Chondrosarcoma (Nasal and Paranasal Sinus) in Dogs

The chondrosarcoma account for ten percent of all primary bone tumors. Fast spreading and very invasive, they affect the nasal cavity and extend into the frontal and other paranasal sinuses. The cause of nasal cancers is unknown, but some breeds seem more predisposed to nasal tumors. Breeds thought to be prone are Basset Hounds, Collies, Airedale Terriers, German Shepherds, and German Shorthaired pointers. The average age reported with this condition is seven years and over. Male dogs seem more at risk than females, and it is believed that animals in urban areas are more likely to be affected than dogs in rural areas.

Nasal passage tumors are a type of cancer that usually affects longer nosed dog breeds, or older animals, and are usually malignant (cancerous) in nature.

• Difficult breathing often combining with an overproduction of mucus which clogs the nasal passages and sinuses 
• Bizarre sneezing, often several sneezes in a row sometimes up to 10-12 times 
• Coughing 
• Increased tear production causing an overflow of tears onto the face
• Occasional nose bleed or discharge from one or both nose canals 
• Facial deformity in advanced stages
• Poor appetite and bad breath 
• Weight loss 
• Seizures in advanced cases
• There is evidence that urban animals are more at risk than their country cousins suggesting an association due to pollution
• Sometimes your dog may paw at his face indicating discomfort

Types 

Most of the nasal cancers identified are sarcomas which are tumors of the connective tissue and are of two types, which are bone sarcomas and soft tissue. The tumor usually occurs on one side of the nasal cavity and extends to the other side over time.

• Fibrosarcoma is the most common and arises from the fibrous connective tissue
• Other types are chondrosarcoma, osteosarcoma lymphomas and then other lesser known sarcomas
• Breeds that are susceptible to this disease include German Shorthaired pointer, Basset Hounds, Collies, Old English Sheepdogs, and Airedale Terriers

It is generally accepted throughout the veterinary community that the cause of these nasal tumors or cancers is an unknown factor. The only thing that is known for sure is that they are: 

• Mostly prevalent in older dogs aged seven years and over
• That male dogs seem to be affected more than females
• Dogs in urban areas are more prone to it than country dogs which may in part be caused from pollution

The best thing is to try and catch it early on in its development. If you see your dog exhibiting any of the symptoms mentioned above, don’t just think they have an allergy to dust or pollen, take them into your veterinary specialist for a check-up and tell them the observations you have noticed with your dog’s behavior.

It will require veterinary skills to perform a diagnosis of what is happening within the nasal and sinus passages, so you will need to take your dog to the clinic as soon as you notice any signs of distress from your pet. Your veterinary caregiver will do a full examination and she will want to know the background medical history of your dog. Blood tests will be taken and may include a blood count and platelet count. The Veterinarian will check the blood samples for evidence of any fungal or bacterial infections. A urinalysis may be suggested as well.

Magnetic resonance imaging(MRI) scan of the nasal passages and paranasal sinuses have become the gold standard for imaging nasal tumors. This imaging tool produces a more substantial image than an X-ray, which is often part of the diagnosis as well. An endoscope, which is a long device with an attached camera that allows for a look at the distressed area, can also be used to go inside the nasal passage for a close-up view of the area but it is difficult because of the small space inside the nose. Other methods include using a fine needle aspiration to collect a sample of the diseased tissue, and suction. Biopsy (analysing a sample of the tissue) is the only way to conclusively diagnose nasal cancer.

Rhinotomy

This involves the opening of the nasal passages and scooping the tumor out, but has since proven to be a negative factor for survival time. If this is followed by orthovoltage radiation therapy it may yield a longer survival time.

Cobalt Radiation Therapy

Most veterinary surgeons use cobalt radiation therapy and CT scan technology for treatment. The use of this needs to be discussed with your consultant regarding the risk / benefit ratio with an honest survival time for your dog. This survival time will depend on the type of tumor your pet has and the stage of the disease. The side effects can be severe and take a long time to heal.

Chemotherapy is often suggested in addition to radiation therapy because it enhances the radiation effects. It is often the less aggressive form of therapy.

Be prepared for extensive home care following treatment, and be aware that your dog will have chronic nasal discharge following the treatment. Be aware that the delicate nasal tissue will never function properly due to permanent injury from the radiation. You must be aware that cataracts and blindness may follow radiation therapy if the orbit has been invaded by the cancer and the eyes are included in the treatment field.

This type of cancer can be very difficult to treat and you must weigh the ethical considerations for your dog (quality of life following treatment) against the cost, time, and ongoing treatments and check-ups involved.

The treatment is severe for your dog, but may result in a further eight months to two years lifespan. Your dog will feel sore, and be in some pain. At home, you will need to set up an area where your pet can rest quietly and keep other pets and small children away as they will not be up to visitors. Occasional trips outside for bladder and bowel functions should be kept short. Medications should be used as instructed by the veterinarian specialist to avoid the risk of overdose. Your dog will require veterinarian health care check-ups regularly after the treatment. Untreated, the prognosis is very poor, but with treatment your dog may extend their life by a few months to a couple of years.