Oral tumours

What is an oral tumour?

A variety of benign and malignant tumour types may occur in the mouth. These tumours may arise from the bones, muscles or gum layer of the upper or lower jaw. They are typically destructive, causing swelling and loss of the bone surrounding the teeth. In the dog, the following malignant tumours have been described: fibrosarcoma, malignant melanoma, squamous cell carcinoma and osteosarcoma. Melanoma are often dark black in colour, but this is not always the case. A variety of benign tumours can also develop in the mouth. Although these tend to be more localised, some can become ulcerated and appear quite unpleasant. The benign tumours are usually arising from around a tooth, so premature tooth loss or a growth about a tooth is often seen.

How can I tell if my pet has an oral tumour?

  • Visible mass along the gumline
  • Bleeding from the mouth
  • Loose teeth
  • Halitosis (bad breath)
  • Pain when eating
  • Difficulty eating
  • Swelling of the face

Most animals present with an oral mass, which has recently been noticed. Occasionally, oral bleeding, halitosis (bad breath) or difficulties eating may be seen. Loose teeth, in a patient with otherwise good dentition, should raise the possibility of underlying neoplasia. Sometimes, the mass is evident as a swelling about the cheek or beneath the eye. 

Tumours at the front of the mouth are usually more easily seen and are therefore spotted more quickly. Sadly, our patients often don’t let us know about problems at the back of their mouth until they have got quite large.

What is the cause of an oral tumour?

The cause of most oral tumours is unknown. There are no obvious breed predispositions.

How is an oral tumour diagnosed?

The physical appearance of many oral tumours is very similar, so simple observation alone is not enough to provide a diagnosis. We also need to assess how much of the jaw has been affected by the tumour so we can understand how best to treat it.

The clinical work-up for most oral tumours will usually include a CT of the head, neck and chest. These images are helpful to assist with surgical planning, and also to assess whether the tumoour has potentially spread beyond the primary site. As part of this evaluation, palpation and cytological evaluation of regional nodes, and an incisional biopsy of the mass may also be obtained.

Large incisional biopsies should be submitted due to the likelihood of superficial ulceration and necrosis obscuring the true nature of the lesion. Wedge biopsy with a scalpel, or a skin punch biopsy can be used. 

How is an oral tumour treated?  

Surgical removal is usually the most successful treatment modality for oral cancer. 

Various surgical procedures have been described for oral tumours. Despite the fairly radical nature of some of the procedures, clinical recovery is usually rapid with animals generally eating very quickly following surgery. Long term function is excellent, and cosmetics is usually acceptable to the owners. Various reconstructive techniques are used in some cases to improve the cosmetic appearance.

Management of even benign lesions will require some degree of bone-removal, since simple excision of the superficial mass at the gum level only usually be associated with recurrence. Thankfully, canine and feline patients tolerate extensive removal of the upper and lower jaw extremely well, with little disruption to quality of life.

What is the prognosis of an oral tumour

The prognosis for all benign tumours is excellent, provided a complete margin is obtained. Conservative surgery may result in tumour recurrence, and the need for further surgery.

The prognosis for malignant tumours is more variable, although most patients can enjoy an improved quality and quantity of life. While a complete cure is not always possible, the improved comfort following removal of the tumour is an important initial goal of treatment. Depending on the specific tumour being treated, there may be options for chemotherapy, radiotherapy or immunotherapy to help prevent tumour recurrence following surgery.