Thyroid Cancer in Cats

Thyroid Cancer in Cats - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What is Thyroid Cancer?

Hyperthyroidism can cause tumors to form on the endocrine glands in the neck. These are noticeable lumps that you can feel upon rubbing the neck of an affected cat. The tumors are generally one of two types of cancer. Benign adenomas are the most common type of cancer related to hyperthyroidism. They are referred to as benign because this type does not metastasize (spread) to other body parts. Malignant adenocarcinomas are cancerous tumors that are aggressive and do spread throughout the body. Of the two types, benign adenomas are easier to treat. Either form of cancer tends to go untreated for quite some time, but the earlier it is caught and treated by a veterinary professional, the better. Failure to treat the condition can result in organ failure and death.

Feline thyroid cancer is a gradually developing cancer that is sometimes seen in older cats (usually above the age of twelve). It can take months or years to manifest. The thyroid consists of two lobes of endocrine glands in the upper neck. It is responsible for the production and secretion of the hormones thyroxine (T4) and triiodothyronine (T3), which regulate the pace of the metabolism and other body functions. When the thyroid starts to produce too many of these hormones, hyperthyroidism develops in the cat. 

Youtube Play

Thyroid Cancer Average Cost

From 520 quotes ranging from $3,000 - $8,000

Average Cost

$6,000

Wag Compare logo

Get a free pet insurance quote in less than 60 seconds!

Easily compare quotes from the most trusted pet insurance companies in the United States.

Get a quote

background

Symptoms of Thyroid Cancer in Cats

The most common sign of thyroid cancer is a sudden, consistent surge in energy. While this may seem like a good thing, it can be the sign of an overactive thyroid. Monitor this, and watch for other symptoms, such as: 

  • Polyphagia (increased appetite)
  • Polydipsia (increased thirst)
  • Polyuria (frequent urination)
  • Urination outside of litter box
  • Diarrhea
  • Vomiting
  • Nausea
  • Weight loss
  • Change in behavior
  • Increase in energy
  • Restlessness
  • Racing heart beat
  • Heart murmur
  • High blood pressure
  • Dull fur
  • Hair loss
  • Incessant meowing
  • Blindness (in very advanced cases)

Causes of Thyroid Cancer in Cats

When the thyroid begins to secrete excessive amounts of thyroid hormones, hyperthyroidism, and in turn, thyroid cancer develops. The exact cause is not fully understood, however, it is believed that a series of events and circumstances lead to cancer. Possible causes include:

  • Diet consisting of too much iodine
  • Environmental chemicals
  • Radiation exposure

Diagnosis of Thyroid Cancer in Cats

If you or your veterinarian suspect thyroid cancer, an appointment should be made to investigate the cat’s condition. A full medical history will be needed to see if the cat has an extensive history of hyperthyroidism. A physical exam will be completed, with focus on the under chin and neck to feel for nodules under the skin. These can be noticeable lumps or chains of tissue. The vet will also take care to differentiate between thyroid cancer and diabetes, as they do share some symptoms. 

Blood work will be needed, including a complete blood count and a biochemical profile. These tests will help see how many blood cells are present. T4 serum levels will be checked to see if they are registering higher than 10 times the normal amount. Another indication of cancer is if the cat has no response to either methimazole or carbimazole. The amount of thyroid hormones present in the body will be tested. Urinalysis may be done to exam the function of the kidneys and liver. 

X-rays can show if the tumors present are irregular or multifocal, and can be used to monitor any spreading. Often, a scintigraphy will be requested, as it is useful for further assessing tumors and determining appropriate dosages for treatment. The cat will need to be kept at the clinic for 2-3 days after this test, as it uses radioactivity that stays present in the cat for a time. Cardiac ultrasound may be needed if heartbeat irregularities are found.  If the cat’s condition is stable enough, an excisional biopsy (full removal of the tumor) will be performed. When microscopically evaluated, this can lead to a definite confirmation of cancer present.

Treatment of Thyroid Cancer in Cats

A few different treatments are available depending on the type of cancer present and how far it has progressed in the cat. Often, a combination of these treatments will be recommended for best results. 

Radioiodine 

Radioactive iodine has been found to be very effective in treating thyroid cancers. It is non-invasive and no general anesthetic is needed. A dosage of radioiodine is injected under the cat’s skin. It will treat all tissue that is hyper functioning in the body, and kill all abnormal cells. The cat will need to stay at the clinic or hospital for up to four days to eliminate all radioactive materials to be considered safe at home. A higher dose is given for cats with adenocarcinomas. This treatment has a 94% success rate.

