Nose Cancer in Dogs

There Are Several Different Types of Nose Cancer in Dogs

There are a variety of different cancer types that can occur in the nasal cavity, so in this article, we are taking a broad view of nose cancer in dogs.

Nearly two-thirds of nasal tumors in dogs are carcinomas, including adenocarcinoma, squamous cell carcinoma, and undifferentiated carcinoma.

The bulk of the remaining tumors are sarcomas, including fibrosarcoma, chondrosarcoma, osteosarcoma, and undifferentiated sarcoma.¹

Let’s look at some of these tumor types more closely. Please note that you may see links to other articles that go more in-depth on the less common types of canine nose cancer.

Adenocarcinoma, the Most Common Canine Nose Cancer

Adenocarcinoma is the most common nasal tumor in dogs. ^2,3 Overall, adenocarcinomas respond better to radiation therapy than squamous cell carcinoma or undifferentiated carcinoma and have a relatively better long-term prognosis.⁴

Squamous Cell Carcinoma

Squamous cell carcinoma may involve the nasal planum or other sites covered with squamous epithelium, such as the gums, tonsils, or tongue. It can also originate from the mucosal lining of the frontal sinus and nasal passage.⁵

Historically, dogs with squamous cell carcinoma don’t respond as well to radiation as dogs with sarcomas or adenocarcinomas do.

Undifferentiated Carcinoma

Undifferentiated carcinoma translates to “undifferentiated tumor.” This refers to a tumor with little or no evidence of differentiation, meaning it does not resemble normal tissue.⁶

Nasal undifferentiated carcinoma is believed to originate from the Schneiderian epithelium (the membranous lining of the maxillary sinus cavity) or the nasal ectoderm of the paranasal sinuses.

Given the undifferentiated nature of this malignancy, immunohistochemical analysis (see below) is constructive so your veterinarian can confidently formulate a treatment plan.⁷

Historically, dogs with undifferentiated carcinoma have a poorer outcome after radiation therapy than those with sarcomas or adenocarcinomas.

Chondrosarcoma

Chondrosarcoma is a malignant tumor involving the cells that produce cartilage matrix (the stuff cartilage is made from).⁹

Dogs with intranasal chondrosarcomas may have better treatment responses than dogs with adenocarcinoma or squamous cell carcinoma⁸.

Osteosarcoma

Osteosarcoma is a malignant mesenchymal tumor and is the most common primary bone tumor in dogs. Osteosarcoma accounts 6% of nasal tumors.¹⁰

Undifferentiated Sarcoma

Undifferentiated sarcoma is a type of soft tissue sarcoma, also called unclassified sarcoma.³⁰

Nose Cancer In Dogs Can Be Hard to Diagnose Accurately

Nasal tumors often represent a diagnostic and therapeutic challenge due to their confined location within the nasal cavities.²

It can be difficult to see them clearly because of the tight space and the complex nasal cavity structures. It can be challenging to treat them for the same reason.

Pain and Nasal Cancer

Most dog cancers do not cause pain, but that’s not the case with nose cancer, no matter the type.

Nose cancer in dogs can be painful. If you think about your own pain when you have something going on in your head, you can assume your dog feels something similar. There is not much “extra room” in the head, and any extra pressure or obstruction can cause discomfort or pain.

You and your veterinarian will want to address pain relief and relieve obstructions  as part of your response to nasal cancer (see below).

This is true no matter what type of nasal cancer you face, your ultimate treatment choices, or your treatment goals.

Stats and Facts about Nose Cancer in Dogs

• Tumors of the nose and paranasal sinuses typically are locally invasive and metastasize infrequently.
• Metastasis is more likely in carcinomas and usually occurs late in the disease process.
• Metastasis at the time of diagnosis is seen in approximately 4% of animals but may be as high as 40–50% at the time of death.¹
• Common sites of metastasis are the regional lymph nodes, lungs, and brain.²⁹
• If treatment is not pursued, the survival time is 3–5 months after diagnosis.²⁹
• Nasal tumors account for approximately 1% to 2% of all cancers in dogs.²
• Malignant tumors of epithelial origin (carcinomas) comprise 70% of intranasal tumors, with adenocarcinoma and squamous cell carcinoma being the most commonly reported. Sarcomas represent a smaller proportion.¹¹

What Causes Nasal Cancer in Dogs

For many cancers, we often cannot determine an exact cause for cancer development, but nasal tumors do have a likely culprit. Passive exposure to tobacco smoke has been identified as a known cause of canine nasal tumors.¹²

Of course, nasal cancer is still a multifactorial disease, meaning many things must go wrong for it to occur.

Risk Factors for Developing Canine Nose Cancer

A few factors can increase your dog’s risk of developing nasal cancer.

