Canine Thyroid Cancer

Canine thyroid cancer is simply this: tumors located in the thyroid glands. The thyroid glands are a pair of small structures that produce hormones that regulate your dog's metabolism. These hormones are vital in maintaining normal body function. The glands are located roughly halfway down a dog's neck.

Thyroid Cancer Facts

Both males and females are equally susceptible to the cancer. However, it is more likely to affect middle-aged to older dogs. Mid-sized to larger breeds are prone to developing the cancer. Some of those breeds include:

  • Boxers
  • Beagles
  • Golden retrievers

Thyroid cancer has the potential to spread to other organs, particularly the lungs and lymph nodes.

Symptoms of Thyroid Cancer

The most common symptom of thyroid cancer is a swelling, or mass in the throat. Other symptoms that are less easy to catch, and could also be symptoms unrelated to thyroid cancer include:

  • Coughing or difficulty in breathing
  • Difficulty in swallowing
  • A change in the tone of the dog's bark

All of these symptoms are caused by the tumor affecting the neck area. The tumor is affecting the windpipe, esophagus and voice box. It is uncommon, but also possible for a dog to show symptoms that are associated with hyperthyroidism. Hyperthyroidism is a condition where the thyroid glands are producing too many hormones. The symptoms are:

  • Weight loss, and loss of muscle strength and mass because of this
  • Irritable or nervous
  • Fur may look shaggy
  • Drinking and urinating more than usual

Just as there is a condition where the thyroid glands are producing too many hormones, they can also produce too little. This is called hypothyroidism, and the symptoms are close to the opposite of hyperthyroidism:

  • Weight gain and obesity
  • Hair loss
  • Lethargy
  • Intolerance to cold
  • Slow heart rate
  • Discoloration in the skin

Keep in mind that your dog may not show all of these symptoms. Catching the symptoms early is key to the survival of your dog.

Diagnosing the Cancer

To properly determine whether or not your dog has thyroid cancer, and is not suffering from another condition, your vet will do a series of tests:

  • X-rays of the neck and chest area
  • Biopsy of the tissue in the growth
  • Blood tests

Movable Tumors

Movable tumors have not attached themselves to the tissue, and can be easily removed by surgery. This accomplishes long-term control of the cancer. It is possible that small amounts of the cancer could have spread to other organs in the dog's body, or haven't been completely removed, and chemotherapy may still be necessary to ensure the cancer has been dealt with.

Fixed Tumors

Fixed tumors are tumors that have attached themselves to underlying tissue. These tumors are often too large for surgical removal, or cannot be completely removed. The best treatment in these cases is chemotherapy, or possibly radioactive iodine treatment. The symptoms of thyroid cancer can be expected to be alleviated, but only for a short amount of time.