Can a Dog's Oral Cancer Spread?

Examine your dog's mouth regularly and report any changes to your vet.
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If your dog has a tumor in his mouth, it could be malignant. The prognosis for your pet depends on whether the cancer has spread, or metastasized. Oral cancers can be painful, but they won't kill a dog if they don't spread beyond the mouth. Cancer spreads to major body organs is what ends up causing an animal's death.

Canine Oral Cancer

Canine oral cancers generally consist of melanomas, squamous cell carcinomas or fibrosarcomas, three distinct types of tumors that spread to parts of the body. Melanomas spread to the lymph nodes and the lungs. Squamous cell carcinomas located in the front of a dog's mouth do not spread fast; but those on the tongue, the rear of the mouth or the tonsils are likely to have already metastasized by the time of diagnosis. Oral fibrosarcomas, tumors of the soft tissue, usually spread to the lungs. Less often, dogs can suffer from oral osteosarcoma, or bone cancer. If located on the upper jaw, this tumor tends to spread rapidly, generally to the lungs. If located on the lower jaw, it spreads less quickly. Surgery can save a dog if done in time.


Besides a growth in the mouth, symptoms of canine oral cancer include bad breath, excessive salivation, facial swelling, loose teeth, eye-bulging and bloody discharge from the nose. Difficulty eating, loss of appetite and weight loss are possible indication of an oral tumor. You might notice swollen lymph nodes around the neck.

Diagnosis and Treatment

Don't panic if your dog develops an oral tumor. Many are benign, meaning they aren't malignant and won't spread. Your vet diagnoses oral cancer via a biopsy of the growth and X-rays of the mouth and chest. The latter X-ray indicates whether the cancer has spread. Surgery is the treatment of choice, but if the tumor is cancerous, your vet must excise at least 2 centimeters of apparently normal tissue surrounding the tumor in order to achieve "clean margins." For certain tumors, much of your dog's jaw might require removal. Reconstructive surgery is a possibility. Depending on the type of cancer and its stage, or likelihood of spreading, your dog might receive radiation or chemotherapy.

Early Detection

As with other types of cancer, early detection of your dog's oral cancer can mean the difference between life and death. Get into the habit of brushing your dog's teeth regularly, preferably on a daily basis. Not only is this a healthy practice for keeping his teeth and gums in good shape, but it will help you more quickly become aware of changes or growths in his mouth. If you notice oral growths, take your dog to the vet as soon as possible for an examination. Surgery undertaken before a cancer has spread gives your dog the best odds for a full recovery.