What is Cancer in Cats?
What is it?
How is it Treated?
Breed Predispositions
Siamese Abyssinian Persian Burmese Ragdoll
Introduction
It was during a routine grooming session that Sarah first discovered a small lump on her beloved Abyssinian cat, Max. Worried about the mysterious growth, she immediately scheduled an appointment with her veterinarian. After a series of tests and a biopsy, Sarah received the heart-wrenching news: Max had cancer. In this blog post, we will explore the complex world of cancer in cats
Cancer is a disease where cells grow out of control and multiply uncontrollably. Cancerous tumors form when cells divide too quickly and become malignant.
Cats are prone to developing certain kinds of cancer because of genetic factors. One of the most common types of cancer found in cats is mammary carcinoma (breast cancer). Other types include squamous cell carcinoma, fibrosarcoma, Mastocytoma, melanoma, lymphoma, leukemia, plasmacytoma, and others.
Types of Cancer in Cats
Cats aren’t just cute—they’re also prone to developing many types of cancer. And while it might seem like we know everything about our furry friends, there are still plenty of things we don’t understand.
1. Lymphoma
Lymphoma occurs when lymphocytes — white blood cells that fight infection — become abnormal and multiply uncontrollably. Because of this, lymph nodes swell up and cause pain. Lymphomas can spread throughout the body and lead to organ failure if left untreated. Lymphoma is common in older cats and may be hereditary. However, the risk of developing lymphomas is shallow. Lymphomas are cancerous tumors that develop from lymphocytes, cells that play an essential role in the immune system. The most common types of lymphoma are Hodgkin’s disease and non-Hodgkin’s leukemia.
2. Squamous Cell Carcinoma
Squamous cell carcinoma is a type of skin cancer that begins in the outermost layer of the epidermis, the stratum corneum. When cancer spreads beyond the stratum corneum into deeper layers of the skin, it becomes invasive. If left untreated, SCCs can spread to other body parts, including the lungs, liver, heart, bones, lymph nodes, kidneys, bladder, and intestines. The risk of developing SCC increases with age. Cats over ten years old are at greater risk than younger cats.
Cats who spend most of their day outdoors are more likely to develop SCC than indoor cats. In addition, some breeds, such as Siamese and Persians, are predisposed to SCC. Other factors include exposure to ultraviolet light, fleas, ticks, and certain foods.
3. Mast Cell Tumors
Feline mast cell tumors (FMCT) are benign skin growths found most commonly on cats’ faces, ears, paws, and tails. They’re usually painless, but some cats may experience discomfort when scratching at them.
Most FMCTs are harmless, but some can be life-threatening. The risk of death increases if the tumor infects or spreads to internal organs.
4. Bone Cancer
Feline bone cancer (feline Osteosarcoma) affects cats’ bones. The most common form of this disease is called Osteosarcoma.
Osteosarcomas are malignant tumors that develop in connective tissue cells, including those found in the bone. They usually affect older cats and may be hereditary.
There are two types of osteosarcomas: primary and secondary. Primary osteosarcomas occur when there is no previous history of a different kind of cancer. Secondary osteosarcomas arise after treatment for another type of cancer.
Primary osteosarcomas grow faster than secondary ones and often spread throughout the body. Conversely, secondary osteosarcomas tend to grow slower and stay localized within the original site of origin.

5. Mammary Cancer
Mammary cancer affects female cats. It starts as an enlargement of one or both breasts. As cancer grows, it can block milk ducts and cause painful infections.
Cats often develop mammary cancer because of hormonal imbalances. Hormones play a role in cell growth and division; some hormones may be linked to mammary cancer.
Because mammary cancer is rare in dogs, most veterinarians aren’t familiar with this condition. However, many pet owners worry about mammary cancer because it’s common in cats.
6. Feline Gastrointestinal Stromal Tumors
Feline gastrointestinal stromal tumors (GIST) are rare cancers that affect cats’ stomachs. They’re similar to human GISTs, which are very common, although not as deadly. Cats with feline GISTs usually live longer than those who develop human GISTs. However, there’s no cure for feline GISTs, just treatment options.
There are two types of feline GISTs: benign and malignant. Benign GISTs grow slowly and rarely spread outside the stomach. Malignant GISTs grow quickly and often spread throughout the body.
7. Feline Melanoma
Feline melanoma (feline cutaneous malignant melanoma) is a skin cancer affecting cats. The disease is most common among older domestic shorthair cats and breeds such as Maine Coons, Siamese, Persians, and Abyssinians.
Cats are prone to developing this form of cancer because they’re born with dark fur, and sunlight exposure increases the risk of developing the disease.