• Long-nosed dogs living in urban environments are at higher risk for developing nasal tumors.¹³
• There is a higher incidence in males than in females.⁴
• On average, dogs are 9.5–10 years old when diagnosed.⁴

Nasal Cancer in Dogs Symptoms

The symptoms you might notice at home will vary depending on the exact location of your dog’s nasal tumor and the type of cancer he or she has.

Here are some symptoms you might see:

• Chronic nasal discharge (this is the most common clinical finding)
• Periodic sneezing
• Nosebleeds
• Abnormal sounds when breathing
• Facial and oral deformities resulting from the destruction of bone or soft tissues
• Protrusion of the eyeball
• Secondary epiphora (tearing of the eye) may occur if the nasolacrimal duct is blocked²⁹

Diagnosing Nasal Tumors in Dogs

It’s important to know upfront that diagnosing nasal cancer can be complicated.

Other diseases of the nasal cavity, such as fungal infections, foreign bodies, and allergies, have symptoms similar to nasal tumors and are more common. Your veterinarian will suspect those and want to eliminate those causes first.

Treating for More Common Problems First

Treating for a fungal infection or allergies first because they are more common, and only considering nasal tumors when those treatments don’t work delays diagnosis. This is unfortunate.

However, it’s also the way that medicine works: we look for and treat the most common cause first, and only move on to other possibilities if that doesn’t work.

As you will see below, the testing necessary to diagnose and treat cancer is much more expensive than treating for simpler and more common issues like allergies.

An Overview of Diagnostics for Nose Tumors

Once your veterinarian has eliminated another cause for your dog’s symptoms, they will use a variety of tests to determine if your dog’s symptoms are caused by cancer and, if so, what type of cancer is present.

Additional testing may include:

• A tissue biopsy for a definitive diagnosis
• Conventional radiography (x-rays) can be helpful, but CT is preferred to get a more detailed look at the extent of the tumor
• If a nasal tumor is diagnosed, three‐view thoracic radiographs of the lungs are recommended to evaluate for metastases
• Needle aspirates of the local lymph nodes are also recommended to evaluate for spread of disease
• Nasal hydropulsion using a high-pressure saline infusion into the nose often yields diagnostic samples (and may also clear some blockages)
• Abdominal ultrasound may be recommended to complete staging¹

Staging and Prognosis for Nasal Cancer in Dogs

Staging is a process of tests that allows your veterinarian or oncologist to determine how severe your dog’s cancer is and if it has spread.

Staging may impact your dog’s prognosis and which treatment options are available. It may also impact your treatment decisions.

Staging of Nose Cancers

Several staging systems based on radiographic or CT findings have been proposed in canine nasal tumors, but their prognostic significance remains controversial.

The Adams modified staging system developed in 2009 is the most recent system that has been adapted for use.¹

• Stage T1: Confined to one nasal passage, paranasal sinus, or frontal sinus with no involvement of bone
• Stage T2: Any bony involvement but no evidence of orbital (around the eye), subcutaneous (under the skin), or submucosal (under the mucous membranes) mass
• Stage T3: Involvement of orbit, subcutaneous, or submucosal mass
• Stage T4: Tumor extension into the nasopharynx (where the nasal cavity meets the soft palate) or cribriform plate (roof of the nasal cavity)

Prognosis for Nose Cancers

The relationship between tumor stage and prognosis is controversial, at least partly due to a lack of consistency in approach and contradictory findings from a few studies.²

With the Adams 2009 modified staging system:

• Dogs with unilateral (one-sided) intranasal involvement confined to the nasal cavity had the longest median survival time of 23.4 months when treated with definitive radiotherapy.
• Those with cribriform involvement had the shortest median survival time of 6.7 months.¹

Treating Nasal Cancer in Dogs

Cancer treatment in dogs is usually not about getting a “cure.” Instead, the focus is on improving and maintaining quality of life while hopefully extending the dog’s life beyond what would happen if the cancer wasn’t treated.

The following treatments are commonly used for nose cancer in dogs.

Radiation

Radiotherapy used alone or combined with surgery or chemotherapy is the standard treatment for canine nasal tumors.

Definitive radiation treatment is when a larger radiation dose is given while limiting late radiation toxicity. This theoretically limits tumor repopulation and/or repair.

A step down from definitive is coarse-fraction radiation therapy, which can be used in dogs with nasal carcinomas to alleviate symptoms.^2,18,19

Palliative (hypofractionated) radiation therapy protocols are used to improve the dog’s quality of life and increase survival time while minimizing acute radiation toxicity. This approach is often used in advanced disease, when the point is not to cure, but to alleviate pain and buy good quality time. It may also be used for practical and financial reasons.

The median survival time for dogs treated with palliative radiation is generally shorter than for dogs treated with definitive radiation (259 days vs 428 days).

Surgery

Curative surgery is impossible for nasal tumors, as bone invasion occurs early in the disease. (This is why radiation therapy is the standard of care for these tumors.)

