Is Your Dog at Risk? How Mouth Cancer Can Spread in Canines

What is mouth cancer in dogs?

Mouth cancer, or oral cancer, in dogs refers to any type of cancer that develops in a dog’s mouth or throat region. It can include cancers of the lips, tongue, gums, palate, tonsils, and back of the throat.

Some common symptoms of mouth cancer in dogs include swelling or ulcers in the mouth, bad breath, bleeding from the mouth, difficulty eating or swallowing, and loose teeth. Tumors may also be visible in the mouth.

Mouth cancer is not very common in dogs, with studies estimating the incidence rate at around 3-4 cases per 1,000 dogs. However, it tends to occur more frequently in older dogs, especially those over age 10.

veterinarian examining a dog's mouth for signs of cancer.

What causes mouth cancer in dogs?

The exact causes of mouth cancer in dogs are not fully understood, but there are some known risk factors and genetic predispositions.

Certain breeds such as Golden Retrievers, German Shepherds, Poodles and Rottweilers seem to have a higher genetic risk for developing oral cancer. The reason for this increased susceptibility in some breeds is not known.

Environmental factors also likely play a role. Dogs with increased exposure to sunlight and resulting sun damage to the lips/mouth may be at higher risk. Exposure to tobacco smoke is another potential risk factor, so avoiding secondhand smoke is recommended.

Other possible environmental triggers include chemical carcinogens, vitamin deficiencies, and chronic mechanical irritation. For example, poorly fitting teeth, fractured teeth, and porcupine quills stuck in the mouth can chronically irritate the tissues over time and potentially lead to cancerous changes.

While the precise causes are still being studied, limiting sun exposure and tobacco smoke exposure may help reduce the risk of mouth cancer in susceptible breeds. Regular veterinary checkups can also aid early detection and treatment.


How is mouth cancer diagnosed in dogs?

Mouth cancer in dogs is diagnosed through several methods by the veterinarian:

Physical Exam – The veterinarian will perform a thorough physical exam of the dog’s mouth, feeling for any abnormalities or swelling. The vet will look closely at the gums, tongue, roof of the mouth and under the tongue for signs of tumors or growths.

Biopsy – If a suspicious growth is found, the vet will likely take a biopsy of the tissue. This involves surgically removing a small sample of the tumor so it can be examined under a microscope. This is the only way to definitively diagnose oral cancer.

Imaging Tests – Tests like x-rays, CT scans or MRI may be used to see how far the cancer may have spread and determine the stage of the disease. Imaging allows the vet to look for abnormalities not visible from a physical exam alone.

With a combination of a physical exam, biopsy and imaging tests, vets are able to accurately diagnose mouth cancer in dogs. Early detection is key for the best outcome and prognosis.


Can mouth cancer spread in dogs?

Unfortunately, mouth cancer (oral cancer) can spread (metastasize) from the original tumor site in dogs. This occurs when cancer cells break away from the primary tumor and travel to other parts of the body through the lymph or blood vessels. There they can form new tumors damaging other tissues and organs.

The lymph nodes, lungs, and bones are common sites for mouth cancer to spread to in dogs. Lymph node metastasis is often the first sign that the cancer has begun to spread. Oral melanoma, an aggressive cancer, has a high tendency to spread to locations like the lymph nodes, lungs, liver, and kidneys. Other oral cancers like squamous cell carcinoma also frequently metastasize.

illustration showing cancer spreading from mouth to lymph nodes.

If the cancer spreads, it makes treating and curing it much more difficult. However, early detection and treatment of mouth cancer in dogs before it has a chance to significantly spread can help prevent metastasis and improve the prognosis.

Routine dental checkups and care are important to closely monitor for any suspicious oral masses or growths that could indicate cancer. Catching mouth cancer early maximizes the treatment options and chances for remission. But once diagnosed, staging tests like lymph node aspirates and imaging will determine if the cancer has already spread from the original tumor site.


How is mouth cancer treated in dogs?

The primary treatment for mouth cancer in dogs is surgery to remove the tumor. Depending on the location and extent of the tumor, this may involve partial removal of the jaw or tongue. Surgical margins are very important with oral tumors to ensure complete removal. Even with clean margins, recurrence rates for oral tumors are around 50%.

Radiation therapy may be recommended after surgery, particularly if margins were narrow or incomplete. Radiation helps eliminate remaining cancer cells and reduces risk of recurrence. It involves a series of treatments over several weeks. Side effects like mouth inflammation can usually be medically managed.

Chemotherapy is sometimes used alongside radiation, but generally isn’t very effective as a sole treatment for mouth cancer in dogs. The most commonly used chemotherapy drug is carboplatin. Side effects like gastrointestinal issues are usually transient.

While mouth cancer in dogs is difficult to cure long-term, combining surgery, radiation, and chemotherapy can provide the best chances of prolonged survival. Work closely with your veterinarian to determine the most appropriate treatment plan based on your dog’s specific cancer type and extent.


What is the prognosis for dogs with mouth cancer?

The prognosis for dogs with mouth cancer can vary greatly depending on the type, location, and stage of the cancer. Some key factors that influence prognosis include:

Survival rates: Studies show that approximately 60% of dogs with oral malignant melanoma survive 1 year or longer after diagnosis. For oral squamous cell carcinoma, 1 year survival rates are around 30-40%. With aggressive treatment, survival times can sometimes be extended beyond these averages.