This form of cancer usually appears as a black dot on the cat’s skin and may be accompanied by swelling, redness, bleeding, ulcers, crusting, scabs, or open sores.
8. Feline Leukemia
Feline leukemia (FeLV) is common cancer affecting cats over one year old. The disease causes white blood cells called lymphocytes to become infected with FeLV virus particles and has a 33% chance of developing cancer.This cancer type responds well to chemotherapy; most cats don’t experience any side effects. However, these infected cells multiply out of control, causing tumors to grow throughout the body.
Cats contracting this type of cancer usually die within two years of diagnosis. However, some survive longer than ten years after contracting the disease. In addition, they may also become increasingly aggressive towards cat owners and other animals.
What are the Common Causes of Cancer in Cats?

Cats get cancer due to the following factors:
- Genetic Factors
Genetic factors play an essential role in the development of feline cancers. Some genetic mutations occur spontaneously, whereas others may be inherited.
For example, congenital hemangiomas are benign tumors that grow in certain breeds of cats. Hemangioma occurs most often in Siamese, Burmese, and Maine Coon cats.
- Environmental Factors
Environmental factors contribute to the development of cancer in cats. For instance, radiation exposure can lead to leukemia.
Exposure to arsenic, benzene, and asbestos can cause lung cancer. Exposure to pesticides can lead to liver cancer. In addition, unhealthy diets can lead to nutritional deficiencies that promote cancer growth.
- Infectious Agents
Specific infectious agents can trigger the development of cancer in animals. For example, feline immunodeficiency virus (FIV) can cause lymphoid malignancies.
Cat herpesvirus 1 (FHV-1) can cause oral papillomatosis. This condition usually affects young kittens.
Feline calicivirus (FCV) can cause upper respiratory tract infections. In addition, FCV infection can result in squamous cell carcinoma.
- Nutrition
Nutrition plays a significant role in developing cancer in dogs and cats. Poor nutrition leads to poor immune system functioning. A poor diet can lead to nutrient deficiencies, especially in older animals, promoting cancer growth.
- Stress
Stress has been shown to play a significant role in developing several types of cancer in cats.
When stress levels rise, cortisol levels increase. Cortisol promotes inflammation and can damage DNA.
It has also been suggested that chronic stress can lead to depression, anxiety, and other psychological disorders. These conditions can negatively impact overall health.
- Other Causes
There are other potential causes of cancer in cats besides those discussed above. These include trauma, toxins, parasites, and hormonal imbalances.
Trauma can cause injury to cells and to soft tissues. Traumatic injuries can lead to cancerous changes. Toxins can enter the body through food, water, air, and soil.
Toxins can cause cancer by damaging DNA or causing cellular mutation.
Parasites can invade the body and cause cancer. In addition, parasitic worms can affect the digestive system.
Hormonal imbalances can disrupt average hormone production. In addition, hormone imbalance can lead to abnormal cell division and proliferation.
Symptoms of Cancer in Cats
Cats are very different animals from dogs. As a result, they don’t show many of the health problems we see in our canine companions. But there are some things you should know about feline health.
Some signs of cancer in cats include a change in eating or drinking habits, unexplained weight loss, discharge from the eyes or nose that is watery and red, enlarged lymph nodes (belly), blood in the urine, new hair growth on the head or body that is not normal for your cat’s age and behavior changes. Please consult your veterinarian if you notice these signs in your cat.
Other common symptoms of cancer in cats.
- Weight Loss
- Vomiting And Diarrhea
- Bleeding From The Nose Or Mouth
- Changes To the Urinary Or Digestive System
- Persistent Pain
- Difficulty Breathing
- Weakness
- Appetite Loss
- Lack Of Energy
- Lethargy
- Unusual Behavior
- Excessive Shedding
- Unexplained Fever
- Abdominal Masses
- Lumps On the Skin Or Body
If Your Feline has Cancer, What Should You Do?
If your cat has cancer, there are many things you should do. The most important thing is to take your cat to the vet immediately.
Your veterinarian will perform tests to determine whether your cat has cancer. These include blood work, x-rays, ultrasound scans, and biopsies.
Once your cat has been diagnosed with cancer, your vet may recommend treatment options. Treatment options depend on the type of cancer your cat has, its stage (how far advanced), and your cat’s overall health.
Cancer Diagnosis in Feline
A cat’s definitive early cancer diagnosis requires an examination by a veterinarian. However, if there are suspicious signs or symptoms, your veterinarian may perform a preliminary diagnosis to rule out other causes of the changes and proceed with more thorough testing. If cancer is suspected, your vet will likely ask about your cat’s medical history (including any previous diagnoses or treatment), physical exam findings, and current health status.
