Nasal planum tumors in cats and dogs.

Nasal Planum Cancer in Cats and Dogs

What are nasal planum tumors?
Nasal planum refers to the tip of the nose and cancer development in this area is associated with exposure to ultraviolet
light and lack of pigment. The most common type of cancer is called squamous cell carcinoma (SCC) which can be
further classified into SCC in situ (localized), superficial SCC, or deeply infiltrative SCC. They may be locally invasive but
rarely metastasize (spread to other organs). Other types of cancer have been reported in the nasal planum such as
lymphoma, fibrosarcoma, hemangioma, melanoma, mast cell tumor, fibroma, and eosinophilic granuloma.

How common are these tumors?
Cancer of the nasal planum is rare in dogs but relatively common in the cat. It is usually observed in older, lightly
pigmented cats.

What are the symptoms?
Invasive SCC typically evolves over time (months to years) and progresses through several stages. In cats, SCC typically
originates in the cornified external surface of the nose whereas in dogs it usually occurs in the mucous membrane of the
nostril or the external planum.

How is the diagnosis made?
The most definitive way to confirm cancer is to perform a wedge biopsy. Because the nasal planum is so sensitive, pets
usually require brief general anesthetic. Advanced imaging such as CT (computed tomography) and MRI (magnetic
resonance imaging) have recently become valuable tools that evaluate the extent of the disease, providing guidance for
subsequent surgery and/or radiation therapy.

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?
Limiting exposure to the sun may prevent or slow down the course of the precancerous growths. Topical sunscreens
don't work effectively since they are easily licked off. Minimally invasive SCC can be managed effectively by a variety of
different treatment options, including cryosurgery, lasers, phototherapy, or intralesional carboplatin chemotherapy,
hyperthermia or radiation therapy. Deeply invasive SCC are resistant to these types of treatments. In cats, invasive
cancer can be completely removed with an acceptable cosmetic appearance outcome. This type of treatment is typically
the treatment of choice for invasive lesions that have not spread to the lip or surrounding skin. If the tumor cannot be
completely removed, radiation therapy after surgery is recommended to kill any remaining cancer cells left behind.

Are there any clinical trials?
There are no clinical trials specifically designed to treat this type of cancer but please click here to check if your pet may
qualify for clinical trials for general malignancy.

What is the prognosis?
The prognosis for early, noninvasive SCC is good. However, other sites of the nasal planum can develop additional
abnormal growths after localized treatment. More advanced stages of SCC can be successfully treated with aggressive
surgery but are less responsive to other forms of treatment. The cancer does not come back at 1 year in more than 80%
of cats with invasive SCC treated with surgery. Because the SCC in the nasal planum rarely metastasizes to other
organs, the pets can enjoy long lives.

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.