Nasal and paranasal tumors in dogs

Nasal cavity tumors and paranasal sinus tumors occur in approximately 1% of the canine population. Typically, they are older patients with an average age of ten years. These tumors originate from cells located in the nasal mucosa or surrounding connective tissue. Depending on the tissue of origin, we differentiate the tumors. If it is glandular tissue, we speak of adenocarcinomas or adenomas. If the tumor originates from epithelial cells, it is called squamous cell carcinoma or papilloma. If the tumor originates from connective tissue or cartilage, it is called fibrosarcoma, chondrosarcoma or, less differentiated, just sarcoma. In some cases, it is not possible to identify the tissue of origin because the cells are not well enough differentiated.

What are the symptoms of a nasal cavity tumor or a sinus tumor?

Dog sitting in stablePlus

Reverse sneezing

Any nasal discharge, whether bloody or purulent, and any persistent reverse sneezing should be thoroughly worked up and clarified. Endoscopy and computed tomography (CT) are available for this purpose, among others. The earlier tumors are detected and the faster therapy is started, the better the prognosis.

Nasal cavity and sinus tumors: Always malignant?

Unfortunately, most tumors of the nasal cavities and sinuses are malignant, i.e. carcinomas or sarcomas. The main characteristic of these tumors is infiltrative growth into the surrounding tissue. Thus, they cause problems locally. The risk of metastases remains low in these tumors. However, up to 10% of patients show metastasis to the regional lymph nodes. Metastasis to the lungs is rare. Nevertheless, thorough staging should be performed because of this risk. In general, staging of these tumors includes puncture of the mandibular lymph nodes and sometimes other lymph nodes of the neck (lymphocentrum retropharyngeum). In addition, a chest x-ray and, if necessary, an abdominal ultrasound should be performed.

How to treat nasal or paranasal tumors?

For the selection of the right therapy, the type of tumor should be known. Due to the infiltrative nature of the tumors, surgery is not recommended in most cases without subsequent radiotherapy, as these tumors tend to grow again within a few weeks, i.e. recur. In addition, complete surgery is sometimes impossible because of the nasal turbinates.

For many years, radiation therapy has been the treatment of choice because it treats not only the visible portion of the tumor but also the infiltrative portions that are not visible. Generally, there are different protocols that can be applied. At EQUINOX HEALTHCARE, a hypofractionated protocol consisting of ten sessions, daily Monday to Friday, over two weeks is predominantly used. If this protocol is not an option, a five-session protocol can be used as an alternative.

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In order for a nasal cavity or sinus tumor to be irradiated, a computed tomography scan is necessary as a planning CT. In this process, a special positioning aid with a bite block, a bite impression and a vacuum mattress is produced. Based on the sectional images, an individual radiation therapy treatment plan is created in a special computer-based planning system. This procedure makes it possible to irradiate the tumor with a high dose while sparing the surrounding normal tissue.

For accurate and precise irradiation of nasal cavity tumors, we use individual positioning aids such as vacuum mattresses, bite blocks and bite impressions. Plastic masks are used at EQUINOX HEALTHCARE only in exceptional cases, as they rarely improve accuracy. PlusPlus
Bite block and vacuum mattress for positioning a dog

In which breeds do nasal or paranasal tumors occur particularly frequently?

There is no clear breed predisposition for a nasal cavity tumor. It is discussed whether dog breeds with a long nose, so-called dolichocephalic breeds, suffer more from nasal cavity tumors. However, it is not uncommon for other breeds of dogs to be affected, such as a French Bulldog or Golden Retriever. However, there are environmental factors that increase the risk of developing a nasal cavity tumor, these include mainly pollution and cigarette smoke.

What is the prognosis for treatment of nasal or paranasal tumors?

The earlier a nasal cavity tumor is diagnosed, the better the chances of long-term tumor control. Small tumors remain controllable for an average of two years. In the case of very large tumors that already break through various bones, the mean tumor control described is unfortunately only 6-9 months in some cases.
Important to know: The smaller the tumor, the easier it is to treat and the better the prognosis. PlusPlus
Computed tomography of a nasal cavity tumor
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