Nasosinal Cancer in Dogs
What are nasosinal tumors?
The nasal cavity is a large air-filled space above and behind the nose. Paranasal sinuses are air-filled spaces,
communicating with the nasal cavity. The most common type of cancers affecting this region are carcinomas and
sarcomas, both of which are locally invasive. The metastatic rate (spread to other organs) is considered low at the time
of diagnosis but can be as high as 50% at the time of death. The most common sites for metastasis are the lymph nodes
and the lungs, but can also include the bone, kidneys, liver, skin, and the brain.

How common are these tumors?
Tumors in the nasal cavity and paranasal sinuses are not very common and account for approximately 1% of all tumors
in dogs. The average age of dogs with this disease is about 10 years and medium to large breeds may be at higher risk.

What are the symptoms?
The average duration of symptoms before diagnosis is 3 months and include bleeding from the nose, nasal discharge,
facial deformity from bone erosion and tumor growth, sneezing, difficulty breathing, or eye discharge due to tumor
obstruction of the ducts.

How is the diagnosis made?
Advanced imaging techniques such as CT scan are superior tools for evaluating the extent of tumors in the nasal cavity
as well as for planning radiation therapy treatment. Standard X-rays are still acceptable and readily accessible imaging
tools but their resolution and level of anatomical detail are not as good as for CT scan.  In order to definitively confirm
cancerous growth in the nasal cavity, a tissue
biopsy should be obtained. For nasal tumors, there is a variety of different
techniques that can be used. These include vigorous nasal flushings in order to dislodge pieces of tumor or transnostril
aspiration, a technique that passes a needle through the nostril into the tumor. If nearby lymph nodes appear swollen,
they should be sampled for
cytology to test for the presence of cancer cells that might have spread.

Do these tumors cause pain?
It is imperative that pets with cancer are provided with pain medication to relieve discomfort caused by the disease as
well as by the treatments. To learn more, please visit the
Cancer Pain Management section.

What food should be fed to pets with cancer?
Pets with cancer need to be fed diets specifically designed to support a cancer patient. To learn more, please visit the
Cancer Nutrition
section.

What are the treatment options?
Because nasosinal cancer begins to invade the bone early, surgery (called rhinotomy) alone is not sufficient to control
the cancer.
Radiation therapy alone directed to the affected area (using cobalt source or linear accelerator) has become
the treatment of choice for canine nasosinal tumors. Its advantage is that it treats the entire nasal cavity together with
the affected bone and has shown the greatest improvement in survival. No controlled studies have been done to
determine whether surgical removal of the tumor prior to radiation therapy provides even better benefit to the patients.
The radiation therapy is typically delivered in 10-18 treatment sessions over the course of 2-4 weeks. The use of CT
imaging prior to initiating radiation therapy can be of tremendous help for effectively directing radiation only toward the
affected areas while sparing normal healthy tissues.

What are the radiation treatment side effects?
Unfortunately, radiation therapy will affect some normal tissues that cannot be excluded from the radiation field (the area
scheduled for irradiation). The amount of damage will depend on the daily dose of radiation, total radiation and how
much of the tissues is being treated. Immediate side effects of radiation therapy usually include inflammation of the oral
cavity, inflammation of the nasal cavity, shedding of the skin, and eye dryness. These immediate side effects usually
disappear 2-8 weeks after therapy and can be treated with antibiotics, pain medication and/or artificial tears if needed. If
the mouth inflammation is severe and the dogs are unable to eat, short-term feeding tubes may have to be inserted to
support the proper nutritional intake. Late side effects of radiation therapy are more long lasting but can be prevented
with proper planning. The affected areas can include the eye lens (cataracts), eye cornea (inflammation, dryness), eye
uvea (inflammation), eye retina (bleeding and wasting), neuronal tissue (possibly causing seizures), bone, and skin.
These late complications develop months to years after therapy and are generally not reversible.

Are there any clinical trials investigating new treatments?
There are no clinical trials specifically designed for nasal cavity tumors in pets, however, there are clinical trials
investigating novel therapies for general malignancy in dogs. To learn more about clinical trials open to enrollment in the
United States, please visit the
Clinical Trials for Any Type of Tumor section. To learn more about veterinary clinical trials,
please visit the
Pet Clinical Trials section.

To help Pet Cancer Center conduct more nasal cavity cancer clinical trials across the United States in order to make
novel and more efficacious therapies available to pets, please

What is the prognosis?
One study of 139 dogs showed that without treatment, the average survival time is 95 days. Another study showed that
dogs who underwent surgery alone had median survival 3-6 months, which is comparable to that reported for no
treatment. Prognosis of dogs who show symptoms of nose bleeding appears to be worse (median survival 88 days)
compared to those without it (224 days). The median survival time after full course of radiation treatment alone ranges
from 8 to 19.7 months, and 43-60% of dogs are alive 1 year after radiation and 11-44% 2 years post-radiation. The use
of CT imaging to plan radiation treatment can increase the survival range to 11-19.7 months. Although radiation therapy
alone is able to provide local control of nasosinal tumors for approximately 10 months and thus prolongs the patients'
overall survival, most will eventually die as a result of local disease progression. New approaches to control these tumors
need to be developed to further improve the response and overall survival.

Sources:
  • Withrow Stephen J, and David M. Vail. Small Animal Clinical Oncology. St Louis: Saunders Elsevier, 2007.
  • Morrison Wallace B. Cancer in Dogs and Cats: Medical and Surgical Management. Baltimore: Williams&Wilkins,
    1998.
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Last updated 11/9/09