According to the Smithsonian, humans have had domesticated pet cats for over 12,000 years. In that time, humans and cats have developed a strong relationship. They continue to quell anxieties, provide comfort, and catch pests, and we care for them, show them love, and make sure that they live healthy lives.
A cat will, on average, live for about 15 years, but even cats can succumb to diseases, including various forms of cancer. While cancer is more common in dogs, it can still be a prevalent disease in your favorite feline friends.
Cancer affects an estimated 6 million cats each year, and it is the leading cause of deaths in about 32 percent of cats. Let’s take a closer look at cat cancer in its different forms, its symptoms, and what you can do to treat or prevent cancer in your cats.
Possible Causes of Feline Cancer
Much like cancer in humans, feline cancer is hard to pin down. There isn’t any single known reason for a cat developing cancer. Many are caused by a mix of genetics and environmental factors that took effect years before the cat’s actual diagnosis.
Genetic mutations can be passed down, increasing a cat’s predisposition to growing certain tumors, but most mutations happen during a cat’s lifetime. Internal factors causing these mutations include exposure to certain hormones, while external factors include everything from tobacco smoke to sunlight.
However, there are some known factors that may contribute to an increased risk of cancer in cats. For example, cats that have been spayed after the age of six months are about seven times more likely to develop mammary tumors (which can point to mammary gland cancer) than cats spayed before six months. Studies also suggest an association between feline immunodeficiency virus and feline leukemia and lymphoma.
Cat Cancer Symptoms
Cats who may have cancer can exhibit a wide range of signs and symptoms, both physical and behavioral. Some common signs of cat cancer you should keep an eye out for include:
› Weight loss: Sudden or gradual loss of weight is the most common sign of possible cancer, often suggesting a gastrointestinal tumor. Cats are heavily motivated by food, so a sudden loss of appetite could point to problems.
› Weight gain: At the other end of the spectrum, your cat should maintain a pretty consistent weight. A sudden increased appetite, bloating, or general weight gain could point to gastrointestinal cancer. This can be especially serious if your cat gains weight while seemingly eating less.
› Hiding: Cats are natural hiders, but if they are spending more time than usual hiding under the bed, bundled under your covers, or in otherwise hard to reach places, you may want to seek help from a vet. This doesn’t necessarily point to cancer specifically, but it is a big indicator that something may be wrong with your cat’s health.
› Nosebleeds: While nosebleeds may be fairly normal for humans, they’re nowhere near normal for cats. In younger cats, a bloody nose might mean your cat got a foreign object stuck in its nose. However, in older cats, nosebleeds can be a major sign of nose cancer.
› Oral issues: These include sores, bleeding, lumps, discolored gums, and consistent bad breath. These can all suggest oral cancer. The worst part: most owners don’t inspect their cats’ mouths enough, which means these symptoms often go unnoticed until too late. Keep an eye on your cat’s mouth when she yawns or eats, and get into the habit of brushing your cat’s teeth regularly.
› Discharge: Discharge from the nose can point to nasal cancer, while irregular discharge from the eyes may mean an eye tumor.
› Irregular bathroom habits: Diarrhea itself isn’t a sign of cancer, but you should take your cat to the vet regardless if it exhibits persistent diarrhea. Other digestive issues you should keep an eye out for include difficulty urinating or moving bowels, blood in stools or urine, or sudden increased use of litter box. While this could just mean an upset stomach, it could also signal tumors in the gastrointestinal tract.
› Skin problems: Watch for lesions or sores that don’t heal or appear itchy.
› Seizures: It goes without saying that you should see a vet if your cat experiences seizures of any kind. Seizures may appear as sudden bursts of activity, jerking legs, chewing, and foaming at the mouth. Atypical seizures may appear more as abnormal behavior, like scratching or biting you, sudden anger, or excessive licking.
› General pain: Aches and pains are a common part of growing old as a cat, but if your normally affectionate feline companion suddenly whines or cries out when you pet them or pick them up, you should consider taking them to the vet.
While tumors are commonly associated with cancer, they could very well be benign. There’s no way to know without a professional test and diagnosis.
The Most Common Types of Feline Cancer
Much like human cancer, feline cancer comes in various forms affecting different organs and organ systems. Some may be more aggressive than others. Some of the most common types of feline cancer include:
› Feline lymphoma, or lymphosarcoma, affects a cat’s lymphocytes, a cell involved in the cat’s immune system. This can lead to potential widespread infection, so lymphoma is itself divided into forms that differ in age of diagnosis, symptoms, and treatment. Forms of cat lymphoma include:
› Spinal (both the brain and spinal cord)
› Mediastinal (lymph nodes located in the chest)
› Multicentric (involving several different organs)
› Fibrosarcoma develops as an aggressive tumor in fibrous connective tissues, often where your cats might have received an injection of antibiotics, vaccines, and other medications and preventatives. This form of feline cancer is rare, only occurring in about 1 out of every 30,000 vaccinations. To reduce the potential for fibrosarcoma, vets will often limit the frequency of vaccinations and suggest specific vaccines that have lowered chance of infection or irritation. When caught early, fibrosarcomas only have up to a 20 percent chance of metastasizing.
