Canine mouth cancer

Updated July 19, 2017

Cancerous tumours do grow in dogs' mouths, but it is impossible to tell the nature of the tumour by simply looking at it. All unusual growths and lesions in your dog's mouth should be pointed out to your veterinarian.


Several types of tumours can develop in a dog's mouth. The most common benign tumour is an epulis, a tumour of the periodontal ligament. Of the malignant tumours, melanoma is the most common.


Malignant melanomas metastasise early and are locally invasive. By the time a diagnosis is made, cancer cells have already spread to the lungs and to regional lymph nodes along the neck.


Melanomas generally appear as dark lumps inside the mouth. They are mostly seen in older dogs and often affect the bones of the jaw as well as the gums.


Veterinarians suspect dogs develop cancer by inhaling carcinogens. Symptoms of mouth cancer include drooling, bleeding from the mouth, facial swelling, decreased appetite and bad breath.


Treatments for mouth cancer include radiation, chemotherapy, surgery, cryosurgery and, in some cases, homeopathic remedies. If the tumour occurs on the soft palate or hard palate, surgery may be complicated and ineffective.

Affected Breeds

According to Dog Health Guide approximately 50 per cent of mouth tumours are found in poodles, cocker spaniels and older dachshunds.

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About the Author

Loraine Degraff has been a writer and educator since 1999. She recently began focusing on topics pertaining to health and environmental issues. She is published in "Healthy Life Place" and "Humdinger" and also writes for various websites. Degraff holds a master's degree in communications design from Pratt Institute.