To diagnose cancer, a veterinarian will do a complete physical examination of your cat to look for any signs of cancer. The vet may also order additional tests, such as a blood panel and chest X-ray, to rule out other causes of the cat’s symptoms. If cancer is suspected, the doctor will likely recommend chemotherapy or radiation therapy as treatments.

Treatment of Cancer in Cats
Cancers in cats are treated using chemotherapy, surgery, radiation therapy, and biotherapy.
Chemotherapy
Kills cancer cells. Chemotherapy drugs can cause nausea, vomiting, diarrhea, hair loss, skin rashes, mouth sores, and fatigue.
There are many different chemotherapy drugs available today. Some work better than others, some are more effective against specific types of cancer, and some are more expensive.
Some chemotherapy drugs are administered intravenously and are injected directly into the bloodstream. Others are given orally, meaning they’re swallowed. Still, others are applied topically, meaning rubbed onto the skin.
Surgery
Cancer surgery is a widespread treatment option for cats with cancer. This procedure aims to remove all traces of cancerous cells from the body. This may include removing tumors, lymph nodes, or organs affected by the disease.
After surgery, your cat needs to recover at home for several days. During recovery, he should be kept warm and comfortable. He may need fluids intravenously during his hospital stay. After discharge, your vet will monitor him closely for any signs of complications.
Alternative treatments are available if your male cat does not respond well to surgery. These include chemotherapy, radiation therapy, immunotherapy, targeted therapies, and natural remedies.
Radiation Therapy
It uses ionizing radiation to destroy cancer cells. The goal is to eliminate every cell containing DNA damage.
Two types of radiation therapy are used to treat cancer: external beam radiation and brachytherapy.
- External beam radiation delivers a concentrated dose directly to the tumor site.
- Brachytherapy has less radiation over an extended period than external beam radiation. As a result, both treatments work well for some cancers.
Both external beam radiation and brachy radiotherapy are safe and effective cancer treatment methods. In addition, they’re often combined to maximize effectiveness.
Biotherapy
It involves administering biological therapies to stimulate the immune system. Biotherapies can slow down the progression of cancer.
Some biotherapies kill tumors, while others help the body fight off infections. The most common use of biotherapy is to prevent disease after surgery.
When we inject biotherapeutics directly into the tumor, they attach themselves to these cytokine receptors and block them. This stops the growth of cancer and shrinks it down to standard size.
Many biotherapeutics exist, including monoclonal antibodies, antibody fragments, peptides, and vaccines. They’re usually injected intravenously, although some may be inhaled or applied topically.
Cancer and Treatment
After treatment, your cat needs regular visits to monitor its progress and ensure that any side effects are appropriately managed.
Additional treatments may be recommended if your cat doesn’t respond well to treatment. Unfortunately, some cats never recover after initial treatment. Others develop resistance to certain types of treatment.
Your vet may refer you to another specialist if your cat develops complications during treatment. This is especially true if your cat experiences severe pain or discomfort.
When your cat recovers from cancer, it may experience long-term side effects. Common side effects include loss of appetite, weight gain, vomiting, diarrhea, constipation, difficulty breathing, coughing, sneezing, urinary tract infections, skin problems, mouth sores, skin irritation, and hair loss.
Some cats live longer than expected because of successful treatment. However, some cats die within weeks or months of diagnosis.
Prevention for Feline Cancer
The following tips can help you prevent the occurrence of feline cancer:
- Feed your cat a healthy, balanced diet. Ensure your cat gets enough protein, vitamins, minerals, and other nutrients.
- Keep your cat indoors during cold weather. Cold temperatures can trigger problems such as respiratory infections and kidney failure.
- Provide plenty of exercise for your cat. Exercise helps maintain a healthy immune system and promotes overall wellness.
- Avoid giving your cat table scraps. Raw meat, bones, fish, eggs, dairy products, and raw vegetables can contain bacteria that could lead to infection.
- Do not give your cat flea medication unless instructed by your veterinarian. Fleas can carry tapeworm larvae, which can infect your cat.
- Vaccinate your cat against rabies. Rabid animals pose a threat to human safety.
- Clean your cat’s litter box regularly. Litter boxes must be cleaned daily to avoid odors and unpleasant smells.
- Maintain proper hygiene. Bathe your cat frequently to remove dirt and debris from its fur.
- Monitor your cat’s behavior. Observe your cat closely for unusual behaviors such as aggression, fearfulness, overgrooming, hiding, sleeping excessively, and eating less than usual.
- Reduce your cat’s exposure to cigarette smoke. Cigarette smoke contains chemicals that can irritate your cat’s lungs and eyes.
Frequently Asked Questions
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