Life expectancy: Without treatment, survival times are very short, often just weeks to months. With treatment, average survival times range from 4-18 months depending on cancer type and stage. Early stage mouth cancers generally have better prognoses. One study found average survival times of 18 months for dogs with early stage oral melanoma.

According to, dogs without negative prognostic factors have a median survival time of 21 months with radiation therapy. However, dogs with metastasis have a much poorer prognosis with survival times of just 2-4 months even with treatment.

Overall, mouth cancer can significantly reduce life expectancy in dogs. But early detection, proper staging, and aggressive treatment can help extend survival times. Regular dental cleanings and oral exams are important for spotting problems early on.

How can mouth cancer be prevented in dogs?

While there’s no sure way to prevent mouth cancer in dogs, there are some steps that may help reduce the risk:

owner brushing dog's teeth to reduce cancer risks.

Get regular veterinary exams. Your vet can look for early signs of oral cancer or other mouth problems during annual checkups. Catching issues early makes treatment more likely to be successful.

Practice good oral hygiene. Regularly brushing your dog’s teeth helps remove plaque and tartar that could otherwise cause gum infection or irritation. Keeping the mouth healthy reduces inflammation that may encourage cancer growth.

Avoid carcinogens. Limit your dog’s exposure to substances linked to cancer, like tobacco smoke. Also be mindful of lawn chemicals, pesticides, herbicides, and other environmental toxins. Reduce sun exposure, as prolonged UV radiation may increase cancer risk.

While oral cancer can be unpredictable, focusing on prevention and oral health is the best way to lower your dog’s chances of developing mouth tumors or growths.

How to care for a dog with mouth cancer

Providing proper care and maintaining a good quality of life is very important when caring for a dog with mouth cancer. Since mouth cancer can be extremely painful, a top priority is keeping your dog comfortable and managing pain.

Pain management will likely involve prescription medications from your veterinarian. Opioids like tramadol are commonly used to control pain related to cancer. Other medications may include NSAIDs like carprofen or meloxicam to reduce inflammation and discomfort. Your vet may recommend a multi-modal pain management plan combining several medications for the most effective pain relief.

Making meal times as comfortable and stress-free as possible is also important. Soft foods that are easy to eat and swallow can help. Hand feeding soft canned food warmed to enhance smell and taste may encourage eating. Avoiding hard kibble can prevent discomfort in a painful mouth.

Providing ample fresh water is essential, and you may need to periodically wipe your dog’s mouth to keep it clean. Using elevated food and water bowls can make eating and drinking easier. Gentle grooming around the mouth will keep the area clean.

Maintaining a calm, soothing environment and giving your dog affection can also help them feel comfortable. Ask your vet about complementary therapies like pain relief medications, dietary supplements, or acupuncture which may enhance quality of life.

With attentive home care and pain management, you can greatly improve comfort for a dog with mouth cancer. Work closely with your veterinarian to continually maximize your dog’s quality of life.


Impact on quality of life

Mouth cancer can significantly impact a dog’s quality of life. The tumors and surgery can make it difficult and painful for the dog to eat, drink, and swallow. As a result, dogs with mouth cancer often experience significant weight loss and become malnourished.

Dog owners need to ensure their dog maintains proper nutrition, which can be challenging. Special diets like soft food, blended food, or feeding tubes may be necessary. It’s critical to work closely with your veterinarian to find ways to keep your dog eating.

Beyond eating issues, mouth tumors or surgery can make it difficult for dogs to bark, play with toys, go on walks, and do other normal dog activities. Dogs may act lethargic and withdrawn.

woman hugging her dog to provide comfort.

Owners should monitor their dog’s pain levels and provide pain medication as needed. Gentle exercise, mental stimulation, and quality time with family can help maintain a good quality of life. But owners need to adjust expectations, as their dog’s activity levels will be diminished.

Even with the best care, dogs with mouth cancer will have a reduced quality of life. But owners can make the most of their dog’s good days and take things one day at a time. Focusing on providing comfort, nutrition, love, and pain control can extend a good quality of life for as long as possible.

When to euthanize a dog with mouth cancer

Deciding when to euthanize a dog with mouth cancer can be very difficult. Quality of life is the most important factor when making this decision. According to PetCure Oncology, euthanasia may be the most humane option if:

  • The cancer has spread and is not responding to treatment
  • The dog is experiencing significant pain that cannot be managed with medication
  • The dog has difficulty eating or swallowing and is losing weight rapidly
  • The dog has frequent infections or bleeding in the mouth that do not respond to treatment
  • The dog is having seizures, neurological problems, or behavior changes from the cancer spreading

PetMD advises monitoring your dog’s symptoms closely and discussing options honestly with your veterinarian. Euthanasia may be recommended if the veterinarian feels your dog’s quality of life is declining rapidly with no chance of improving. It is a personal decision, but focusing on minimizing suffering and maintaining dignity can help guide you.

According to Paws Into Grace, you may need to consider euthanasia if your dog has uncontrolled symptoms, a poor prognosis, and his/her quality of life is declining. While the decision is difficult emotionally, choosing euthanasia at the right time can be the final act of love and kindness you give your dog.

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