Mouth Cancer (Gingiva Fibrosarcoma) in Dogs

Gingiva fibrosarcoma is a malignant cancer in the mouth derived from fibrous connective tissue. Although they have a lowered metastatic rate their propensity for aggressively invading bone and other tissue that surrounds them makes them a serious health concern. They may appear clinically similar to other oral tumors so biopsy of the affected tissue will be needed for diagnosis. Fibrosarcomas are resistant to radiation therapy and chemotherapy. Prompt attention to symptoms and removal of tumor or tumors gives your pet the best chance for a positive outcome.

Gingiva fibrosarcoma is an aggressive malignant cancer of the mouth derived from an overgrowth of fibrous connective tissue. Early diagnosis and removal of cancerous tissue are required.

Fibrosarcoma is a rapidly growing cancer, and symptoms that point to any form of cancer in the mouth should prompt a call to your veterinarian as soon as possible.

• Oral bleeding
• Traces of blood in saliva
• Difficulty chewing and eating
• Difficulty swallowing
• Enlarged lymph nodes
• Excessive drooling 
• Facial swelling
• Growth or growths in mouth
• Persistent halitosis
• Unexplained weight loss

Types

This particular form of cancer is known to invade nearby bones and treatment often requires the removal of all or part of the bones of the jaw. These surgical procedures are called either mandibulectomy or maxillectomy.

Mandibulectomy

• The surgical removal of all or part of the lower jaw
• Animals usually recover remarkably well from a mandibulectomy and the recovery period is usually only 12-72 hours

Maxillectomy

• The surgical removal of all or part of the upper jaw
• Patients usually recover well from a maxillectomy as well, often with very little change to their cosmetic appearance

The origins of any cancer are indefinite but there are some conditions that may increase the likelihood of canine fibrosarcomas developing. 

• Advancing age
• Exposure to chemicals
• Genetic predisposition (Larger dogs are more likely to develop this cancer than the smaller breeds, and Golden Retrievers have an increased risk)
• Male dogs are more likely to be affected by fibrosarcomas in general
• Infections
• Radiation

Your veterinarian will want to start with a physical examination of the masses or lesions in the mouth and get a tissue sample so that it can be more closely examined to determine its makeup. A complete blood count, biochemistry profile, and urinalysis will also be obtained in order to expose any underlying or concurrent diseases. Depending on the size and the placement of the tumor, the veterinarian will generally use either a needle aspiration or full excision technique to take a sample of the affected tissue. The sample will then be examined under a microscope, using a technique known as cytology. X-rays will be completed to look for evidence of cancer on the skeletal system as fibrosarcoma tumors have a propensity for invading nearby bones. Testing of the lymph nodes, usually by needle aspiration, will also occur to determine if the cancer has metastasized. If the tumor was excised in order to biopsy it, the edges will be also checked at this point to ensure they got the entire tumor.

Treatment usually starts with the removal of the tumor itself as well as excising any extensions into surrounding tissue and bone. With gingiva fibrosarcomas this may necessitate removing a large portion of the jaw bone if a spread is noted or suspected. If the tumor and all affected tissues are cleanly and completely removed and if the cancer has not already metastasized the prognosis for this treatment is effective in extending survival rates by a year or two. Although fibrosarcomas that develop in the mouth are less likely to be metastatic than other sarcomas, it is still sometimes recommended that the area be treated with radiation. Radiation may also be used if the tumor is inoperable because of size or position, however, oral fibrosarcomas are known to be somewhat resistant to radiation treatments. Gingiva fibrosarcomas are also resistant to traditional chemotherapy so it is rarely considered as a treatment option.

After any surgical excision it is important to keep the site clean and free from dirt and debris. You will need to keep your pet from interfering with the site, and examine it regularly for swelling, bleeding or pus. Keeping the recovering patient in a calm and quiet environment will help speed healing, as will having appropriate food and water within reach of them.  Specialized feeding and care instructions may be given by your veterinarian to facilitate healing to the excision. If a mandibulectomy or maxillectomy was performed to remove the cancer, your dog may have a protruding tongue where the bone was removed until they get used to retracting their tongue on their own. You may also observe an increase in salivation and clicking noises that occur when your dog chews. There may also be a visible narrowing or drooping of the nose due to the removal of bone.