You might be tempted to ask for surgery, but surgical resection as the sole treatment of nasal tumors is not recommended. It offers no advantage over more recent treatments and has significant morbidity (side effects) and mortality (death).

Surgery might be used to debulk a tumor, which means removing part of a tumor to make it smaller. Several studies suggest that surgical debulking before radiation might improve prognosis compared to radiation alone. Other studies refute this, so attempting debulking surgery is usually decided on a case-by-case basis.

A combination of a tumor-reducing surgery followed by radiation therapy for treating nasal tumors has been evaluated but has not been shown to improve clinical outcomes in dogs when compared to megavoltage radiation alone.^1,2

Chemotherapy

Chemotherapy is seldom used as the only treatment for nose cancers because there is not much consensus on when chemo is beneficial for nasal cancers, and results have varied widely:

• Different single chemotherapeutic agents (doxorubicin, carboplatin, cisplatin, mitoxantrone, fluorouracil, cyclophosphamide, and L-phenylalanine mustard) or in combination with surgery or radiation have been used, often with disappointing results.²
• Treatment with alternating carboplatin and doxorubicin in conjunction with oral piroxicam may benefit dogs with nasal adenocarcinoma, carcinoma, and sarcoma.¹⁵
• Metronomic chemotherapy may be a good option to treat dogs with stage IV nasal tumors.
• Combination of doxorubicin and toceranib phosphate (Palladia) may be a good option for nose cancers.¹⁷

Electrochemotherapy (ECT) is a new treatment modality gaining territory in oncology. It consists of the application of an electric field to a tumor to increase the uptake of chemotherapy (bleomycin or cisplatin) that was previously administered locally or intravenously at a very low dose.¹⁶

Immunotherapy

Several immunotherapies are being studied to treat both mouth and nose cancer in the veterinary field, including antibody-based therapies,²⁰ biological response modifiers,²¹ oncolytic viruses²², and vaccines.²³

Your oncologist will be up to date on the latest methods or treatments that might be helpful for your dog’s nasal cancer.

Vaccine

A peptide vaccine (EGFR/HER2) may synergize or increase sensitivity to radiation therapy or adjuvant chemotherapy. It may be a viable therapeutic strategy for the treatment of nasal osteosarcomas that overexpress EGFR (epidermal growth factor receptor), and potentially other canine tumors, either alone or as adjunct to other forms of therapy, including radiation and chemotherapy.^23,24

Diet

There are no specific dietary recommendations for dogs with nose cancer. Feeding your dog a soft diet may be necessary if the tumor is painful or prevents normal chewing.

For general nutrition for dogs with cancer, please check out our diet articles.

Supplements

An in-vitro study showed that curcumin could enhance the treatment of nasopharyngeal carcinoma.^25,26

Yunnan baiyao is an interesting supplement that may help stop bleeding. It may help your dog if their nasal tumor bleeds a lot. Many veterinarians and oncologists are familiar with yunnan baiyao and are comfortable with its use.

Other general cancer supplements may also prove beneficial. Always consult your veterinarian before adding a supplement to ensure that it is a good fit for your dog and won’t interfere with any of her medications or treatments.

Integrative Therapies

Integrative therapies may play a role in your dog’s cancer treatment plan.

Acupuncture may help manage the symptoms of cancer treatment , such as nausea.

One study showed that using various traditional Chinese veterinary medicine modalities improved clinical signs and decreased the mass size in a Pug diagnosed with nasal adenocarcinoma.²⁸

Nasal hydropulsion (mentioned above in the diagnosis section) is a palliative, last-resort treatment in case of obstructive nasal tumors in dogs. A jet of saline is sent up the nasal passages to “blow out” pieces of the tumor. This is also sometimes used to get a tissue sample when a biopsy is hard to obtain. It is generally used when radiation therapy or surgery is not affordable, available, or desired.²⁷

The End Stages of Nasal Cancer in Dogs

Nasal tumors will continue to grow without treatment and may continue to grow even with treatment. Eventually, these tumors severely impact your dog’s quality of life.

Late in the disease, if the tumor extends into the cranial vault and impacts the brain, central nervous system signs such as disorientation, blindness, seizures, stupor, and coma may develop.²⁹

These tumors can also cause difficulty breathing, which is always an emergency and requires immediate veterinary care.

This is why death is usually attributable to local disease progression rather than metastatic cancer for dogs with nose cancer.

If you are concerned that your dog is suffering, having an open and honest discussion with your veterinarian about hospice care is a good idea. You may, in the end, opt for humane euthanization.

With the inherent difficulties in treating nasal cancer and the probable pain involved with a head tumor, this is a completely rational and kind choice at any point in your dog’s illness if you feel your dog is suffering more than their life quality warrants.

Prevention Strategies for Nasal Tumors in Dogs

In addition to good food, fresh air, exercise, and keeping up with your dog’s annual veterinary exams, avoid exposing your dog to tobacco smoke and urban environments, especially for long-nosed breeds.^12,13