Thyroid Cancer in Cats: A Quick Guide Causes, Symptoms, and Treatment of Thyroid Cancer in Cats

Thyroid Cancer in Cats: A Quick Guide

While thyroid cancer in cats is rare, it can result in life-threatening complications. Learn more about its causes, symptoms, and treatment in this article.

Thyroid cancer is a relatively rare but serious condition that can affect cats of all ages and breeds. This type of cancer is caused by the uncontrolled growth of cells in the thyroid gland, which is located in the neck and plays an important role in regulating the body's metabolism. 

In this article, we will provide a quick guide to thyroid cancer in cats, including its causes, symptoms, diagnosis, and treatment options. Whether you are a new cat owner or a seasoned pet parent, it is important to be aware of the signs and symptoms of thyroid cancer in order to ensure that your feline friend receives the best possible care.



The symptoms of thyroid cancer in cats can vary depending on the stage and progression of the disease. Some common signs of thyroid cancer include:

  • Weight loss and decreased appetite, despite a normal or increased food intake

  • Increased thirst and urination

  • Vomiting and diarrhea

  • Difficulty breathing or coughing

  • Enlargement of the thyroid gland, which can be felt as a lump in the neck

  • Hyperactivity or restlessness

  • Changes in coat and skin condition, such as hair loss or dry, itchy skin

These symptoms can also be caused by other conditions, so it is essential to consult a veterinarian if your cat is displaying any of these signs. Early detection and treatment is essential in managing thyroid cancer in cats. Regular veterinary check-ups, including blood work and physical examination, can help detect the condition in its early stages and improve the chances of a successful outcome.


Hyperthyroidism, or the excess secretion of hormones from the endocrine glands in a cat’s neck (thyroid glands), can lead to the formation of tumors. 

The exact causes of thyroid cancer in cats are not well understood, but there are several factors that may increase the risk of developing this condition. Some of these include:

  • Genetics: Some breeds of cats, such as Siamese and Burmese, may have a higher risk of developing thyroid cancer.

  • Age: Thyroid cancer is more common in older cats, with the average age of onset being around 10-12 years.

  • Gender: Female cats may be more likely to develop thyroid cancer than males.

  • Exposure to certain toxins and chemicals: Long-term exposure to certain pesticides and pollutants may increase the risk of thyroid cancer in cats.

  • Other medical conditions: Cats with pre-existing medical conditions, such as hyperthyroidism, may be at a higher risk of developing thyroid cancer.

Many cases of thyroid cancer in cats are idiopathic, meaning that the cause is unknown. Environmental factors such as exposure to radiation, poor diet, and lack of exercise can also contribute to the development of the condition.



Diagnosing thyroid cancer in cats typically involves a combination of physical examination, laboratory testing, and imaging.

Physical Examination: A veterinarian will perform a thorough physical examination, including palpation of the neck, to check for any enlarged thyroid gland or masses.

Laboratory testing: The veterinarian may run blood tests to check for high levels of thyroid hormones, which can be an indication of thyroid cancer. They may also run other tests, such as a complete blood count and a biochemistry profile, to check for any other abnormalities that may be related to cancer.

Imaging: Imaging tests such as ultrasound, radiography, and computed tomography (CT) scans can be used to confirm the diagnosis of thyroid cancer and determine the size, location, and stage of the tumor.

Fine needle aspiration (FNA) may also be done, where a small sample of cells is taken from the suspected tumor and examined under a microscope.

After all the data has been collected, the veterinarian will use all the information to confirm a diagnosis of thyroid cancer and determine the stage of cancer. Staging is important because it will help determine the best course of treatment for your cat.

A definitive diagnosis of thyroid cancer can only be made by a biopsy when a sample of the tissue of the tumor is taken and examined under a microscope by a pathologist.


Treatment for thyroid cancer in cats will depend on the stage of cancer and the overall health of the cat. The main treatment options for thyroid cancer include:

  • Surgery: Surgery is the most common treatment for thyroid cancer in cats. The goal of surgery is to remove the cancerous tumor, along with a small margin of healthy tissue around it. Surgery is typically recommended for cats with localized, early-stage cancer.

  • Radiation therapy: Radiation therapy uses high-energy rays to destroy cancer cells. This treatment may be recommended for cats with locally advanced or recurrent cancer that cannot be surgically removed.

  • Chemotherapy: Chemotherapy is the use of drugs to destroy cancer cells. This treatment may be recommended for cats with metastatic cancer that has spread to other parts of the body.

  • Hormone therapy: Hormone therapy may be recommended for cats with hyperthyroidism that is caused by cancer. This treatment involves administering drugs that suppress the production of thyroid hormones.

  • Palliative care: Palliative care is supportive care that aims to improve the quality of life for cats with advanced or incurable cancer. This may include medications to control pain and other symptoms, as well as hospice care.

The treatment plan will also depend on the overall health of the cat and the owner's decision based on the quality of life for the cat and the financial aspect.



The recovery process for thyroid cancer in cats will depend on the treatment that was administered.

If surgery was performed, the cat would typically need to stay in the hospital for a few days to recover from the anesthesia and to have the wound checked. The cat will also need to wear an Elizabethan collar to prevent them from licking the surgical site. The cat should be kept quiet and confined to a small area for the first few days after surgery. The cat's appetite, activity level, and wound should be closely monitored.

After surgery, the cat will need to go back to the vet for follow-up examinations and tests to ensure that cancer has not returned.

If radiation therapy or chemotherapy was administered, the cat might experience side effects such as fatigue, loss of appetite, nausea, and hair loss. These side effects are typically temporary and can be managed with medication.

If hormone therapy was administered, the cat's thyroid hormone levels would need to be closely monitored to ensure that they are being controlled at the appropriate level.

Recovery time can vary for each individual cat, and some cats may need additional time and care to recover fully. Cat parents need to maintain good nutrition with a special thyroid support diet and ensure proper hydration for the cat during the recovery period. It is also crucial to provide a comfortable and low-stress environment for the cat to recover.

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