stressed out. Palliative measures are also needed to curb any pain and side-effects of cancer and surgery. It is important to note that osteosarcoma affects the life expectancy of your pet, depending on the severity at the time treatment begins.
The median life expectancy for dogs treated for osteosarcoma with SRS and chemotherapy, as well as those treated with amputation and chemotherapy is about one year. Up to 16-28% dogs are alive at 2 years. (Source: dogcancerblog.com).
Symptoms of Cancer in Dogs and Cats
Cancer could be difficul to detect in pets. The fur on their body may hide the tumors until they grow too big. Our pets cannot report pain & inflammation, and we often have to rely on secondary symptoms to manifest. Sometimes, the symptoms of cancer may be misdiagnosed as other local infections or medical issues. It’s important that we recognize the symptoms of cancer and catch them as soon as they manifest. Timely action can save your pet’s life. Following are some of the common symptoms of Cancers in Pets.
- Chronic Weight & Appetite Loss
If your pet loses a significant amount of weight, without you having to put them on a diet, you need to get him checked by a veterinarian. This is not solely a sign of cancer but does indicate that there is something wrong that needs addressing. Pets with cancer display a sudden loss in weight.
- Offensive Oral Odor & Pale Gums
An oral tumor may cause your pet to change his food preferences from hard to soft food, they may also change their usual chewing pattern. A foul odor from the mouth or unusually pale gums are indicators of oral tumors. A thorough oral examination by your vet can tell if there is an underlying issue.
- Persistent Coughing
Though there can be many causes of a cough in dogs and cats, a dry cough in older pets should not be ignored. A cough is the most common sign of lung cancer is pets.
- Chronic Vomiting or Diarrhea
Tumors of the Gastrointestinal tract can cause unexplained vomiting or diarrhea. They prompt the need for further examination and a radiograph, ultrasound or endoscopy may help diagnose the cause.
- Lameness or Stiffness
Bone cancer may cause lameness in your dog or cat, especially if they are a large, heavy breed. A radiograph of the affected limb can help conclude the reason for lameness.
- Straining to Urinate
If your pet has been straining to urinate, or you have spotted blood in their urine, it may be a urinary tract infection. If the bleeding and straining do not subside or stop, a cancer in the bladder could be the cause. A cystoscopy can help your veterinarian come to a conclusion on the cause.
- Unexplained Bleeding or Bodily Discharge
Bleeding disorders in younger pets are common, but when unexplained bleeding is observed in an older pet, an examination is required. Any bleeding from the mouth, nose, penis, vagina, gums that is not due to trauma should be addressed with urgency.
- Abdominal Distension
A rapid enlargement of the abdomen or bleeding in the area may be indicative of a mass or tumor in the abdomen. A radiograph or ultrasound of the abdomen help in diagnosis and concluding if cancer is a reason.
- A Growing or Changing Lump
A lump of any kind on your pet dog or cat should be examined at the earliest. Lumps are the most common sign of a developing tumor and a biopsy should be conducted when one is noticed.
- Swollen Lymph Nodes
Lymph nodes are located throughout the body but can most easily be found behind the jaw or knee of your pet. A swelling in lymph nodes is an indicator of lymphoma. A biopsy or cytology of these nodes can help in the diagnosis.
Preventing Pet Cancer in your Dog or Cat
Having your pet diagnosed with cancer can be a heartbreaking experience for you as a pet parent. But as much as you’d like to blame it on fate, the choices you make for your pet do dictate a lot on how his health and life pan out. One wrong decision severely affects their lives, and a few wise choices may help you provide them with the best they deserve. No one must have to see their pet go through a cancer, and to ensure your pet is healthy and safe, you need to take note of a few things.
- Know the risks
As mentioned under the various types of cancers above, certain breeds are genetically susceptible to certain types of cancer. Know the risks your pet’s breed has and make choices for them accordingly. Have your pet male/female spayed or neutered while they are young to avoid the risk of testicular or mammary gland cancer. Have regular check-ups done for the cancers your pet could develop. And get advice from your veterinarian to help counteract any possible mutations in the future.
- Always check for abnormalities
Observing your pet’s habits and noticing any changes they display can help you detect a cancer in its early stage. Other than behavioral changes watch out for swellings, lumps, stiffness in any part of your pet’s body. Do not shrugg off lethargy, dehydration, loss of appetite and thirst, excessive vomiting and diarrhea.
- Give them healthy food, clean water, plenty of exercise and lots of love!
Just like humans, the basic components of your pet’s health are healthy food, clean water and a lot of exercise. Toxins in tap water can affect pets the same way it can affect humans. The lack of exercise coupled with an unhealthy diet can lead to obesity which is the foundation of all health issues.
We also cannot stress enough on the need for a healthy, nourishing diet. When your pet’s body receives all the nutrition it needs, the probability of any any health condition, however minor or major, affecting them reduces drastically! Pet bodies were not made to get their fill from overly processed packaged kibble. Not only does commercial pet food fail to meet your pet’s needs, but it also comes loaded with preservatives and toxins that your pet should not have to digest ever. Every pet deserves real food, it helps them not only survive but thrive.
Lastly, every pet deserves as much love as one can give. They come into our lives and give it a whole new meaning, they give us a reason to look forward to a new day. Sadly, humans have not left the world an easier place for them. Ensure you shower your pet with a lot of love every day and cherish their presence while they’re here.
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