Surgical Debulking or Removal 

This treatment is often combined with radioiodine administration. At the time of biopsy, all tumors greater than 3-4cm in diameter will be removed. If congestive heart failure is occurring due to thyroid cancer, a full removal of the thyroid glands may be needed. This requires general anesthesia and is a higher risk surgery. Surgical complications are common. 

Medication 

In very progressed cases of thyroid cancer, medication to slow progression may be the only option. Antithyroid medication can reduce rapid onset of thyroid issues and lengthen life expectancy. These medications will need to continue for the duration of the cat’s life and can be expensive.

Petted logo

Worried about the cost of treating your pet's symptoms?

Pet Insurance covers the cost of many common pet health conditions. Prepare for the unexpected by getting a quote from top pet insurance providers.

Get a quote

background

Recovery of Thyroid Cancer in Cats

If the cat responds positively to radioiodine treatment, the general prognosis is very good. Extended survival lengths have been noted even in advanced cases of thyroid cancer. It takes 3-4 weeks to verify whether the treatment is fully successful or not. If it is, there is only a 0.3% chance of remission.

If the cat has undergone surgery, check frequently that the incision is clean and dry. The vet may prescribe calcium or vitamin D supplements for the healing process. In all treatments, the vet will monitor T4 levels in 4-6 weeks, and then periodically after that. Recurrence does happen, especially when radioiodine has not been administered. If the cat is not a good surgical candidate due to advanced cancer, a very restrictive diet may be prescribed to improve and lengthen lifespan. 

Thyroid Cancer Average Cost

From 520 quotes ranging from $3,000 - $8,000

Average Cost

$6,000

arrow-up-icon

Top

Thyroid Cancer Questions and Advice from Veterinary Professionals

dog-breed-icon

Unknown

dog-name-icon

Cuddles

dog-age-icon

15 Years

thumbs-up-icon

0 found this helpful

thumbs-up-icon

0 found this helpful

My pet has the following symptoms:
Jaw-Lump, Urinating + Drinking Lots
Our Cuddles is 15. He was in the vet clinic with extensive lab work 6 months ago because of extreme weight loss. They put him on Felimazole 2.5mg twice a day and said that he will have to be on this for the rest of his life. He still didn't seem to gain any weight and his thyroid levels have been checked several times since then and were always right where they are supposed to be. Eventually I noticed that his jaw on one side seemed to hurt him when I touched it plus there seemed to be a lump and I brought him in for a dental cleaning since the vet couldn't see much. There, the vet found that he had an infected area (pulled three teeth in a row) and a tooth that was broke of (pulled that as well). Now where the infected area was there is still a lump on the jaw after 2 weeks of Amoxicillin Trihydrate and Clavulanate Potassium Tablets. At first, I was hoping that the lump was from the tooth infection but now that doesn't seem to be the case. We moved Cuddles into the house (he used to live in the barn) and have also noticed that he urinates and drinks a lot, probably pees 8 times (big balls in the scoop litter) in a 24 hour period. He has started to eat better now that his teeth are pulled and gained almost a pound in a couple of weeks but I worry much about this lump and this constant drinking and urinating. Do you advice for me?

dog-breed-icon

American Shorthair

dog-name-icon

Junior

dog-age-icon

15 Years

thumbs-up-icon

0 found this helpful

thumbs-up-icon

0 found this helpful

My pet has the following symptoms:
Urinating Outside Litterbox,
My 15 year old male cat was diagnosed with thyroid cancer 5 years ago. He had surgery and was doing fine. I could not afford radiation therapy. A year ago or so the vet examined him and said it looked like the cancer was back as he saw the lump on his throat again. I think blood tests were run and he advised me that it appeared the cancer had spread. My cat has all the symptoms mentioned plus what seems to be hearing loss. He is also throwing up dark or completely clear large puddles twice or more times a week. He cries out loudly at times a horrible yell like cry. He urinates outside the litter box so I have put down pee pads. But I am conflicted about what to do because he is very affectionate and purrs when people carress him. I don’t know if and when to put him to sleep. I don’t want him to suffer but I can’t tell when would be the appropriate time. He eats constantly but I know that is part of his symptoms. People advised to not put him to sleep until he stops eating but he eats because of the cancer. Just looking for advice to putting him to sleep and when.

Thyroid Cancer Average Cost

From 520 quotes ranging from $3,000 - $8,000

Average Cost

$6,000

Wag Compare logo

Get a free pet insurance quote in less than 60 seconds!

Easily compare quotes from the most trusted pet insurance companies in the United States.

Get a quote

background
Need pet insurance?
Need pet insurance?

Learn more in the Wag! app

Five starsFive starsFive starsFive starsFive stars

43k+ reviews

Install


© 2024 Wag Labs, Inc. All rights reserved.