› Squamous cell carcinoma is a type of cat skin cancer that cats may develop on their noses, ears, eyelids, and other areas of exposed skin. White cats in sunny climates may especially be at risk for squamous cell carcinomas, which account for about 15 percent of all skin tumors in cats. Cats who frequently receive sun exposure may first develop solar dermatitis, which can appear as pink, scaly skin, for which your vet will prescribe sun restriction and sunscreen. However, exacerbated solar dermatitis can turn into open wounds or growths that look like cauliflower. At this point, the vet may test to see if the cells have become cancerous.
› Mammary gland carcinomas usually occur in older cats ages 10 to 14 years. Sadly, mammary tumors are more aggressive in cats than in other species. About 80 to 90 percent of mammary gland tumors are found to be malignant. They are usually locally invasive, spreading to immediately adjacent areas with a high chance of metastasizing.
A Look at Feline Leukemia Virus
When humans hear leukemia, they assume it’s much like the human equivalent of cancer of the blood cells. In reality, feline leukemia virus (FeLV) is not cancer but a viral disease more comparable to human HIV. While related, FeLV is not the same as feline immunodeficiency virus.
Feline leukemia suppresses a cat’s immune system, making it more susceptible to infections and illnesses. When left unchecked, FeLV can lead to blood disorders and cancer. Signs of FeLV include:
› Loss of appetite
› Inflammation of the gums and mouth
Swollen lymph nodes
FeLV is most often spread by cats who are already infected with the disease. The virus has a high concentration in saliva, urine, feces, and milk of infected cats. The disease can be spread via bite wounds, mutual grooming, and sharing feeding dishes and litter boxes.
Thankfully, FeLV can be managed. Only about 30 to 35 percent of those infected with FeLV will continue to carry the virus, but anti-virals, immunity builders, and nutritional supplements can help your cat live a long, relatively undisturbed life.
Treatment for Feline Cancers
Depending on the type of cancer your cat is diagnosed with and the site of the tumor, you have a variety of treatments available to you. Surgery to remove the tumor and cancerous tissue is the most common treatment. This may comprise partial removal to improve the quality of life. It’s common to also remove surrounding tissue that appears healthy as it may contain abnormal cells.
Surgery is often paired with radiation therapy. Radiation, or radiotherapy, commonly involves using external beam radiation to kill cancer cells. External beam radiation, a more intense form of the radiation used in x-rays, is focused on the site of cancer cells.
With proper calculations of frequency and dosage, radiotherapy can effectively kill cancer cells without causing damage to surrounding tissue. For more localized treatment, like treating squamous cell carcinomas, specialists may use brachytherapy wherein radiation sources are placed inside or on the surface of the tumor. Radiation therapy, on the whole, exhibits very few side effects.
Chemotherapy is an option for cats with lymphoma cancer. Lymphoma is the most treatable cancer and most responsive to chemotherapy. Chemotherapy can be an aggressive cancer treatment plan, as well as expensive. It’s important to consider all factors like quality of life of your feline when making decisions about treatment options.
Palliative Care and Living with Cancer in Cats
The best thing you can do for a cat with cancer is to provide a healthy, balanced diet filled with necessary nutrients. To maintain a healthy appetite, provide your feline friend with a variety of foods. You may also consider nutritional supplements. It’s also a good idea to keep a diary recording your cat’s diet, appetite, behavior, and abnormalities.
If your cat is experiencing pain from cancer or from treatments, your doctor may prescribe analgesic painkillers or anti-inflammatory drugs. If your cat exhibits a low white blood cell count or develops an infection, consult your doctor for the use of antibiotics.
Preventing Cancer in Cats
The genetic component of cancer makes it difficult to completely prevent any form of cancer in cats, but certain steps can reduce your cat’s risk of cancer.
› Spay your cats young. Female cats should ideally be spayed before their first heat cycle, nearly eradicating the potential for her developing mammary cancer.
› Avoid overfeeding. Fat is a part of the endocrine system, meaning it can actually secrete hormones into your cat’s system, leading to increased inflammatory response and making your cat more susceptible to cancer.
› Have your cat tested for feline leukemia virus and feline immunodeficiency virus. Blood test are quick and easy, and diagnosing these diseases early allows for more effective treatments.
› Secondhand smoke has been found to negatively affect cat lungs and contribute to cancer. Avoid smoking around your cat or consider quitting altogether.
› Be cautious when using household cleaners and pesticides. Consistent exposure to certain chemicals could lead to the development of cancer. Consult your veterinarian to find chemicals and medications that are safe and effective.
› Take your cat to the vet regularly for checkups. Early detection is the best way to ensure successful treatment of cancer.
Whether or not your cat has cancer, never be afraid to consult your veterinarian if you have questions or need advice. Remember to always provide your cat with plenty of love and care.