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.
The clinical symptoms of a tumor of the nose can be very variable. Affected patients often show nasal discharge, this can be purulent, but also nosebleeds, sneezing or so-called reverse sneezing is possible.
.For tumors that are localized in the back of the nasal cavity and that have already grown through the bony barrier between the nasal cavity and the brain, neurologic symptoms may also be possible. Sometimes these patients first show epileptic seizures. In the later stages, all tumors can cause what is known as bone lysis, or dissolution of the adjacent bones. They can grow behind the eye or under the skin at the bridge of the nose, causing facial asymmetry and a bulging eye called exophthalmos.
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.
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.
.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.